JP2003018887A - Device and method of controlling motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device and a method of controlling a motor such as a permanent magnet synchronous motor capable of driving motors in parallel without causing a cost increase. SOLUTION: In this device of controlling the motor for driving the first and the second permanent magnet motors 13A, 13B with an inverter 11, respective stator windings of the first and the second permanent magnet motors 13A, 13B are connected in series at every phase, and one end of the series connection is connected to the inverter 11 and the other end is short-connected between the respective phases.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor control device and method suitable for being applied to a vehicle drive control device.

[0002]

2. Description of the Related Art Conventionally, an induction motor is generally used as an electric motor used for driving a vehicle of this type. This is because the induction motor can stably perform so-called parallel driving in which the motors are connected in parallel and then driven by one inverter device, so that the cost of the inverter device can be reduced. In recent years, there has been an attempt to apply a permanent magnet electric motor to a vehicle driving electric motor for the purpose of further increasing the efficiency.

[0003]

However, the permanent magnet synchronous motor cannot be easily driven in parallel because of the following reasons, and it must be a so-called individual drive system in which one inverter device is prepared for one motor. Therefore, it was a high-cost system.

Parallel drive of permanent magnet motors is not easy because it is a type of synchronous motor. A plurality of synchronous motors, which are directly connected to wheels having different diameters or connected by gears, generally rotate at different rotational speeds.

Therefore, if synchronous motors having different rotational speeds are connected in parallel, regardless of the inverter operation,
An excessive cross current is generated due to the phase difference between the counter electromotive voltages, and the current causes an oscillating torque, which makes it impossible to secure a stable driving force, which is the original purpose.

Further, assuming that the permanent magnet electric motor is applied to a vehicle drive system, an IGBT (Insulated Gate B) that constitutes an inverter device should be assumed.
When a semiconductor element such as an i-polar transistor causes a short circuit failure, a large short circuit current continues to flow due to a back electromotive voltage generated by the rotation of the permanent magnet motor, which makes it impossible to move the vehicle.

As a solution to this problem, a system has been proposed in which an open switch for disconnecting electrical connection is provided between the inverter device and the electric motor, and the open switch is disconnected when the inverter device fails.

FIG. 6 shows the structure of a vehicle drive system provided with such an open switch, which includes a power feed system 10 including an overhead wire, a pantograph, etc., first and second inverter devices 11A and 11B, and a first inverter device 11B. 1, the second opening switch 12
A, 12B and the first and second permanent magnet electric motors 13A, 1
3B and the first and second rotor position sensors 14A, 14B
And first and second gears 15A and 15B, and first and second wheels 16A and 16B. Reference numeral 17 is a dolly.

However, the open switches 12A, 1
Since 2B is designed to withstand a relatively high voltage for vehicles, it is generally expensive and has a large volume, which adversely affects system cost reduction.

It is an object of the present invention to provide an electric motor control device and method capable of driving an electric motor such as a permanent magnet synchronous electric motor in parallel without increasing the cost.

[0011]

In order to solve the above-mentioned problems, the invention according to claim 1 is a motor control device for driving a plurality of multi-phase synchronous motors by an inverter device. A motor controller, wherein each phase is connected in series, one end of the series connection is connected to an inverter device, and the other end is short-circuited between the phases.

Further, in order to solve the above problems, a second aspect is provided.
The invention according to claim 2, wherein a plurality of multi-phase synchronous motors in which the stator windings are connected in series for each phase and one end of the series connection is connected to the inverter device and the other end is short-circuited between the phases A plurality of rotor position sensors that detect the rotor position of each of the electric motors, and position information of the electric motor that is the most delayed in phase based on the rotor position information from each of the rotor position sensors as the reference phase. And a control means for vector control of the electric motor.

Further, in order to solve the above problems, a third aspect
The invention according to claim 1 provides a plurality of multi-phase synchronous motors in which stator windings are connected in series for each phase and one end of the series connection is connected to an inverter device and the other end is short-circuited between the phases. In a motor control method for vector control, detecting the rotor position of each of the motors, and vector-controlling each of the motors with the rotor position information of the motor having the most delayed phase based on the rotor position information as a reference phase. A method for controlling an electric motor, comprising:

According to the first aspect of the present invention, the cross current can be prevented from occurring by connecting a plurality of electric motors in series.

