JPH06113401A - Controller of inverter for driving electric motor vehicle - Google Patents

Abstract

PURPOSE:To prevent instability of control of an inverter and guiding fault of an external signal mechanism by preventing resonance at the time of varying a voltage due to charging/discharging filter capacitors of a plurality of filter circuits. CONSTITUTION:The controller of an inverter for driving an electric motor vehicle comprises a plurality of inverters 2, 3 connected in parallel to drive induction motors 8, filter capacitors 2, 3 for smoothing input voltages of the inverters 2, 3, main circuit switches 9M, 10M for switching the inverters 2, 3, and means for detecting voltage values of the capacitors 6, 7. When the switches 9M, 10M are closed and when the voltage difference of the capacitors is larger than a set value, the capacitors 6, 7 are so forcedly discharged as to control the capacitor voltages within the set value. Further, the controller comprises capacitor voltage control means for substantially equalizing the capacitor voltages of the filters.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an electric vehicle driving inverter that drives each of a plurality of inverters connected in parallel.

[0002]

2. Description of the Related Art An induction motor type electric vehicle is configured to drive an induction motor for each of a plurality of inverters connected in parallel. A filter is provided on the input side of each inverter to suppress harmonic current. Each inverter is configured to be connected in parallel from each protective switch that opens when its own abnormality occurs. Each of the inverters connected in parallel is connected to a current collector via a common main circuit switch, and is supplied with a DC voltage from a train line. The main electric circuit switch is closed by operating the handle of the main controller to give a powering signal. Such an induction motor type electric vehicle is disclosed in Japanese Unexamined Patent Application Publication No. Sho 61-61.
-88704. When an abnormality occurs in one inverter while the induction motor is operating with a plurality of inverters, the protective switch of the abnormal inverter is opened and the operation of the abnormal inverter is stopped. At this time, another healthy inverter continues to operate. After that, when the abnormality is removed, the inverter in which the abnormality has occurred closes the protective switch and restarts the operation.

[0003]

In order to restart the operation of the inverter in which an abnormality has occurred, when the protective switch is closed, the filter capacitor of the inverter that is healthy and continues to operate and the filter capacitor of the inverter that has an abnormality have occurred. Causes a voltage difference. The filter capacitor of a healthy inverter is at a voltage approximately equal to the line voltage,
When the protective switch of the inverter that has an abnormality is turned on,
A current flows into the filter capacitor of the inverter that has anomaly due to the voltage difference between both filter capacitors. As a result, the voltage of the healthy filter capacitor of the inverter drops. Then, the resonance action of both filters causes the potential to oscillate, making the inverter operation unstable, and in the worst case, stopping the operation. In addition, there is a problem that the signal equipment is inductively affected by the influence of the oscillating current. An object of the present invention is to provide a control device for an electric vehicle drive inverter, which is suitable for preventing the resonance action of the filter from occurring and performing stable control.

[0004]

In order to achieve the above object, when there is a difference between the voltages of the filter capacitors, control is performed so that resonance phenomenon does not occur in each capacitor. Desirably, it has a means for discharging the charged charge of each capacitor.

[0005]

When the voltage values of the filter capacitors are different from each other, the charge of each capacitor is discharged so that the voltage difference is eliminated. This can prevent the occurrence of the resonance phenomenon.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a main circuit configuration of an induction motor type electric vehicle control device to which the present invention is applied, and FIG. 2 shows an embodiment of the present invention and shows a voltage control device for capacitors 6 and 7. In FIG. 1, two inverters 2 and 3 drive two induction motors 8, respectively. A reactor 4 and a capacitor 6 which form a filter are connected to the input side of the inverter 2, and a reactor 5 and a capacitor 7 which form a filter are connected to the input side of the inverter 3. The voltage across the capacitors 6 and 7 is detected by the voltage detector 16 or 17, respectively. The train line sides of the reactors 4 and 5 are connected via a protective switch 14 or 15. The inverters 2 and 3 are connected in series with the protection switches 14 and 15, respectively. The current collector 1B collects a DC voltage from the train line 1A. Current collector 1B and protective switch 14,
The main circuit breakers 9M and 10M, the circuit breaker 11 and the breaker 12 are connected in series between 15 and 15. A charging resistor 13 for suppressing an inrush current is connected in parallel to the switch 12.
The main circuit switches 9M and 10M are opened and closed by the coils of the switches 9 and 10 which are energized by the notch signal. Figure 2
In, the voltage values V ₁ c and V ₂ c detected by the voltage detectors 16 and 17 are added by the adder 24 with the polarities shown. The voltage difference ΔVc is the absolute value |
Calculated as ΔVc | and set value ΔVs in the comparator 19
Compared to. The comparator 19 turns on the transistor 25 when ΔVc> ΔVs. Normally open contact 2 of switch 20
0a, the normally closed contacts 9b and 10b of the switches 9 and 10 and the switch 21 are connected in series. When the switch 21 is excited, the normally open contacts 21a1, 21a2 are closed. In addition,
22 and 23 are discharge resistors of the capacitors 6 and 7.

