JP2003018886A - Motor drive controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor drive controller capable of attaining cost reduction in an inverter device, in individually driving a plurality of multi-phase synchronous motors. SOLUTION: This motor drive controller drives first and second permanent magnet motors 11, 12 with the first and the second inverter devices 21, 22 connected to the motors respectively. The first and the second inverter devices 21, 22 are connected in series on a DC side, connected with a bidirectinal chopper device 3 through switches 41, 42, 43, 44; and cut-off switches 71, 72 are provided between the first and the second inverter devices 21, 22 and the motors 11, 12. Switching is performed between the first and the second inverter devices 21, 22 and the bidirectional chopper device 3 by controlling switching operations of the switches 41, 42, 43, 44.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric motor drive control device 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 improving the efficiency.

[0004]

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, when the synchronous motors having different rotational speeds are connected in parallel, an excessive cross current is generated due to the phase difference of the counter electromotive voltages regardless of the operation of the inverter device, and an oscillating torque is generated by the current. However, it becomes impossible to secure the stable driving force which is the original purpose.

Further, since the switching element, which is a main component of the main circuit of the inverter device, can directly apply a high voltage of, for example, 1500 V, which is the overhead line voltage in the conventional individually controlled inverter device, IGBT (Insulated G) with a voltage rating of 3300 V or higher
A semiconductor switching element such as an ATE Bipolar Transistor is generally used.

However, it is much more expensive than the IGBT element widely used in the general industry with a maximum voltage rating of 1700 V or less, and the switching loss and the conduction loss are also large, so that the heat generated by the inverter operation is absorbed. The cooler is also large and expensive.

An object of the present invention is to provide an electric motor drive control device capable of reducing the cost of an inverter device when individually driving a plurality of multi-phase synchronous electric motors.

[0010]

In order to solve the above-mentioned problems, an electric motor drive control device of the present invention is a motor drive control device for driving and controlling a plurality of multi-phase synchronous electric motors by a plurality of inverter devices connected to the respective electric motors. In the plurality of inverter devices, the direct current side is connected in series, a bidirectional chopper device is connected via a switch, and a switch is provided between the inverter device and the electric motor. The inverter device and the bidirectional chopper device are switched.

According to the present invention, even if one or a plurality of inverter devices should fail, the bidirectional chopper device can drive and control the electric motor by controlling the opening / closing of the switch.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a motor drive control device according to the present invention will be described below with reference to the drawings.

The electric motor drive control device according to this embodiment is an example of application to a vehicle drive control device, and includes first and second three-phase permanent magnet electric motors 11 and 12, and first and second inverter devices 21 and 21. 22, a bidirectional chopper device 3, and a first
The switch 41, the second switch 42, the third switch 43, the fourth switch 44, the first disconnecting switch 71, the second disconnecting switch 72, and the capacitors 3A, 21A, and 22A. Composed.

The first permanent magnet motor 11 is connected to the first inverter device 21 via a first disconnecting switch 71. This first disconnection switch 71 is
Of the permanent magnet electric motor 11 of the first inverter device 21.
When it is desired to disconnect the first permanent magnet electric motor 11 and the first inverter device 21 such as in the case of the failure of, the disconnection operation is performed by an external signal.

Similarly, the second permanent magnet motor 21 is connected to the second inverter device 22 via the second disconnecting switch 72. The second disconnect switch 72 is
It is composed of a switch that can electrically disconnect each phase of the second permanent magnet motor 12, and it is desired to disconnect the second permanent magnet motor 12 and the second inverter device 22 when the second inverter device 22 fails. Sometimes, it operates by disconnecting by an external signal.

Further, the first permanent magnet electric motor 11 has the first
The rotational torque is transmitted to the first wheel 11B via the gear 11A. The first permanent magnet electric motor 11 is equipped with a rotation sensor 11C such as a resolver that detects rotor position information. The second permanent magnet electric motor 12 similarly has a second
The rotational torque is transmitted to the second wheel 12B via the gear 12A. The second permanent magnet electric motor 12 is equipped with a rotation sensor 12C such as a resolver that detects rotor position information.

The DC negative side of the first inverter device 21 is
It is electrically connected to the DC positive side of the second inverter device 22. The DC positive side of the first inverter device 21 is connected to the first switch 41 (SWinv1) and the DC reactor 5
And the overhead line 7 on the positive side of the DC power source via the pantograph 6.
Connected to. The DC negative side of the second inverter device 22 is connected to the rail 8 on the DC power source negative side via the second switch 42 (SWinv2).

The bidirectional chopper device 3 has two IGBT elements connected in series in which diodes are connected in anti-parallel to each other.
One end of the reactor is connected to the middle point of the T element.

