JPH07322413A - Rotary electric machine controller and electric car - Google Patents

Abstract

PURPOSE:To provide a highly safe rotary electric machine controller and electric car that avoid reverse rotation and torque variation by reversing the V-W phase sequence of all winding assemblies and temporarily reducing current during pole changing. CONSTITUTION:A control circuit 14, which incorporates an rpm checker 21 and pole changer 22, converts DC power supplies 1a, 1b into AC when the rpm of a rotor 5 of a rotary electric machine 3 has exceeded a specified value, in order to control a drive signal to be outputted to the gate circuit of switching elements of inverters 2a, 2b that supply AC current to two stator windings 71, 72 comprising a group of stator windings 7. The control circuit 14 also changes the sequence of V1 and W1 phase currents in a stator winding assembly 71, and V2 and W2 phase currents in a stator winding assembly 72, thereby changing the number of stator poles from 4 to 2 while reducing the current.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary electric machine control device for converting the number of poles and expanding the operating range, and more particularly to a rotary electric machine control device suitable for an electric vehicle.

[0002]

2. Description of the Related Art A rotating electric machine for an electric vehicle is required to be small in size, light in weight, and highly efficient in order to extend a one-charge traveling distance of a battery. Further, in order to increase the maximum speed and improve the acceleration performance, it is important to widen the operating range (rotational speed-torque operable range) of the rotating electric machine. And as one way to realize this, Japanese Patent Publication Sho 58
No. 29718 is disclosed.

According to this, a plurality of sets of windings of the induction motor are provided, each of the thyristor-structured inverse converters for individually supplying an AC output to each of the plurality of sets of windings, and phase control of each of these inverse converters. And a phase switching circuit for switching the number of poles of the induction motor by shifting the phase of one of the inverse converters by 180 ° in the gate circuit. A pole number switching device is described.

[0004]

However, in the above-mentioned prior art, when the number of poles is converted, the current of each one phase is 180 °.
Since it is a method of reversing, it does not have a positive phase rotating magnetic field in the same direction as the winding forward direction, but a reverse phase rotating magnetic field in the opposite direction, so there is a risk of reverse rotation after pole number conversion and pole number conversion. There were drawbacks such as generation of large pulsating torque.

An object of the present invention is to provide a rotating electric machine control device and an electric vehicle that are highly safe by avoiding the risk of reverse rotation and the occurrence of pulsating torque.

[0006]

The above object is to provide a rotating electric machine having a plurality of winding groups each consisting of a multiphase winding group in which single-phase windings are combined, and a DC power source for each of the plurality of winding groups. An individual power conversion unit that supplies the converted AC power supply and a control unit that controls the power conversion unit and controls the current phase of the AC power supply are provided. In a rotating electric machine control device for controlling the number of poles of a rotating electric machine, a rotating speed detecting means for detecting the rotating speed of the rotating electric machine, a rotating speed judging means for judging whether or not the rotating speed is a predetermined value, and the judging means. Phase order changing means for changing the order of the current phases of all the winding sets including the other on the basis of the above.

An electric vehicle that achieves the above object is
The rotating electric machine as a drive unit for the wheels is controlled.
Alternatively, the rotary electric machine control device according to claim 2 or 3 is provided.

[0008]

According to the structure of the present invention, since the rotating magnetic field after the pole number conversion becomes the rotating magnetic field of the positive phase, the fear of reverse rotation can be avoided. In addition, by temporarily reducing the current when converting the number of poles, it is possible to reduce torque fluctuation due to switching of the current direction. With these, it is possible to provide a rotating electric machine control device and an electric vehicle with high safety.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a rotary electric machine control device according to an embodiment of the present invention. The rotary electric machine control device includes direct current power supplies 1 a and 1 b, two sets of inverters 2 a and 2 b including switching elements, one rotary electric machine 3, and a control circuit 14. The DC power supplies 1a and 1b may be the same.

The rotating electric machine 3 comprises a stator 4 and a rotor 5, and is, for example, a three-phase induction motor. Stator 4
Has stator winding sets 71 and 72 which are two sets of windings including a group of stator windings 7. And DC power supply 1
The electric power of a is supplied to one stator winding set 71 of the rotary electric machine 3 via the inverter 2a. Further, the electric power of the DC power supply 1b is supplied to the other stator winding set 72 via the inverter 2b. In this case, since it is a three-phase induction motor, U1 phase, V1 phase, W
It is supplied to one phase and the U2 phase, V2 phase, and W2 phase of the stator winding set 72.

