JP2017063518A - Rotary electric machine system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve a rotary electric machine system capable of saving energy, increasing an amount of power generation, reducing torque and output pulsation, and reducing vibration and noise.SOLUTION: The rotary electric machine system includes: power conversion circuits 30a to 30i capable of changing a magnitude and phase of a current flowing through each of a plurality of coils; a stator 10 having windings formed of a plurality of coils; and a rotor 20 having a coil, a permanent magnet, or a magnetic salient pole iron core. The power conversion circuits 30a to 30i can individually change the magnitude and the phase of the current flowing through each of the plurality of coils.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a rotating electrical machine system of an individual coil current control system. For example, it can be used for hybrid vehicles, electric vehicles, railways in transportation systems, thermal power, hydropower, wind power, ocean current generators in energy systems, home appliances such as elevators and air conditioners in social systems and home appliances, motor driven industrial devices The present invention also relates to a rotating electrical machine system that can also be used.

  Currently, it is said that approximately 50% of the world's total energy consumption comes from motors. Therefore, there is a demand for energy saving and high efficiency of motors and drive systems.

  Conventionally, in a rotating electrical machine such as a motor or a generator, a three-phase coil through which a three-phase alternating current flows is provided in a stator and a coil for each phase is connected to form a three-phase winding. In a rotating electric machine having this three-phase winding, an external three-phase power converter is connected to the terminals of each of the three-phase windings for energy conversion, and the rotor is rotated to extract the rotational force. The electric power output from the stator side by the rotation is taken out.

  In such a three-phase rotating electric machine, in order to reduce torque pulsation and output pulsation, the number and arrangement of coils are optimized to make the magnetomotive force approach a sine wave. However, since the number of slots cannot be increased without limit, the amount of harmonics to be reduced is limited. Moreover, even if it electrically optimizes the number of slots and the iron core shape to reduce the vibration and noise generated by the electromagnetic force due to the winding current, it can be reduced only to a certain extent.

  Further, in variable speed motors and variable speed generators for wind power such as hybrid cars and railways, low loss from low speed to high speed is the most important in terms of performance. However, with the number of poles fixed in the device design, there is a rotational speed range in which good output performance can be obtained depending on the number of poles, so it is difficult to achieve high efficiency over a wide range from a low speed range to a high speed range.

Tetsufumi Ogawa and Kazuhito Tsuji: “Basic research on electronics motor drive systems”, 2013 IEEJ Industrial Application Conference, Y-80 (2013) Matsui, et al .: "Reduced rare earth / de-rare earth motor", Nikkan Kogyo Shimbun (2013) Kazuhito Tsuji and Shigeaki Yuzawa: “Principle and basic characteristics of a pole-changing permanent magnet motor without switching the number of turns”, 2013 Dentsu University No. 5-008 (2013) Masanori Okayasu, Satoshi Ogawa, Kazuhito Tsuji: “Prototype and Experiment of Electronics Motor Drive System”, 2015 Annual Conference of the Institute of Electrical Engineers of Japan, 4-048 (2015) Tsuboi Kazuo, Isuzuka Isao, Mizuno Takayuki, Ashikaga Tadashi: "Study on smooth pole number switching method of 6-phase pole number switching induction motor for EV", 2000 Electron Theory D, Vol. 120, No. 11, p. 1351-1359 (1996) Takanori Niizuma, Satoshi Kuramochi, Kazuhito Tsuji: “Study on Pole / Constant Parameter Conversion Electronics Motor”, 2012 Denki University, No. 5pp. 32-33 (2012)

  The present invention has been made in view of such conventional technical problems, and an object of the present invention is to provide a rotating electrical machine system that can save energy, increase power generation, reduce torque and output pulsation, and reduce vibration and noise. And

  The present invention relates to a power conversion circuit capable of changing the magnitude and phase of a current flowing in each of a plurality of coils, a stator having a winding composed of the plurality of coils, and a coil, a permanent magnet, or a magnetic salient pole. It is characterized by a rotating electrical machine system composed of a rotor having an iron core.

  The present invention also provides a power conversion circuit capable of changing the magnitude and phase of the current flowing through each of the plurality of coils, a stator having a winding composed of each of the plurality of coils, and a coil, permanent magnet, or magnetic In a rotating electrical machine system including a rotor having a salient pole iron core, the rotating electrical machine system in which the power conversion circuit is capable of individually changing the magnitude and phase of a current flowing through each of the plurality of coils. Features.

