JP2000324891A - Inverter drive motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inverter drive motor circuit capable of suppressing high-frequency leakage current without providing noise filters. SOLUTION: In the inverter drive motor 4 comprising a stator for generating a revolving field, a rotor rotated by the field of the stator to generate mechanical power, and a plurality of systems of windings A, B for supplying power to the stator, thereby controlling currents supplied to the windings by a switching operation of the inverter 3 to generate a magnetic field in the stator, switching circuits 3A, 3B of the inverter 3 are controlled so that the total sum of terminal voltages of the windings becomes substantially constant. Furthermore, the windings are connected to eliminate voltage change at a neutral point of the windings of the respective phases, thereby obviating voltage change for the DC side of the inverter and suppressing generation of a high-frequency leakage current. The windings are respectively wound concentratedly.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inverter drive motor using AC power converted by an inverter as a power source.

[0002]

2. Description of the Related Art Conventionally, a DC power source such as a battery is converted into AC power of a predetermined frequency and voltage by an inverter, or an AC power source is converted into DC power by a converter or a rectifier circuit. Is converted to AC power of a predetermined frequency and voltage by
As an inverter drive motor used as a motor power supply, FIG.
Is known.

In this conventional inverter drive motor, DC power from a battery 1 as a DC power supply is supplied to an inverter 3 via an electrolytic capacitor 2 for reducing a ripple current.
, And is converted into UVW three-phase AC power of a predetermined frequency and voltage by the switching control of the inverter 3, and the power is supplied to the UVW three-phase windings of the stator of the three-phase AC motor 4.

[0004]

However, such a conventional inverter drive motor has the following problems. FIG. 20 shows a switching state when each of the switching elements SW1 to SW6 of the inverter 3 is driven by a rectangular wave. The voltage at the neutral point of the winding of each of the three phases of UVW of the AC motor 4 is Fluctuates depending on the switching timing of the switching element. As a result, a high-frequency leakage current is generated, and when the AC motor is used for driving a vehicle, noise is generated in a vehicle-mounted electric device such as a vehicle-mounted radio.

In order to solve this problem, as shown in FIG. 21, noise filters 5 and 6 made of a common mode reactor are inserted in series on the DC side and the AC side of the inverter 3 to reduce the high frequency leakage current. May be reduced.

However, even if such a common mode reactor is employed, there is a problem that a sufficient effect of reducing the high frequency leakage current cannot be obtained. In addition, since the reactor has a large volume and a large weight, the inverter 3 has There is a problem that the case capacity is increased and the weight is increased, and as a result, the mountability to the vehicle is deteriorated. In addition, since the reactor is expensive, the price of the inverter is also high.

SUMMARY OF THE INVENTION The present invention has been made in view of such a conventional problem, and can suppress generation of high-frequency leakage current without providing a noise filter, without increasing the case volume and weight of the inverter. It is another object of the present invention to provide an inverter drive motor that does not increase in cost.

[0008]

According to a first aspect of the present invention, there is provided a stator for generating a rotating magnetic field, a rotor for generating mechanical power by rotating the stator by the rotating magnetic field, and a plurality of systems for supplying electric power to the stator. The windings of the plurality of systems are respectively connected to the plurality of parallel switching circuits of the inverter, and the total sum of the terminal voltages of the windings of the plurality of systems is substantially changed by the switching operation of the plurality of switching circuits. In an inverter drive motor for controlling a current flowing through each of the plurality of windings so as to be constant, the plurality of windings are concentratedly wound.

In the inverter drive motor according to the first aspect of the present invention, the occurrence of high-frequency leakage current is suppressed without providing a noise filter, the case volume and weight of the inverter are not increased, and the cost is not soared.

According to a second aspect of the present invention, in the inverter driving motor according to the first aspect, each of the two windings connected to each of the two switching circuits is wound in opposite directions. The winding length of each system is shortened.

