JP7255140B2 - electric motor drive - Google Patents

Description

The present invention relates to an electric motor drive device that drives an electric motor with two inverters.

2. Description of the Related Art Conventionally, there has been known a technique for driving an AC motor with high output and high efficiency using the outputs of two inverters connected to both ends of an open winding of the AC motor. For example, the inverter device disclosed in Patent Document 1 combines the output of the first inverter and the output of the second inverter, which have opposite polarities.

In this inverter device, for example, the dq-axis output voltage command vectors given to two inverters of the same design are made to have the same magnitude but opposite polarities, and a voltage twice the output voltage of one inverter is applied to the armature winding. .

Japanese Patent No. 3352182

In this specification, regarding the phase difference between the voltage command vectors of the two inverters, the phase difference calculated as it is without inverting one of the vectors symmetrically with respect to the origin is defined as "pure phase difference". Hereinafter, the operation when the net phase difference between the voltage command vectors of the two inverters is 180° is called "reversal operation", and the operation when the net phase difference between the voltage command vectors of the two inverters is other than 180°. It is called "non-inverting operation". Japanese Patent Laid-Open No. 2004-100003 basically describes the configuration of the reversing operation, and merely describes the concept of control in an ideal state by general PWM control, and does not specify the specific control contents.

In addition, in paragraph [0030] of Patent Document 1, as a special use of this technology, when the voltage command vectors are not of opposite polarity but different in magnitude and direction, the vector sum of the output voltages of the two inverters is supplied to the motor. It is stated that However, there is no description at all about the specific control configuration of the non-inverting operation.

Furthermore, in the prior art of Patent Document 1, regarding the operation in the entire control region including the reversing operation and the non-reversing operation, the control state of the system is always controlled when a switching deviation occurs due to various causes, when a disturbance is input, when a transient change occurs, etc. have yet to grasp the Therefore, it may not be possible to stably achieve the desired output and torque while grasping the margin up to the control limit.

The present invention was created in view of the above-mentioned problems, and its object is to control the system regardless of the phase in the entire control area, including the case where the net phase difference between the voltage command vectors of the two inverters is other than 180°. To provide an electric motor driving device capable of grasping the control state of

A motor driving device according to the present invention uses two inverters to control the driving of a motor (80) having two or more phase windings (81, 82, 83) whose ends are open. This motor drive device includes a first inverter (60), a second inverter (70), and a control section (200). The first inverter has a plurality of first switching elements (61-66) provided corresponding to each phase of the winding, and is connected to one end of the winding. The second inverter has a plurality of second switching elements (71-76) provided corresponding to each phase of the winding, and is connected to the other end of the winding.

Based on the torque command, the control unit includes a first inverter control circuit (201) that generates a first voltage command that is an output voltage command to the first inverter , and a second voltage command that is an output voltage command to the second inverter. It has a second inverter control circuit (202) to generate and a combined voltage command calculator (203) .

Based on the phase and amplitude of the first voltage command vector on the dq coordinates corresponding to the first voltage command and the second voltage command vector on the dq coordinates corresponding to the second voltage command, the combined voltage command calculation unit The phase and amplitude of the composite voltage command vector on the dq coordinates corresponding to the composite voltage command output by the inverter are uniquely calculated.

Based on the first voltage command vector and the second voltage command vector, including the case where the net phase difference, which is the phase difference between the first voltage command vector and the second voltage command vector, is a value other than 180°, Determine the composite voltage command vector. Therefore, in the present invention, it is possible to grasp the control state of the system regardless of the phase in the entire control region, including the case where the pure phase difference between the voltage command vectors of the two inverters is other than 180°.

Specifically, the phase of the voltage command vector is defined to increase in the counterclockwise direction on the dq coordinates with reference to the positive direction of the q axis. Then, the phase of the first voltage command vector is Vθ1, the amplitude is Vamp1, the phase of the second voltage reversal vector symmetrical to the second voltage command vector is Vθ2r, the amplitude is Vamp2, the phase of the combined voltage command vector is Vθ, the amplitude is Represented as Vamp. The combined voltage command calculation unit calculates the phase of the combined voltage command vector according to formula (2.1) when formula (1.1) holds, and on the other hand, when formula (1.2) holds, formula (2 .2).

Also, the composite voltage command calculation unit calculates the amplitude of the composite voltage command vector by Equation (3).

Further, the control unit preferably includes an output management unit (204) that manages the output characteristics and output amounts of the two inverters based on the phase and amplitude of the composite voltage command vector calculated by the composite voltage command calculation unit. This enables highly accurate and stable driving while always managing the system output. In addition, it is possible to grasp the degree of margin with respect to the output limit.

1 is an overall configuration diagram of a system to which an electric motor drive device of each embodiment is applied; FIG. 4 is a schematic configuration diagram of a control unit of each embodiment; FIG. FIG. 3 is a block diagram showing the configuration of a composite voltage command calculator; FIG. 4 is a vector diagram for explaining the derivation of the phase and amplitude output formulas of the composite voltage vector; Flowchart for explaining processing according to each embodiment FIG. 11A is a diagram showing synthesized voltage vectors by inverting operation and (b) non-inverting operation; FIG. 4 is a diagram showing the trajectory of the composite voltage vector when the first voltage vector is fixed and the phase of the second voltage vector is changed by 360°; FIG. 4 is a diagram showing changes in synthesized voltage amplitude with respect to managed phase difference; The figure which shows the phase change of the synthetic|combination voltage vector in equal torque. FIG. 4 is a diagram showing the relationship between the phase of a combined voltage vector and torque; FIG. 2 is a block diagram of a control unit according to the first embodiment; FIG. (a) Phase limiter map for 1 power supply 1 inverter system, (b) Phase limiter map for 2 power supply 2 inverters system. The figure which shows the relationship between a voltage phase and a torque. 4 is a flowchart showing optimum phase control according to the first embodiment; 15 is a sub-flowchart of S25 in FIG. 14; The time chart which shows the operation at the time of torque priority. 4 is a time chart showing operation when power is given priority; The vector diagram explaining the concept of control of 2nd Embodiment. A map that defines the relationship between combined voltage amplitude and rotation speed and torque. Time charts showing the operation of the second embodiment.

A plurality of embodiments of the electric motor drive device will be described below with reference to the drawings. In a plurality of embodiments, substantially the same configurations are denoted by the same reference numerals, and descriptions thereof are omitted. Also, the first and second embodiments are collectively referred to as "this embodiment". The electric motor drive device of the present embodiment is a device that controls the drive of the MG, which is a three-phase AC motor, in a system that drives a motor generator (hereinafter referred to as "MG"), which is the power source of hybrid vehicles and electric vehicles. "MG" and "MG control device" in the embodiments correspond to "electric motor" and "electric motor driving device".

First, the basic configuration common to each embodiment will be described with reference to FIGS. 1 to 10. FIG. FIG. 1 shows the overall configuration of a system in which "two power sources and two inverters", that is, two power sources 11, 12 and two inverters 60, 70 are used. The MG 80 is a permanent magnet synchronous three-phase AC motor having a U-phase winding 81 , a V-phase winding 82 and a W-phase winding 83 . When applied to a hybrid vehicle, the MG80 functions as an electric motor that generates torque for driving the drive wheels, and as a generator capable of generating power by being driven by the kinetic energy of the vehicle transmitted from the engine and the drive wheels. have a function.

The MG 80 of this embodiment has an open winding configuration in which the end points of the three-phase windings 81, 82, and 83 are not coupled. Each phase output terminal of the first inverter 60 is connected to one ends 811, 821, 831 of the three-phase windings 81, 82, 83, and each phase output terminal of the second inverter 70 is connected to the three-phase windings 81, 82 and 83 are connected to the other ends 812 , 822 and 832 . The rotation angle sensor 85 is composed of a resolver or the like, and detects the mechanical angle θm of the MG80. The mechanical angle θm is converted into an electrical angle θe by the electrical angle calculator 87 of the controller 200 .