According to a second aspect of the present invention, a plurality of electric motors are connected in series, and each electric motor is vector-controlled by using position information of the electric motor having the most delayed phase as a reference phase based on rotor position information of each electric motor. , If, for example, a semiconductor element has a short-circuit fault, a short-circuit current flows due to the combination of the back electromotive forces of the motors, but torque is generated in each motor due to the short-circuit current, and the rotation speed changes due to idling between the wheel rails. As a result, the counter electromotive voltages converge to a phase difference that cancels each other out, so that the short-circuit current in a steady state can be reduced.

According to the third aspect of the invention, the semiconductor elements are vector-controlled by using the position information of the motors having the most delayed phase as the reference phase on the basis of the rotor position information of each motor. In this case, a short circuit current flows due to the combination of the back electromotive forces of the motors, but torque is generated in each motor by the short circuit current, and the rotation speed changes due to idling between the wheel rails. Since they converge to the phase difference that cancels each other out, it is possible to reduce the short-circuit current in a steady state.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment in which the present invention is applied to a vehicle drive control device will be described below.

FIG. 1 is a block diagram of the apparatus of this embodiment in which the same parts as those in FIG. 6 which is a conventional example are designated by the same reference numerals.

The vehicle drive control device in this embodiment is
Three-phase inverter device 11, first and second permanent magnet motors 13A and 13B, and first and second rotor position sensors 1
It is composed of 6A and 16B.

The three-phase inverter device 11 includes a main circuit portion 100 composed of a semiconductor switching element such as an IGBT,
It is composed of the control unit 200, and is the same as a general inverter device that has been conventionally used in railway vehicles.
A voltage such as 00V is supplied through the pantograph of the power supply system 10, and the main circuit unit 20 is calculated according to the calculation result of the control unit 100.
A three-phase AC voltage having a desired voltage and frequency is output according to the ON / OFF pattern of each semiconductor switching element of 0.

The first permanent magnet electric motor 13A transmits the rotational torque to the first wheel 16A via the first gear 15A. Similarly, the second permanent magnet electric motor 13B transmits the rotational torque to the second wheel 16B via the second gear 15B.

First and second permanent magnet motors 13A, 13
The rotor of B may have the same structure as a general three-phase permanent magnet motor. First and second permanent magnet motors 13A, 13B
The stator winding of the conventional three-phase permanent magnet motor has one end output to the outside of the motor and connected to a three-phase AC power source such as an inverter device, and the other end inside the motor.
Although the phases are short-circuited, both ends are output to the outside of the electric motor and can be electrically connected to the outside.

One end of the three-phase winding is connected to U, V, and
W and the other end are named X, Y, and Z, respectively. U of the first permanent magnet motor 13A is a three-phase inverter device 11
Of the first permanent magnet motor 13A connected to the U phase of
Is similarly connected to the V phase and the W phase of the three-phase inverter device 11, respectively.

U of the second permanent magnet motor 13B is the first
Connected to X of the permanent magnet motor 13A, and V and W of the second permanent magnet motor 13B are similarly connected to the first permanent magnet motor 1
Connect to Y and Z of 3A.

X, Y, Z of the second permanent magnet motor 13B
Short-circuit each other.

In the vehicle drive control device having the above structure, even if the first permanent magnet motor 13A and the second permanent magnet motor 13B have different rotation states and different back electromotive force phases, the three-phase inverter device is provided. When 11 is not operated, that is, when all the semiconductor switching elements are off, an unintended excessive current does not flow.

Even if any one of the semiconductor switching elements constituting the main circuit portion of the three-phase inverter device 11 causes a short-circuit fault, as shown by the waveforms in FIG. The short circuit current flowing due to the short-circuiting of the sum of the counter electromotive voltages of the electric motor 13A and the second permanent magnet electric motor 13B generates electric motor torque, which causes idling between the wheels and the rail. As a result, the rotor phases θ1 and θ2 of the single motor have a phase difference of 180 ° and almost no short-circuit current flows.

