DE102004038882A1 - Traction motor has coolant ring with teeth meshed with coils of stator to cool and absorb reaction torque of axial electric motor - Google Patents

Abstract

The traction motor has a coolant ring having teeth coupled to a stator (36). The teeth of the coolant ring are meshed with the coils (37) of the stator to cool and absorb reaction torque of the traction motor. A motor shaft is coupled to the rotor (32,34). The rotor is rotated by the magnetic field produced by the coils of the stator.

Description

These Application claims the benefit of US Provisional Application Nos. 60 / 494,249; 60 / 494.250 and 60 / 494,251, all filed on August 11, 2003.

TECHNICAL TERRITORY

The The present invention generally relates to an electric motor. More specifically, the present invention relates to a method and a device to cool an electric motor and the counter torque to cope with the engine.

BACKGROUND

One Electric motor can generally be seen as having a stator and a rotor to be discribed. The stator is fixed in position, and the rotor moves in relation to the stator. In AC or axial motors the stator is typically the live component of the motor, which generates a magnetic field to interact with the rotor to step. The rotor in an AC or axial motor can be a squirrel cage or magnetic rotor have. The field generated by the stator drives the rotor over a magnetic field with respect to the stator or rotates.

The operation of an electric motor generates heat in the form of current / resistance I ² R losses, iron losses, leakage and mechanical losses in the rotor and stator. The stator and rotor are cooled to avoid overheating, which would result in demagnetization of magnets in the motor or melting or burning of other parts of the motor. Heat dissipation is the limiting factor in the design and rating of the motor. The motor current is directly related to the power output as well as the heat generated by the motor. In applications with electric motors where space is valuable, such as in electric and hybrid vehicles, motors with relatively small footprint and high ratings are desired.

It There are a variety of propulsion or propulsion technologies that used to power vehicles. The technologies include electric traction motors such as e.g. DC motors, AC induction motors, switched reluctance motors, synchronous reluctance motors, brushless DC motors and corresponding power electronics for controlling the motors. in the State of the art it is common the traction motor (s) using a mechanical Powertrain with reduction gears and a differential with the front or rear wheels to couple the vehicle. Sometimes the engines in the drive wheels are without Differential mounted and by speed reducer or reduction gear with the wheels coupled.

Although such systems are functional, they suffer as a result of the mechanical Powertrain (gears, Differentials, gears etc.) between the engine (s) and the wheels at a higher level Weight, lower reliability and a lower efficiency. It is desirable for heat to be so efficient as possible dissipated and the weight of the engine is minimized. The more efficient the heat dissipation, the smaller the base area an engine for a specific rated power. Furthermore, it is desirable to have such engines to create a shape suitable for installation directly into a mold Vehicle wheel or such adjacent is suitable. Other desirable ones Features and characteristics of the present invention will become apparent the subsequent detailed Description and attached claims become apparent in conjunction with the accompanying drawings and the foregoing technical field and background becomes.

SHORT SUMMARY

A device for an axial electric motor is provided. The apparatus includes a stator having coils thereon for generating a magnetic field, a rotor rotated by the magnetic field, an output shaft coupled to the rotor, and a ring having a coolant passage circumferentially abutting the stator for receiving heat and counter torque from the stator , It is preferable that the ring has inwardly extending teeth that mesh with the coils on the stator. Of the Space between the teeth and the coils is preferably filled with a substantially solid, thermally conductive material to transfer the counter-torque of the stator to the teeth and to cool the stator. The coils are preferably made of a flat band with a portion of its major surface perpendicular to the teeth. A support frame is desirably fixed to the ring and rotatably coupled to the output shaft.

SHORT DESCRIPTION THE DRAWINGS

The The present invention will hereinafter be described in connection with the following Drawings described, wherein like numerals are the same Denote elements and

1 a partially cutaway simplified plan view of a traction motor according to the present invention;

2 a side view of the traction motor of 1 is;

3 a simplified plan view of a portion of the stator of the traction motor of 1 - 2 is that shows more details;

4 a side view of a portion of the stator and the rotors of the traction motor of 1 - 2 is that shows more details;

5A and 5B Plan views of the inner surface of rotors of the traction motor of 1 - 2 which show further details and correspond to further embodiments, and 5C a plan view of an enlarged segment of the rotor of 5A or 5B is that shows even more details;

6 Figure 11 is an illustration of an observed back electromotive force tension on the windings of the traction motor of the present invention versus time for a preferred embodiment of the present invention;

7 Figure 4 is an illustration of shaft power versus shaft speed for the engine of the present invention under various operating conditions;

8th Figure 3 is an illustration of no-load power consumption versus speed for two motors, one not including the preferred embodiment of the present invention and the other;

9A and 9B Contours of the torque against the speed at constant efficiency for two motors, one with a preferred embodiment of the present invention in 9B and the other without them in 9A Is provided;

10 a perspective view of a rotor carrier according to a preferred embodiment of the present invention;

11 a perspective view of the rotor carrier of 10 with rotors mounted thereon, showing more details;

12A is a simplified edge view and 12B a simplified plan view of a portion of a rotor of 11 is that show more details;

13A - 13B are simplified plan views of a segment of a stator and a stator support of the traction motor of the present invention, wherein 13A shows the stator and stator carrier separated and 13B showing them assembled;

14 Figure 12 is a partially cutaway cross-sectional view through the traction motor of the present invention incorporating rotors, stator and stator support;

15 is a simplified representation of the longitudinal-transverse magnetic axes, which is used in analyzing the engine of the present invention;

16A is a representation of the observed and calculated engine torque against the control angle α and 16B is a representation of a calculated longitudinal axis flow against the control angle and 16C Figure 12 is an illustration of the calculated cross-axis flux vs. control angle for the engine of the present invention;

17 Fig. 10 is a flowchart illustrating a method of calculating optimized control parameters for the engine of the present invention;

18A -B representations of the torque versus speed for various values of the optimal control parameters, the longitudinal and transverse axis currents I _d , I _q , where 18A has an optimized I _q as the parameter and 18B has an optimized I _d as the parameter;

19 Figure 12 is an illustration of the observed torque versus speed under various operating conditions for the engine according to the preferred embodiment of the present invention;

20A -B are simplified block diagrams of a process architecture of an engine control system according to a preferred embodiment of the present invention, wherein 20A provides an overview and 20B provides another detail;

21A B are representations of the longitudinal axis current for the engine of the present invention under a plurality of operating conditions; and

22 Fig. 10 is a simplified schematic diagram of a computerized system suitable for carrying out the control processes of the present invention.

DETAILED DESCRIPTION

The following detailed Description is merely exemplary in nature and is intended to be the invention or not limit the application and uses of the invention. moreover It should not be by any given or implied theory limited be in the previous technical field, background, the short summary or the following detailed description becomes. The terms "motor" and "machine" are hereafter used interchangeably to access the traction motor / generator to refer to the present invention.

Referring to the two 1 - 2 is 1 a simplified partially cutaway plan view, and 2 is a side view of rotor and stator parts of the traction motor 30 according to the present invention. The engine part 30 includes a first annular or washer-shaped rotor plate 32 , on the permanent magne (PMs) 33 are fixed, a second annular or washer-shaped rotor plate 34 , on the PMs 35 are attached, and a stator 36 with a core 41 and live coils (windings) 37 passing through stator pole pieces 42 are separated. In 1 became the part 38 of the first engine 32 cut away to the permanent magnets (PMs) 33 expose that above the stator 36 lie, and part 40 was together with the PMs 33 cut away to the underlying stator core 41 that's the windings 37 with the stator pole pieces 42 between the windings 37 bears, to show. bolt holes 44 . 46 are expediently in the rotors 32 respectively. 34 provided by which a (not shown) rotor carrier or a yoke can be provided to the rotors 32 . 34 to couple with an engine output shaft (not shown) which is about a center 48 rotates. The pole pieces 42 of the stator core 41 are by an angular amount 47 referenced generally as the stator pole pitch (SPP), separated circumferentially about the stator 36 spaced. In general, the coils are 37 similar to the stator 36 spaced. The spools 37 are preferably wound from flat strip conductors; but this is not essential.

The rotors 32 . 34 are usually the moving parts coupled to the vehicle wheels, and the stator 36 is generally attached to the vehicle frame in some way. This is the preferred arrangement because it avoids commutation of power leads to the stator; but this is only expedient and not essential. In the engine of the present invention, either the rotors or the stator may be coupled to the vehicle wheels and the other coupled to the vehicle frame. Both arrangements are useful. For the purposes of the description, it is assumed below that the rotors are coupled to the vehicle wheel and the stator to the vehicle frame; but this is not meant to be limiting.

For the purpose of explanation and clear illustration of the important features of the engine 30 are the yoke or the rotor arm, which are the rotors 32 . 34 Coupled with the motor output shaft, and the structure connecting the stator 36 attached to the vehicle frame, off 1 - 2 omitted. (A preferred arrangement is in 14 However, it will be understood by those skilled in the art that any convenient arrangement for coupling the rotors to the engine output shaft and to the wheels may be used without an intermediate mechanical drive train (eg, no differential, reduction gear, etc.) and for coupling the stator to the vehicle frame. Further, based on the description herein, those skilled in the art will understand that the rotors 32 . 34 be borne by bearings that the rotors 32 . 34 with respect to the stator 36 adjust or align while allowing their mutual rotation.

The first and second rotor 32 . 34 with the attached permanent magnets (PMs) 33 . 35 are coupled with each other and move together, being under the influence of those of the PMs 33 . 35 and the coils 37 supplied magnetic fields around an axis 48 with respect to the stator 36 move. The PMs 33 become with their magnetic poles substantially perpendicular to the plane of the rotors 32 . 34 and the stator 36 magnetized, and the magnetization direction of adjacent PMs alternated. For example (see 1 ) has, if a PM 330 a north pole (N) in contact with the rotor 32 (and therefore an (S) -pol, which is the stator 36 facing), then the PM 331 an S pole in contact with the rotor 32 , the PM 332 an N pole and the PM 333 an S-pole and so on. Pairs of PMs are on the rotors 32 . 34 arranged so that they pass over the stator 36 facing each other. Opposing PMs on the rotors 32 . 34 preferably have the entgegenge magnetization direction. For example (see 2 ) show arrows 430 . 432 . 434 the magnetization direction of PMs 330 . 332 . 334 on the rotor 32 which the stator 36 facing S-poles have. Opposite PMs 350 . 352 . 354 on the rotor 34 point through arrows 450 . 452 . 454 shown magnetization directions, wherein the S-poles also the stator 36 are facing. Thus, each opposing pair has PMs on the rotors 32 . 34 opposite magnetization directions (see eg the arrows 434 . 454 for PMs 334 respectively. 354 ). This is the preferred arrangement; however, the other arrangement in which the facing magnets have the same magnetic orientation is also possible and useful. The PMs 33 . 35 are at the rotors 32 . 34 attached by any suitable means; but a fastener that includes magnetic attraction is preferred. Glue or another glue can be used to make the PMs 33 . 35 on the rotors 32 . 34 to install. It is desirable that the glue provide a shear strength equal to about 3 N / mm ² or higher. The permanent magnets 33 . 35 Conveniently consist of sintered Nd-Fe-B. Suitable are 655 HR class VACODYM supplied by Vaccumschmelze of Hanau, Germany, and class SC35UH supplied by Italfit Magneti of Udine, Italy.