The first power source 11 and the second power source 12 are two independent power sources that are insulated from each other, and each of them is a chargeable/dischargeable power storage device such as a secondary battery such as nickel metal hydride or lithium ion, or an electric double layer capacitor. . For example, an output type lithium ion battery may be used for the first power source 11 and a capacity type lithium ion battery may be used for the second power source 12 . The two inverters 60 and 70 receive DC power from the two power sources 11 and 12 individually. First power supply 11 can exchange power with MG 80 via first inverter 60 , and second power supply 12 can exchange power with MG 80 via second inverter 70 .

The MG 80 is supplied with power from the first power supply 11 via the first inverter 60 and is supplied with power from the second power supply 12 via the second inverter 70 . A U-phase voltage VU1, a V-phase voltage VV1, and a W-phase voltage VW1 are applied to the three-phase windings 81, 82, and 83 on the first inverter 60 side. A U-phase voltage VU2, a V-phase voltage VV2, and a W-phase voltage VW2 are applied to the three-phase windings 81, 82, and 83 on the second inverter 70 side.

For example, a current sensor 84 is provided in the power path from first inverter 60 to MG 80 to detect phase currents flowing through three-phase windings 81 , 82 , 83 . In the example of FIG. 1, V-phase current Iv and W-phase current Iw are detected, but any two-phase or three-phase current may be detected. Further, current sensor 84 may be provided in the power path from second inverter 70 to MG 80 or may be provided in both paths of first inverter 60 and second inverter 70 .

The first capacitor 16 is connected between the high potential side wiring P1 and the low potential side wiring N1, and the second capacitor 17 is connected between the high potential side wiring P2 and the low potential side wiring N2. The first voltage sensor 18 detects an input voltage VH1 input from the first power supply 11 to the first inverter 60 . The second voltage sensor 19 detects an input voltage VH2 input from the second power supply 12 to the second inverter 70 .

The MG control device 100 includes a first inverter 60 , a second inverter 70 , a control section 200 and drive circuits 67 and 77 . The first inverter 60 has six first switching elements 61 to 66 which are provided corresponding to the respective phases of the windings 81, 82, 83 and are bridge-connected. Switching elements 61, 62, and 63 are upper arm switching elements of the U, V, and W phases, respectively, and switching elements 64, 65, and 66 are lower arm switching elements of the U, V, and W phases, respectively. element. The second inverter 70 has six second switching elements 71 to 76 which are provided corresponding to the respective phases of the windings 81, 82, 83 and are bridge-connected. Switching elements 71, 72, and 73 are upper arm switching elements of the U, V, and W phases, respectively, and switching elements 74, 75, and 76 are lower arm switching elements of the U, V, and W phases, respectively. element.

Each of the switching elements 61 to 66 and 71 to 76 is composed of, for example, an IGBT, and is connected in parallel with a free wheel diode that allows a current flowing from the low potential side to the high potential side. In order to prevent a short circuit between the high potential side wirings P1, P2 and the low potential side wirings N1, N2, the upper arm element and the lower arm element of each phase should not be turned on at the same time, but turned on and off complementarily. , is controlled so that when one is on, the other is off.

The control unit 200 is configured by a microcomputer or the like, and includes a CPU, ROM, I/O (not shown), bus lines connecting these components, and the like. The control unit 200 performs software processing by executing a program pre-stored in a physical memory device such as a ROM (that is, a readable non-temporary tangible recording medium) by the CPU, and hardware processing by a dedicated electronic circuit. Perform control by processing.

The control unit 200 controls a first inverter control circuit 201 that generates a first voltage command, which is an output voltage command to the first inverter 60, based on information on the torque command trq ^* and the detected value, and the output to the second inverter. It has a second inverter control circuit 202 that generates a second voltage command that is a voltage command. Information such as phase currents Iv and Iw, electrical angle θe, and input voltages VH1 and VH2 are input to the inverter control circuits 201 and 202, respectively. First drive circuit 67 outputs a gate signal based on the first voltage command generated by first inverter control circuit 201 to first inverter 60 . Second drive circuit 77 outputs a gate signal based on the second voltage command generated by second inverter control circuit 202 to second inverter 70 .

FIG. 2 shows a schematic configuration of the control unit 200. As shown in FIG. In the following figures, the inverter is described as "INV". The first inverter control circuit 201 and the second inverter control circuit 202 may be provided in individual microcomputers, respectively, or may be provided in one common microcomputer. Each inverter control circuit 201, 202 generates an independent and coordinated voltage command in order to drive as a system of two power supplies and two inverters.

As the information acquired by the control unit 200, since the MG80 is common, the detected values of the angle (specifically, the electrical angle θe) and the three-phase current may be common. However, as indicated by broken lines, a plurality of current sensors 84 and rotation angle sensors 85 may be provided, and respective inverter control circuits 201 and 202 may acquire corresponding detection values. Coordinate conversion from three-phase currents to dq-axis currents based on the electrical angle θe, current feedback control, torque feedback control based on estimated torque calculated from the dq-axis currents, and the like are well-known techniques in the field of motor control, and description thereof will be omitted. Each inverter control circuit 201, 202 generates a first voltage command vector to the first inverter 60 and a second voltage command vector to the second inverter 70 by dq control.

In the prior art disclosed in Patent Document 1 (Japanese Patent No. 3352182), the output of the two inverters is superimposed by performing a "reversal operation" in which the voltage command vectors given to the two inverters are reversed in polarity. . Although this provides maximum output, the 180° reversal operation is not necessarily desirable in consideration of efficiency and stability. For example, if there is a deviation in the sampling timing of various sensors, the control timing of the microcomputer, or the information sharing of the inverter control circuit, the 180° inversion switching may not be established and the output may be affected.

In other words, it may be desirable to perform a "non-reversal operation" in which the net phase difference between the two voltage command vectors is other than 180°. In the non-inverting operation, when the two voltage command vectors have the same phase and the net phase difference is 0°, the outputs of the two inverters 60 and 70 cancel each other. In particular, when the amplitudes of the voltage command vectors are equal, the vector sum becomes 0 and the MG 80 is not driven, so it may be substantially excluded.

Therefore, in this embodiment, the voltage command vector to each inverter 60, 70 is geometrically represented by the phase and amplitude on the dq coordinates, and the system output output by the two inverters 60, 70, that is, the combined voltage command is Derive a uniquely determined output expression. By using this output formula, the control unit 200 can perform highly accurate and stable driving while always managing the system output.

Next, with reference to FIGS. 3 and 4, the configuration for calculating the composite voltage command will be described. As shown in FIG. 3, the controller 200 has a combined voltage command calculator 203 and an output manager 204 . Hereinafter, the "command" of the "voltage command vector" will be omitted and will be referred to as "first voltage vector V1" and "second voltage vector V2". In FIG. 4, the first voltage vector V1 is indicated by a dashed line arrow, and the second voltage vector V2 is indicated by a solid line arrow. A second voltage reversal vector V2r that is symmetrical with respect to the second voltage vector V2 is indicated by a dashed line. A composite voltage vector V obtained by combining the first voltage vector V1 and the second voltage reversal vector V2r is indicated by a block arrow.

Also, the phase and amplitude of each vector are indicated by the following symbols. Each voltage phase is defined to increase in the counterclockwise direction on the dq coordinate with reference to the positive direction of the q-axis, and is expressed in units of [° (deg)].
Vθ1: Phase of first voltage vector V1 Vamp1: Amplitude of first voltage vector V1 Vθ2: Phase of second voltage vector V2 Vθ2r (=Vθ2-180): Phase of second voltage inversion vector V2r Vamp2: Second voltage vector V2 and the amplitude of the second voltage inversion vector V2r Vθ: the phase of the composite voltage vector V Vamp: the amplitude of the composite voltage vector V

As described above, the amplitude Vamp2 of the second voltage vector V2 and the second voltage reversal vector V2r are equal, and the phase Vθ2r of the second voltage vector V2 is the phase Vθ2 of the second voltage vector V2 minus 180.