The IG which constitutes the bidirectional chopper device 3
The serial positive side of the BT element is connected to the intermediate point between the first switch 41 (SWinv1) and the DC reactor 5 via the switch 43 (SWch1).

Further, I constituting the bidirectional chopper device 3
The series negative side of the GBT element has a switch 44 (SWch2).
Is connected to the middle point between the second switch 42 (SWinv2) and the rail.

Regarding the electric motor drive control device of the present embodiment configured as described above, first, the normal operation when the two inverter devices 21 and 22 and the bidirectional chopper device 3 are not defective will be described. To do.

During normal operation, the four switches 41, 42,
43, 44 and the two disconnecting switches 71, 72 are all closed.

The first inverter device 21 is a main inverter of the first inverter device 21 so that the first permanent magnet motor 11 can output a torque that follows a torque command TorqRef given from a driver's cab command or the like. The pulse width modulation operation is performed on the six switching elements forming the circuit section.

The control operation of the first inverter device 21 is as follows.
This is a generally known vector control method for a permanent magnet motor.

The operation of the control unit will be described below with reference to FIG.

The control unit of the first inverter device 21 inputs a torque command TorqRef based on a driver command or the like, and the rotations from the rotation sensors 11C and 12C provided on the first and second permanent magnet electric motors 11 and 12, respectively. The child position information is also input to control the main circuit units of the first and second inverter devices 21 and 22.

The control unit is the current command calculation unit 102.
A d-axis current control unit 103 and a q-axis current control unit 104
And a dq three-phase conversion unit 105 and a three-phase dq conversion unit 106.

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.

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.

First, when the motor to be controlled is a surface magnet type permanent magnet motor, the following calculation is performed.

[0031]

[Equation 1]

The surface magnet type permanent magnet motor does not generate reluctance torque because it has no rotor magnetic saliency. Therefore, even if the 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, and highly efficient driving becomes possible.

Next, when 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, a zero satisfying the following formula is satisfied. By setting the non-d-axis current command IdRef, the maximum torque can be output with the same current as in the above.

[0034]

[Equation 2]

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.

[0036]

[Equation 3] KpACR is a current control proportional gain, KiACR is a current control integral gain, and s is a differential operator.

In the q-axis current control unit 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.

[0038]

[Equation 4] KpACR is a current control proportional gain, KiACR is a current control integral gain, and s is a differential operator.

In the dp three-phase converter 105, the d-axis voltage command Vd, the q-axis voltage command Vq, and the vector control reference phase θr are input and the three-phase voltage commands Vu, Vv, Vw are obtained by the following calculation. Output.

[0040]

[Equation 5]

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.

[0042]

[Equation 6]

A PWM generally used for triangular wave comparison and the like for the three-phase voltage command output from the dq three-phase conversion unit 105.
By converting to the inverter operation by the (pulse width modulation) method and outputting the voltage according to the command, it becomes possible to generate the torque according to the torque command in the permanent magnet motor.

The controller of the second inverter device 22 is also the first
The same operation as the control unit of the inverter device 21 is performed.

Next, the control operation of the bidirectional chopper device 3 will be described with reference to FIG.

As shown in FIG. 3, the bidirectional chopper device 3
The control unit 31 controls the input voltage Vd of the bidirectional chopper device 3.
cC and the input voltage Vdc2 of the second inverter device 22.
And the bidirectional chopper device 3 output current Ich as an input, the voltage command Vc of the bidirectional chopper device 3 is calculated by the following calculation.
Calculate and output h.

[0047]

[Equation 7] KpCH is a chopper voltage control proportional gain, KiCH is a chopper voltage control integral gain, and Kp is a vibration control gain.

In the first term on the right side of the above equation, the voltage Vdc2 of the second inverter device 22 is 1/2 of the DC input voltage VdcC.
It means that the proportional-plus-integral control is performed so that the DC neutral point of the inverter device is controlled to approximately half the input DC voltage.

The second term on the right side is a vibration suppression term for stabilizing the control, and is an electrical resonance phenomenon that occurs between the reactor of the bidirectional chopper device 3 and the input capacitors 21A and 22A of the inverter devices 21 and 22. It is necessary to suppress.

The Vch obtained by the above calculation is output as the gate signal GchP of the arm on the bidirectional chopper device 3 in accordance with the generally used triangular wave comparison PWM method. The gate signal of the lower arm of the bidirectional chopper device 3 is
When GchP is 1, it is 0, and when GchP is 0, it is 1 and the reverse operation is performed.