Next, the operation will be described. To operate the inverters 2 and 3, a driver operates a handle of a master controller (not shown) to give a powering signal to excite the main circuit breakers 9 and 10. At this time, the circuit breaker 11 and the protective switches 14, 1
5 is closed, capacitors 6 and 7 are charging resistors 13
Be charged through. When the charging of the capacitors 6 and 7 is completed, the switch 12 is closed and the charging resistor 13 is short-circuited.
After that, the inverters 2 and 3 are operated and the induction motor 8
To drive. When the inverters 2 and 3 are operated in this manner, the voltage of the capacitors 6 and 7 is detected by the voltage detectors 16 and 17. Voltage detector 16, 17
The deviation ΔVc is obtained from the voltage values V ₁ c and V ₂ c detected by the adder 24 and the absolute value | ΔV is obtained by the absolute value calculator 18.
Find c│. The comparator 19 has a voltage difference ΔVc and a set value Δ.
Vs is compared, and when ΔVc> ΔVs, a 1-level signal is output and the transistor 25 is turned on. Set value ΔVs
Is selected to a voltage difference value that does not cause resonance development. When the transistor 25 is turned on, the switch 20 is excited and the normally open contact 20a is closed. The contact 20a is closed,
When the normally closed contacts 9b, 10b of the main circuit breakers 9, 10 are closed, that is, when the power running signal is not given,
The switch 21 is excited and its main contact (normally open contact) 21a
1, 21a2 are closed. By closing the main contacts 21a1, 21a2, the charges of the capacitors 6, 7 are discharged via the resistors 22 and 23, respectively. Capacitors 6,7
Is continuously discharged until the voltage difference ΔVc becomes equal to or less than the set value ΔVs. In this way, when the main circuit breakers 9 and 10 are opened and the inverters 2 and 3 are not operating, if the voltage difference between the filter capacitors 6 and 7 is equal to or greater than the set value, both filters are forcibly forced. The capacitors 6 and 7 are discharged so that there is no voltage difference, and there is no problem even if a powering signal is given. Therefore, then
Even if a power running signal is given, the inverters 2 and 3 do not resonate, and the inverter can be operated stably. In addition, no oscillating current flows in the train line 1A, and the occurrence of inductive obstacles can be prevented. In the embodiment of FIG. 2, the switch 21 discharges the capacitors 6 and 7, but the same can be done by using the thyristors 28 and 29 as shown in FIG.

FIG. 4 shows another embodiment of the present invention. Figure 4
When the capacitors 6 and 7 have a voltage difference, the normally-closed contact 20b of the switch 20 causes the main circuit breakers 9 and 10 to operate.
It is designed so that is not input. Reference numerals 9a and 10a are normally open contacts for self-holding of the main circuit breakers 9 and 10.
In the present embodiment, when there is a voltage difference between the capacitors 6 and 7, the transistor 25 is turned on to excite the switch 20 and open its normally closed contact 20b. Therefore, the main circuit breakers 9 and 10 are not turned on. However, if a voltage difference occurs for some reason while the main circuit breakers 9 and 10 are turned on, that state is maintained as long as there is a powering signal. However, if the power running signals are once released thereafter and there is still a difference, the normally closed contact 20b is opened, and the normally open contacts 9a and 10a for self-holding of the main circuit breakers 9 and 10 are opened. This prevents the main circuit breakers 9 and 10 from being turned on again.

Next, in the above-mentioned embodiment, the capacitors 6 and 7 are used.
Although the voltage of 16 is detected by the voltage detectors 16 and 17, it can be performed without detecting this voltage. Figure 5
Shows an example thereof. In FIG. 5, when the power running signal is once opened and the main circuit breakers 9 and 10 are opened, and there is a voltage difference between the capacitors 6 and 7, even if the power running signal is immediately input, the main circuit breaker 9 is input. , 10 cannot be re-input.
That is, the normally open contacts 9a2,1 of the main circuit breakers 9,10
Even if 0a2 is opened, the delay circuit 27 continues to operate for a predetermined time and opens its normally closed contact 26b. For this reason, even if the power running signal is input, the main electric circuit switches 9 and 10 cannot be reclosed unless a predetermined time elapses. Here, as the predetermined time, at least the time from the time when the difference between the capacitor voltages is maximum to the time when the difference between the capacitor voltages is reduced to a value that causes no practical problem is necessary, and is set by the delay circuit 27. In this example, it is not necessary to detect and compare the voltages, and the device can be simplified.