In FIG. 3, the combined voltage command calculator 203 acquires the dq-axis voltage commands vd1 and vq1 from the first inverter control circuit 201 and converts them into the phase Vθ1 and the amplitude Vamp1 of the first voltage vector V1. Also, the combined voltage command calculator 203 acquires the dq-axis voltage commands vd2 and vq2 from the second inverter control circuit 202 and converts them into the phase Vθ2 and the amplitude Vamp2 of the second voltage vector V2. Furthermore, the combined voltage command calculation unit 203 calculates the phase Vθ2r of the second voltage inversion vector V2r from the phase Vθ2 of the second voltage vector V2.

Then, the composite voltage command calculation unit 203 calculates the phase Vθ and the amplitude Vamp of the composite voltage vector V using the following output equations. The phase Vθ of the combined voltage vector V is calculated by the formula (2.1) when the formula (1.1) holds, and is calculated by the formula (2.2) when the formula (1.2) holds. Also, the amplitude Vamp of the combined voltage vector V is calculated by equation (3).

The output management unit 204 manages the output characteristics and output amounts of the two inverters 60 and 70 based on the phase Vθ and the amplitude Vamp of the composite voltage vector V calculated by the composite voltage command calculation unit 203 . For example, as will be described later, the output management unit 204 calculates the optimum phase of the combined voltage vector V at which the torque of the MG 80 is maximized or the power of the two inverters 60 and 70 approaches the target value. Then, the phase of at least one of the first voltage vector V1 and the second voltage vector V2 is advanced or retarded so that the phase Vθ of the combined voltage vector V becomes the optimum phase.

In this embodiment, based on the combined voltage vector V calculated using the output equations (2.1), (2.2), and (3), the current system output is grasped and the output is maintained. It is possible to selectively use the inverting operation having the output-prioritized characteristic and the non-inverting operation having the efficiency-prioritized characteristic. Therefore, it is possible to give flexibility to the range and types of effects that can be achieved by the two inverters 60 and 70 . In addition, it becomes easy to grasp the degree of margin for the system output limit, and by implementing torque limitation and output limitation based on the combined voltage vector V, the system can be stably operated. The detailed significance of the above output formula will be described later.

Next, the process of deriving equations (2.1), (2.2) and (3) will be described. As shown in FIG. 4, the first voltage vector V1 rotates clockwise from the second voltage vector V2, includes cases where it overlaps with the second voltage reversal vector V2r, and extends counterclockwise from the second voltage reversal vector V2r. shall exist in the domain. In the opposite region, the first voltage vector V1 and the second voltage vector V2 may be interchanged. When Vθ1 and Vθ2r are defined in the ranges of 0≦Vθ1<360 and −180≦Vθ2r<180, the relationship “Vθ1≧Vθ2r” holds.

In FIG. 4, O is the dq coordinate origin, A is the end point of the second voltage vector V2, B is the end point of the first voltage vector V1, C is the end point of the composite voltage vector V, and D is the end point of the second voltage reversal vector V2r. do. If straight line AB is defined as vector Vshift, vector Vshift is parallel to composite voltage vector V (ie, straight line OC). Let OP be a perpendicular drawn from the origin O to the straight line AB.

Let ∠OAB be α (0≦α<180) and ∠OBA be β (0≦β<180) in triangle OAB. Since ∠DOC is the isometric angle of ∠OAB, it is equal to α, and ∠COB is the alternate angle of ∠OBA, so it is equal to β. Therefore, equations (4.1) and (4.2) hold. Also, the formula (4.3) is derived from the formulas (4.1) and (4.2). When Vθ=Vθ1=Vθ2r, α=β=0.

α=Vθ−Vθ2r (4.1)
β=Vθ1−Vθ (4.2)
α+β=Vθ1−Vθ2r (4.3)

Therefore, when the length of the straight line AB is obtained in the triangles OPA and OPB, the output expression (3) of the amplitude Vamp of the composite voltage vector V is derived.

Also, since the equation (5) holds for the length of the straight line OP, the amplitude ratio (Vamp1/Vamp2) between the first voltage vector V1 and the second voltage vector V2 is represented by the equation (6.1). Equation (5) can also be derived from the sine theorem.

Here, when equation (1.1) holds, cos β≠0, that is, β≠90, and equation (6.1) can be rewritten as equation (6.2). On the other hand, when equation (1.2) holds, cos β=0, ie β=90.

Rearrangement of equation (6.2) yields equation (7) for tan β and equation (8) for angle β. Under the premise that 0≦β<180 and β≠90, the angle β is uniquely determined from Equation (8).

When formula (1.1) holds, formula (2.1) is derived from formulas (4.2) and (8). Also, when formula (1.2) holds, formula (2.2) is derived from formula (4.2). As described above, the output equations (2.1) and (2.2) of the phase Vθ of the composite voltage vector V are derived.

As described above, the control unit 200 of the present embodiment determines the phase Vθ and amplitude Vamp of the composite voltage vector V from the phases Vθ1 and Vθ2 and the amplitudes Vamp1 and Vamp2 of the voltage vectors V1 and V2 commanded to the inverters 60 and 70. can be uniquely determined.

The flowchart of FIG. 5 shows the processing according to this embodiment. This processing routine is repeated while the MG80 is being driven. In the description of the flowchart, the symbol "S" means step. In S11, the first inverter control circuit 201 and the second inverter control circuit 202 calculate dq-axis voltage commands vd1 and vq1 to the first inverter 60 and dq-axis voltage commands vd2 and vq2 to the second inverter 70, respectively. . In S12, each dq-axis voltage command is converted into voltage vector phases Vθ1, Vθ2 and amplitudes Vamp1, Vamp2.

The combined voltage command calculation unit 203 calculates the phase Vθ of the combined voltage vector V from the output equations (2.1) and (2.2) in S13, and calculates the combined voltage vector V from the output equation (3) in S14. The amplitude Vamp of V is calculated. The output management unit 204 manages the output characteristics and output amount in S20. The detailed content of S20 will be described later.

Next, the significance of the above output formulas or findings obtained from the above output formulas will be described with reference to FIGS. 6 to 10. FIG. 6(a) and 6(b) show the trajectory of the end point of the composite voltage vector V. FIG. Here, since the starting point of the voltage vector is determined to be the origin, hereinafter, the term "trajectory of the end point of the vector" will be omitted and simply referred to as "trajectory of the vector". Further, the phase difference (Vθ1−Vθ2) between the first voltage vector V1 and the second voltage vector V2 is defined as the “pure phase difference”, whereas the phase difference between the first voltage vector V1 and the second voltage reversal vector V2r is defined as “pure phase difference”. The phase difference (Vθ1−Vθ2r) is defined as “managed phase difference ΔVθ”. The absolute value |ΔVθ| of the controlled phase difference is defined within the range of “0°≦|Δθ|≦180°”. The following embodiments will be described mainly on the premise that "Vθ1≧Vθ2r, ΔVθ≧0".

FIG. 6(a) shows the composite voltage vector V in the case of "reversal operation". In the reversal operation, the controlled phase difference ΔVθ (=Vθ1−Vθ2r) is 0°, and the pure phase difference (Vθ1−Vθ2) is 180°. At this time, the phase V.theta. of the combined voltage vector is "V.theta.=V.theta.1=V.theta.2r". Further, since cos0=1 in Equation (3), as shown in Equation (9), the amplitude Vamp of the combined voltage vector is the amplitude Vamp1 of the first voltage vector V1 and the amplitude Vamp2 of the second voltage inversion vector V2r. become peace.

Thus, the trajectory of the composite voltage vector V in the reversal operation is drawn as a voltage circle with a radius of (Vamp1+Vamp2). Therefore, a rectangular wave voltage equivalent to that of the one-power-supply-one-inverter configuration that makes the most of the power supply voltage is output. Therefore, when priority is given to the output, it is preferable that the control unit 200 calculates the voltage command so as to cause the inverters 60 and 70 to perform the reverse operation. the following,

FIG. 6(b) shows the combined voltage vector V in the case of the "non-inversion operation" in which the managed phase difference ΔVθ is other than 0°, that is, the net phase difference is other than 180°. The amplitude Vamp of the combined voltage vector V is smaller than the voltage sum (Vamp1+Vamp2) of the two power supplies. Therefore, the trajectory of the composite voltage vector V is drawn as a circle inside the maximum voltage circle in FIG. 6(a).