According to a third aspect of the present invention, in the inverter driving motor according to the first aspect, two windings connected to each of the two switching circuits are alternately wound. The torque ripple due to the winding is improved.

According to a fourth aspect of the present invention, in the inverter driving motor according to the second aspect, the number of slots of the stator is set to an integral multiple of a normal number of slots, and the two-system winding connected to the two switching circuits is provided. The wires are wound in opposite directions, so that the winding length of each system is shortened and the torque ripple is also improved.

According to a fifth aspect of the present invention, in the inverter driving motor according to the third aspect, the number of slots of the stator is set to an integral multiple of a normal number of slots, and the winding of the two systems connected to the two switching circuits is provided. The alternating winding of the wire further improves torque ripple.

According to a sixth aspect of the present invention, in the inverter driving motor according to the second to fifth aspects, each of the two windings is wound in parallel for each phase. Can be wound in the same manner, thereby simplifying manufacturing.

[0015]

As described above, according to the first aspect of the present invention,
The generation of high-frequency leakage current is suppressed without providing a noise filter, and the case volume and weight of the inverter are not increased, and the cost is not soared.

According to the invention of claim 2, in addition to the effect of the invention of claim 1, the winding length of each system can be shortened.

According to the third aspect of the invention, in addition to the effect of the first aspect, the torque ripple due to the two windings can be improved.

According to the invention of claim 4, in addition to the effect of the invention of claim 2, torque ripple can be improved.

According to the fifth aspect of the invention, in addition to the effect of the third aspect of the invention, the torque ripple can be further improved.

According to the sixth aspect of the invention, in addition to the effects of the second to fifth aspects, the windings of the respective windings in the respective phases can be made the same, thereby simplifying the manufacture.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a circuit configuration of the first embodiment of the present invention. On the stator of the three-phase AC motor 4, a winding A and a winding B are wound in parallel with a U-phase, a V-phase, and a W-phase, respectively. , 3B so as to receive three-phase AC power.

The switching circuits 3A and 3B of the two systems A and B of the inverter 3 are configured in parallel. The switching circuit 3A has switching elements SW1 to SW6, and the switching circuit 3B has switching elements SW7 to SW.
12 is assembled in a bridge. Further, a control unit 10 is provided for on / off driving of each of the switching elements SW1 to SW12 of the inverter 3.

The control unit 10 controls the switching circuits 3A and 3B of the inverter 3 for supplying current to the stator winding A and the winding B of the motor 4 in the opposite manner. The element SW1 and the switching element SW8, and the switching element SW2 and the switching element SW7 are driven by the same signal. Then, as shown in FIGS. 2A and 2B, the control unit 10 switches the switching elements SW of the two switching circuits 3A and 3B.
Control is performed to switch on / off states of 1 to SW12 at 60 ° intervals. Hereinafter, for the sake of simplicity, the description will be made assuming that each switching element is driven by a rectangular wave.

FIG. 2A shows a current state on the motor winding A side by the switching operation of the switching circuit 3A. Here, “H” indicates that the switching is in the on state,
“L” indicates that the switching is off. By switching “H” and “L” at intervals of 60 °, current flows of the U, V, and W phases as shown in FIG.

At this time, the voltage at the neutral point NA of the U, V, and W phases is 1/1 when the input voltage of the inverter 3 is Ed.
It varies between 3 Ed and 2/3 Ed.

On the other hand, the current state on the motor winding B side by the switching operation of the switching circuit 3B is shown in FIG.
As shown in (b), “H”,
The "L" switching operation is performed in the opposite direction. As a result, current flows of the U, V, and W phases as shown in FIG.
At this time, the voltage at the neutral point NB of the U, V, and W phases is also 1/3 Ed when the input voltage of the inverter 3 is Ed.
To 2/3 Ed. However, for example, when the switching element SW1 is “H”, the switching element SW7 is “L”, and when the switching element SW2 is “L”, the switching element SW8 is “H”. Since the switching is performed in the opposite manner in the switching circuits 3A and 3B, the voltage value for the switching timing is different from that for the winding A.