Therefore, it is not necessary to provide a current cut-off switch for preventing the inverter device or the wiring cable from being burnt out due to the continuous short-circuit current, and the system cost can be reduced.

Next, a second embodiment of the present invention will be described with reference to FIGS. The system configuration of the vehicle drive control device according to the second embodiment is the same as that of the first embodiment, and is characterized by the control unit of the three-phase inverter device 11.

The control unit 100 of the three-phase inverter device 11 in the second vehicle drive control device includes a setting unit 101, a current command calculation unit 102, a d-axis current control unit 103, a q-axis current control unit 104, and dq3. Phase conversion unit 105 and three-phase dq
The conversion unit 106 and the reference phase selection unit 107 are included.

In the present embodiment, the d-axis is defined as the magnetic flux direction of the permanent magnet, and the q-axis is defined as the direction perpendicular thereto.

The current command calculator 102, the d-axis current controller 103, the q-axis current controller 104, and the dq three-phase converter 1
05 and the three-phase dq converter 106 can use the vector control method of the permanent magnet motor described in general literature as they are. The reference phase selecting unit 107 is particularly characteristic in this embodiment.

In the reference phase selector 107, the rotor phase θ1 output from the rotor position sensor 14A such as a resolver attached to the first permanent magnet motor 13A.
And the rotor phase θ2 output from the rotor position sensor 14B attached to the second permanent magnet electric motor 13B, the delay phase signal is selected by the following calculation and output as the vector control reference phase θr. To do.

(1) When 0 <θ1−θ2 <180 °, θr = θ2 (2) When 180 ° <θ1−θ2 <360 °, θr =
θ1 By taking the vector control reference phase in this way, the current is controlled to the operating point with the maximum torque, which will be described later.
The torque of the motor whose phase is delayed among the units always outputs a larger torque than the other motor, and as a result, the speed and phase of the two motors can be stably balanced.

FIG. 5 shows the operation when vector control is performed by the control block shown in FIG. 4 from the state where the initial phase difference is 45 ° when the diameters of the wheels to which the two electric motors are connected differ by 1%. It is a figure which shows a waveform.

Since the wheels have different diameters, when the wheels rotate at the same number of revolutions, the minute idling speed (generally called creep) between the wheels and the rail differs, so that the two electric motors in the steady state are operated. It can be seen that the output torque is different and the phase difference is not completely zero, but unstable operation such as vibration torque between the two electric motors does not occur.

In the current command calculation unit 102, the torque command TorqRef is input and the d-axis current commands IdRef and IqRef are obtained and output by the following calculation.

(1) When the motor to be controlled is a surface magnet type permanent magnet motor, the following formula is used.

[0039]

[Equation 1] ΦPM is a permanent magnet magnetic flux.

The surface magnet type permanent magnet motor does not generate reluctance torque because it has no rotor magnetic saliency. Therefore, even if a d-axis current is supplied, the current does not contribute to the torque. Therefore, with the above setting, the maximum torque can be output with the same current, high-efficiency driving is possible, and the two series electric motors are phase-synchronized in consideration of the operation of the reference phase selection unit 107. Also has the effect of balancing in the direction.

(2) If the motor to be controlled is a motor based on the principle of using reluctance torque and permanent magnet torque in combination, such as a permanent magnet reluctance motor and an embedded magnet type permanent magnet motor, the following equation is satisfied. By setting the non-zero d-axis current command IdRef, it becomes possible to output the maximum torque with the same current, as in the above.

[0042]

[Equation 2] ΦPM is a permanent magnet magnetic flux.

ΔL = Ld-Lq, where Ld is the d-axis inductance and Lq is the q-axis inductance.

[0044]

[Equation 3] Is the current amplitude.

In the d-axis current control unit 103, the deviation between the d-axis current command IdRef and the d-axis current feedback value Id is input, and the result of PI (proportional / integral) control is set so that the deviation becomes zero. The voltage command Vd is output.

[0046]

[Equation 4] Where KpACR is the current control proportional gain, and Ki
ACR is a current control integral gain, and s is a differential operator.

In the q-axis current controller 104, the deviation between the q-axis current command IqRef and the q-axis current feedback value Iq is input, and the result of PI (proportional / integral) control is set so that the deviation becomes zero. Output as voltage command Vq.