In this case, since the combined voltage that depends on the power supply voltage cannot be increased any further, the control unit 200 advances the voltage phase Vθ by field-weakening control, thereby increasing the d-axis current on the negative side and increasing the torque. Converge on the torque line. Therefore, it is considered necessary to set a phase limit, which is the limit value of the phase Vθ of the composite voltage vector V. FIG. When priority is given to efficiency, it is preferable to operate the phases Vθ1 and Vθ2 of the respective voltage vectors V1 and V2 by non-inverting operation to optimize the phase Vθ of the combined voltage vector V. FIG.

In FIG. 7, the first voltage vector V1 is fixed and the phase Vθ2 of the second voltage vector V2 is set to 360 on the premise that the voltages of the two power sources in the two power source and two inverter configuration, that is, the amplitudes of the voltage command vectors are equal (Vamp1=Vamp2). The trajectory of the composite voltage vector V when the angle is changed is indicated by a solid circle. For comparison, the maximum voltage circle in the one-power-supply-one-inverter configuration is indicated by a dashed circle. The locus of the combined voltage vector V passes through the origin O when the controlled phase difference ΔVθ is 180°, and passes through the point Q on the maximum voltage circle when the controlled phase difference ΔVθ is 0°. Therefore, the amplitude Vamp of the composite voltage vector V changes from 0 to twice the amplitude Vamp1 (=Vamp2) of each of the voltage vectors V1 and V2 according to the change in the voltage phase Vθ.

FIG. 8 shows the relationship between the managed phase difference ΔVθ (=Vθ1−Vθ2r) and the amplitude Vamp of the composite voltage vector V based on Equation (3). FIG. 8 shows not only the case of “Vθ1−Vθ2r≧0” but also the case of “Vθ1−Vθ2r<0”. The amplitude Vamp monotonically decreases as the absolute value |ΔVθ| of the controlled phase difference approaches 0° to 180°. When the absolute value of the controlled phase difference |ΔVθ| is 0°, the amplitude Vamp is maximized at (Vamp1+Vamp2), and when the absolute value of the controlled phase difference |ΔVθ| is 180°, the amplitude Vamp is minimized at (Vamp1−Vamp2). becomes. When the amplitudes Vamp1 and Vamp2 of the voltage vectors V1 and V2 are equal, the amplitude Vamp of the composite voltage vector V is the voltage amplitude Vamp1 (=Vamp2) of each inverter when the absolute value |ΔVθ| is doubled, and becomes 0 when the absolute value |ΔVθ| of the controlled phase difference is 180°.

FIG. 9 shows the relationship between the phase Vθ and the torque trq for each amplitude Vamp of the combined voltage vector V. In FIG. Torque trq is expressed by Equation (10) based on phase Vθ and amplitude Vamp of combined voltage vector V, MG rotation speed ω, pole logarithm p, back electromotive force constant φ, and dq-axis self-inductances Ld and Lq.

From FIG. 9, it can be seen that the smaller the voltage amplitude Vamp, the larger the phase Vθ required for a constant torque output. That is, in order to keep the torque trq constant, it is necessary to advance the voltage phase Vθ corresponding to field weakening control as the voltage amplitude Vamp decreases.

FIG. 10 shows the relationship between the phase V.theta. The phase Vθ of the combined voltage vector V determines the torque trq. A positive torque means power running operation, and a negative torque means regenerative operation. The range from the minimum torque phase Vθmin at which the negative torque is minimum during regeneration to the maximum torque phase Vθmax at which the positive torque is maximum during power running and corresponds to the MG maximum performance point is the phase control range. The phase Vθ of the composite voltage vector V can be set only within the phase control range, and when the range is exceeded, the control diverges. FIG. 10 makes it easy to grasp the degree of margin with respect to the system output limit, and by implementing torque limitation and output limitation based on the combined voltage vector V, the system can be stably operated.

As described above, in this embodiment, the output characteristics and output amount of the combined voltage vector V are managed using the output equations (2.1) and (2.2), and the inverting operation and the non-inverting operation are performed according to the operation request. can be used properly, and the range and types of effects that can be achieved by the two inverters 60 and 70 can be given a degree of freedom. Further, Japanese Patent Application Laid-Open No. 2017-175700 discloses a voltage multi-level technology that combines the operations of two three-phase inverters to switch winding end voltages of five levels. In this embodiment, by freely manipulating the operations of the two inverters 60 and 70, voltage multi-leveling can be easily realized.

Next, a specific method of managing the output characteristics and output amount by the output management unit 204 will be described for each embodiment. The output management unit 204 controls the phase Vθ of the composite voltage vector V to the optimum phase, especially in the high output region. Also, the output management unit 204 optimizes the managed phase difference ΔVθ within a limited range. In the following description of the embodiments, the managed phase difference ΔVθ is simply referred to as "phase difference ΔVθ". Further, "phase Vθ1 of first voltage vector V1" is "first voltage phase Vθ1", "phase Vθ2 of second voltage vector V2" is "second voltage phase Vθ2", and "phase Vθ2r of second voltage reversal vector V2r" is ” will be referred to as “second voltage inversion phase Vθ2r”. Also, "phase Vθ of synthesized voltage vector V" is referred to as "synthesized voltage phase Vθ", and "amplitude Vamp of synthesized voltage vector V" is referred to as "synthesized voltage amplitude Vamp".

(First embodiment)
A first embodiment will be described with reference to FIGS. 11 to 17. FIG. FIG. 11 shows a configuration example of the control unit 200. As shown in FIG. In the control unit 200, one of the two inverter control circuits 201 and 202 manages the torque of the MG80 and the other manages the electric power. In the configuration example of FIG. 11, the first inverter control circuit 201 manages torque by feedback control for the torque command trq ^* . The second inverter control circuit 202 manages power based on the target power distribution ratio of the two inverters 60 and 70 or the target power amount of the second inverter 70 . Since the two inverter control circuits 201 and 202 share the management, the power supply states of the two power supplies 11 and 12 can be appropriately managed while the MG 80 outputs torque according to the torque command trq ^* .

FIG. 11 mainly shows the configuration related to the calculation of the phases Vθ1 and Vθ2 of the voltage vectors output to the two inverters 60 and 70, and omits the configuration related to the calculation of the voltage amplitudes Vamp1 and Vamp2. Further, the first inverter control circuit 201 and the second inverter control circuit 202 mutually communicate information by serial communication.

The first inverter control circuit 201 receives a torque command trq ^* from, for example, a torque command calculator of a host ECU. A torque subtractor 32 calculates a torque deviation between the torque command trq ^* and the actual torque trq_real. The feedback controller 33 PI-operates the first voltage phase Vθ1 so that the torque deviation approaches zero. The actual torque trq_real to be fed back may be a directly detected torque value or an estimated torque value estimated based on the current detected by the current sensor. The switching operation of the first inverter 60 is controlled based on the first voltage phase Vθ1 calculated by the feedback controller 33, and the first voltage phase Vθ1 is transmitted to the phase calculator 36 of the second inverter control circuit 202.

The power control unit 50 of the second inverter control circuit 202 controls the actual power distribution ratio of the two inverters 60 and 70 to follow the target power distribution ratio, or the actual power amount of the second inverter 70 to the target power amount. A phase difference ΔVθ (=Vθ1−Vθ2r) is calculated so as to follow . Based on the first voltage phase Vθ1 and the phase difference ΔVθ, the phase calculator 36 calculates the second voltage phase Vθ2 using Equation (11), and outputs the second voltage phase Vθ2 to the second inverter 70 . Alternatively, the phase calculator 36 may output the second voltage inversion phase Vθ2r, and the second inverter 70 may perform switching operation based on the second voltage inversion phase Vθ2r.
Vθ2=Vθ2r+180=Vθ1−ΔVθ+180 (11)

Thus, the first inverter control circuit 201 manages the torque of the MG 80 by feedback control of the actual torque trq_real with respect to the torque command trq ^* , and the second inverter control circuit 202 supplies the torque to the two inverters 60 and 70. Manage the power distribution ratio or amount of power. The control parameter of the first inverter control circuit 201 on the torque management side is the first voltage phase Vθ1, and the control parameter of the second inverter control circuit 202 on the power management side is the phase difference ΔVθ. Note that the first inverter control circuit 201 and the second inverter control circuit 202 may be interchanged.