3 is a simplified plan view of a part 80 of the core 41 of the stator 36 of the traction motor 30 from 1 which shows further details and illustrates a preferred type of construction. The core 41 is preferably radially laminated, that is, many layers of a spirally wound iron strip 83 educated. The stripe 83 is preferably of the same general type of high magnetization material used in electric machines. Non-oriented Class M-15 electrical steel supplied by AK Steel Corporation, Middletown, OH is a non-limiting example of a suitable material. slots 56 that are needed to the coils 37 are formed from cut out areas that are in the strip 83 were punched before turning into a toroidal shape for the core 41 is wound. The distances between the cut out areas of the strip 83 are grouped such that as the strip is wound layer upon layer on a temporary mandrel or temporary form, the cut out areas line up with the cut out areas of the previous layer in each new layer so that they will slot in the finished core 56 form. The spools 37 then be useful in the right place in the slots 56 wound. Although this method of assembling the core 41 and the coils 37 is preferred, it is not essential. For example, and not by way of limitation, an alternative arrangement is the core 41 in short circumferential segments, one segment for each coil. The core segments can be made, for example, using powder metallurgy techniques. A pre-wound coil is then placed on the segment, and successive segments are snapped or otherwise attached to each other around the toroidal shape of the stator 36 with the core 41 and the coils 37 to complete. The coils may be electrically coupled together in the desired electrical configuration either before or after assembly. Both arrangements are useful.

4 is a side view (essentially in the direction of the arrow 53 in 1 - 2 looking) of a part 54 of the stator 36 of the traction motor 30 of the 1 - 2 , more magnified and more details representing the static flow through the core 41 and the rotors 32 . 34 illustrated by PMs 33 . 35 is produced. PMs 331 . 351 are particularly illustrated. Now up 2 and 4 together taking, the coils are 37 in the slots 56 of the stator core 41 between the stator pole pieces 42 assembled. air gaps 49 . 49 ' are between the pole pieces 42 of the stator core 41 and the PMs 33 . 35 intended. In the preferred embodiment, the coils are 37 divided into three groups, each driven by one of three phases of alternating current. These phases are referred to as Φ _a , Φ _b , Φ _c . The currents Ia, Ib, Ic are supplied to the phases Φ _a , Φ _b and Φ _c , respectively. As is conventional in the art, these three phases are "Y" connected with or without a neutral wire. The coils spaced around the stator are electrically coupled in spaced pairs. Now up 2 referring is the coil 371 with the coil 374 coupled in series, is the coil 372 With 375 coupled in series and is the coil 373 with the coil 376 coupled in series. The sink 371 thus receives Φ _{a +} , the coil 372 receives Φ _c- , the coil 373 receives Φ _{b +} , the coil 374 receives Φ _a- , the coil 375 receives Φ _{c +} , and the coil 376 receives Φ _b- . The coil assembly is wound around the stator 36 repeated. Although three-phase AC windings are preferred, this is not essential, and fewer or more phases may be used depending on the requirements of the vehicle design.

One Problem with axial flow machines of the type described here is stuck, is the getting stuck or cogging, which results from the stator design with Core results. A cogging torque results from the interaction of the magnetic edges with the stator slots. The cogging occurs as pulsations in the torque output of the engine on. If they are not compensated, these pulsations can occur be transmitted to the drive train of the vehicle, causing unwanted vibration be generated. The cogging also causes harmful harmonics be generated. If cogging is serious, these are harmonics visible in the voltage and current waveforms of the motor. It it was discovered that cogging can be virtually eliminated, by dividing the PMs into two or more groups on the rotors are spaced.

5A and 5B are plan views of the inner surface 61 . 61 ' of the rotor 60 . 60 ' according to further embodiments of the present invention and suitable for use in place of rotors 32 . 34 of the traction motor 30 of the 1 - 2 so as to reduce or eliminate cogging. The inner surface 61 . 61 ' of the rotor 60 . 60 ' is towards the stator 36 turned, and the rotor 60 . 60 ' revolves around a middle 62 . 62 ' analogous to the middle 48 in almost the same way as the already described rotors 32 . 34 , On the surface 61 . 61 ' of the rotor 60 . 60 ' are PMs 64 . 64 ' mounted, which is essentially the PMs 33 . 35 the rotors 32 . 34 are similar, but with (a different circumferential distance, ie a different PM pitch 51 . 51 ' , As by PMs 640 . 641 . 642 . 643 of the rotor 60 and PMs 640 ' . 641 ' . 642 ' . 643 ' of the rotor 60 ' As illustrated, the north-south magnetic orientation alternates in the same manner as for the PMs 33 . 35 the rotors 32 . 34 , For example, if the PM 640 has an S-pole from the surface 61 axially facing away (ie in the direction of the stator 36 ), then has the PM 641 an N pole, the PM 642 an S-pole, the PM 643 an N pole, etc., which is the stator 36 and, accordingly, their coated equivalents on the rotor 60 ' , In 5A are the PMs 64 suitably in two groups 66 . 68 shared, and in 5B are the PMs 64 ' suitably in four groups 65 ' . 66 ' . 67 ' . 68 ' shared, but a different number of groups can also be used, and the examples in 5A -B should not be limiting. The groups 66 . 68 are through column 50 separated, and the groups 65 ' . 66 ' . 67 ' . 68 ' are through column 50 ' separated.

If the stator 36 M pole pieces and M coils and is driven by a 3-phase supply, then M / 3 coils are each assigned to a phase. Each PM bridges about three stator poles 42 and three coils 37 (please refer 2 . 4 ). Thus, the preferred arrangement uses M / 3 PMs. The stator pole pitch (SPP) is 360 / M. SPP is the angular distance between the centerlines of successive stator poles 42 (ie the angle 47 in 1 ). Are the PMs around the circumference of the rotors 32 . 34 evenly distributed, the PM pitch (PMP) is 3x (360 / M). In the embodiment of 5A There are M = 90 coils and pole pieces on the stator 36 and M / 3 = 30 PMs on the rotors 32 . 34 . 60 , Thus, SPP = 360/90 = 4 degrees, and for evenly distributed PMs PMP = 360/30 = 12 degrees.

It has been found that cogging without adverse side effects can be significantly reduced by shortening the pitch of the PMs, for example, in groups 66 . 68 by an amount equal to about one-half of the SPP for each group. In the preferred embodiment, columns 50 between the groups 66 . 68 about 2 × SPP / 2 = 2 × 360 / (2M) = 360/90 = about 4 degrees for M = 90. This is achieved by reducing the distance between the PMs and / or narrowing the circumferential width of each PM slightly, such that the required number (360 × 12) / n fits into each group, where n is the number of groups. In 5A There are PMs for a 90-pole machine with three poles per PM and two groups 15 in each group. Consequently, in the embodiment of FIG 5A for a three-phase motor with a M = 90 pole, a rotor 60 using shortened distance, PMPs 51 Wanting desirably more or less equal to about (180 - 4) / 15 = 11.73 degrees mechanical or 176 degrees electrical. Electrical degrees are equal to mechanical degrees multiplied by a number of rotor pole pairs (for 5A 15). The skilled person understands that the column 50 at the distance of PM groups of a rotor 60 may deviate from these ideal numbers with a shortened distance. By way of example and not limitation, the column 50 usefully in the range of about 1 to 7 degrees, more preferably between about 2 and 6 degrees, and preferably about 4 degrees. PMPs 51 will be according to the size of the column 50 and the number of PMs and columns used.

5B illustrates another embodiment, the four groups PMs 65 ' . 66 ' . 67 ' . 68 ' uses that through column 50 ' are spaced. Each group has 8 PMs, so the total number of PMs 32 is. As in 4 3, there are desirably 3 slots and coils per PM, so that there are a total of 3 x 32 = 96 slots and coils with the array of 5B gives. Thus, in 5B M = 96. A shortened permanent magnet distance PMPs 51 ' is suitably about (90 - 3.75) / 8 = 10.78125 mechanical degrees or 172.5 electrical degrees. The person skilled in the art, based on the description herein, recognizes that although two and four groups in FIG 5A , B are illustrated, but not by way of limitation, and more groups may also be used. In general, it is desirable to use an even number of groups.

More generally, the shortened permanent magnet spacing PMPs can be determined in mechanical degrees from the equation PMPs = (γn360 / M) (1 / n-1 / M) = 360γ [(M-n) / M ² ], where M is the number of poles on the stator, n is the number of groups into which the permanent magnets are divided (eg n = 2, 3, 4, ...), and γ the number of phases (eg 2, 3, 4, ... ). Thus, results for the arrangements of 5A - B, each as PMPs ( 60 ) or PMPs ( 60 ' evaluating the previous equation the values for shortened permanent magnet spacings PMPs ( 60 ) = (3 * 2 * 360/90) (1/2 - 1/90) = 11.73 degrees and PMPs ( 60 ' ) = (3 * 4 * 360/96) (1/4 - 1/96) = 10.78 degrees, as noted above.

5C is a plan view of an enlarged segment 60-1 the rotors 60 . 60 ' of the 5A or 5B showing further details according to another embodiment. The segment 60-1 illustrates three adjacent PMs 64 , ie PMs 64-1 . 64-2 . 64-3 , It is especially mentioned that the gap 52 between adjacent PMs 64 from 5C is not uniform, but as a function with a radial distance from radially inner edges 64-IN from PMs 64 to radially outer edges 64-OUT from PMs 64 varied. In the example of 5C is the gap or the gap 52-1 from magnet to magnet at radially outer edges 64-OUT smaller than the gap 52-2 at radially inner edges 64-IN , In other words, opposite edges 64-R . 64-L neighboring PMs (eg PMs 64-2 . 64-3 ) not parallel, but away from each other or towards each other, as preferred by the designer. In the example of 5C the opposite edges tilt 64R . 64L apart when looking from the radially outer PM edge 64-OUT to the radially inner PM edge 64-IN progresses; but this is not meant to be limiting, and they may also incline towards each other. Accordingly, the arrangement of opposite edges 64R . 64L so that they become a radial line 60C passing through the middle 62 . 62 ' of the rotor 60 . 60 ' runs, preferably are not parallel. It is preferred that opposite edges 64R . 64L not parallel to each other or parallel to the radial line 60C are. This reduces cogging without significant torque loss and is a prior art arrangement with opposite edges 64R . 64L with respect to a radial line 60C are generally superior in efficiency.