The sum of the terminal voltages of the motor 4 is the sum of the voltages at the neutral points NA and NB of the winding A and the winding B, as shown in FIG. As a result, the motor 4
Is always 3/3 Ed irrespective of the switching timing, and the leakage of the high-frequency current to the DC side of the inverter 3 can be suppressed.

However, in this state, the connection between the windings A and B of the AC motor 4 is still the state shown in FIG. Now, the current flowing through the winding A at the phase angle of 60 ° flows simultaneously from the U phase to the V phase and the W phase. Then, the current flowing through the winding B flows simultaneously from the V phase and the W phase into the U phase. Therefore, the directions in which the currents of the U, V, and W phases flow in the windings A and B are just opposite, and the induced magnetic fluxes cancel each other out, so that the motor cannot be driven.

Therefore, in the case of this embodiment, the connection between the switching circuit 3B and the neutral point NB in the winding B is established by the switching circuit 3A and the winding A, as shown in the motor 4 in FIG. 2A, a current is applied to the winding B in the same direction as that of the winding A as shown in FIG. 2D. Can be driven.

As a result, as described above, the sum of the terminal voltages of the motor 4, which is the sum of the voltages at the neutral points NA and NB of the windings A and B, is made constant, and a high-frequency current is not generated. In addition, the motor can be driven by an inverter.

In the above description, a rectangular wave signal as shown in FIG. 4A is used for the on / off control of the switching element of the inverter 3, but the present invention is not limited to this. The driving waveform shown in ()) may be a sine wave driving by PWM. In the case of driving by PWM, as shown in FIGS. 5A and 5B, the ON / OFF of each of the switching SW1 to SW12 is performed.
Although the OFF switching timing is extremely fast, the control principle is the same as in the above embodiment. At each timing, for example, when the switching element SW1 is “H”, the switching element SW7 is “L”, When the switching element SW2 is at "L", the switching element SW8 performs "H" so that the switching in each of the U, V, and W phases is performed by the switching circuits 3A and 3B in the opposite manner.

As a result, as shown in FIG.
The sum of the terminal voltages of the motor 4, which is the sum of the voltages at the neutral points NA and NB of the winding A and the winding B, is always 3 / 3Ed regardless of the switching timing. Can be prevented from leaking.

Next, how to wind the windings A and B will be described with reference to FIGS. FIGS. 6 and 7 show a three-phase, eight-pole, 12-slot concentrated winding motor in which current is supplied from two switching circuits 3A and 3B, respectively.
B shows how to wind two winding systems.

The windings are U, V, W, U, V, W, U ',
V ', W', U ', V', W 'are wound in this order. Then, a winding system A of UVW and a winding system B of U'V'W '
And the winding directions are reversed.

According to this winding method, the lengths of the windings can be minimized by winding the windings of the same system of A and B side by side.

Further, the winding method of the winding may be the one shown in FIGS. FIGS. 8 and 9 show a three-phase, eight-pole, 12-slot concentrated winding motor having windings U, V, W, U ', V', W ', U, V,
W, U ', V', W 'are wound in this order. And U
The winding directions of the VW winding system A and U'V'W 'winding system B are reversed.

As described above, by winding each of the windings A and B at the position facing each other across the center of the stator, torque ripple due to unbalance of the winding system existing in manufacturing can be reduced. .

The winding method of the winding is shown in FIGS.
It can also be as shown in. FIGS. 10 and 11 show a three-phase, eight-pole, 12-slot concentrated winding motor having windings U, V ', W, U', V, W ',
It winds in the order of U, V ', W, U', V, W '. Then, a winding system A of UVW and a winding system B of U'V'W '
And the winding directions are reversed.