Next, the derivation of the optimum phase according to this embodiment will be described in comparison with the "one power supply one inverter" method using one power supply and one inverter. 9 and 10, the upper and lower limits of the voltage phase Vθ must be restricted. This is the same in the one-power-supply one-inverter system, but in the two-power-supply two-inverter system, there are various combination patterns of the two voltage vectors V1 and V2, which causes difficulties.

FIG. 12(a) shows a phase limiter map that defines the relationship between the voltage amplitude Vamp, the rotational speed ω, and the limit phase Vθlim in the one-power-supply one-inverter system. A parameter limited by the phase limiter map is the voltage phase Vθ itself, which is a control parameter. In the one power supply one inverter system, the voltage amplitude Vamp is basically constant as long as the input voltage VH of the power supply does not fluctuate. When the voltage amplitude Vamp is constant, the higher the rotational speed ω, the lower the limit phase Vθlim is set.

The initial limit phase Vθlim_st at the start of control is defined by a solid line map, and the limit phase Vθlim_st at the initial rotation speed ω_st is represented by black circles. After that, when the voltage amplitude Vamp decreases from large to small, the limit phase Vθlim is defined by the dashed map. That is, the limit phase Vθlim is controlled to change from the black dot to the white dot by decreasing the voltage amplitude Vamp or increasing the rotational speed ω during the limit.

FIG. 12(b) shows a phase limiter map in the two-power-supply two-inverter system. The map itself is similar to the one-power-supply one-inverter formula, and the parameter limited based on the voltage amplitude Vamp and the rotational speed ω being limited using the phase limiter map is the synthesized voltage phase Vθ. On the other hand, the control parameters of the control unit 200 of the two-power-supply two-inverter system are the first voltage phase Vθ1 and the phase difference ΔVθ. That is, the first voltage phase V.theta.1 and the phase difference .DELTA.V.theta., which are control parameters in the two-power-supply two-inverter system, are not directly limited.

Assuming "ΔVθ≠0, Vθ2r<Vθ1", the first voltage phase Vθ1, the second voltage inversion phase Vθ2r, and the composite voltage phase Vθ have a relationship of "Vθ2r<Vθ<Vθ1". In FIG. 12B, the initial limited phase Vθ1lim of the first voltage phase is represented by black squares, and the second voltage inversion phase Vθ2r obtained by subtracting the phase difference ΔVθ from the limited phase Vθ1lim of the first voltage phase is represented by black triangles. Therefore, in the first inverter control circuit 201 on the torque management side, it is necessary to reflect the change in the limited phase Vθlim of the composite voltage phase Vθ in the limited phase Vθ1lim of the first voltage phase.

FIG. 13 shows the relationship between phase and torque. As shown in FIG. 10, the positive torque becomes maximum at the maximum torque phase V.theta.max during power running, and when the maximum torque phase V.theta.max is exceeded, the phase control range is exceeded and the control breaks down. Therefore, a phase slightly smaller than the maximum torque phase Vθmax, that is, a phase smaller by a margin δ is set as the limit phase Vθlim of the composite voltage so that the maximum torque phase Vθmax is not exceeded when the phase Vθ of the composite voltage is increased. be done. Here, depending on the value of the phase difference ΔVθ, the first voltage phase Vθ1 may exceed the maximum torque phase Vθmax as shown in FIG.

At the start of control, on the torque curve indicated by the solid line, the black dot before the maximum torque phase Vθmax_st is set as the initial limit phase Vθlim_st of the composite voltage. Also, the black square points are set as the limit phase Vθ1lim_st of the first voltage phase. After that, due to the decrease in the combined voltage amplitude Vamp and the increase in the rotation speed ω, the point of the white circle on the torque curve indicated by the dashed line is set as the new combined voltage limit phase Vθlim. Also, reflecting this change, the white square point is set as the new limit phase Vθ1lim of the first voltage phase.

As a result, in the first inverter control circuit 201 on the torque management side, the maximum torque can be realized while avoiding control failure. Specifically, the composite voltage limiting phase Vθlim is calculated from the composite voltage amplitude Vamp and the rotation speed ω by the map of FIG. 12(b). Alternatively, the simultaneous equations of the combined voltage vector formulas of formulas (2.1), (2.2) and (3) and the torque formula of formula (10) may be solved directly.

The limited phase Vθ1lim of the first voltage phase is calculated by the formula (12.1) under the conditions of the formula (1.1) based on the combined voltage vector formula of the formulas (2.1) and (2.2). Under the condition (1.2), it is calculated by the formula (12.2). (Vθ1−V2θr) in equation (12.1) can be rewritten as the phase difference ΔVθ.

The second voltage inversion phase Vθ2r in the second inverter control circuit 202 on the power management side is controlled using the first voltage phase Vθ1 and the phase difference ΔVθ as control parameters. Note that the change in the second voltage inversion phase Vθ2r on the power management side is sufficiently slow with respect to the first voltage phase Vθ1 on the torque management side. Therefore, by using the combined voltage vector formula, the limit phase Vθ1lim of the first voltage phase can be calculated regardless of the control mode on the power management side. With the above control, at least the combined voltage phase V.theta. is prevented from exceeding the limit phase V.theta.lim, and control failure can be prevented.

When the absolute value of the phase difference |ΔVθ| approaches 180°, the combined voltage amplitude Vamp becomes smaller as shown in FIG. 8, so the maximum torque of MG 80 decreases. Hereinafter, "prioritizing torque" means giving priority to maximizing the torque of the MG80, and "prioritizing power" means giving priority to bringing the power of the two inverters closer to the target value. Meaning. Which of torque and electric power has priority may be uniformly determined in the initial stage. Alternatively, it may be selected each time according to the temperature, SOC, charge/discharge power amount (Win/Wout) of the batteries that constitute the two power sources 11 and 12, vehicle state such as vehicle speed, accelerator opening, and the like.

In the present embodiment, the phase difference ΔVθ is controlled depending on whether torque or electric power is given priority. Specifically, when priority is given to torque, the output management unit 204 sets the phase difference upper limit ΔVθlim is set to 0. On the other hand, when power is prioritized, the output management unit 204 sets the value of the phase difference ΔVθ at the time of the initial limitation, that is, when the combined voltage phase Vθ exceeds the limit phase Vθlim for the first time. This makes it possible to control the phase difference ΔVθ according to needs. Further, even if the recognized voltage deviates due to a communication delay during torque or rotational speed transients, it is possible to prevent the combined voltage phase Vθ from exceeding the limit phase Vθlim.

Next, referring to the flow charts of FIGS. 14 and 15 for the optimum phase control according to the first embodiment. S11 to S14 in FIG. 14 are the same as in FIG. 5, and S20 of "output characteristic, output amount management" in FIG. 5 is developed in detail after S21. In S21, the output management unit 204 calculates the limit phase Vθlim of the composite voltage vector V from the composite voltage amplitude Vamp and the rotation speed ω. In S22, the limit phase Vθ1lim of the first voltage phase Vθ1 is calculated by equations (12.1) and (12.2). Then, in S23, the first voltage phase Vθ1 is limited to the limit phase Vθ1lim or less.

Preferably, after S21, S24 to S26 are executed in parallel with S22 and S23. In S24, it is determined whether or not the composite voltage phase Vθ exceeds the limit phase Vθlim. If the composite voltage phase Vθ exceeds the limit phase Vθlim, YES is determined in S24, and the process proceeds to S25. In S25, the output management unit 204 calculates the upper limit ΔVθlim of the phase difference ΔVθ.

As shown in FIG. 15, the calculated phase difference upper limit ΔVθlim differs depending on whether priority is given to torque or electric power. If torque is prioritized over electric power, YES is determined in S251, and ΔVθlim=0 is calculated in S252, that is, the first voltage phase Vθ1 and the second voltage inversion phase Vθ2r are calculated to be the same phase. On the other hand, if power is prioritized over torque, NO is determined in S251, and the phase difference upper limit ΔVθlim is calculated to the value at the time of the initial limitation. That is, the value of the phase difference ΔVθ when the combined voltage phase Vθ exceeds the limit phase Vθlim for the first time is fixed as the phase difference upper limit ΔVθlim.