  The present invention also provides a power conversion circuit capable of changing the magnitude and phase of the current flowing through each of the plurality of coils, a stator having a winding composed of each of the plurality of coils, and a coil, permanent magnet, or magnetic In a rotating electrical machine system including a rotor having a salient pole iron core, the power conversion circuit divides the coil into windings for each group in which a plurality of coils are connected, and the magnitude of current flowing through the windings for each group. It is characterized by a rotating electrical machine system that is a power conversion circuit capable of individually changing the phase and phase.

  According to the rotating electrical machine system of the present invention, the power conversion circuit individually controls the magnitude and phase of the current flowing through each of the plurality of coils of the stator winding, thereby saving energy, increasing power generation, torque and output pulsation. Performance improvement such as reduction, reduction of vibration and noise, expansion of variable speed operation range, energy saving from light load to high load and low speed to high speed rotation.

Explanatory drawing of the rotary electric machine system of the 1st Embodiment of this invention. The circuit diagram of the rotary electric machine system of the said 1st Embodiment. Operation | movement explanatory drawing of the rotary electric machine system of the said 1st Embodiment. FIG. 9 is a nine-phase voltage waveform diagram in the rotating electrical machine system according to the first embodiment. The output torque characteristic and cogging torque characteristic figure of the rotary electric machine system of the said 1st Embodiment. The output torque characteristic and cogging torque characteristic figure of the conventional three-phase rotary electric machine system. Explanatory drawing of the rotary electric machine system of the 2nd Embodiment of this invention. The distribution map of the rotating magnetic field during four-pole operation by the rotating electrical machine system of the second embodiment. The distribution map of the rotating magnetic field at the time of 8-pole operation by the rotating electrical machine system of the second embodiment. Explanatory drawing which shows pole number conversion of the pole number at the time of low speed driving | running | working in the variable speed driving | operation of a variable speed motor, and the pole number at the time of high speed driving | operation. The block diagram of the rotary electric machine system of the 3rd Embodiment of this invention. Sectional drawing of the motor part of the rotary electric machine system of the said 3rd Embodiment. The output pattern table | surface of the inverter in the rotary electric machine system of the said 3rd Embodiment. The motor parameter table | surface of the rotary electric machine system of the said 3rd Embodiment. The no-load analysis condition table of the rotating electrical machine system of the third embodiment. The inverter output current characteristic figure in the rotary electric machine system of the said 3rd Embodiment, the output voltage characteristic figure of an inverter, and a rotational speed characteristic figure. The output voltage characteristic view of the inverter in the rotary electric machine system of the said 3rd Embodiment. The motor rotational speed characteristic figure of the rotary electric machine system of the said 3rd Embodiment. An on-load analysis condition table for the rotating electrical machine system according to the third embodiment. The rotational speed characteristic figure at the time of the load of the motor of the rotary electric machine system of the said 3rd Embodiment. The slip characteristic figure at the time of the load of the motor of the rotary electric machine system of the said 3rd Embodiment. The torque characteristic figure at the time of the load of the motor of the rotary electric machine system of the said 3rd Embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

<First Embodiment>
As shown in FIGS. 1 and 2, the rotating electrical machine system according to the first embodiment is a motor 1, and a 9-slot stator core 11 and coils 13 (13 a) disposed in each slot 12 of the stator core 11. 13i) and a rotor 20 having a 4-pole or 8-pole magnetic pole in which a permanent magnet 22 is embedded in a rotor iron core 21, and a coil 13a in each slot 12 of the stator 10. Each of 13b,..., 13i has an independent power conversion circuit 30a, 30b,. An air gap 40 is formed between the inner peripheral surface of the stator 10 and the outer peripheral surface of the rotor 20.

  The power conversion circuits 30a, 30b,..., 30i in the present embodiment are configured by full-bridge single-phase inverter circuits. Thereby, the power conversion circuits 30a, 30b connected to each of the plurality of coils 13a, 13b,..., 13i so that a current having a current phase shifted by 40 ° flows to each of the plurality of coils 13a to 13i of the stator 10. .., 30i by controlling the switching operation of the power elements, the motor 1 as a whole can pass nine-phase currents that are out of phase by 40 ° in electrical angle through the nine coils 13a to 13i. As a result, the motor 1 can be driven as a nine-phase motor.