Shortening the pitch of the PMs and varying the spacing of opposing edges of adjacent PMs, as in FIG 5A - 5C illustrates a significant improvement in cogging and harmonic distortion as shown in FIG 6 can recognize which voltage waveforms 100 . 101 . 102 the counterelectromotive force of the three phases of a traction motor 30 shows the rotors with shortened distance of the in 5A contains shown type. It is observed that the waveforms are very sinusoidal, indicating that there is little generation of harmonics and therefore little snagging. The reduction in sticking is a particular feature of the present invention. Shortening the pitch of the PMs averages the slotting effect of the interaction of the rotor magnets and stator pole pieces, thereby reducing snagging. The invented arrangement with shortening of the pitch of the PMs is particularly effective. The use of non-parallel opposing magnetic margins also helps to reduce sticking or cogging.

4 illustrates another aspect of the present invention. One of the problems associated with axial flow motors is the low phase inductance, especially at higher speeds. This adversely affects the speed range over which the engine is at substantially constant power beitet. In addition, this low inductance can increase the longitudinal axis current feed required at higher speeds for field weakening, resulting in lower efficiency at higher speeds. In addition, the slotting effect due to the slots between the PMs mounted on the rotors increases the load-free spin loss of the machine due to a magnetic flux induced eddy current. These problems are substantially eliminated by the inclusion of magnetic stray flux shunts or wedges 63 in the stator core 41 above the coils 37 (please refer 3 - 4 ). The material of magnetic wedges 63 desirably has a permeability much higher than that of air, but much lower than the permeability of a steel lamination strip 83 which is used to the core 41 (please refer 3 ), and preferably does not saturate. This choice of this material for magnetic wedges 63 minimizes short-circuit leakage into the magnetic wedges while still providing an improvement in the inductance of the machine. This provides a magnetic path for leakage, thereby improving inductance at all torque levels. Improving the inductance of the machine improves both the high-speed constant-power range and the high-speed efficiency. Another advantage or benefit of magnetic wedges 63 is to increase the counter-electromotive force of the machine, whereby the torque is improved without increasing the magnetic content and thus without increasing the cost. This improvement in counter electromotive force is achieved by improving the magnetic circuit permeability due to the addition of magnetic wedges 63 reached to stator flow paths. The introduction of magnetic wedges 63 It also reduces the stator's slotting effect, which is a major source of no-load spin loss. As a result, by using wedges 63 reduces the load-free spin loss. Soft magnetic composite steel such as Somaloy 500_ + 0.6% LB1 steel, sold by Hoganas AB of Sweden, is a non-limiting example of the class of materials used for the wedges 63 useful; but other materials that meet the general specification given above may also be used. Although the trapezoidal shape of the wedges 63 , in the 1 is illustrated, allowing them to fit in notches 58 in slots 56 used and held in place, this is not essential, and any form of wedges or leakage flux shunts 63 that allows them at least partially over the openings of coil slots 56 is also useful. Non-limiting examples of other forms for magnetic wedges 64 are trapezoidal, rectangular, elongated hexagonal, semi-cylindrical shapes, etc. However, it is preferable that they are not essential in a room 49 . 49 ' between pole pieces 42 and PMs 33 . 35 protrude (see, eg 4 ).

Back on 3 Referring to Figure 2, there are two examples of magnetic wedges 63 shown in notches 58 from coil slots 56 are installed. A magnetic wedge 631 in the coil slot 561 partially extends over a coil slot 561 between a radially inwardly directed surface 411 and a radially outward surface 412 an annular core 41 , A magnetic wedge 632 that is in the coil slot 562 located, extends over the surfaces 411 . 412 out. The arrangement of the magnetic wedge 632 is preferred but not essential and is not intended to be limiting. A smaller or larger overlap of the slots 56 can also be used.

7 shows curves 103 - 106 the shaft power against the speed of the motor 30 , the magnetic wedges 63 of the 3 - 4 contains. The curve 103 shows a calculated and measured regeneration operation at 250 volts, the curve 104 The desired minimum motor shaft power, which is desired as a function of speed, indicates the curve 105 shows a calculated and measured engine operation at 250 volts, and the curve 106 shows the calculated and measured engine operation at 350 volts. It is noted that the measured and calculated machine performance curves substantially coincide, indicating that the machine's magnetic model is reliable and that the target engine specification is met or exceeded at all speeds. Further, it can be seen that at higher speeds, eg 600-1200 rpm, the power output for the nominal voltage of 250 volts of the machine becomes approximately constant. For the application of vehicle propulsion, maintaining a long range of constant power is highly desirable. It is further noted that from zero to about 600 rpm (ie at 250 volts, curve 105 ) the power output increases linearly with the speed, indicating that the motor provides substantially constant torque over that range. This is also desirable.

8th shows curves 107 - 108 the load-free power consumption against the speed of two machines; Machine A (curve 107 ) without wedges 63 and machine B (curve 108 ) with wedges 63 both operating under otherwise substantially identical conditions. The two machines have a comparable counterelectromotive force. It is particularly noted that the machine B (curve 108 ) with wedges 63 uses much less power and therefore has a significantly lower load-free spin loss. In addition to reducing the no-load spin loss, the addition of magnetic wedges improves 63 to the stator 36 Furthermore, the overall efficiency of the machine. This is through the contours 109 . 110 for the torque against the Speed at constant efficiency shown in 9A - 9B are presented. Each of the contours 109 . 110 is the locus of the permissible torque and the permissible speed at constant efficiency, the highest efficiencies in each case the innermost contours corre sponding. 9B shows data for the machine B with magnetic wedges 63 , and 9A shows data for an otherwise substantially identical machine A without the wedges 63 , Both engines were operated at 250 volts. In 9B corresponds to the innermost contour 109-1 an efficiency of ninety percent while in 9 -A the innermost contour 110-1 an efficiency of only eighty-seven percent. Consequently, the machine has B with the wedges 63 generally a higher efficiency. In addition, for nearly each level of efficiency, the torque-speed contours of machine B (with the wedges 63 ) in 9B a larger operating area. This means that for almost any given efficiency level, the machine B with the wedges 63 over a larger torque and speed range than the machine A without the wedges 63 can work. This can be seen, for example, by looking at the curves 109-2 and 110-2 which both correspond to an efficiency of eighty-five percent. The area of the contour 109-2 is much bigger than that of 110-2 , The inclusion of magnetic wedges 63 is an important aspect of the present invention.

10 is a perspective view of a rotor carrier or yoke 70 according to a preferred embodiment of the present invention, and 11 is a perspective view of an assembly 87 with the rotor carrier or yoke 70 with rotors mounted on it 32 . 34 , In the following discussion it is understood that the rotors 32 . 34 also the configuration of the rotor 60 . 60 ' of the 5A -C and thus as in the references to the rotors 32 . 34 combined with 10 - 14 should apply. The rotor carrier 70 includes an axial clearance area 72 whose axial width 71 Conveniently (but not necessarily) the axial distance of the rotors 32 . 34 certainly. In the axial spacer 72 are expediently holes 73 included to reduce its weight. The carrier 70 desirably, but not necessarily, also includes a radial spacer 74 on top of the rotors 32 . 34 with respect to the axis of rotation 48 centered. The radial spacer 74 can as part of the axial spacer 72 be prepared. Both arrangements work. The axial spacer 72 and radial spacers 74 are connected together and are relative to the axis of rotation 48 by radial reinforcing plates or webs or spoke (s) 67 held in the correct position, the purpose of which is the rotors 32 . 34 to pair with whatever traction engine 30 is driven, and the moving parts (eg the rotors 32 . 34 ) in the correct adjustment with respect to the axis of rotation 40 and a stator (not shown) 36 to keep. The jetty 67 has expediently, but not necessarily, holes 77A -B, which are provided therein to facilitate assembly and reduce the weight. The jetty 67 may also be in the form of one or more spokes emanating from a central ring rather than a solid plate with holes, as for ease of explanation in FIG 10 - 11 is shown. Both arrangements work. The jetty 67 is attached to a wheel, a shaft or other part (not shown), that of the traction motor 30 is to be driven, mounted in any suitable manner according to the requirements of the vehicle designer. The rotors 32 . 34 have expediently, but not necessarily, ventilation openings 75 . 75 ' in it (see 11 ), which allows for air circulation in an interior 65 between the rotors 32 . 34 Worry where the stator is 36 located (see eg 2 . 14 ). This helps maintain uniform indoor temperatures. The openings 75 . 75 ' also reduce the weight of the rotors 32 . 34 which is desirable. For convenience of illustration, PMs 33 . 35 in 11 not shown.

12A is a simplified border view, and 12B is a simplified plan view of a part 81 the rotors 32 . 34 from 11 , which shows even more details. Now up 11 and 12A - 12B referring are the rotors 32 . 34 with recessed or hollowed out areas 76 . 76 ' on their outer surfaces, ie on the rotor surfaces 78 . 78 ' provided by the area 65 between the rotors 32 . 34 are turned away where the stator 36 located. (Excluded or hollowed out areas 76 ' on the surface 78 ' of the rotor 34 are in 11 . 12A - 12B not visible, but are in 14 displayed in phantom.) Now up 12A - 12B referring are the recessed or hollowed out areas 76 . 76 ' with the depth 98 on the outside surfaces 78 . 78 ' , essentially directly behind the permanent magnets 33 . 35 on interior surfaces 79 . 79 ' the rotors 32 respectively. 34 lie, and have substantially a similar area or lateral extent as the magnets 33 . 35 on. The depth 98 the recessed and hollowed out areas 76 . 76 ' is chosen to be the magnetic flux 84 does not interfere significantly between adjacent permanent magnets 331 . 332 . 333 etc. on the rotor 32 and analog on the rotor 34 coupled. For example, the recessed or hollowed out area lies 761 essentially directly behind the permanent magnets (PM) 331 , the area 762 behind PM 332 , the area 763 behind PM 33 etc. in the circumferential direction around the rotor 32 , The magnetic flux 84 runs from the PM 331 to the PM 332 and from the PM 332 to the PM 333 etc. by the rotor 32 , where he does not exclude or hollowed out areas 851 . 852 etc. between the PMs 33 in the Essentially without significant interference from the recessed or hollowed out areas 761 . 762 . 763 etc. crossed. The rotor 34 is arranged in a similar way. This reduces the weight of the rotors 32 . 34 significantly without sacrificing PM flux linkage and engine performance significantly. The total flux in the rotor core behind the magnet is a minimum in the middle of the magnet minimally and increases gradually towards the two magnetic edges. Therefore, the recessed or hollowed out area in the iron of the rotor backside does not significantly affect the entire magnetic flux, nor does it affect the achievable torque. However, a significant reduction in rotor mass is achieved. This is a special feature of the present invention.