FIG. 6 shows another embodiment of the present invention. Figure 6
Shows an example in which when one of the inverters becomes abnormal and the protective switch is opened, the driver performs powering again after turning off the main controller. In FIG. 6, the same symbols as those in FIG. 2 indicate the equivalents. In the comparators 30 and 31, the voltage value Vc1,
Vc2 is compared with the polarity shown. Comparator 30 has Vc2>
When it is Vc1, it outputs a 1-level signal, and the comparator 31 outputs Vc.
When 1> Vc2, a 1-level signal is output. The AND circuits 32 and 33 input the outputs of the comparator 19 and the comparator 30 or 31. One of the high voltage capacitors 6 and 7 is selected from the AND circuits 32 and 33. The outputs of the AND circuits 32 and 33 and the power running signal are guided to the delay circuits 36 and 37 via the OR circuits 34 and 35. The ON / OFF signal of the delay circuit 36 and the switch 14 is given to the transistor 40 via the AND circuit 38, and the delay circuit 37 and the switch 15 are also connected.
The ON / OFF signal of is supplied to the transistor 4 via the AND circuit 39. Now, assuming that an abnormality has occurred in the inverter 2, the powering signal is still supplied at this time, the delay circuit 36 is producing an output, and the AND circuit 3
Reference numeral 8 inputs a cutoff signal of the switch 14 to turn off the transistor 40 and open the switch 14. After that, the power running signal is cut off by the driver's operation, so the main circuit breakers 9, 1
0 is released. The voltage Vc2 of the capacitor 7 is the voltage Vc1
Since it is larger, the switch 15 is opened. Next, when the abnormal signal generated in the inverter disappears due to the opening of the main circuit breakers 9 and 10, an input signal of the switch 14 is given to close the switch 14. Next, when a powering signal is given by the driver's operation, the switches 9 and 10 are closed.
After that, when the voltages of both capacitors 6 and 7 become substantially equal, the switch 15 is turned on. In this way, even if one of the inverters becomes abnormal and the protective switch is opened / closed, it is possible to smoothly shift to the powering again.

[0011]

According to the present invention, when there are differences in the voltage values of the filter capacitors of a plurality of inverters connected in parallel, the voltage values of all the capacitors are forcibly decreased, or decreased. Since the switch is turned on after waiting for the start of the operation, it is possible to prevent the control from becoming unstable during the inverter operation due to the resonance phenomenon of the filter circuit, and to prevent the induction failure to the signal equipment due to the outflow of the oscillating current. It is possible to prevent such problems.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a configuration diagram of a main part of an embodiment of the present invention.

FIG. 3 is a configuration diagram showing another embodiment of the present invention.

FIG. 4 is a configuration diagram showing another embodiment of the present invention.

FIG. 5 is a configuration diagram showing another embodiment of the present invention.

FIG. 6 is a configuration diagram showing another embodiment of the present invention.

[Explanation of symbols]

 1 Current Collector 2, 3 Inverter Device 4, 5 Filter Reactor 6, 7 Filter Capacitor 8 Induction Motor 9, 10, 12, 14, 15, 21 Switch 11 Shaker 13 Charging Resistor 16, 17 Voltage Detector 18 Absolute value calculator 19 Comparator 22, 23 Discharge resistor 27 Delay circuit

Claims (6)

[Claims] 1. A plurality of inverters connected in parallel, each driving an induction motor, a filter capacitor provided on the input side of each inverter, and a main circuit switch for turning on / off power supply to the plurality of inverters. And a capacitor voltage control means for controlling the voltage of the filter capacitor for each of the inverters to be substantially equal to each other. 2. A plurality of inverters connected in parallel to each drive an induction motor, a filter capacitor for smoothing the input voltage of each inverter, and a main circuit switch for turning on / off the power supply to the plurality of inverters. And a capacitor voltage control means for forcibly discharging the electric charge of the filter capacitor of each inverter to control the voltage of each filter capacitor to be substantially equal to each other. 3. A plurality of inverters connected in parallel for driving an induction motor, a filter capacitor provided for each inverter to smooth an inverter input voltage, and a main power line for turning on / off power supply to the plurality of inverters. A switch,
When the main circuit switch is turned on, when the voltage difference between the capacitors is larger than a set value, a capacitor voltage control means for controlling the capacitor voltage within the set value is provided. Inverter control device. 4. A plurality of inverters connected in parallel to drive an induction motor, a filter capacitor provided for each inverter to smooth the inverter input voltage, and a main circuit switch for turning on / off the power supply to the inverter. And a capacitor voltage control means for controlling the voltage of the capacitor so that each of the filters does not cause a resonance phenomenon. 5. A plurality of inverters connected in parallel for driving an induction motor, a filter capacitor provided for each inverter for smoothing an inverter input voltage, and a main unit for turning on / off power supply to the plurality of inverters. An electric circuit switch, a voltage detection unit that detects the voltage of each capacitor, and a closing prevention unit that prevents the main circuit switch from being closed when the voltage difference between the capacitors is larger than a set value. A control device for an electric vehicle drive inverter. 6. The main circuit switch according to claim 5, when the main circuit switch is released from the closed state, and when there is a difference in the voltage value of each filter capacitor from that time, the time corresponding to the time when it disappears is A control device for an inverter for driving an electric vehicle, characterized in that the main electric circuit switch is not reclosed.