Returning to FIG. 14, in S26, the phase difference ΔVθ is limited to the upper limit ΔVθlim or less. When the second voltage inversion phase Vθ2r is larger than the first voltage phase Vθ1, the phase difference ΔVθ between S25 and S26 may be replaced with the "absolute value of phase difference |ΔVθ|". If the composite voltage phase Vθ is equal to or less than the limit phase Vθlim in S24, it is determined as NO, and S25 and S26 are skipped. The process of FIG. 14 is repeatedly executed while the MG80 is being driven. The combined voltage phase Vθ becomes equal to or less than the limit phase Vθlim, and the processes of S25 and S26 are repeated until it is determined NO in S24.

Next, an operation example of the first embodiment will be described with reference to the time charts of FIGS. 16 and 17. FIG. FIG. 16 shows an example of operation when priority is given to torque, and FIG. 17 shows an example of operation when priority is given to power. At the top of each figure, the torque command trq ^* is indicated by a dashed line, and the actual torque trq_real is indicated by a solid line. In the second stage, the phase difference command ΔVθcom is indicated by a broken line, the phase difference upper limit ΔVθlim is indicated by a long broken line, and the phase difference after limitation ΔVθ is indicated by a solid line. In the third row, the sum of the input voltages (VH1+VH2) is indicated by a dashed line, and the composite voltage amplitude Vamp is indicated by a solid line. The solid line indicates the phase limit flag on the fourth level. At the bottom, the composite voltage phase Vθ is indicated by a solid line, the composite voltage limit phase Vθlim is indicated by a long dashed line, the first voltage phase Vθ1 is indicated by a one-dot chain line, and the second voltage inversion phase Vθ2r is indicated by a two-dot chain line.

First, with reference to FIG. 16, an operation example when torque is prioritized will be described. In FIG. 16, the phase difference command ΔVθcom is a constant value greater than 0, and the torque command trq ^* increases with time and then decreases. Also, the phase difference upper limit ΔVθlim is set to zero. Before time ta1, the combined voltage phase Vθ is smaller than the limit phase Vθlim, the phase limit flag is OFF, and the phase difference command ΔVθcom is not limited. The first voltage phase Vθ1, the second voltage inversion phase Vθ2r, and the composite voltage phase Vθ increase almost parallel with time. At this time, the combined voltage amplitude Vamp is smaller than the sum of the input voltages (VH1+VH2). Also, the actual torque trq_real matches the torque command trq ^* .

As the torque command trq ^* gradually increases, the combined voltage phase Vθ also gradually increases and exceeds the limit phase Vθlim at time ta1. Triggered by this, the phase limit flag is turned ON, and the limitation on the phase difference command ΔVθcom is started. At this time, a sudden change in the phase causes disturbance of the characteristics of the rectangular wave control, so the phase is gradually changed so as to have a slope with respect to time. As a result, the post-limited phase difference ΔVθ decreases toward 0, which is the phase difference upper limit ΔVθlim, during the period I from time ta1 to time ta2.

When the post-limiting phase difference ΔVθ becomes 0 at time ta2, the combined voltage amplitude Vamp matches the sum of the input voltages (VH1+VH2). After that, in period II from time ta2 to time ta3, the post-limiting phase difference ΔVθ is maintained at 0, and the state where the combined voltage amplitude Vamp is constant continues. Also, the actual torque trq_real is a constant value smaller than the torque command trq ^* . On the other hand, the torque command trq ^* changes from increasing to decreasing during period II.

When the composite voltage phase Vθ begins to decrease at time ta3, the phase limit flag is turned OFF, and the restriction on the phase difference command ΔVθcom is released. In order to avoid disturbance of the rectangular wave control characteristics due to a sudden phase change, the post-limiting phase difference ΔVθ increases from 0 toward the phase difference command ΔVθcom during the period from time ta3 to time ta4. Along with this, the combined voltage amplitude Vamp decreases from the sum of the input voltages (VH1+VH2). At time ta4, the post-limiting phase difference ΔVθ returns to the phase difference command ΔVθcom. After time ta4, the state returns to the same non-restricted state as before time ta1.

Here, as a comparative example corresponding to the one-power-supply one-inverter system, when the phase difference upper limit ΔVθlim is not set to 0, as indicated by the thin two-dot chain line in the uppermost stage, the actual torque trq_real is such that the phase limit flag is turned on at time ta1. is limited by the value when That is, in period I, the actual torque trq_real falls below the torque command trq ^* .

In contrast, in the first embodiment, when the phase limit flag is turned ON, the phase difference upper limit ΔVθlim is set to 0, so that the actual torque trq_real in period I can realize the torque command trq ^* . That is, the period during which the actual torque trq_real cannot achieve the torque command trq ^* is shortened to period II only. Therefore, as an effect of the first embodiment, the torque difference Δtrq_eff in FIG. 16 corresponds to the extra torque that can be output.

Next, with reference to FIG. 17, an operation example when power is given priority will be described. In FIG. 17, the torque command trq ^* is constant, and the phase difference command ΔVθcom increases from 0 over time, then decreases and returns to 0. Phase difference upper limit ΔVθlim is set to the value of phase difference command ΔVθcom at time tb1. Real torque trq_real always matches torque command trq ^* . At the initial time tb0, the phase difference command ΔVθcom is 0, and the combined voltage amplitude Vamp is equal to the sum of the input voltages (VH1+VH2).

From time tb0 to time tb1, phase difference command ΔVθcom increases, and composite voltage amplitude Vamp decreases from the sum of input voltages (VH1+VH2). The synthesized voltage phase Vθ is smaller than the limit phase Vθlim, the phase limit flag is OFF, and the phase difference command ΔVθcom is not limited. Between time tb0 and time tb1, as the phase difference command ΔVθcom increases, the difference between the first voltage phase Vθ1 and the second voltage inversion phase Vθ2r widens, and the composite voltage phase Vθ gradually increases. On the other hand, the limit phase Vθlim gradually decreases.

When the synthesized voltage phase Vθ exceeds the limit phase Vθlim at time tb1, the phase limit flag is turned ON with this as a trigger. Then, the value of the phase difference command ΔVθcom at this time is set as the phase difference upper limit ΔVθlim, and the limitation on the phase difference command ΔVθcom is started. After that, from time tb1 to time tb2, the post-limiting phase difference ΔVθ is limited to the phase difference upper limit ΔVθlim, and the first voltage phase Vθ1, the second voltage inversion phase Vθ2r, and the composite voltage phase Vθ are kept constant. . On the other hand, phase difference command ΔVθcom changes from increasing to decreasing from time tb1 to time tb2.

At time tb2, when the phase difference command ΔVθcom falls below the phase difference upper limit ΔVθlim, the combined voltage phase Vθ falls below the limit phase Vθlim and the phase limit flag is turned OFF. After that, substantially symmetrically with the operation before time tb1, as the phase difference command ΔVθcom decreases, the difference between the first voltage phase Vθ1 and the second voltage inversion phase Vθ2r narrows, and the combined voltage phase Vθ gradually decreases. On the other hand, the limited phase Vθlim gradually increases. As described above, in the first embodiment, it is possible to realize the maximum output within the limit while preventing control failure at the time of the output limit.

(Modification)
A modification of the first embodiment will be described. In S24 of FIG. 14, YES is determined when the combined voltage phase Vθ exceeds the limit phase Vθlim. YES may be determined when the As the limit phase here, the limit phase Vθlim of the composite voltage may be commonly used.