The rotors 32 . 34 are magnetic so as to provide a low reluctance magnetic path between adjacent PMs 33 on the rotor 32 and PMs 35 on the rotor 34 to accomplish. Armco Iron, supplied by AK Steel of Middeltown, OH, is a non-limiting example of a suitable material for the rotors 32 . 34 , In general, the rotors need 32 . 34 not laminated; but this is not excluded. The rotor carrier structure or the yoke 70 is preferably made of a lighter and usually non-magnetic material. Aluminum, magnesium, titanium, various non-magnetic metal alloys, plastics, metal-plastic composites, plastics loaded with non-magnetic materials (eg, glass, carbon, ceramic fibers or fragments, etc.), and combinations thereof are nonlimiting examples of materials that for the support structure or the yoke 70 are suitable. It is important that the support structure or the yoke 70 sufficiently stiff, so the rotors 32 . 34 in axial and radial alignment with respect to the stator 36 (eg see 14 ) to withstand the forces generated by the operation of the engine 30 be generated by the engine 30 coupled torque to the vehicle wheel (not shown) to be substantially corrosion resistant and to have the minimum possible weight, which is compatible with the structural requirements. By using lighter weight structural materials for the rotor arm 70 used and heavier magnetic materials of the rotors 32 . 34 be limited to exactly the areas that require a low magnetic reluctance, the total weight and moment of the motor 30 minimized, and the overall performance of the traction motor 30 is increased. This is a special feature of the present invention.

13A - 13B are simplified plan views of a segment 86 of the stator 36 and stator carrier 88 of the traction motor 30 the present invention, wherein 13A a stator 36 and stator carrier 88 shows separately and 13B she shows composite. The stator 36 has an annular core 41 with Poland 42 and with coils 37 between the poles 42 are inserted. By 1 - 4 and 13A -B seen together, you realize that the coils 37 over the stator core 41 in the radial direction (perpendicular to the axis 48 ), but not in the axial direction (parallel to the axis 48 ) protrude. This is a significant design feature as it allows the circumferential stator torque from the stator 36 with the help of on the stator 88 engaged coils 37 on the stator carrier 88 is transmitted. The spools 37 are preferably wound from a flat band and therefore have a significant lateral strength (in the circumferential direction). The spools 37 can thus withstand much larger, directed in the circumferential direction forces than would be possible with coils wound from wires.

The ring-shaped stator carrier 88 preferably, but not necessarily, has a hollow interior 90 through which a coolant 91 circulated. From the stator carrier 88 run inward tooth-like projections 92 that are shaped and spaced so that they are exactly between the coils 37 and in close proximity to the core 41 of the stator 36 how to fit in 13B can recognize. This arrangement provides low thermal impedance, allowing heat to be readily dissipated from the coils 37 of the stator 36 as by arrows 93 represented and from the poles 42 of the core 41 of the stator 36 as by arrows 95 can be extracted or subtracted. In the preferred embodiment, the stator is 88 at the stator 36 by thermally conductive epoxy, such as an injection molded or molded thermally conductive plastic or equivalent material 99 that between the protrusions 92 , the coils 37 and pole pieces 42 of the core 41 is placed. This places a very close thermal contact between the carrier 88 and the stator 36 for sure. Epoxy Stycast Type 2850 MT, supplied by Emerson and Cuming of Canton, MA, USA, is a non-limiting example of a suitable thermally conductive material 99 , The stator carrier 88 also responds to the circumferential forces coming from the engine 30 be generated, for example by means of fastening rings 88A . 88C and of in 14 illustrated housing 113 through which the engine 30 is coupled to the vehicle frame (not shown). The fastening rings 88A . 88C and the case 113 from 14 are non-limiting examples of how the stator support 88 can be attached to the vehicle. It will be understood by those skilled in the art, based on the description herein, that this is only a way of illustration and not intended to be limiting, and the particular means for securely attaching the stator support 88 to the vehicle will depend on the particular vehicle configuration.

14 shows a partially cutaway and simplified cross-sectional view through the structure 112 of the traction motor of the present invention, wherein the engine 30 with the rotors 32 . 34 , the rotor carrier 70 , the stator 36 , the stator carrier 88 and the housing 113 are composed in a functional relationship. An inner ring construction 88A is suitably fixed to the stator 88 appropriate. An outer ring or an outer plate 88C is suitably by bolts 88D for example by engagement thread 88B on the ring 88A appropriate; but this is not crucial. Any suitable means of attachment may be used. The outer ring or the outer plate 88C Again, by a suitable means on the housing 113 firmly attached. In this way, the counter torque of the engine 30 from the stator 36 to the housing 113 and finally transferred to the vehicle frame. The exact way to attach the external housing 113 on the vehicle frame depends on the particular vehicle design and is omitted here.

A centrally located output shaft 114 is suitably with the web part 67 of the rotor carrier 70 for example by bolts 77AA coupled to the threaded holes 77A attack; but this is not essential. Any means for coupling the rotor bar 67 with the output shaft 114 of the motor 30 of the construction 112 can be used. Although the design and operation of the engine 30 and the engine structure 112 with regard to a rotor carrier 70 which is coupled to the wheel, and a stator carrier 88 Further, it is only for the convenience of description and is not intended to be limiting. The connection of the engine 30 and the engine structure 112 between the wheel and vehicle frame could be reversed in the same way, ie the stator 88 can be coupled with the wheel, and the rotor carrier 70 can be coupled to the vehicle frame. Both arrangements are useful.

The upper half of 14 ie above the axis of rotation 48 , shows the interior 69 of the engine structure 112 in which the rotors 32 . 34 with PMs 33 . 35 and cooling holes 75 , a rotor carrier 70 with mounting holes 77A and holes 77B for mass reduction and adjustment ranges 72 . 74 , a stator 36 with coils 37 and pole pieces 42 a core 41 , a stator carrier 88 with a cooling chamber 90 and inward teeth 92 for engaging the coils 37 and pole pieces 42 etc. are arranged in a functional relationship. The lower half of 14 ie below the axis of rotation 48 shows an exemplary housing 113 that has an interior area 69 surrounds. Inside the case 113 or adjacent to it are desirably bearings 115 . 115 ' provided to the output shaft 114 (and therefore the rotors 32 . 34 ) with respect to the housing 113 and stator carrier 88 to wear and to align. Camps 115 . 115 ' have inner races 116 . 116 ' on that with the output shaft 114 coupled to the machine, and outer races 118 . 118 ' that with the case 113 are coupled, which in turn with the stator 88 is coupled. ball-bearing 117 . 117 ' roll between the races 116 . 118 respectively. 116 ' . 118 ' , By the races 116 . 116 ' at the output shaft 114 and the races 118 . 118 ' on the housing 113 be firmly attached, will be gaps 94 . 94 ' between PMs 33 . 35 and stator pole pieces 42 . 42 ' formed and kept at the right size. The housing 113 with the camps 115 . 115 ' is intended to be exemplary only and not restrictive. The person skilled in the art will understand on the basis of the description herein that the mechanical arrangement for supporting the rotors 32 . 34 with respect to the stator 36 may differ depending on the particular vehicle or other device to which the engine 30 and the construction 112 are attached. Accordingly, a wide variety of housing and support assemblies may equally well be used, and the following claims are not to be construed as limited to the examples presented herein for purposes of illustration.

The electrical and magnetic operation of the engine 30 will now be described in more detail. In a Y-connected three-phase machine without neutral wire, the sum of the three phase currents I _a , I _b , I _{c is} zero. Therefore, the actual number of variables is two, and the third phase current can be calculated from the other two. In this way, a three-phase machine with phase currents I _a , I _b , I _{c can be represented} mathematically by two phases. This two-phase representation is known in the art as the dq or longitudinal transverse axis representation, in which the machine behavior can be described by means of reactive currents I _d , I _q , the d- or longitudinal axis usually being aligned with the permanent magnet axis and the q - or transverse axis is less than 90 electrical degrees to the magnetic axis. This is in 15 which provides a simplified representation of the dq magnet axes used in analyzing the motor of the present invention. The control angle α is the electrical angle between the phase current I _s and the transverse axis current I _q . The phase current I _S is the vector sum of the longitudinal and transverse axis currents I _d , I _q . For sinusoidal phase currents, I _{s is} the peak of the phase current. In general, for positive values of the control angle α, the longitudinal axis current I _{d is} negative, ie it is opposite to the PM field. As is well known in the art, the operation of a multi-phase motor with PMs is represented by I _d , I _q and α = arctan (-I _d / I _q ).

The control technique of the present invention can be implemented for both a surface and internal type PM machine, and makes it possible to maximize system performance characteristics such as efficiency, torque per amp, etc. By providing improved field weakening, the (in 20A -B, 22 illustrated) control controller in a non-linear (overdrive) range of operation, wherein the operation is close to the six-step or square wave mode of a controller. Six-stage control of a three-phase PM motor is well known in the art and described, for example, in Power Electronics, Converters, Applications, and Design, Second Edition by Ned Mohan, by John Wiley and Sons, Inc., New York, New York, was published. In the six-stage control mode, timed current pulses are delivered to combinations of two of the three phases, which combination changes every sixty electrical degrees as the rotor rotates. By enabling transitions to the non-linear operating range, the improved controller of the present invention improves both high speed performance and efficiency. The arrangement according to the invention works particularly well for a strong flow machine such as the axial flow machine of the present invention and works well in the presence of harmonics such as slot harmonics or winding harmonics. The torque command T *, the motor speed ω _r , the bus voltage Vdc and stored engine characteristics are used to determine the optimum phase currents for efficient operation. The current commands are calculated using the system's current and voltage limits while being used efficiently. These feedforward current commands are then used to control the machine, and since they are calculated using the voltage and current limits, they are ideally suited to powering the machine even during a run to control de-energizing or field weakening operation at high speed. However, due to variations in the model parameters of the machine and the actual machine parameters, some deviation is expected, and thus a de-excitation field term is provided for feedback to correct the error between the commanded current and the actual required current. Since the control approach of the invention utilizes the actual motor characteristics, the correction term is generally small and a smooth transition to the overdrive area is obtained. Regarding the variables mentioned herein, the convention is adopted to add a superscript (*) to a size to indicate that it is a commanded size. For example, T represents the actual engine torque, and T * represents the commanded torque, ie, the torque command given by the user to the engine controller; I _d represents the actual longitudinal axis current, and I _d * represents the commanded longitudinal axis current, ie the longitudinal axis current requested by the controller logic, etc. for the other variable.

16A shows curves 130 the calculated and observed torque of the motor 30 as a function of the control angle α, 16B shows curves 132 the calculated longitudinal axis flux as a function of the control angle α, and 16C shows curves 134 a calculated transverse axis flux as a function of the control angle α at different current values. The positive current decreases in the directions of the arrows 131 . 133 . 135 to. Characteristic data of the engine (engine), as in 16A . 16B and 16C are used to develop a non-linear model of the machine that includes both saturation and cross-saturation effects. Once the non-linear model is generated, it is used to search for the optimal control parameters and the longitudinal and transverse axis current commands, with the in 17 illustrated methodology. For each torque T, each speed ω _r and bus voltage V _dc, there is a unique set of control parameters I _d , I _q that maximize the performance characteristics of the machine. This model searches for these control parameters for all operating points of the torque and the speed of the machine for different bus voltages. As will be explained subsequently, the resulting optimized control parameters are stored in look-up tables provided by the engine control system 160 (please refer 20 ) of the present invention are used to operate the engine.