By the above operation, the bidirectional chopper device 3
Is the first inverter device 21 and the second inverter device 2
It is possible to suppress the DC neutral point imbalance due to the output imbalance with 2.

Next, the IGB of the first inverter device 21
The operation when the T element fails will be described with reference to FIGS.

In FIGS. 4 and 5, the same parts as those in FIG. 1 are designated by the same reference numerals, and the failed first inverter device 21 is not shown.

When the first inverter device 21 fails, there is a possibility that the both ends of the IGBT element are short-circuited as a possibility of failure. In this case, if a DC voltage is applied as in the normal state, the first inverter device 21 will fail. Is short-circuited, and the total DC voltage is applied to the second inverter device 22, so that the second inverter device 22 is also damaged by the overvoltage.

When the first inverter device 21 fails, the first switch 41 and the first disconnecting switch 7
1 is separated, and the operation is continued only by the second inverter device 22 and the bidirectional chopper device 3.

The electrical connection at this time is as shown in FIG.
The overhead line voltage 1500V is stepped down by the bidirectional chopper device 3 to supply the power to the second inverter device 22 to form a main circuit configuration. The operation of the control unit of the second inverter device 22 is
The operation is the same as the operation of the control unit of the second inverter device 22 at the normal time.

The operation of the control unit 31 of the bidirectional chopper device 3 will be described with reference to FIG.

The control unit 31 of the bidirectional chopper device 3 receives the input voltage VdcC of the bidirectional chopper device 3, the input voltage Vdc2 of the second inverter device 22, and the output current Ich of the bidirectional chopper device 3 as input and outputs the following. By calculation, the voltage command Vch of the bidirectional chopper device 3 is obtained and output.

[0059]

[Equation 8] KpCH is a chopper voltage control proportional gain, KiCH is a chopper voltage control integral gain, and Kp is a vibration suppression gain.

VdcRef is the second inverter device 22.
Is a DC voltage command value of, and in consideration of the maximum voltage rating of the IGBT element of the second inverter device 22, for example, 1000
A value such as V is used.

The first term on the right side of the above equation is that the second inverter device 22 voltage Vdc2 is the inverter device voltage command VdcR.
ef represents that proportional / integral control is performed, and as a result, the inverter device DC neutral point is controlled so as to follow the DC voltage command value.

The second term on the right side is a vibration suppression term for stabilizing the control, and is an electrical resonance phenomenon that occurs between the reactor of the bidirectional chopper device 3 and the input capacitors 21A and 21B of the inverter devices 21 and 22. It is necessary to suppress.

The Vch obtained by the above calculation is output as the gate signal GchP of the upper arm of the bidirectional chopper device 3 in accordance with the generally used triangular wave comparison PWM method. The gate signal of the lower arm of the bidirectional chopper device 3 is
When GchP is 1, it is 0, and when GchP is 0, it is 1 and the reverse operation is performed.

With the above configuration and operation, even when the first inverter device 21 fails, the second inverter device 22 can drive the second permanent magnet motor as usual, The redundancy of the system can be improved.

Next, the second inverter device 22 is connected to the IGB.
The operation when a T element failure occurs will be described with reference to FIG.

In FIG. 6, the same parts as those in FIG. 1 are designated by the same reference numerals, and the illustration of the defective second inverter device 22 is omitted.

When the first inverter device 21 has a failure, there is a possibility of a short-circuit failure at both ends of the IGBT element as a possibility of failure. In this case, when the DC full voltage is applied as in the normal state, the second inverter device 22 is short-circuited. Since the total DC voltage is applied to the first inverter device 21, the first inverter device 21 is also broken due to the overvoltage. When the second inverter device 22 fails, the second switch 4
2 and the second disconnection switch 72 are disconnected, and the operation is continued only by the first inverter device 21 and the bidirectional chopper device 3.

The electrical connection at this time is as shown in FIG.
The overhead line voltage 1500V is stepped down by the bidirectional chopper device 3 to supply the first inverter device 21 with a main circuit. The operation of the control unit of the first inverter device 21 is
The operation is the same as that of the control unit of the first inverter device 21 in the normal state.

Here, the control unit 3 of the bidirectional chopper device 3
The operation of No. 1 will be described with reference to FIG.

The control section 31 of the bidirectional chopper device 3 receives the input voltage VdcC of the bidirectional chopper device 3, the input voltage Vdc1 of the first inverter device 21, and the output current Ich of the bidirectional chopper device 3 as inputs. By the calculation of
Bidirectional chopper device 3 Obtains and outputs a voltage command Vch.

[0071]

[Equation 9] KpCH is a chopper voltage control proportional gain, KiCH is a chopper voltage control integral gain, and Kp is a vibration suppression gain.