The rotor 5 has, for example, a cage winding, and the rotor 5 is provided with an encoder E which is a rotational speed detecting means for detecting the rotational speed of the rotary electric machine 3. .

The control circuit 14 controls the inverters 2a and 2b which convert direct current into alternating current and supply the alternating current to the two stator winding sets 71 and 72. That is, the control circuit 1
Reference numeral 4 controls the drive signal output to the gate circuits of the switching elements of the inverters 2a and 2b, and the stator winding set 71
U1 phase, V1 phase, W1 phase of the above, and U2 of the stator winding set 72
The magnitude and the current phase of the current flowing in the phase, the V2 phase, and the W2 phase are controlled.

Further, the control circuit 14 includes a rotation speed judging means 21 for judging based on the rotation speed signal of the encoder E and a pole number converting means 22 for converting the pole number based on the judgment. The pole number converting means 22 includes a phase order changing means which will be described later. The rotation speed determination means 21 and the pole number conversion means 22 do not have to be included in the control circuit 14.

As a method of converting the number of poles, for example, for the U1 phase of the stator winding set 71, the U of the stator winding set 72 is used.
There is a method of shifting the current phases of the two phases by 180 °, and similarly, shifting the V2 phase by 180 ° and the V2 phase by 180 ° with respect to the V1 phase.

Generally, when the rotational speed of the rotary electric machine 3 becomes high, the number of poles is converted from four to two. This is to avoid the influence of the winding impedance increase in the high rotation speed region and to secure the torque characteristic of the rotary electric machine 3 in the high rotation speed region.

Therefore, the rotation speed determination means 21 determines whether or not the rotation speed of the rotary electric machine 3 has exceeded a predetermined value. Then, when it is determined that the current is exceeded, the pole number conversion means 22 performs control for shifting the current phase.

Further, the rotary electric machine control device is configured to control the speed command V
Based on a signal from s, the encoder E, or the like, the rotary electric machine 3 is controlled by a control method such as speed control or torque control of the control circuit 14, V / F control that is variable speed rotation control of the induction motor, or vector control. To control.

FIG. 2 is a diagram showing an example of a cross section of the rotary electric machine 3 of FIG. The rotating electric machine 3 includes a stator 4 and a rotor 5.
And the end bracket 12. And
The stator 4 includes a housing 11, a stator core 6 fixed to the inner peripheral surface of the housing 11, and a plurality of sets of three-phase stator windings 7 wound around the stator core 6.

The rotor 5 is composed of a rotor core 8 made of laminated silicon steel plates, a cage winding made of a rotor bar 9 and end rings, a shaft 10, a bearing 13, and an encoder E. The bearing 13 is fitted into the end bracket 12 and rotatably holds the shaft 10. The encoder E detects the rotational position and rotational speed of the rotor 5.

FIG. 3 is a view showing an AA cross section of the rotary electric machine 3 of FIG. The stator core 6 has a stator core tooth portion 61.
And a stator core portion 63. A large number of stator windings 7 are wound around the stator core slot portion 62, which is a winding groove between the teeth of the stator core tooth portion 61. In the embodiment shown in the figure, one of the 24 stator core slot portions 62 is
Two stator windings 7 are wound and a three-phase induction motor having a four-pole structure is shown.

That is, the number of stator core slot portions per stator winding 7 for each pole and phase is two, and the U phase, V
24 for 6 phases, 4 for each phase, 24 for each phase
There are individual stator core slot portions 62.

Here, U + -phase U + and U- indicate one stator winding 7 that is electrically connected. The same applies to the V and W phase stator windings 7. The two stator windings 7 inserted in the different winding grooves form one phase. For example, the U1 phase includes U1 +, U1-, U1 +, and U1.
-And are connected in series. And U1
Phase, V1 phase, W1 phase stator winding 71 and U2 phase, V2
Phase and W2 phase stator windings 72 are housed in 24 stator core slot portions 62 as shown in the figure.

Returning now to FIG. 1, the stator winding 71 and the stator winding 72 are connected to the inverter 2 as shown in the figure.
Star-connected to a and 2b. That is, the stator winding set 71 and the stator winding set 72 form independent winding sets.