17 illustrates a method 790 to calculate optimized control parameters. This method is preferably offline and may be, for example, from a computer system 500 from 22 or any other computer system supplied with the required input data. The calculated control parameters thus obtained are added as a look-up table, for example in a memory 506 in a real-time machine controller 500 (please refer 22 ) is stored. The procedure 790 starts with START 792 , In an initial step 794 For example, the inputs are the values of the torque command (T *), the rotor speed (ω _r ), the DC bus voltage (V _dc ) and the maximum peak inverter current (I _max ), for which the control parameters (the longitudinal and transverse axis currents) are calculated should be. The procedure 790 calculates the optimized control parameter for all torque-speed operating points (T-ω _r ) of the machine for a range of operating _battery voltages (V _dc ). Alles these control parameters are then stored in memory 506 the real-time controller 500 such as stored in lookup tables. I _max is an upper limit of the phase current usually imposed by the thermal limit of the inverter. All the control parameters must be calculated to operate within the supply voltage (V _dc ) and the current limit (I _max ). In step 800 For example, a standard procedure for searching for roots, such as the procedure of bisection etc., is performed to obtain the control parameters I _s and α = arctan (-I _d / I _q ) (see 15 ), operating within the _maximum inverter current I _max and the DC bus voltage V _dc needed to produce the commanded torque T *. A query 802 is then executed to determine if all possible control parameters, all currents (ie from 0 to I _max ) and all control angles (ie from 0 to 90 degrees) are taken into account to ensure that the optimal combination is selected. If the result of the query 802 YES (TRUE) is, meaning that all possible combinations have been considered, then the procedure ends 790 at STOP 804 , If the result of the query 802 NO (FALSE) is, which means that not all possible combinations have been considered yet, then goes the procedure 790 continue to step 806 Torque calculation in which the torque T _calc for the current choice (from block 800 ) of the control parameters I _s and α is calculated. To calculate the torque T _calc , the characterization data of the machine of 16A used. A query 808 is then executed to determine whether the absolute difference between the calculated torque T _calc and the commanded torque T * is less than a predetermined small number ε. In the preferred embodiment, ε is selected such that the calculated torque T _{calc is} within 0.1% of the commanded torque T * or _less . Higher or lower values of ε can also be used depending on the desired level of accuracy. If the result of the query 808 NO (FALSE), then the procedure returns 790 to block 800 and selects another set of control parameters I _s and α for the commanded operating point (T *, ω _r ) and the voltage and current limits (V _dc and I _max ) and repeats the steps 800 - 808 until the result of the query 808 YES (TRUE) or STOP 804 occurs, ie the result of the block 802 YES (TRUE), which means that all control parameters (I _s varying between 0 and I _max and the control angle α varying between 0 and 90 degrees) have been checked for a valid set of control parameters. If the result of the query 808 YES (TRUE), meaning that a useful set of control parameters has been found which will produce the desired commanded torque T * at the machine output, then the procedure goes 790 continue to a step 810 where the longitudinal axis and transverse axis flux linkages Ψ _d and Ψ _q , respectively, are determined. To calculate the flux linkages of the machine, the characterization data of the 16B and 16C used. The through the steps 800 - 808 selected control parameters (I _s and α) produce the commanded torque T *, which operates within the current limit of I _max . However, the voltage _limit imposed by the battery voltage V _dc must also be considered. The next few steps calculate the machine's _{supply voltage} and check that the machine _voltage remains within the battery _voltage V _dc . For a bus voltage of V _dc , the maximum phase voltage available to the machine is (2 / π) × V _dc , this mode being called the six-step mode where the full battery voltage is applied between machine terminals. In the preferred embodiment, not the full six-step mode is used, but approximately 95% of the six-step mode voltage. The constant M _high (see Table I) in block 814 is selected accordingly. The step 812 Stress calculation is performed using the machine phase voltage V _s (defined in equation [4]) using the steps in 810 certain flux linkages and equations [2] - [5] described later. A query 814 is then performed, wherein the peak of the phase voltage V _{s is} compared with the DC bus voltage V _dc multiplied by a constant (2 / π) × M _high . The quantity (2 / π) × V _dc is the maximum phase voltage available to the machine for a battery voltage of V _dc . This mode is known as the six-step mode. The constant M _high defines the inverter limit in the overdrive range as discussed later in conjunction with Table I and 20A -B is explained in more detail. If M _{high is set} to 1, the inverter will work 182 (please refer 20 ) in six-step mode. In the preferred embodiment, M _{high is set} to ~ 0.95, which means that the inverter 182 operating at 95% of the six-level voltage limit. The inverter 182 operates in six-step mode when the full bus voltage V _{dc is applied} to the terminals of the machine 30 in 20A -B is created. While the preferred value of M _high = 0.95, useful values are in the range of 0.90 ≥ M _high ≥ 1.0, and desirably 0.92 ≥ M _high ≥ 0.98. If the result of the query 814 YES (TRUE) is, which means that the selected control parameter would require more inverter voltage than available, then the procedure returns 790 like through paths 815 . 823 shown to block 800 back where another set of control parameters is selected. If the result of the query 814 NO (FALSE), then the current set of control parameters will reach the commanded torque without exceeding the current and voltage limits I _max and V _dc, respectively. In the subsequent step 816 the system losses (machine, inverter etc.) are calculated and in one step 818 the efficiency of the system is calculated. The losses are then the sum of the inverter loss (IL) and the machine loss (ML), ie Σ (IL) + (ML). The person skilled in the art understands how these losses are to be determined. The efficiency η is given by the equation η = [(ω _r × T *) / (ω _r × T * + Σ (IL) + (ML))]. A query 820 is then performed to compare the currently calculated efficiency η _calc with the greatest efficiency _value η _{max obtained} with a previous valid set of control _parameters . If the result of the query 820 NO (FALSE) indicates that the current efficiency is less than the previously calculated efficiency, then the procedure returns 790 to block 800 back, as through a path 821 . 823 is shown to select a different set of control parameters. If the result of the query 820 YES (TRUE), then goes the procedure 790 to step 822 where the current set of control _parameters I _S and α are stored, η _{max is set} equal to the current value η _calc , and the new value of η _{max is} also stored, such as in memory 506 of the system 500 (please refer 22 ). partial steps 822A and 822B are executed in any order. After completing step 822 the procedure returns 790 to block 800 back, as through a path 823 is shown. The procedure 800 - 823 Repeat until the entire control range (I _s , which varies between 0 and I _max , and the control angle α, which varies between 0 and 90 degrees) is checked for the optimal control parameters. The process described above should yield a valid set of control parameters (I _s , α) that maximizes the efficiency of the system for the required operating point (T *, ω _r ) and the voltage and current limits (V _dc and I _max ) of the machine. The one of the selection of another operating point (block 794 ) from beginning of the entire process to the end should be performed for all operating points of the machine (eg the entire torque-speed level) and working ranges of the battery voltages. Once all the control parameters have been received, they are stored in memory 506 the real-time controller 500 for example, as a lookup table 162 of the 20A -B saved.

18A and 18B show curves 136 . 138 the torque versus the speed for optimum control parameters, the commands for the longitudinal and transverse axis currents, for all torque-speed operating points of the machine whose characteristics in 16A -C are shown.

The bus voltage Vdc is 250 volts. These illustrate a typical set of optimal control parameters for the PM machine of 14 , which maximizes the efficiency η of the drive system. The curve 136 from 18A shows contours of constant currents of the command for the transverse axis current, and the curve 138 from 18B shows contours of constant currents of the command for a cross-axis current. The parameter values on the different curves are I _q values in 18A and I _d values in 18B ,

Optimal control parameters are calculated for multiple bus voltages and for both motor and regeneration operations. As will be explained in more detail below, these control parameters are stored in look-up tables provided to the engine control system 160 ( 20A -B) and the system 500 ( 22 ) be available. It is important to separately calculate look-up tables for engine and regeneration operations. For the same torque-speed operating point, the terminal voltage of the machine is lower during a regeneration operation due to a reverse direction of the current flow than for a motor operation. As a result, more torque is available as compared to motor operation during a field weakening regeneration operation.

19 shows a plot 140 of the observed torque versus speed under various operating conditions for the machine 30 according to the preferred embodiment of the present invention. The curve 142 corresponds to a motor operation at Vdc = 184 volts, the curve 143 regeneration at Vdc = 184 volts, the curve 144 engine operation at Vdc = 250 volts, the curve 145 a regeneration at Vdc = 250 volts and the curve 146 engine operation at Vdc = 316 volts and the curve 147 a regeneration at Vdc = 316 volts. It will be appreciated that at a high speed during a regeneration operation, significantly more power (torque x speed) is available compared to a motor operation for the same bus voltage Vdc.

T*:

Drehmomentbefehl

ω_r:

Rotordrehzahl in Rad/s

ω_ε:

elektrische Frequenz in Rad/s

θ_r:

die gemessene oder geschätzte Rotorstellung

V_dc:

Gleichstrom-Busspannung

I_d:

Längsachsenstrom

I_d*:

Befehl für den Längsachsenstrom

I_d**:

(durch den feldschwächenden Block 186) modifizierter Befehl für den Längsachsenstrom

I_q:

Querachsenstrom

I_q*:

Befehl für den Querachsenstrom

ψ_d:

Querachsen-Flussverkettung (die Flussverkettung ist der eine Spule verkettende Fluss, der von einer anderen stromführenden Spule oder einem Permanentmagneten erzeugt wird)

ψ_d*:

Längsachsenfluss, erzeugt durch den Befehl I_d* für den Längsachsenstrom

ψ_d**:

Längsachsenfluss, erzeugt durch den modifizierten Befehl I_d** für den Längsachsenstrom

ψ_q:

Querachsenflussverkettung

ψ_q*:

Querachsenfluss, erzeugt durch den Befehl I_q* für den Querachsenstrom

R_S:

Widerstand pro Phase der Maschine (engl. per phase resistance)

U*_d:

Befehl für die Längsachsenspannung (an den Inverter)

U*_q:

Befehl für die Querachsenspannung

U_D*:

Längsachsenspannung im stationären Bezugssystem

U_Q*:

Querachsenspannung im stationären Bezugssystem

M_index:

Modulationsindex, der den vom Inverter genutzten Spannungsbetrag definiert. (Ein Modulationsindex 1 gibt eine 100 % Nutzung der Gleichstrom-Busspannung an.)

M*_index:

Befehl für den Modulationsindex

M_ref:

Referenzmodulationsindex. Dieser definiert den Spannungsbetrag, der vom Inverter genutzt werden soll.