As described above, the windings A and B are wound at the positions facing each other with the windings of the same system sandwiching the center of the stator.
In addition, by winding such that a winding of another system always comes next to it, the unbalance of the winding system existing in manufacturing and the unbalance in the end coil portion can be eliminated, and the torque ripple can be reduced more effectively.

Further, in each of the above examples, the winding of each phase of the UVW is wound in series, but as shown in FIG. 12, in each of the above examples, the winding of each phase of the UVW is changed. It can be wound in parallel depending on the requirements of electrical design and manufacturing.

Next, a second embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. The circuit configuration of the inverter drive motor according to the second embodiment is the same as that of the first embodiment shown in FIG. 1. Inverters 3 are connected in parallel to the two windings A and B, respectively. Switching element S
W1 to SW6; connections in which current is supplied from each of the switching circuits 3A and 3B in which SW7 to SW12 perform on / off operations in opposite directions. However, AC motor 4
Is different from that of the first embodiment.

In the second embodiment, the number of slots in the stator of the AC motor 4 is 24 times the integer N (here, N = 2) times the normal number of slots 12 in the three-phase eight-pole motor. It is.

The windings of the windings A and B are U, V,
W, U, V, W, U, V, W, U, V, W, U ',
V ', W', U ', V', W ', U', V ', W',
Wind in the order of U ', V', W '. Since the number of slots is twice as large as normal, when windings of the same system are wound side by side, forward (indicated as U, V, W, U ', V', W ') and reverse ( U , V). V , W , U ', V ', W '). Further, similarly to the first embodiment, the windings of the different systems A and B are wound such that the windings of the different systems at the positions facing each other across the center of the stator are in opposite directions. I have.

That is, U, V , W, U , V, W , U,
V , W, U , V, W , U ', V ', W ', U ', V ',
W ', U', V ', W', U ', V', W 'are wound.

In the first winding example of the second embodiment, similar windings of the same system are wound next to each other as in the first winding example of the first embodiment shown in FIG. By
The length of the winding can be minimized.

In the second embodiment, the windings can be wound in different manners as shown in FIGS. The winding method of the winding shown in FIGS.
In a concentrated winding motor having 8 phases and 24 slots, the windings are U, V, W, U ', V', W ', U, V, W,
U ', V', W ', U, V, W, U', V ', W',
It is wound in the order of U, V, W, U ', V', W '. Then, a winding system A of UVW and a winding system B of U'V'W '
, And the winding direction is the same, and only the V phase of each system is wound in the opposite direction to the others.

That is, U, V , W, U ', V ', W ',
U, V , W, U ', V ', W ', U, V , W, U',
V ', W', U, V , W, U ', V ', W 'are wound.

By adopting such a winding method,
Even in the case of another system, if they are in the same phase, they can be wound in the same direction, which facilitates production.

In addition, since the windings of the same system are wound facing each other with the center of the stator interposed therebetween, torque ripple due to unbalance of the winding system existing in manufacturing can be reduced.

In the second embodiment, the winding of the winding can be made different from those shown in FIGS. 17 and 18. The winding method of the winding shown in FIGS. 17 and 18 is as follows.
In a 3-phase, 8-pole, 24-slot concentrated winding motor,
The windings are U, V ', W, U', V, W ', U, V', W,
U ', V, W', U, V ', W, U', V, W ', U,
V ', W, U', V, W 'are wound in this order.

In this case, all the windings can be wound in the same direction and the same length, which facilitates manufacture.

In addition, by winding another type of winding next to it, imbalance can be eliminated even at the end coil portion, and the torque ripple can be extremely reduced. Also, even if one of the switching circuits 3A and 3B of the inverter 3 fails, the motor can be driven only by the other healthy switching circuit (although the rotation direction is reversed),
High fault tolerance and high reliability.

[Brief description of the drawings]

FIG. 1 is a circuit diagram according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing fluctuations of a current flowing through each phase winding of the AC motor and a voltage of a neutral point due to an electrical angle in the embodiment.