[Reduction of torque ripple]
In order to verify the characteristics of the motor 1 of the present embodiment, a nine-phase current having a phase shift of 40 ° in terms of the electrical angle shown in FIG. 4 is applied to the coils 13a to 13i of the stator 10 of the motor 1 by electromagnetic field analysis. When the no-load operation was performed as an 8-pole induction motor, the drive characteristics shown in FIG. 5 were obtained. FIG. 6 shows the driving characteristics of a conventional three-phase motor for reference.

  As shown in FIGS. 3 to 5, power conversion circuits 30 a, 30 b,..., 30 i are connected to the coils 13 a, 13 b,. For example, in the a-phase power conversion circuit 30a, a current I4 having an electrical angle of 2π (4/9) phase is passed through the coil 13a. Similarly, in the b-phase power conversion circuit 30b, a current of 2π (3/9) phase is supplied. I3 is caused to flow through the coil 13b, a 2π (2/9) phase current I2 is caused to flow through the coil 13c in the c phase power conversion circuit 30c, and a 2π (1/9) phase current I1 is caused to flow in the coil 13c. In the e-phase power conversion circuit 30e, a 2π (0/9) phase current I0 is caused to flow in the coil 13e, and in the f-phase power conversion circuit 30f, 2π (−1/9) = 2π (8/9). ) A phase current I8 is caused to flow through the coil 13f, and a 2π (−2/9) = 2π (7/9) phase current I7 is caused to flow through the coil 13g in the g-phase power conversion circuit 30g. Then, 2π (-3/9) = 2π (6/9) phase Current i6 is caused to flow through the coil 13h, and in the i-phase power conversion circuit 30i, a current I5 having a phase of 2π (−4/9) = 2π (5/9) is caused to flow through the coil 13i. A single-phase current having a phase difference was supplied to each of the coils 13a, 13b,.

  As a result, the torque ripple of the conventional three-phase motor is 5.70% as shown in the characteristic graph of FIG. 6, whereas the motor 1 of the present embodiment has the torque ripple as shown in the characteristic graph of FIG. The torque ripple was 1.99%, and it was confirmed that the torque ripple was significantly reduced to less than half that of the conventional three-phase motor. The cogging torque was the same.

[Torque and output fluctuation reduction]
By individually adjusting the tangential direction component of the electromagnetic force generated in each of the plurality of coils 13a, 13b,..., 13i, the total torque and output fluctuation of the motor 1 can be reduced. The tangential component of each electromagnetic force can be controlled mainly by varying the q-axis current of each of the plurality of coils 13.

[Reduction of vibration and noise]
The generation factor of vibration and noise is a normal direction component of electromagnetic force generated by the current of the motor 1. Therefore, the normal force generated in each of the plurality of coils 13a, 13b,..., 13i is individually adjusted to reduce the vibration mode and the noise mode that appear distributed in the entire motor 1 so as to reduce the vibration mode and the noise mode. ,..., 13i are adjusted. Each normal force is controlled mainly by changing the d-axis current of each of the plurality of coils 13a, 13b,.

  Thus, according to the rotating electrical machine system of the present embodiment, the following operations and effects are achieved.

  (1) By changing the current phase of each of the plurality of coils 13a, 13b,..., 13i, a multi-phase AC motor or generator can be obtained, so that fluctuation during phase switching is reduced and torque pulsation and output pulsation are reduced. it can.

  (2) Since the number of phases and the number of poles can be converted by changing the current phase of each of the plurality of coils 13a, 13,..., 13i, the operation is performed by switching to the appropriate number of phases and the number of poles according to the rotational speed. Copper loss and iron loss can be reduced. As a result, high-efficiency motors and generators can be obtained in a wide range from low-speed rotation to high-speed rotation, and energy can be saved and the amount of power generation can be increased in the total operation time.

  (3) Actively reducing torque fluctuations and output fluctuations, which are tangential forces of motors and generators, by controlling the magnitudes and phases of the currents I0, I1,..., I8 of the coils 13a, 13b,. it can. In addition, vibration and noise that are normal forces of the motor and the generator can be actively reduced.