M_low:

unterer Schwellenwert für M_index

M_high:

höherer Schwellenwert für M_index

PI:

Proportional-Integral-Controller.

20A -B are simplified block diagrams of a process architecture 160 an engine control system according to a preferred embodiment of the present invention, wherein 20A provides an overview, and 20B provides more details. The hardware to run the in 20A -B illustrated functions is in 22 shown. The control system of the present invention achieves two goals: first to maximize engine power and secondly to effectively utilize the DC bus voltage V _dc at high speed. The first goal is through the optimized control table in the block 162 reached. The second goal is achieved by the field weakening caused by a feedback modulus (field weakening function) 186 in cooperation with the block 162 for optimized control parameters. In a permanent magnet (PM) machine, the PM flow is always present. As the rotor rotates, the rotating magnetic flux induces a voltage in the stator windings called counterelectromotive force (back EMF). As the revs get higher and higher, so does the counterelek tromotive force too. Above a certain speed, the back electromotive force may exceed the DC bus voltage V _dc . At this point, control of the flow through the machine is no longer possible. Therefore, there is a need to reduce the magnetic flux to reduce the back electromotive force so that the machine current can be controlled. This reduction in magnetic flux is referred to as de-excitation or field weakening. In a PM machine, the PM flow itself can not be reduced; therefore, a negative Längsach senstrom is fed into the machine at high speeds to counteract part of the PM flow, whereby the counter electromotive force is reduced. The of the real-time controller 501 executed control function 160 is particularly effective and allows a higher utilization than a 95% use of the bus voltage with stable control and good control response. The following parameters are for use in conjunction with the control function 160 of the 20A -B and the control system 500 from 22 Are defined:

T *:

torque command

ω _r:

Rotor speed in Rad / s

ω _ε :

electrical frequency in rad / s

θ _r:

the measured or estimated rotor position

V _dc :

DC bus voltage

I _d :

axis current

I _d *:

Command for the longitudinal axis current

I _d **:

(through the field weakening block 186 ) modified instruction for the longitudinal axis current

I _q :

Cross-axis current

I _q *:

Command for the transverse axis current

ψ _d:

Cross-axis flux linkage (flux linkage is the flux chained by a coil produced by another current-carrying coil or a permanent magnet)

ψ _d *:

Longitudinal axis flux generated by command I _d * for the longitudinal axis current

ψ _d **:

Longitudinal axis flux generated by the modified command I _d ** for the longitudinal axis current

ψ _q :

Transverse axis flux linkage

ψ _q *:

Transverse axis flux generated by the command I _q * for the cross-axis current

R _S:

Resistance per phase of the machine (per phase resistance)

U * _d :

Command for the longitudinal axis voltage (to the inverter)

U * _q :

Command for the transverse axis voltage

U _D *:

Longitudinal stress in stationary reference frame

U _Q *:

Transverse axis voltage in the stationary reference system

M _index :

Modulation index that defines the amount of voltage used by the inverter. (A modulation index 1 indicates a 100% usage of the DC bus voltage.)

M * _index :

Command for the modulation index

M _ref :

Reference modulation index. This defines the amount of voltage that should be used by the inverter.

M _low :

lower threshold for M _index

M _high :

higher threshold for M _index

PI:

Proportional-integral controller.

The table 162 for optimized current commands, the inputs T *, ω _r and V _dc defined above are received. table 162 is conveniently a look-up table using in conjunction with 16 - 19 is determined offline, with examples of data optimized control parameters are shown. The measured data defines the conditions that give optimum performance, such as optimum efficiency, and involves feeding a negative, high-velocity, longitudinal axis current to field weakening. Based on: (i) the actual rotor speed ω _r resulting from the function 184 for measured sizes 20A -B (and the hardware block 512 from 22 ), (ii) one of a user input commanded torque T *, and (iii) the DC bus voltage V _dc determined by the function 184 for measured sizes 20A -B (and the hardware block 512 from 22 ) returns the table 162 the commanded longitudinal axis current I _d * and the commanded transverse axis current I _q *, which should reach the commanded torque T * at the speed ω _r . I _d * provides stability for current regulation by reducing the counter electromotive force voltage of the machine at high speed. Ideally I _d * of 162 from the top to reduce counterelectromotive force and provide stability to the current regulator. Any deviation between the optimized command table parameters and the actual engine power is determined by the function 186 considered for field weakening correction, which will be described in more detail later. The function 186 returns an error correction term ΔI _d * that is in the SUM function 199 _is added to I _d *. This modified longitudinal axis current _is referred to as I _d **, ie I _d ** = (I _d * + ΔI _d *). The I _q * output of the function 162 and the output I _d ** = (I _d * + ΔI _d *) of the SUM function 199 be in the current regulator 185 fed, the necessary Ansteuertaktzyklen D _a , D _b , D _c for the inverter 182 calculated, in turn, the machine 30 controls or drives. A feedback 187 (please refer 20A ) is through the current regulator 185 to the field weakening function 186 delivered, so that the output of the regulator 185 (by modifying the commanded longitudinal axis input current) to optimize overall performance and account for small variations in machine characteristics.

Now up 20B Reference is made to the output I _q * of the block 162 and the output I _d ** = (I _d * + ΔI _d *) of the SUM block 199 into the SUM functions 163 respectively. 165 fed, where from the function 184 for actual quantities obtained, actual values I _d , I _{q are} subtracted, giving the differences (errors) between the commanded value and actual values, which then errors in PI functions 168 . 170 be fed. The functions 168 . 170 are proportional-integral (PI) controllers, which are well known in the art. A suitably designed PI controller will zero the above-mentioned current errors by appropriately modifying the voltage applied to the machine. The outputs of the PI functions 168 . 170 be in the SUM functions 172 respectively. 174 where fed by the PI function 168 received data with the size (ω _r Ψ _d * + I _q * R _s ) are summed by the PI function 170 received data are summed with the size (-ω _r Ψ _d * + I _d * R _s ) and the results in the override function 176 be fed. The above-mentioned two feedforward terms or terms for positive feedback are basically the respective terms for the (longitudinal and transverse axis) speeds and resistance voltages. Adding these two positive feedback terms to the current control loop improves the dynamics of the current regulators. An overmodulation is a technique by which the inverter 182 from operation in the linear region to operation in a nonlinear region to maximize the voltage fed into the machine. There are several overdrive techniques known in the art. The function 176 implements an algorithm described by Holtz et al. in IEEE Transactions on Power Electronics, Vol. 8, No. 3, October 1993, pp. 546-553. This algorithm continuously and smoothly varies the fundamental output voltage of the inverter with the modulation index up to its operation in the full six-step mode. The function 176 make sure the inverter 182 continuously provides a stable control of the phase currents I _a , I _b , I _c even at high values of the modulation _index M _index when the inverter 182 no longer works linearly. The modulation _index M _index is a measure of the AC peak output of the inverter against the DC _injection V _dc . M _index = 1.0 means that of the inverter 182 delivered output AC voltage is zero, and M _index = 1.0 means that the full battery voltage V _{dc is applied} to the machine terminal (this mode is also known as six-stage mode). Up to about M _index = 0.9069, where inverter 182 provides 90.69% of the battery voltage to its output AC waveforms, is the operation of the inverter 182 essentially linear. In addition, the nonlinear. The block 176 uses the program of Holtz et al. (ibid.) to ensure that an operation in this area is still stable and provides longitudinal or lateral axis voltage commands U * _d and U * _q , respectively, to a function 178 for transformation from the synchronous to the stationary reference system.

worin x eine beliebige Maschinenvariable wie z.B. die Maschinenspannung, der Maschinenstrom etc. ist und θ_r die Rotorstellung ist. Der Inverter 182 ist herkömmlich. Der Inverter 182 arbeitet in geeigneter Weise mittels Pulsbreitenmodulation (PWM). Der Taktzyklusrechner 180 bestimmt die Breite der Impulse, um die gewünschte Spannung (am Ausgang des Inverters) wie vom Stromregler befohlen zu erzeugen. Je breiter die Impulse sind (größer der Taktzyklus ist), desto größer ist die Spannung und desto größer sind daher die Ausgangsströme. Die Funktion 180 berechnet die Invertertaktzyklen D_a, D_b, D_c für jede Phase a, b, c, die als Antwort auf Eingaben U_D* und U_Q* benötigt werden, so dass der Inverter 182 die befohlenen Spannungen U_D* und U_Q* an den Maschinenanschlüssen erzeugen wird, um die gewünschten Phasenströme I_a, I_b, I_c zu erzeugen. D_a, D_b, D_c werden in den Inverter 182 eingespeist. Der Inverter 182 empfängt D_a, D_b, D_c und V_dc und liefert die notwendigen Spannungsimpulse an den Motor (die Maschine) 30, um die Phasenströme I_a, I_b, I_c zu liefern. Die Funktion 184 für gemessene Größen misst in geeigneter Weise Phasenströme I_a, I_c, die vom Inverter 182 zur Maschine 30 fließen, und berechnet aus diesen beiden den Phasenstrom I_b. In einer Y-Konfiguration ohne Neutralschaltung bzw. -draht ist die Vektorsumme I_a, I_b, I_c Null, so dass beliebige Zweiphasenströme ausreichen, um den dritten zu bestimmen. Jedes beliebige Mittel oder Verfahren zum Bestimmen von I_a, I_b, I_c kann jedoch verwendet werden. Die Funktion 184 empfängt die Batterie spannung V_dc und empfängt auch in geeigneter Weise (z.B. von einem Sensor eingespeist) ω_r und θ_r von der Maschine 30; dies ist aber nicht wesentlich. In der Technik ist bekannt, dass beide Größen durch eine Analyse der Phasenströme oder andere Mittel bestimmt werden können, die keine separaten Sensoren an der Maschine 30 benötigen. Beide Anordnungen sind nützlich. Die Funktion 184 nutzt diese Eingaben, um die entsprechenden Werte von I_d und I_q zu berechnen. Die Funktion 184 wird durch den Detektorblock 512 für gemessene Größen von 22 ausgeführt.The approximately sinusoidal signals sent to the machine 30 delivered have a certain frequency. If an observer sits close to the peak or peak of the sine wave and rotates at the same frequency, the signal appears to be stationary in time. This is referred to in the art as the "synchronous frame of reference" as opposed to the "stationary frame of reference" wherein the observer sees the actual time varying AC signals. In the synchronous reference system, the synchronous AC magnitudes appear as DC magnitudes and are therefore easier to control. The phase current I _s and its longitudinal axis and transverse axis components I _d and I _q are actually sinusoidal, but appear in the synchronous reference system as DC magnitudes. The function 178 converts these DC magnitudes of the synchronous reference system back into substantially sinusoidal AC magnitudes in the stationary (real time) reference system. The function 178 provides outputs U _D * and U _Q * which are sent to the clock cycle computer block 180 to be delivered. D and Q are the stationary counterpart of the quantities d and q in the synchronous reference system. The following expression is used to convert quantities in the synchronous frame of reference to the stationary frame of reference, and vice versa