More specifically, the stator winding set 71 comprises a group of U1 phase, V1 phase and W1 phase stator windings 7. U1 phase is from one stator winding U1 + to U1
-Go to one more stator winding U1 + to U
Connected to 1-. That is, one winding U1 + of the stator winding 7 is connected to the inverter 2a as shown in FIG.
Is connected to the U-phase of the
, And U1- of the other winding is connected to a neutral point to which the other phase is also connected. The V1 and W1 phases are similarly connected.

The stator winding set 72 includes U2 phase, V2 phase, W
It consists of a group of two-phase stator windings 7. The connection is the same as above, and is connected to the inverter 2b.

Furthermore, FIG. 1 shows the current direction and the phase sequence before and after the conversion for converting the number of poles from four poles to two poles. The arrows indicate the current direction, and U, V, and W indicate the phase sequence. Moreover, -U shall show a-direction (reverse direction).

Now, the pole number conversion according to the present invention will be described. The rotation speed determination means 21 determines whether the rotation speed of the rotary electric machine 3 has exceeded a predetermined value. Then, when it is determined that the current has been exceeded, the pole number conversion means 22 performs control to shift the current phase. The current direction and phase sequence before and after the conversion will be described from the stator winding set 71 on the left side of the drawing.

The current direction before conversion is the + direction to the right. The changed current direction is also the + direction to the right. However, the phase sequence before conversion is U-V-W, whereas the phase sequence after change is U-W-V. In the prior art, the phase sequence after conversion was also UV-W. As described above, it is a feature of the present invention that the phase order of the V and W phases is changed (reversed) after the pole number conversion.

For the stator winding set 72 on the right side of the drawing, the current direction before conversion is the left + direction. Then, the changed current direction is the-direction (reverse direction) to the right. Then, the phase sequence U-V-W before conversion is set to the sequence (-U)-(-W)-(-V) after conversion. In this way, also for the stator winding set 72, the phase sequence after conversion of the V and W phases is changed (reversed).

The above will be described with reference to the current phase shift. For example, before conversion, the current phase shift of the V1 phase is 120 ° and the current phase shift of the W1 phase is 240 ° with the U1 phase as a reference. Further, the current phase shift of the U2 phase with respect to the U1 phase is 0 °. Similarly, the V2 phase for the V1 phase and the W2 phase for the W1 phase are also 0 °.

After conversion, with reference to the U1 phase,
The V1 phase current phase shift is 240 °, and the W1 phase current phase shift is 120 °. At the same time, U1
The current phase shift of the U2 phase with respect to the phase is 180 °, and the V2 phase with respect to the V1 phase and the W2 phase with respect to the W1 phase are similarly set.
180 °. Therefore, at this time, with reference to the U2 phase, V
The current phase shift of the two phases is 240 °, and the current phase shift of the W2 phase is 120 °.

In the prior art, the phase sequence after conversion was also U-V-W. That is, after conversion, the current phase shift of the V phase remains 120 ° with the U phase as the reference. It means that the current phase shift of the phase also remains at 240 °.

From the above description, the pole number converting means 22 is
It can be seen that it can be integrated with the phase sequence changing means.

It can be said that the phase sequence in this case is the time sequence when the current is supplied from the inverter to the windings of each phase. Further, in the above case, the example in which the U phase is used as a reference has been described, but any reference may be used. Further, in the above description, the phase order changing means is included in the pole number converting means 22, but it may be a separate body.

By the above operation, even if the four poles are converted into the two poles, the rotating magnetic field of the opposite phase that the rotating magnetic field is generated in the direction opposite to the forward direction of the winding is avoided, and the forward direction of the winding is avoided. A positive-phase rotating magnetic field that a rotating magnetic field is generated in the same direction is secured.

As a result, the risk of reverse rotation after the pole number conversion is eliminated, and safe pole number switching is possible. This operation can be easily achieved only by controlling the inverter by the control circuit 14 without providing another means for changing the connection of the stator windings. Therefore, the advantages of pole number conversion such as small size, light weight, and high efficiency can be realized without concern about safety and price.

FIG. 4 is a diagram for explaining the operation of the rotary electric machine according to the present invention as four poles. In the circuit shown in FIG.
This is a case where the stator winding set 71 and the stator winding set 72 have the same current direction. That is, it shows the magnetic poles of the U-phase stator winding 7 when the current is applied in phase sequence with the current direction before conversion.