VdcRef is the first inverter device 21.
Is a DC voltage command value of, and in consideration of the maximum voltage rating of the IGBT element of the first inverter device 21, for example, 1000
A value such as V is used.

The first term on the right side of the above equation is that the voltage Vdc1 of the first inverter device 21 is the inverter device voltage command Vdc.
Indicates that proportional-integral control is performed on Ref. As a result,
The DC neutral point of the inverter device is controlled so as to follow the DC voltage command value. The second term on the right side is a vibration suppression term for stabilizing the control, which is a reactor of the bidirectional chopper device 3 and the input capacitors 21A, 22 of the inverter devices 21, 22.
It is necessary to suppress the electrical resonance phenomenon that occurs between A and A.

The control gain is the first inverter device 21.
It was Kp when the failure occurred, but -Kp is used in this failure mode. This is because the connection between the bidirectional chopper device 3 and the output DC is opposite to that when the first inverter device 21 fails.

The Vch obtained by the above calculation is output as the gate signal GchN of the lower arm of the bidirectional chopper device 3 in accordance with the generally used triangular wave comparison PWM method. The gate signal of the upper arm of the bidirectional chopper device 3 is
When GchN is 1, the reverse operation is 0, and when GchN is 0, the reverse operation is 1.

With the above configuration and operation, even when the second inverter device 22 fails, the first inverter device 21 can drive the first permanent magnet motor as usual, The redundancy of the system can be improved.

Next, the operation when the bidirectional chopper device 3 fails will be described with reference to FIGS. 7 and 8.

When the bidirectional chopper device 3 fails,
The third switch 43 and the fourth switch 44 are separated.
Note that FIG. 7 shows the bidirectional chopper device 3 in FIG. 1 from which the bidirectional chopper device 3 is omitted, and FIG. 8 shows the operation in the configuration of FIG.

In the control section of the first inverter device 21,
The first permanent magnet electric motor 1 is based on a new torque command TorqRef that is composed of a torque command TorqRef0 from the driver's cab and a torque command correction value ΔTorqRef that is the result of the balance control of the DC midpoint voltage shown below.
The three-phase voltage commands Vu, Vv, Vw are output so that the output torque of 1 follows the torque command value TorqRef.

The calculation from TorqRef to the three-phase voltage command is the same as that shown in the control block shown in FIG.
The balance control of the DC intermediate point is performed by the first inverter device 2
Using the DC input voltage Vdc1 of 1 and the input voltage VdcC of the bidirectional chopper device 3, the torque command correction value ΔTorqRef is obtained by the following calculation.

[0081]

[Equation 10] KpNV is a balance control proportional gain, and KiNV is a balance control integral gain.

A new torque command TorqRef is obtained by the following calculation using the torque command TorqRef0 from the driver's cab and the torque command correction value ΔTorqRef obtained by the above calculation.

TorqRef = TorqRef0 + ΔTorqRef In the control section of the second inverter device 22, the torque command correction value ΔT which is the result of the balance control of the torque command TorqRef0 from the driver's cab and the DC midpoint voltage shown below.
new torque command Torq synthesized with orqRef
Based on Ref, the three-phase voltage commands Vu, Vv, Vw are output so that the output torque of the second permanent magnet electric motor 12 follows the torque command value TorqRef. TorqRef
Calculations from 1 to 3 phase voltage command are the same as those shown in the control block shown in FIG.

For the balance control of the DC midpoint, the torque command correction value ΔTorqRef is obtained by the following calculation using the DC input voltage Vdc2 of the second inverter device 22 and the input voltage VdcC of the bidirectional chopper device 3.

[0085]

[Equation 11] KpNV is a balance control proportional gain, and KiNV is a balance control integral gain.

A new torque command TorqRef is obtained by the following calculation using the torque command TorqRef0 from the driver's cab and the torque command correction value ΔTorqRef obtained by the above calculation.

ΔTorqRef = TorqRef0 + ΔTorqRef By the above inverter operation, even if the bidirectional chopper device 3 fails, the DC midpoint voltage is stably controlled to approximately half of the overhead line voltage, and only one inverter device has an overvoltage. It is not applied and thus allows the operation to continue.

As described above, in this embodiment, it is possible to use a switching element having a low maximum voltage rating.
Connect the inverter units of the stand in series and then connect to the overhead line DC power supply. With this alone, in the unlikely event that one inverter device fails, the voltage cannot be supplied to the other inverter device, and the redundancy of the system is reduced.