where x is any machine variable such as the machine voltage, machine current, etc., and θ _{r is} the rotor position. The inverter 182 is conventional. The inverter 182 operates in a suitable manner by means of pulse width modulation (PWM). The clock cycle calculator 180 determines the width of the pulses to produce the desired voltage (at the output of the inverter) as commanded by the current regulator. The wider the pulses the larger the voltage, the larger the output currents. The function 180 calculates the inverter clock cycles D _a , D _b , D _c for each phase a, b, c needed in response to inputs U _D * and U _Q * such that the inverter 182 will generate the commanded voltages U _D * and U _Q * at the machine terminals to produce the desired phase currents I _a , I _b , I _c . D _a , D _b , D _c are in the inverter 182 fed. The inverter 182 receives D _a , D _b , D _c and V _dc and supplies the necessary voltage pulses to the motor (the machine) 30 to deliver the phase currents I _a , I _b , I _c . The function 184 for measured quantities suitably measures phase currents I _a , I _c , that of the inverter 182 to the machine 30 flow, and calculates the phase current I _b from these two. In a Y configuration without a neutral circuit or wire, the vector sum I _a , I _b , I _{c is} zero, so that any two-phase currents are sufficient to determine the third. However, any means or method for determining I _a , I _b , I _c may be used. The function 184 receives the battery voltage V _dc and also receives in an appropriate manner (eg fed by a sensor) ω _r and θ _r from the machine 30 ; but this is not essential. It is known in the art that both quantities can be determined by analyzing the phase currents or other means that do not have separate sensors on the machine 30 need. Both arrangements are useful. The function 184 uses these inputs to calculate the corresponding values of I _d and I _q . The function 184 is through the detector block 512 for measured sizes of 22 executed.

The following describes the function 186 the field weakening correction. For each current I _s and its control angle α and therefore for each longitudinal axis and transverse axis current, the machine generates 30 a certain longitudinal axis and transverse axis flow. The size of these flux linkages does not change with speed and is therefore static in nature. These flow values are by curves 132 . 134 in 16B - 16C shown. The function 188 With the static flow table, the commanded longitudinal and transverse axis flux linkages compute or suggest ψ _d **, ψ _q * resulting from the modified longitudinal axis and lateral axis current commands I _d **, I _q * that are dependent on the function 162 were obtained. I _d ** is the command for the longitudinal axis current from the function 162 plus one in the SUM function 199 added term for field weakening correction. The outputs of the function 188 be in the function 190 which calculates the commanded modulation index M * _index based on I _d **, I _q *, R _s , ω _r , V _dc , and ψ _d **, ψ _q * according to the following equations: V d * = I d ** R s - ω e ψ q * [2] V q * = I q ** R s + ω e ψ q ** [3] V s * = [(V d *) 2 + (V q *) 2 ] 1.2 [4] M * index = (πV s *) / (2V dc ) [5]

M * _index is used to fill in the saturation function 198 used limits and the reference modulation _index M _ref , which will be explained later in Table I.

The function 192 of the module 186 for field weakening, the square of size M calculates _index . The outputs of the functions 172 and 174 (which the inputs of the function 192 are) the longitudinal and transverse axis voltages that would be applied by the inverter to the machine. Using the equivalent equations of [4] and [5], M _{index is} calculated. In calculating M _index , the actual voltages to be applied by the inverter are used in contrast to the commanded voltages used in equations [2] - [5]. The output of the function 192 will be in SUM 194 fed, where | M _index | ² of | M _ref | ² , where M _{ref is} the reference _{modulation index} (see Table I), and the result is in the PI function 196 fed. M _ref defines the fraction of the available DC voltage available from the inverter 182 should be used. The PI function 196 generates the desired additional longitudinal axis current feedback needed to match the modulation _index M _index to the reference modulation _index M _ref . The output of the PI function 196 gets into the nonlinear compensator 198 with the upper and lower limits set on the feedback error current ΔI _d * according to Table I. The feedback error current ΔI _d * modifies the current I _d * given by the table 162 for optimized commands. Ideally, the feedback error current should be zero because of the function 162 should feed the proper amount of longitudinal axis current into the field weakening control machine at high engine speeds. The of the function 162 through the controller or current regulator 185 derived feedforward control or positive feedback control can not guarantee stability because there are sometimes fluctuations between those in the function 162 stored machine parameters and the actual machine due to aging effects, a fluctuation in the operating conditions such as the temperature, a fluctuation from one machine to another due to Ferti differences in distribution, etc. Therefore, the function takes into account or takes into account 186 for field weakening correction, such variations are provided by providing the correction term ΔI _d * _that is in the SUM function 199 _is added to I _d *.

The size of M _ref , in block 194 is fed, and the setting of the I _d boundaries in the saturation block 198 activates or deactivates the voltage loops. This is explained in the following table. Three cases are considered. The logical operations defined in Table I are used to define the boundaries in the blocks 198 set and the entered M _ref in the block 194 define. Table I: Settings of limits

Case 1 (M * _index <M _low ):

M _ref is set to M _high and I _dsat ⁺ is set to zero. With these settings, the error signal is to the PI block 196 positive, and the output of the voltage loop 186 is zero, since the upper saturation limit in the saturation block 198 set to zero. Consequently, the voltage loop 186 disabled. The negative saturation limit of the block 198 has no consequence, but is, for convenience, -K2 | I _d * | set.

Case 2 (M * _index > M _low and M * _index <M _high ):

M _ref is set to M * _index . The upper and lower saturation limits in the block 198 are on K1 | I _d * | or K2 | I _d * | set. These settings activate the voltage loop 186 , The voltage loop 186 is activated when M * _index exceeds the lower limit M _low . This lower limit can be set to any value. Typically, when a current regulator 160 operates in the linear range (eg M * _index <0.9069), the inverter has 182 adequate voltage margin, and help from the voltage loop 186 is generally not required. Therefore, the lower limit M _{low can be set} at the transition value between the linear and nonlinear range or slightly lower. This allows a smooth transition from the linear to the non-linear range.

The command I _d * for the longitudinal axis current is in the block 162 to maximize system performance while properly using the bus voltage. Therefore, under steady state conditions, M * _index should ideally _fit closely with M _index , and from the voltage loop 186 No help would be required. In other words, the output would be ΔI _d * of the saturation block 198 Zero. The voltage loop 186 however, would be needed during a transient operation to overcome the additional transient voltages (eg, from the inductive wastes). Due to the differences between the actual characteristics of the machine and the measured characteristics, which in 16A Also, it is expected that the actual modulation _index M _{index will be} different from the commanded modulation index M * _index . The deviation level will depend on the error between the measured and actual machine characteristics. In such a case, the voltage loop corrects the error and would allow stable control. Therefore, the constants K1 and K2 can be set to low values. Typical values of 0.1 or 0.4 or lower would be sufficient. Allowing a non-zero positive saturation limit significantly helps to bring the modulation index close to the commanded value when the PI block output 196 once it becomes positive.

Case 3 (M * _index > M _high ):

If M * _index exceeds a certain predefined limit M _high (see also 17 ), then M _{ref is set} to M _high . The value M _high basically represents the upper limit of the operation in Übersteuerungsbe rich. In our experiment we set this value to the 95% of the six-step operation. However, voltage control for full six-step operation would not be recommended since the voltage margin between a six-step operation and 95% of a six-step operation from the current loop is needed to account for any transient operation. The saturation limits of the block 198 are therefore compared to the values of the case 2 keep unchanged.

The overall operation of the function 160 of the control system of 20A -B (executed by the system 500 from 22 ) will now be described. The voltage loop of the control function 160 with the functions 188 . 190 . 192 . 194 . 196 . 198 and the decision table described in Table I directly modify the longitudinal axis flow of the machine to control the machine voltage. Based on the torque command T *, the engine speed ω _r and the DC bus voltage V _dc generates (eg, beats) the table 162 for optimal current commands, the longitudinal and transverse axis current commands I _d *, I _q *, which should most efficiently drive the machine to meet these performance expectations. The longitudinal axis command can be replaced by a field-weakening correction ΔI _d * of the function 186 be modified. The calculated current commands are next compared to the measured currents I _d , I _q , and PI protected controller functions 160 . 170 operate on the error signals to generate voltage commands and therefore drive the error between the commanded and the actual current to zero. The terms for positive feedback of the voltage (+ ω _r Ψ _d * + I _q * R _s ) and (-ω _r Ψ _d * + I _q * R _s ), which are basically the speed voltage and the resistance drop, become the output the PI controller 168 . 170 added to improve the transient performance of the current controller. An anti-windup current regulator can also be used to minimize over-current; but this is not essential. Anti-overflow schemes are known in the art which provide the integrator term of the PI controller functions 168 . 170 modify to prevent their saturation. The anti-overflow scheme presented in, for example, PID Controller: Theory, Design, and Tuning by K. Astrom, T. Hagglund, published in Instrument Society of America, Research Triangle Park, North Carolina, can be implemented. The output of the current controller (functions 168 - 174 ) becomes an override function 176 fed the scheme as described by Holtz et al. (ibid.), and therefore into a function 178 for converting between a synchronous and stationary reference system, wherein the voltage commands in the synchronous reference system are converted into voltage commands in the stationary reference system. The function 178 uses the measured or estimated rotor position θ _r for the transformation. The outputs of the transformation function 178 become a clock cycle calculator function 160 wherein the clock cycles needed to provide the appropriate gating signals to an inverter 182 create, generated and to the inverter 182 which then applies the appropriate voltages to the machine to produce the desired currents I _a , I _b , I _c (I _a , I _b , I _c are representations in the stationary reference system of the commanded currents I _d * and I _q * im synchronous reference system) in the machine 30 to create.

The module 186 for field weakening correction modifies the longitudinal axis current command I _d * to set the voltage for high speed operation. In a PM machine, the PM flow of the machine is not actually reduced; rather, a negative demagnetizing longitudinal axis current is applied to reduce the overall machine flux, thereby reducing the back electromotive force and allowing control of the phase current to continue. For high flow machines such as the axial flow machine of the present invention, the longitudinal axis current has a strong influence on the machine voltage, therefore the longitudinal axis current is controlled to control that the machine voltage works well. To improve transient and steady state performance, ensure stability and smooth transition into the override range of the inverter 182 is the PI-based feedback control module 186 intended.

The outputs of the controller (functions 168 - 174 ) for commanded currents are in the function 192 for the calculation of modulation indices, where the size of the modulation _index M _{index is} calculated. The individual longitudinal axis and transverse axis voltages as well as the total voltages allow to reach the voltage limit for the six-step operation. During a six-stage operation, the entire bus voltage is applied to the machine terminal, ie the clock cycle is 1. A detailed explanation of a six-stage operation can be found in the text of Mohan (ibid.) Which will be explained later. The size of the modulation _index M _index is in block 194 compared with the size M _ref to determine the error. M _ref is not a fixed reference, but depends on the operating conditions. To determine M _ref, one must know the modulation _{index instruction} M * _index . M * _index is calculated from the I _d ** and I _q * values given to the function 188 for the calculation of flux linkages. The flux linkages then become the calculation function 190 determined based on the flux linkages, the bus voltage V _dc , the engine speed ω _r , the phase command currents I _d *, I _q * and the phase resistance R _s according to equations [2] - [5] M * _index .