In the dq three-phase converter 105, the d-axis voltage command Vd, the q-axis voltage command Vq,

[Equation 5]

Three-phase voltage commands Vu, Vv, Vw are obtained and output by the following calculation using the vector control reference phase θr as an input.

[0050]

[Equation 6]

In the three-phase dq converter 106, the U-phase current feedback value Iu, the W-phase current feedback value Iw, and the vector control reference phase θr are input, and the dq-axis current feedback values Id and Iq are calculated by the following calculation. Ask and output.

[0052]

[Equation 7]

In the above embodiment, the surface magnet type permanent magnet electric motor, the permanent magnet reluctance electric motor or the embedded magnet type permanent magnet electric motor is exemplified as the controlled electric motor, but the present invention can be applied to other permanent magnet synchronous electric motors. .

[0054]

As described above, according to the present invention, by taking the phase of the motor with the longest delay as the vector control reference phase and controlling the current to the operating point with the maximum torque, the motor with the delayed phase can be controlled. It is possible to provide a motor control device and method capable of constantly outputting a torque larger than that of other motors, and as a result capable of stably balancing the speeds and phases of a plurality of motors.

[Brief description of drawings]

FIG. 1 is a diagram showing a system configuration of a first embodiment.

FIG. 2 is a diagram illustrating a connection between an electric motor and wheels according to the first embodiment.

FIG. 3 is a diagram showing waveforms when the inverter device semiconductor switching element is short-circuited in the configuration of the first embodiment.

FIG. 4 is a control block diagram according to a second embodiment.

FIG. 5 is a diagram showing waveforms when control is performed in the control configuration of the second embodiment.

FIG. 6 is a diagram showing a system configuration of a conventional embodiment.

[Explanation of symbols]

10 ... Power supply system 11 ... Inverter device 100 ... Control unit 101 ... Setting unit 102 ... Current command calculation unit 103 ... d-axis current controller 104 ... q-axis current controller 105 ... dq three-phase converter 106 ... Three-phase dq converter 107 ... Reference phase selection unit 200 ... Main circuit section 13A, 13B ... First and second permanent magnet motors 14A, 14B ... First and second rotor position sensors 15A, 15B ... First and second gears 16A, 16B ... first and second wheels 17 ... trolley

Continued front page    F-term (reference) 5H115 PA08 PC02 PG01 PI03 PI29                       PU11 PV09 PV23 QN09 QN22                       QN23 RB11 RB15 RB22 RB26                       SE03 SE10 TO12 TO30                 5H572 AA01 BB02 CC01 DD05 EE06                       GG04 HA10 HB08 HB09 HC02                       JJ24 LL22 LL32                 5H576 AA01 CC01 DD02 DD05 EE01                       GG04 HA04 HB02 JJ24 LL22                       LL41

Claims (4)

[Claims] 1. A motor control device for driving a plurality of multi-phase synchronous motors by an inverter device, wherein stator windings of each of the motors are connected in series for each phase, and one end of the series connection is connected to the inverter device. In addition, the motor control device is characterized in that the other end is short-circuited between the phases. 2. A plurality of multi-phase synchronous motors in which stator windings are connected in series for each phase and one end of the series connection is connected to an inverter device and the other end is short-circuited between the phases. A plurality of rotor position sensors for detecting the rotor position of each of the electric motors, and the rotor position information of the electric motor having the most delayed phase based on the rotor position information from each of the rotor position sensors as the reference phase. An electric motor control device, comprising: a control unit that vector-controls each electric motor. 3. A plurality of multi-phase synchronous motors in which stator windings are connected in series for each phase, one end of the series connection is connected to an inverter device, and the other end is short-circuited between the phases. In a motor control method for vector control, detecting the rotor position of each of the motors, and vector-controlling each of the motors with the rotor position information of the motor having the most delayed phase based on the rotor position information as a reference phase. A method for controlling an electric motor. 4. The torque of the motor with the delayed phase is set to be larger than that of the other motor by controlling the current to the operating point with the maximum torque by using the rotor position information of the motor with the delayed most phase as a reference phase. The electric motor control method according to claim 3, wherein the electric motor is controlled to output.