N poles and S poles can be alternated to form four poles.
Naturally, the composite magnetic field including the V and W phases also has four poles.
Also, the electrical angle of each phase is 120 ° between U, V, and W phases as shown in the figure, and the current is sent in a sinusoidal shape in time so that it is in the same direction as the forward direction of the winding. , A rotating magnetic field that rotates clockwise is created.

FIG. 5 is a diagram for explaining the operation of the rotating electric machine according to the present invention when the number of poles is converted into two. In the circuit shown in FIG. 1, the current directions of the stator winding set 71 and the stator winding set 72 are opposite to each other, and the V and W phases are also opposite in sequence. That is, when energized in the phase direction with the converted current direction,
The magnetic poles of the U-phase stator winding 7 are shown.

By operating in this manner, the current direction and the magnetic poles of each phase at the time of four poles shown in FIG. 4 change as shown in FIG. 5 to become two poles. The composite magnetic field including the V and W phases naturally has two poles as well.

Also in this case, the electrical angle of each phase is 120 ° between U, V, and W phases as shown in the figure, and the current is passed in a sinusoidal manner with time, so that it is converted after the pole number conversion. As before, a rotating magnetic field that rotates clockwise can be created. Therefore, a positive phase rotating magnetic field is secured.

On the other hand, when the number of poles is converted as described above, the current direction changes largely between forward and reverse, so that a large pulsating torque is generated in the rotating electric machine. In order to reduce this, there is a method of reducing the current flowing through the winding at the time of conversion from the normal control state and converting. For example, based on the determination of the rotation speed determination means 21, the timer means operates at the same time when the pole number conversion means 22 executes the pole number conversion, and at the same time, the pole number conversion means 22 causes the stator winding set 71 and the stator winding. The current flowing through the set 72 is reduced, and after it is determined that the conversion is completed, the timer means restores the original control state.

Instead of the pole number converting means 22, a current reducing means integrated with the timer means may be separately provided. By the way, the time required for conversion in this case is 10
It is less than ms, and the timer time for temporarily reducing the current is about 50 ms. Therefore, the influence of this current decrease time on the rotating electric machine can be ignored.

Further, changing the phase order of V and W phases at the time of conversion
By changing at the moment when the current values of the V and W phases become almost the same, a smoother pole number conversion is possible. "Almost the same" means that even if there is a slight difference in the V-phase and W-phase currents, the torque fluctuation during conversion is small, and therefore it is not necessarily the same.

When the pole number conversion control is adopted in the drive motor of an electric vehicle, it is necessary to avoid the risk of human life, and the above is particularly important.

In the embodiment shown in FIG. 1, the rotary electric machine 3, the switching elements 2a and 2b, and the control circuit 14 have three separate structures, but they are integrated in the rotary electric machine 3. It can be configured to be incorporated. As a result, these three are concentrated at one location, so that the piping of the cooling system and the wiring connecting the three become short and simple, which has the effect of reducing the cost. Further, there is an effect that the influence of electromagnetic noise generated from the wiring is reduced. Furthermore, since the resistance loss of the wiring is reduced, the electrical loss is reduced, and a highly efficient rotating electrical machine system can be obtained.

Further, there are two sets of control devices, and even if one of the control devices fails, the other can temporarily operate, and a fail-safe configuration can be realized. This is even more important particularly in electric vehicles that are exposed to severe conditions such as vibration.

Although the above-described embodiment of the present invention is applied to the rotary motor drive, it can also be applied to the linear motor drive. In addition to the three phases, the present invention can also be applied to a multi-phase rotating electric machine having a stator structure of a concentrated winding structure in which windings of each phase do not wrap.

[0049]

According to the present invention, a fear of reverse rotation after pole number conversion and a large torque fluctuation at the time of pole number conversion are avoided, so that a rotary electric machine control device with high safety is provided. Further, it is possible to put into practical use a rotary electric machine control device that is small, lightweight, highly efficient, and has a wide operating range.

By using the rotary electric machine control device according to the present invention to control the drive motor, it is possible to provide an electric vehicle which is highly safe, can travel a long distance, and can be driven at high speed.

[Brief description of drawings]

FIG. 1 is a diagram showing a rotary electric machine control device according to an embodiment of the present invention.

FIG. 2 is a diagram showing an example of a cross section of the rotary electric machine 3 of FIG.

3 is a diagram showing a cross section taken along the line AA of the rotary electric machine 3 of FIG.