FIG. 3 is a circuit diagram of a circuit (a circuit that cannot generate motor torque) showing a connection relationship between an inverter and a winding of an AC motor that makes the total of terminal voltages of the AC motor constant over time.

FIG. 4 is a waveform chart showing switching drive waveforms of each phase during rectangular wave driving and PWM driving of the inverter according to the embodiment.

FIG. 5 is an explanatory diagram showing a change in a current flowing through windings of each phase of an AC motor and a voltage at a neutral point due to an electrical angle during PWM driving in the embodiment.

FIG. 6 is an explanatory diagram showing a state of a motor winding wound by one winding method in the embodiment.

FIG. 7 is an explanatory diagram showing how to wind the above windings in the above embodiment.

FIG. 8 is an explanatory diagram showing a state of a motor winding wound by another winding method in the embodiment.

FIG. 9 is an explanatory diagram showing how to wind the windings in the embodiment.

FIG. 10 is an explanatory diagram showing a state of a motor winding wound in still another winding manner in the embodiment.

FIG. 11 is an explanatory diagram showing how to wind the windings in the embodiment.

FIG. 12 is an explanatory diagram showing a state of a motor winding wound in still another winding mode in the embodiment.

FIG. 13 is an explanatory diagram showing a state of a motor winding wound in one winding method according to the second embodiment of the present invention.

FIG. 14 is an explanatory diagram showing how to wind the windings in the embodiment.

FIG. 15 is an explanatory diagram showing a state of a motor winding wound by another winding method in the embodiment.

FIG. 16 is an explanatory diagram showing how to wind the windings in the embodiment.

FIG. 17 is an explanatory diagram showing a state of a motor winding wound in still another winding manner in the embodiment.

FIG. 18 is an explanatory diagram showing how to wind the windings in the embodiment.

FIG. 19 is a circuit diagram of a conventional example.

FIG. 20 is an explanatory diagram showing a change in the current flowing through each phase winding of the AC motor and the voltage at the neutral point due to the electrical angle in the conventional example.

FIG. 21 is a circuit diagram of another conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Battery 2 Electrolytic capacitor 3 Inverter 3A, 3B Switching circuit 4 AC motor SW1-SW12 Switching element NA, NB Neutral point

Continued on the front page (72) Inventor Toshio Kikuchi 2 Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa Prefecture F-term (reference) 5H576 AA15 BB03 BB04 BB05 BB06 CC02 DD02 DD04 DD05 EE11 HA01 HB02 KK08 LL22 LL24 LL41

Claims (6)

[Claims] An inverter includes a stator that generates a rotating magnetic field, a rotor that rotates by the rotating magnetic field of the stator to generate mechanical power, and a plurality of windings that supply power to the stator. The plurality of windings are connected to the respective parallel switching circuits, and the plurality of windings are connected such that the sum of terminal voltages of the plurality of windings becomes substantially constant by switching operations of the plurality of switching circuits. An inverter drive motor for controlling current flowing in each of the plurality of systems, wherein the plurality of windings are concentrated windings. 2. The inverter drive motor according to claim 1, wherein the two windings connected to the two switching circuits are wound in opposite directions. 3. The inverter drive motor according to claim 1, wherein two windings connected to each of the two switching circuits are wound alternately. 4. The method according to claim 1, wherein the number of slots of the stator is set to an integral multiple of a normal number of slots, and the two windings connected to the two switching circuits are wound in opposite directions. Item 3. An inverter drive motor according to item 2. 5. The method according to claim 3, wherein the number of slots of the stator is set to an integral multiple of a normal number of slots, and the two windings connected to the two switching circuits are alternately wound. An inverter drive motor according to claim 1. 6. A winding system according to claim 2, wherein each of said two windings is wound in parallel for each phase.
An inverter drive motor according to any one of the above.