<Second Embodiment>
The rotating electrical machine system according to the second embodiment shown in FIG. 7 is constituted by a cage rotor provided with a copper conductor bar 23 as a structure of the rotor 20 ′. The structures of the stator 10 and the power conversion circuit 30 are the same as those in the first embodiment. The stator 10 and the rotor 20 'constitute a squirrel-cage induction motor 1'.

  In the squirrel-cage induction motor 1 ′ according to the second embodiment, the rotor 20 ′ has no fixed number of poles, and the rotor 20 is driven by a current induced in the conductor bar 23 by a rotating magnetic field formed by the stator current. A pole equivalent to is automatically formed to produce an output.

  FIG. 8 shows a case of a quadrupole rotating magnetic field, and FIG. 9 shows a case of an octupole rotating magnetic field. Thus, when converting the number of poles of the motor, it is only necessary to change the phase of the current flowing through each of the coils 13a, 13b,..., 13i of the stator 10, and the number of poles of the rotor 20 ′ is converted. It becomes unnecessary. As a result, pole number conversion is facilitated, and instantaneous current fluctuation and output fluctuation during pole number conversion are also reduced.

<Third Embodiment>
The third embodiment is an electronic motor drive system in which two three-phase inverters are used, and the number of motor poles can be varied to 8/4 poles by 3-phase input. If the number of poles of the motor is made variable according to the rotational speed, high performance can be achieved over the entire operation range. As shown in FIG. 10, the number of poles is converted to 8 poles in the low speed rotation range and 4 poles in the high speed rotation range. In the case of a permanent magnet motor with high output and high efficiency, the number of poles is changed by changing the number of poles by changing the magnetization of the permanent magnet of the rotor, and switching the stator winding with the switching circuit of the power element. Perform the conversion. In the case of an induction motor, similarly, the stator winding is switched by a power element switching circuit to convert the number of poles of the stator, and the rotating magnetic field of the stator generated by each coil current is controlled to control the rotor magnetic field. By determining, the number of poles is converted.

There are two methods of electrical pole number conversion. As shown in the first and second embodiments, an inverter 30 is installed in each coil 13, and each coil current is directly controlled individually (hereinafter referred to as "coil current direct control system"). ) And a method of controlling current using a six-phase inverter. Furthermore, a method using a plurality of three-phase inverters is also conceivable. (Hereinafter referred to as “n × 3 phase inverter control system”.)
Since the coil current direct control method can control each coil current, it can be expected to improve motor drive performance such as reduction of output pulsation, reduction of harmonic components, and expansion of the operation range by the control. Although the degree of freedom of control is limited in the n × 3 phase inverter control method as compared with the former, the conventional inverter control circuit can be used and the adaptation to the current control method is relatively easy. The present embodiment is an n × 3 phase inverter control type rotating electrical machine system.

  There are PM motor type and IM motor type configurations of the pole number conversion motor. The PM motor includes a stator having concentrated winding coils in 12 slots, and a rotor in which 16 low coercivity magnets are arranged radially. The IM motor is a concentrated squirrel-cage induction machine in which each coil of the stator is made independent.

  Hereinafter, an IM motor 1 ″ that does not require conversion of the number of rotor poles will be described as a rotating electrical machine system according to the third embodiment with reference to FIGS. 11 and 12. The stator core 11 ″ on the stator 10 ″ side. Twelve coils 13 ″ installed in the slot 12 ″ in the inside are connected in parallel with two diagonal coils, and the current of the six coils 13 ″ is equivalently supplied by two units of three-phase inverters INV0 and INV1. Control. The controller 50 controls the outputs a, b, c of the inverter INV0 and the outputs a ', b', c 'of the inverter INV1 in synchronization. The rotor 20 ″ is a squirrel-cage rotor provided with conductor bars 23, as in the second embodiment.

  The controller 50 is open loop control VVVF control. In addition, a pole conversion function is defined, and an 8-pole rotating magnetic field and a 4-pole rotating magnetic field are switched by a control variable by a control variable. FIG. 12 shows a configuration in which motor coils are connected in parallel and an inverter connection configuration. An inverter output pattern is shown in FIG.

[3-phase 8-pole / 4-pole conversion simulation]
Drive control is performed by independent inverters INV0 and INV1, and pole number conversion is performed by turning on and off the main circuit power supply. The control system adapts open loop VVVF control. The motor parameters used in the simulation are those of a general-purpose squirrel-cage induction machine. Parameters other than the number of poles are set as equivalent. FIG. 14 shows the motor parameters.