FIG. 4 is an operation explanatory diagram of a rotating electric machine according to the present invention as four poles.

FIG. 5 is an operation explanatory diagram when the number of poles of the rotating electric machine according to the present invention is converted into two poles.

[Explanation of symbols]

1a, 1b: DC power supply 2a, 2b: Inverter 3:
Rotating electric machine 4: Stator 5: Rotor 6: Stator core 61: Stator core tooth 62: Stator core slot 63: Stator core core 7: Stator winding 71, 72: Stator winding Set 8: Rotor iron core 9: Rotor bar 10: Shaft 11: Housing 12: End bracket 13: Bearing 14: Control circuit 21: Rotation speed determination means 22: Pole number conversion means.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Nobuyoshi Muto Inventor, No. 1-1 Omika-cho, Hitachi City, Ibaraki Prefecture Hitachi Ltd. Hitachi Research Laboratory (72) Inventor Riki Omae 7-chome Omika-cho, Hitachi City No. 1 in Hitachi, Ltd. Hitachi Research Laboratory

Claims (9)

[Claims] 1. A rotating electric machine having a plurality of winding sets each consisting of a multi-phase winding group in which single-phase windings are combined, and an individual AC power source converted from a DC power supply to each of the plurality of winding sets. The rotating electric machine includes: a power conversion unit; and a control unit that controls the power conversion unit to control a current phase of the AC power supply, and controls the current phase of one winding set of the plurality of winding sets. In a rotary electric machine control device that performs pole number conversion, a rotation speed detection unit that detects the rotation speed of the rotary electric machine, a rotation speed determination unit that determines whether the rotation speed is a predetermined value, and the other based on the determination. And a phase sequence changing means for changing the sequence of the current phases of all the winding groups including the above. 2. A rotating electric machine having a plurality of winding groups each comprising a U-, V-, and W-phase winding group, and individual power conversions for supplying an AC power source converted from a DC power source to each of the plurality of winding groupings. Means and control means for controlling the electric power conversion means to control the current phase of the AC power supply, and controlling the current phase of one of the plurality of winding groups to control the number of poles of the rotating electric machine. In a rotating electric machine control device that performs conversion, a rotating speed detecting unit that detects the rotating speed of the rotating electric machine, a rotating speed determining unit that determines whether the rotating speed is a predetermined value, and the other based on the determination are also included. A rotary electric machine control device comprising: a phase sequence changing unit that changes the sequence of the current phases of the V phase and the W phase with respect to the U phase for all the winding groups. 3. A winding set consisting of winding groups of U, V and W phases.
Rotating electric machine having two sets, two power conversion means for supplying an alternating current power converted from a direct current power supply to each of the two winding sets, and the alternating current supplied to the winding set by controlling the power conversion means. A rotating electric machine control device for converting the number of poles of the rotating electric machine, the rotating speed detecting means detecting the rotating speed of the rotating electric machine, and whether the rotating speed is a predetermined value or not. Rotation speed judging means for judging whether or not, and V based on the U phase for the two winding groups based on the judgment.
A rotating electrical machine control device, comprising: a phase order changing unit that changes the order of the current phases of the W phase and the W phase. 4. The current temporary reduction means according to claim 1, 2 or 3, wherein the current of the AC power supply supplied to the winding group is temporarily reduced when the pole number conversion is performed. A rotating electrical machine control device provided. 5. The temporary current reduction according to claim 1, 2, or 3, wherein when changing the order of the current phases, the current of the AC power supply supplied to the winding set is temporarily reduced. A rotating electrical machine control device comprising means. 6. The phase sequence changing means according to claim 1, 2 or 3, wherein the magnitude of the current of each of the alternating current power supplies supplied to the winding group whose phase sequence is changed. The rotating electric machine control device is characterized in that the order of the current phases is changed when the values become substantially the same. 7. The rotary electric machine control device according to claim 1, 2, or 3, wherein the power conversion means and the control means are built in the rotary electric machine. 8. An electric vehicle comprising the rotary electric machine control device according to claim 1, 2 or 3, which controls a rotary electric machine as a wheel driving means. 9. A motor drive means having a plurality of winding sets consisting of a multiphase winding group in which single-phase windings are combined, wherein the current phase of one of the plurality of winding sets is controlled, A motor drive control method for converting the number of poles of a motor drive means, wherein the order of the current phases of all the winding groups is changed before and after the pole number conversion.