If M * _{index is} below the linear working range of the inverter 182 is the rectified terminal voltage of the machine is lower than the DC bus voltage, and the field weakening loop (ie the function 186 ) is not needed. In such a case, M _{ref is set} to the upper limit of the voltage loop as shown in Table I. The positive saturation _{flux level} (I _dsat ⁺ ) in function 198 is also set to zero. Therefore, the voltage loop 168 locked (ie the modulation index error is positive, so that ΔI _d * = 0), and the command I _d * for the longitudinal axis current from the optimized function 162 is unchanged in the current regulator 168 . 170 fed. Once M * _index exceeds the linear nonlinear threshold M _low , it enters the non-linear overdrive range of the inverter 182 on, the modulation _index reference M _{ref is set} equal to M * _index . The current commands I _d *, I _q * are calculated to maximize system performance while suitably utilizing the bus voltage. Ideally, therefore, under steady state conditions, M * _{index should} closely match M _index , and it will be from the feedback loop 186 little or no help needed. In other words, the output ΔI _d * would be the saturation function 198 about zero. However, there is generally some help from the loop 186 during transient operations needed for the transient voltage. Due to variations of the actual machine characteristics against the measured characteristics of the machine 16A -C, the actual modulation _index M _{index may} also be slightly different from the commanded modulation index M * _index . In such a case, the feedback loop becomes 186 correct the error and allow stable control. The setting of M _ref = M * _index allows a very smooth transition of the inverter 182 in the override area. If M * _index exceeds a certain predefined limit M _high , then M _{ref is set} equal to M _high , which is basically the upper limit of the operation of the override range. The value M _high is suitably about 95% of the six-step limit of the operation, but larger or smaller values may also be used. However, voltage control to the full six-step limit is generally undesirable since the voltage margin between the full six-step boundary and 95% of the current loop (functions 163 . 165 . 168 . 170 . 172 . 174 . 176 . 178 and 180 ) is needed to account for a transient operation. Even under steady state conditions, however, there may be some variation between the commanded and actual modulation index due to variations between the model and the actual machine and due to measurement errors. These differences are made by the feedback loop function 186 corrected. The upper and lower limits of the saturation function 198 are also set by checking M * _index . If M * _{index exceeds} M _lower , the upper (I _dsat ⁺ ) and lower (I _dsat ^- ) saturation _{limits of} the function become 198 is set to (K ₁ | I _d * |) or (-K ₂ | I _d * |). The commanded and actual modulation indices should be close to each other such that K ₁ and K ₂ are small with typical values of K ₁ = about 0.1 and K ₂ = about 0.4; but larger or smaller values can also be used. By allowing a positive non-zero saturation limit, this significantly aids in bringing the modulation index close to the commanded value when the output of the PI function 196 once it becomes positive. As noted earlier, this positive limit is set to zero when the current controller (functions 163 . 165 . 168 . 170 . 172 . 174 . 176 . 178 and 180 ) operate in the linear range, creating a feedback loop 186 is locked. The control system described above for operating the machine 30 provides excellent steady state and transient response.

21A -B show plots 202 . 206 of commands for longitudinal axis currents for the engine of the present invention under a plurality of operating conditions. These plots show the anti-overflow effect of a synchronous stream regulator (functions 163 . 165 . 168 . 170 . 172 . 174 . 176 and 180 (however, the anti-overflow scheme is in 20 not shown)) at 1200 rpm in response to a _{250V dc} (curves 204 . 208 ) and 350 V _dc (curves 203 and 207 ) transient 100% torque (ie 0-500 Nm). For the curve 204 is the current scale 100 A / div, and for the curves 203 . 204 . 207 is the current scale 120 A / div. In the enlarged part 209 the curve 203 shows the relatively slowly changing track 203-1 I _d **, and the fast-changing track 203-2 shows the measured longitudinal axis current I _d . The track 203-2 I _d approximates, which actually moves up and down in the form of steps. The traces 204 . 207 . 208 show a similar behavior. The actual current follows the current command exactly as you go in 21A -B can recognize. For this experiment, 1200 rpm was the maximum speed of the drive. At the maximum speed, the counter-electromotive force of the machine is much higher than the bus voltages of 250 V and 350 V. The feedforward control or positive feedback control (command output of the function 162 to the current regulator or the controller function 185 ), which together with the voltage feedback loop function 186 works, ensure the stable performance of the drive even during the step command from zero to the top torque of the machine of 500 Nm.

22 is a simplified schematic diagram of a computerized system 500 , which is suitable for carrying out the control processes of the present invention. The system 500 includes a control module 501 with a processor 502 , a program memory 504 for storing the operation instructions for executing the control process 160 , a temporary storage 505 to save of variables during operation or operation of the control module 501 and the system 500 , a store 506 for machine properties, to set the machine properties for the table of optimized commands of the function 162 to save that by the procedure 790 determined and in the control process 160 is used, output buffers 508 for coupling the controller 501 with an inverter 182 and input buffers 510 for receiving measured quantities 184 from the detector 512 for measured sizes. The processor 502 , the memory 504 . 505 . 506 and I / O buffers 510 . 508 are by a bus or wires 503 coupled. The output buffers 508 are over a bus or lines 509 with the inverter 182 coupled. The input buffers 510 are by a bus or wires 511 with the detector 512 coupled for measured sizes. The detector 512 for measured quantities, measures sizes and directions of the phase currents I _a , I _c via lines 513 . 514 , receives the engine speed and the rotor angle via lines 31 and receive over a line 515 V _dc and transmits the determined quantities on lines 511 to the module 501 , The inverter 182 also receives via a wire 183 V _dc , as previously explained. The input buffers 510 also receive the commanded torque T * supplied by the user. In a vehicle application, this is typically derived from the accelerator pedal position. The system 500 illustrates the controller 501 who is to carry out the procedure 790 offline (although not essential) and providing real-time control of the engine 30 is suitable using the sequence of operations and functions described in 20A -B are illustrated.

Although at least one exemplary embodiment has been presented in the foregoing detailed description, it should be recognized that there are a vast number of variations. Although, for example, a coolant ring 88 engaged with the outer circumference of the annular stator 36 is shown and this arrangement is preferred, it may alternatively or complementarily on the inner periphery or other parts of the annular stator 36 with a suitable modification of the rotor bar 70 attack or abut. Further, although the present invention has been described as being particularly adapted to a direct drive of a vehicle wheel without a reduction gear or the like, the use of such reduction gears is not excluded. In addition, although two rotors are preferred, this is not essential, and one or more rotors may be used. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples and are not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the foregoing detailed description offers one skilled in the art a suitable layout for carrying out the exemplary embodiment or exemplary embodiments. It should be understood that various changes in the function and arrangement of elements may be made without departing from the scope of the invention as set forth in the appended claims and their legal equivalents.

Claims (25)

Axial electric motor, with: a stator with Coils thereon for generating a magnetic field; one through the magnetic field turned rotor; one coupled to the rotor Motor shaft; a coolant ring with teeth, which are coupled to the stator; and taking the teeth with comb the coils of the stator, to cool and to receive a counter torque of the axial-electric motor. Motor according to claim 1, characterized in that the stator has a ferromagnetic core and the coils over the Core out radially. Motor according to claim 2, characterized in that the coolant ring surrounds the stator in the circumferential direction. Engine according to claim 3, characterized in that his teeth radially inward extend toward the core and between the coils. Motor according to claim 1, characterized by a essentially massive thermally conductive filler between the teeth and the coils. Motor according to claim 1, characterized in that the coolant ring an internal channel for circulating a coolant. Motor according to claim 1, characterized in that the coils are created from a substantially flat band. Motor according to claim 7, characterized in that the substantially flat band has a major surface, one part is oriented substantially perpendicular to the teeth. Motor according to claim 1, characterized in that the rotor vents for circulating a refrigerant to the stator. Axial electric motor, with: a stator with a Core; spaced, on the stator core adjacent coils to a To generate magnetic field; one rotated by the magnetic field Rotor; a first torque output device, with the Rotor is coupled; a second torque output device, coupled to the stator for receiving a counter torque; and wherein the second torque output device comprises a coolant ring has, which bears against the stator. Motor according to claim 10, characterized in that that the coolant ring abuts a circumference of the stator. Motor according to claim 10, characterized in that that the coolant ring furthermore, teeth which is on parts of the over attacking the core outgoing coils. Engine according to claim 11, characterized in that that the coolant ring furthermore, teeth having, in the direction between parts of the spaced coils run to the core. Motor according to claim 10, characterized in that that the coolant ring abuts on an inner circumference of the stator in the circumferential direction. Motor according to claim 10, characterized in that in that the spaced coils have a flat conductive band having a main area having a part substantially parallel to the core. Motor according to claim 10, characterized in that that the rooms between the coolant ring and the spaced coil with a thermally conductive, im Essentially massive material are filled. Motor according to claim 10, characterized in that that the rotor has one or more openings for ventilation of the stator. Motor according to claim 10, characterized in that that the spaced coils have portions that extend radially to outside over the Core out; and the coolant ring inwardly extending Has teeth, the at the radially outward extending portions of the spaced coils attack, thereby the counter torque of the motor from the stator with the coolant ring is coupled. Axial electric motor, with: an annular stator with coils mounted thereon for generating a magnetic field; one or more essentially washer-shaped rotors with rotors mounted thereon Permanent magnets axially spaced from the stator and with this are magnetically coupled; an output shaft with the coupled to one or more rotors to an output torque to deliver; an absorber for the counter torque, the one with the stator in the circumferential direction coupled coolant ring contains; one Support frame, with the absorber for the counter torque substantially firmly coupled and rotatable with the one or more rotors is coupled. Motor according to claim 19, characterized in that the stator has an annular core for supporting the coils; the coils have portions extending radially outwardly beyond the core; and the coolant ring has radially inwardly extending teeth interposed between the outwardly extending coil portions. Motor according to claim 20, characterized that the coils are created from a substantially flat band are, of its main surface a part to the between the outwardly extending coil sections pasted tooth is substantially perpendicular. Motor according to claim 20, characterized that at least certain rooms between the inward teeth and outward Coil sections with a substantially massive thermally conductive material filled are. Motor according to claim 19, characterized that the cooling ring a channel for conveying a cooling fluid contains. Engine according to claim 23, characterized that the channel with respect of the stator is oriented substantially in the circumferential direction. Motor according to claim 19, characterized by a ventilated Rotor support structure, that between the one or more rotors and the output shaft coupled to carry the rotors and to ventilate the stator.