[3-phase 8-pole / 4-pole no-load pole number conversion characteristics]
Using a circuit simulator, we obtained the transient response characteristics when the number of poles was converted at no load. FIG. 15 shows the analysis conditions. 16A to 16C show transient response characteristics of each inverter output current, line voltage, and rotation speed when converting the number of poles from 8 poles to 4 poles. Iu, Iv, and Iw are values obtained by combining the output currents of the inverters INV0 and INV1. From FIG. 16A and FIG. 16B, when the number of poles is converted from 8 poles to 4 poles, it can be confirmed that the cycle of current and voltage changes twice, and that stable driving is possible.

[3-phase 8-pole / 4-pole load pole number conversion characteristics]
Next, a transient response characteristic when the pole number conversion is performed at the time of load will be described. FIG. 17 shows the analysis conditions. 18A to 18C show transient response characteristics of rotational speed, slip, and torque at the time of 8-pole / 4-pole conversion. Since VVVF control was applied and the modulation factor gain was made equal to that at no load, the inverter output current and the line voltage confirmed the same waveform. When converting from 8 poles to 4 poles from FIGS. 18A to 18C, it can be confirmed that the slip at the same torque (the same amount of load) is increased.

  As described above, according to the rotating electrical machine system of the third embodiment, the pole number conversion control operation can be performed by the n × 3 phase inverter control method, and the degree of freedom of control is limited as compared with the coil current direct control method. However, there are advantages that a conventional inverter control circuit can be used and that adaptation to the current control method is relatively easy.

1, 1 ', 1 "motor 10, 10" stator 11 stator core 12, 12 "slot 13a, 13b, ..., 13i, 13" stator coil 20, 20', 20 "rotor 21 rotor core 22 Permanent magnet 23 Conductor bars 30a, 30b, ..., 30i Power conversion circuit 40 Air gap 50 Controller INV0, INV1 Inverter

Claims (8)

  A power conversion circuit capable of changing the magnitude and phase of a current flowing in each of the plurality of coils, a stator having a winding composed of each of the plurality of coils, and a coil, a permanent magnet, or a magnetic salient pole iron core A rotating electrical machine system comprising a rotor. A power conversion circuit capable of changing the magnitude and phase of a current flowing in each of the plurality of coils, a stator having a winding composed of each of the plurality of coils, and a coil, a permanent magnet, or a magnetic salient pole iron core In a rotating electrical machine system composed of rotors,
The rotating electrical machine system, wherein the power conversion circuit is capable of individually changing a magnitude and a phase of a current flowing through each of the plurality of coils. A power conversion circuit capable of changing the magnitude and phase of a current flowing in each of the plurality of coils, a stator having a winding composed of each of the plurality of coils, and a coil, a permanent magnet, or a magnetic salient pole iron core In a rotating electrical machine system composed of rotors,
The power conversion circuit is a power conversion circuit that divides the coil into windings for each group in which a plurality of coils are connected, and can individually change the magnitude and phase of the current flowing through the windings for each group. A rotating electrical machine system characterized by that.   The rotating electrical machine system according to any one of claims 1 to 3, wherein the number of phases is changed by changing a phase of a current flowing through each of the plurality of coils.   The rotating electrical machine system according to any one of claims 1 to 4, wherein the number of poles is made variable by changing a phase of a current flowing through each of the plurality of coils.   A control function for reducing the pulsation by shifting the magnitude and phase of the current flowing through each of the plurality of coils so that the torque pulsation waveform and the output pulsation waveform generated in each of the plurality of coils are opposite to each other or shifted in phase. The rotating electrical machine system according to any one of claims 1 to 5.   A control function for reducing the pulsation by changing the magnitude and phase of the current flowing through each of the plurality of coils so that the torque pulsation waveform and the output pulsation waveform generated in each of the plurality of coils are in opposite phases, or shifted in phase. The rotating electrical machine system according to claim 1, comprising: When the rotating magnetic field formed by the entire coil during energization forms a plurality of rotating magnetic fields having different pole numbers at the same time, the plurality of currents that form a rotating magnetic field having an opposite phase to the rotating magnetic field having the number of poles that are not required The rotating electrical machine according to claim 1, wherein a current waveform superimposed on a current flowing through each of the coils is formed by changing a magnitude and a phase of a current flowing through each of the plurality of coils. system.