Therefore, two arms composed of switching elements in which diodes are connected in anti-parallel are connected in series and connected to both DC ends of the series-connected inverter device, and the connection intermediate point of the series inverter device and the two arms are connected. The bidirectional chopper device 3 in which the reactor is provided between the serial connection points of is formed.

Further, a switch that can be electrically disconnected is provided in each wiring which is not a connection point between the inverter devices of the DC input of the two inverter devices connected in series, and both ends of the input of the bidirectional chopper device 3 are provided. Also, switches 43 and 44 that can be electrically separated are provided.

For example, when the first inverter device 21 connected in series fails, the DC positive side switch of the first inverter device 21 is disconnected, and the bidirectional chopper device 3 changes the voltage across the second inverter device to a desired voltage. For example, when the overhead line voltage is 1500V, it is controlled to 750V, which is half the voltage. By supplying power to the synchronous motor connected as a load by the second inverter device in a normal operation, the second inverter device can be accelerated with half the propulsive force when the two inverter devices are not in failure.

Similarly, when the second inverter device fails, the negative side switch of the second inverter device is disconnected, and the bidirectional chopper device 3 controls the voltage across the first inverter device.

When the bidirectional chopper device 3 fails,
The two switches attached to the inputs of the bidirectional chopper device 3 are separated from each other and operated by only two inverter devices. When a load power difference occurs due to a difference in the number of rotations of the electric motors attached to the inverter devices 21 and 22, the DC intermediate points connected in series become unbalanced, and one inverter device is applied with a voltage higher than the maximum rating. However, by detecting the imbalance of the DC midpoint voltage and correcting the output torque commands of the two electric motors so that the DC voltages are balanced, the imbalance can be suppressed. That is, for example, when the DC voltage of the first inverter device 21 becomes higher than the DC voltage of the second inverter device 22, the torque command of the synchronous motor 11 connected to the first inverter device 21 is increased, and at the same time, the torque command is increased. By decreasing the torque command of the synchronous motor 12 connected to the 2-inverter device 22, the current flowing into the DC intermediate point increases and the voltage imbalance can be suppressed.

[0094]

As described above, according to the present invention, it is possible to apply a semiconductor switching element which has a relatively low maximum voltage rating and is widely used in general industry, so that the cost of the apparatus can be reduced. In addition, even if one inverter device fails, the bidirectional chopper device can continue the operation with half the torque by operating the motor drive that can increase the redundancy of the system. A control device can be provided.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a circuit configuration in an electric motor drive control device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a control block of a permanent magnet motor.

FIG. 3 is a diagram for explaining a control operation of the bidirectional chopper device at the time of soundness.

FIG. 4 is a diagram illustrating a circuit configuration when the first inverter device fails.

FIG. 5 is a diagram illustrating a control operation of the bidirectional chopper device when the first inverter device fails.

FIG. 6 is a diagram for explaining the control operation of the bidirectional chopper device when the second inverter device fails.

FIG. 7 is a diagram illustrating a circuit configuration when the bidirectional chopper device fails.

FIG. 8 is a diagram for explaining the control operation of the first inverter device when the bidirectional chopper device fails.

[Explanation of symbols]

3 ... Bidirectional chopper device 5 ... DC reactor 6 ... Pantograph 7 ... overhead line 8 ... Rail 11, 12 ... First and second permanent magnet motors 21, 22 ... First and second inverter devices 41, 42, 43, 44 ... Switch 71, 72 ... First and second disconnection switches

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H02P 7/63 303 H02P 7/63 303V 21/00 5/408 C F term (reference) 5H115 PA00 PC01 PG01 PI03 PI29 PU10 PV10 RB11 SE03 5H572 AA01 CC01 CC09 DD05 EE05 EE10 GG04 HA10 HB08 HB09 HC07 JJ24 LL22 LL32 5H576 AA01 CC01 DD02 DD07 EE01 EE11 GG04 HA04 HB02 HB05 JJ24 JJ29 LL22 LL41 LL58

Claims (2)

[Claims] 1. A motor drive control device for driving and controlling a plurality of multi-phase synchronous motors by a plurality of inverter devices connected to the respective motors, wherein the plurality of inverter devices are connected in series on the DC side and via a switch. A bidirectional chopper device is connected, a switch is provided between the inverter device and the electric motor, and the inverter device and the bidirectional chopper device are switched by opening / closing control of the switch. Control device. 2. The bidirectional chopper device, wherein first and second arms each composed of a switching element in which diodes are connected in anti-parallel are connected in series and connected to both DC ends of the series connected inverter device, 2. The electric motor drive control device according to claim 1, wherein a reactor is provided between a connection intermediate point of the inverter devices connected in series and a series connection point of the first and second arms.