In this case, assuming that the phase difference ΔVθ is 0, the sum (VH1+VH2) of the input voltages VH1 and VH2 of the two power supplies may be used as the voltage amplitude of the phase limiter map for calculating the limit phase Vθlim. As a result, the phase difference limitation can be easily realized without adding the calculation of the combined voltage vector to the algorithm of the one-power-supply one-inverter system. However, if the absolute value of the phase difference |ΔVθ|

(Second embodiment)
A second embodiment will be described with reference to FIGS. 18 to 20. FIG. As in the first embodiment, also in the second embodiment, it is assumed that the first inverter control circuit 201 manages the torque of the MG 80 and the second inverter control circuit 202 manages power. In the two-power-supply two-inverter system, achieving the target power distribution ratio or the target power amount and achieving the MG maximum torque in the high output region are in conflict with each other. Therefore, the technical idea of the second embodiment is to allow the maximum power distribution ratio or power amount within the range in which the torque command trq ^* can be realized.

FIG. 18 shows a vector diagram similar to FIG. 4 for explaining the control concept of the second embodiment. The relationship between the amplitude Vamp1 of the first voltage vector V1, the amplitude Vamp2 of the second voltage vector V1, and the amplitude Vamp of the composite voltage vector V is represented by Equation (13), which is different from Equation (3). Equation (13) is derived by substituting “∠OBC=180−ΔVθ” in the equation of the law of cosines for triangle OBC.

From equation (13), it can be seen that when the phase difference ΔVθ is 0°, cos(ΔVθ) is 1 and the synthesized voltage amplitude Vamp is maximum, and the synthesized voltage amplitude Vamp decreases as the phase difference ΔVθ approaches 180°. That is, it is considered that the phase difference ΔVθ, which is a control parameter on the power management side, dominates the influence on the combined voltage amplitude Vamp. Therefore, in the second embodiment, the second inverter control circuit 202 on the power management side performs control so as to minimize the phase difference ΔVθ, thereby preventing the maximum torque from decreasing.

A specific control configuration will be described with reference to FIG. The controlled object of the second embodiment is only when the voltage utilization rate of the combined voltage vector V is maximum, that is, when both the first voltage command and the second voltage command are rectangular wave voltages with no degree of freedom in amplitude. In the first embodiment, the first voltage phase Vθ1 and the phase difference ΔVθ are used as control parameters, whereas in the second embodiment, the phase difference ΔVθ is used as the control parameters.

Here, too, the description will be made on the assumption that the first voltage phase Vθ1 is equal to or greater than the second voltage inversion phase Vθ2r and the phase difference ΔVθ is equal to or greater than 0. If there is a possibility that the second voltage inversion phase Vθ2r is greater than the first voltage phase Vθ1, the phase difference ΔVθ can be interpreted by replacing it with the "absolute value of the phase difference |ΔVθ|".

FIG. 19 shows a map that defines the relationship between the combined voltage amplitude Vamp, the rotational speed ω, and the torque trq. The solid line indicates the maximum torque curve TCX under the condition that the voltage amplitude Vamp is maximized, that is, the phase difference ΔVθ is 0 and the voltage amplitude Vamp is the sum of the input voltages VH1 and VH2 of the two power supplies (VH1+VH2). A maximum torque curve TCX represents the allowable maximum torque that the MG 80 can output, as in the one-power-supply one-inverter system. The maximum torque trq_max at the current rotational speed ωp on the maximum torque curve TCX is represented by black dots.

When the rotation speed ωp is constant and the phase difference ΔVθ increases from 0, the combined voltage amplitude Vamp decreases, and the current torque curve TCp is represented by the dashed line. A limit torque curve TClim in which the maximum torque trq_max at the rotational speed ωp matches the torque command trq ^* is indicated by a chain double-dashed line. The phase difference ΔVθ corresponding to the limit torque curve TClim is set as the phase difference upper limit ΔVθlim. The torque command trq ^* at the rotation speed ωp is represented by a rhombus, and the current maximum torque trq_max is represented by a white circle.

In FIG. 19, the maximum torque on the current torque curve TCp is below the torque command trq ^* . That is, the current phase difference ΔVθ exceeds the phase difference upper limit ΔVθlim. In this case, the current phase difference ΔVθ is limited to the phase difference upper limit ΔVθlim. Thereby, the maximum torque trq_max at the current combined voltage amplitude Vamp and the rotation speed ωp can be matched with the torque command trq ^* . In the above description, it is assumed that the torque is positive during power running, but if the expression includes regeneration during which the torque is negative, the absolute value of the maximum torque trq_max is smaller than the absolute value of the torque command trq ^* . , is controlled to limit the phase difference ΔVθ to the phase difference upper limit ΔVθlim.

This is because the power calculation on the power management side is slow in the control of the second embodiment. The order of operations may be partially changed, but it is estimated that the effect is not large. Moreover, since the limiting parameter is different from that of the phase limiter of the first embodiment, there is no control interference and compatibility is possible.

Next, an operation example of the second embodiment will be described with reference to the time chart of FIG. At the top of FIG. 20, the torque command trq ^* is indicated by a dashed line, and the actual torque trq_real is indicated by a solid line. A long dashed line indicates the maximum torque trq_max on the torque curve based on the combined voltage amplitude Vamp and the rotation speed ω. In the second stage, the phase difference command ΔVθcom is indicated by a broken line, the phase difference upper limit ΔVθlim is indicated by a long broken line, and the phase difference after limitation ΔVθ is indicated by a solid line. In the third row, the sum of the input voltages (VH1+VH2) is indicated by a dashed line, and the composite voltage amplitude Vamp is indicated by a solid line. The power (or phase difference) limit flag is indicated by a solid line on the fourth level. At the bottom, the first voltage phase Vθ1 is indicated by a one-dot chain line, and the second voltage inversion phase Vθ2r is indicated by a two-dot chain line.

In FIG. 20, the torque command trq ^* is constant, and the phase difference command ΔVθcom increases from 0 over time, then decreases and returns to 0. Phase difference upper limit ΔVθlim is set to the value of phase difference command ΔVθcom at time tc1. That is, the phase difference upper limit ΔVθlim corresponding to the limit torque curve TClim in the map of FIG. 19 is set. Real torque trq_real always matches torque command trq ^* . At the initial time tc0, the phase difference command ΔVθcom is 0, and the combined voltage amplitude Vamp is equal to the sum of the input voltages (VH1+VH2).

From time tc0 to time tc1, the phase difference command ΔVθcom increases under the condition that the phase difference upper limit ΔVθlim is less than the power limit flag is OFF. Along with this, the combined voltage amplitude Vamp decreases from the sum of the input voltages (VH1+VH2), and the maximum torque trq_max based on the combined voltage amplitude Vamp decreases in a range exceeding the torque command trq ^* . Between time tc0 and time tc1, the difference between the first voltage phase Vθ1 and the second voltage inversion phase Vθ2r gradually increases as the phase difference command ΔVθcom increases.

At time tc1, when the maximum torque trq_max based on the combined voltage amplitude Vamp drops to the torque command trq ^* , the electric power limit flag is turned ON. Then, the value of the phase difference command ΔVθcom at this time is set as the phase difference upper limit ΔVθlim, and the limitation on the phase difference command ΔVθcom is started. After that, from time tc1 to time tc2, the post-limiting phase difference ΔVθ is limited to the phase difference upper limit ΔVθlim, and the first voltage phase Vθ1 and the second voltage inversion phase Vθ2r are kept constant. On the other hand, phase difference command ΔVθcom changes from increasing to decreasing from time tc1 to time tc2.

At time tc2, the phase difference command ΔVθcom falls below the phase difference upper limit ΔVθlim, and at the same time, the maximum torque trq_max based on the combined voltage amplitude Vamp exceeds the torque command trq ^* , turning OFF the phase limit flag. After that, substantially symmetrically with the operation before time tc1, the difference between the first voltage phase Vθ1 and the second voltage inversion phase Vθ2r gradually decreases as the phase difference command ΔVθcom decreases. As described above, the second embodiment can also achieve maximum output within limits.

(Other embodiments)
(a) In the output formula of the above embodiment, the phase difference (Vθ1−Vθ2r) between the first voltage vector V1 and the second voltage reversal vector V2r is used. Conversely, the first voltage reversal vector V1r may be defined and the phase difference (Vθ2−Vθ1r) between the second voltage vector V2 and the first reversal voltage vector V1r may be used. In addition, the distinction between the configurations regarding the first inverter 60 and the second inverter 70 is for convenience, and may be replaced as appropriate.

(b) The first inverter control circuit 201 and the second inverter control circuit 202 in the first embodiment are exchanged, and instead of the first voltage phase Vθ1, the second voltage inversion phase Vθ2r is limited to the limit phase or less of the voltage vector. You may Also, both the first voltage phase Vθ1 and the second voltage inversion phase Vθ2r may be limited to the limit phases of the respective voltage vectors or less.

(c) The two inverters 60 and 70 are not limited to being supplied with power from two independent power supplies, but may be supplied with power from one common power supply. Moreover, in the configuration using two independent power sources, each power source is not limited to a configuration in which both power sources are secondary batteries represented by batteries or capacitors. For example, one power source may be a secondary battery, and the other power source may be configured by a fuel cell or a generator.

(d) The number of phases of the open windings of the electric motor is not limited to three, and may be four or more. Alternatively, a configuration in which two-phase open windings are bridge-connected may be used.

(e) The 2-power source 2-inverter type electric motor drive device is used in pure electric vehicles such as electric vehicles and fuel cell vehicles, PHVs (plug-in hybrids), range extenders and other hybrid powertrains that are rich in electricity, and furthermore, It is applied to light electric vehicles such as 12-48V ISG (Integrated Starter Generator). This technology is based on a voltage-type circuit topology that can be applied to applications that achieve high output with high efficiency without using a booster circuit using a reactor, which is an example of conventional technology. It is suitable for applications that require high output even in a region where it is thermally difficult to achieve.

As described above, the present invention is by no means limited to the above embodiments, and can be embodied in various forms without departing from the spirit of the present invention.

100... MG control device (motor drive device),
200... control section,
201... First inverter control circuit,
202... second inverter control circuit,
203 ... synthetic voltage command calculation unit,
60 ... first inverter, 61 to 66 ... first switching element,
70 ... second inverter, 71 to 76 ... second switching element,
80 ... MG (motor generator, electric motor),
81, 82, 83... Windings.

Claims (7)

A motor driving device for controlling the driving of a motor (80) using two inverters and having two or more phase windings (81, 82, 83) whose end points are open,
a first inverter (60) having a plurality of first switching elements (61 to 66) provided corresponding to each phase of the winding and connected to one end of the winding;
a second inverter (70) having a plurality of second switching elements (71 to 76) provided corresponding to each phase of the winding and connected to the other end of the winding;
A first inverter control circuit (201) for generating a first voltage command , which is an output voltage command to the first inverter, based on the torque command; and generating a second voltage command, which is an output voltage command for the second inverter. a second inverter control circuit (202), and the phase and amplitude of a first voltage command vector on dq coordinates corresponding to said first voltage command and a second voltage command vector on dq coordinates corresponding to said second voltage command a composite voltage command calculation unit (203) for uniquely calculating the phase and amplitude of the composite voltage command vector on the dq coordinates corresponding to the composite voltage command output by the two inverters based on the first voltage Based on the first voltage command vector and the second voltage command vector, including the case where the pure phase difference, which is the phase difference between the command vector and the second voltage command vector, is a value other than 180°, the composite voltage command a control unit (200) for determining a vector ;
with
The phase of the voltage command vector is defined to increase in the counterclockwise direction on the dq coordinate with reference to the positive direction of the q axis,
The phase of the first voltage command vector is Vθ1, the amplitude is Vamp1,
Vθ2r is the phase of the second voltage inversion vector that is symmetrical with respect to the second voltage command vector, Vamp2 is the amplitude,
Denoting the phase of the combined voltage command vector as Vθ and the amplitude as Vamp,
The combined voltage command calculation unit includes:
The phase of the combined voltage command vector is calculated by formula (2.1) when formula (1.1) holds, and is calculated by formula (2.2) when formula (1.2) holds. ,

An electric motor driving device for calculating the amplitude of the combined voltage command vector by Equation (3) .

The control unit further comprises an output management unit (204) that manages the output characteristics and output amounts of the two inverters based on the phase and amplitude of the composite voltage command vector calculated by the composite voltage command calculation unit,
The output management unit
The first voltage command vector or the second 2. The motor drive device according to claim 1 , wherein the phase of at least one of the voltage command vectors is adjusted. The output management unit
A limit phase (Vθlim) of the composite voltage command vector is calculated based on the amplitude of the composite voltage command vector and the rotation speed of the electric motor, and the phase of the composite voltage command vector becomes equal to or less than the limit phase of the composite voltage command vector. 3. The motor driving device according to claim 2 , wherein the phase of at least one of the first voltage command vector and the second voltage command vector is limited to a limit phase (Vθ1lim) or less of the voltage command vector. The output management unit
limiting the phase of either the first voltage command vector or the second voltage command vector to a limit phase of the voltage command vector or less;
When the phase of the combined voltage command vector exceeds the limit phase of the combined voltage command vector, the absolute value of a controlled phase difference (ΔVθ), which is the phase difference between the first voltage command vector and the second voltage reversal vector. 4. The electric motor driving device according to claim 3 , wherein (0°≦|ΔVθ|≦180°) is limited to an upper limit (ΔVθlim) or less. Either the first inverter control circuit or the second inverter control circuit manages the torque of the electric motor by feedback control of the actual torque (trq_real) with respect to the torque command (trq ^* ), and the first inverter control circuit or In the configuration of the control unit, the other of the second inverter control circuits manages the power distribution ratio or the amount of power supplied to the two inverters,
The output management unit
If priority is given to maximizing the torque of the electric motor, setting the upper limit of the controlled phase difference to 0,
If priority is given to bringing the power of the two inverters closer to the target value, the upper limit of the management phase difference is set to the management phase when the phase of the combined voltage command vector exceeds the limit phase of the combined voltage command vector for the first time. 5. The motor driving device according to claim 4 , wherein the phase difference value is set. The output management unit
estimating the maximum torque (trq_max) that the electric motor can output based on the amplitude of the combined voltage command vector and the rotation speed of the electric motor;
The absolute value (0°≦|ΔVθ) of the controlled phase difference (ΔVθ), which is the phase difference between the first voltage command vector and the second voltage reversal vector, so that the maximum torque becomes equal to or greater than the torque command (trq ^* ) |≦180°) is limited to an upper limit (ΔVθlim) or less . A program for a motor drive device that uses two inverters and controls the drive of a motor (80) having two or more phase windings (81, 82, 83) whose end points are open,
The electric motor drive device
a first inverter (60) having a plurality of first switching elements (61 to 66) provided corresponding to each phase of the winding and connected to one end of the winding;
a second inverter (70) having a plurality of second switching elements (71 to 76) provided corresponding to each phase of the winding and connected to the other end of the winding;
Based on the torque command, a first inverter control circuit (201) that generates a first voltage command that is an output voltage command to the first inverter, and a second voltage command that is an output voltage command to the second inverter. a control unit (200) having a second inverter control circuit (202) that generates
with
For the control unit,
The two inverters output based on the phase and amplitude of the first voltage command vector on the dq coordinates corresponding to the first voltage command and the second voltage command vector on the dq coordinates corresponding to the second voltage command. The phase and amplitude of the composite voltage command vector on the dq coordinates corresponding to the composite voltage command are uniquely calculated, and the pure phase difference, which is the phase difference between the first voltage command vector and the second voltage command vector, is other than 180° Operate to determine the combined voltage command vector based on the first voltage command vector and the second voltage command vector, including the value of
Furthermore, the phase of the voltage command vector is defined to increase in the counterclockwise direction on the dq coordinates with reference to the positive direction of the q axis,
The phase of the first voltage command vector is Vθ1, the amplitude is Vamp1,
Vθ2r is the phase of the second voltage inversion vector that is symmetrical with respect to the second voltage command vector, Vamp2 is the amplitude,
Denoting the phase of the combined voltage command vector as Vθ and the amplitude as Vamp,
The phase of the combined voltage command vector is calculated by formula (2.1) when formula (1.1) holds, and is calculated by formula (2.2) when formula (1.2) holds. ,

A program that operates to calculate the amplitude of the combined voltage command vector according to equation (3).

Images