JPH0614402A - Controller for inverter of electric motor vehicle - Google Patents

Abstract

PURPOSE:To provide a controller for an inverter of an electric motor vehicle adapted to avoid an unnecessary operation of a protecting apparatus on the ground to generate at the time of shutting OFF regenerative load in the vehicle to be regeneratively driven. CONSTITUTION:A controller for an electric motor vehicle comprises an AC motor for driving the vehicle, an inverter having functions for traveling and regeneratively driving, a capacitor inserted between positive and negative electrodes of a DC side of the inverter, a reactor inserted in series with a power source side of the capacitor, and a breaker connected to the power source side of the reactor. A voltage 33 of the capacitor is compared at least at two stage levels 44, 45. If it exceeds a lower voltage, a gate signal 34 (a)-(f) of the inverter is turned OFF to stop it, the breaker is opened by a signal 31. Further if the voltage of the capacitor exceeds a higher voltage, a semiconductor switch of a discharge circuit of the capacitor is turned ON by a signal 32.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inverter control device for an electric vehicle that performs regenerative operation, and more particularly to an inverter control device for an electric vehicle that does not cause malfunction of a ground protection device when a regenerative load is cut off.

[0002]

2. Description of the Related Art FIG. 2 shows a circuit example of a general inverter control device for an electric vehicle. Conventionally, in an electric vehicle, electricity is collected from a substation on the ground via an overhead line 3 by a pantograph 11 of the electric vehicle, and a reactor 14 is connected via a line breaker 12 and a circuit breaker 13 on the power source side of the electric vehicle. , To the capacitor 17. This reactor 14, capacitor 1
Reference numeral 7 plays a role of a filter and is called a filter reactor and a filter capacitor, respectively. Further, an inverter conversion device composed of six sets of self-arc-extinguishing type semiconductors 21 and diodes 22 converts direct current into alternating current and supplies it to alternating current motor 23. When the electric vehicle equipped with this control device performs regenerative operation, a current is generated in the reverse direction from the inverter, that is, in the pantograph 11 direction from the inverter. This current is applied to the filter capacitor 17 and the filter reactor 1
After being stabilized by 4, the pantograph 11 returns to the overhead line 3. In order for such a regenerative current to flow, it is a prerequisite that the load 24 naturally absorbs this current. Figure 3
Shows the state of the regenerative current in this state. The regenerative current i1 from the electric vehicle equipped with the inverter control device is absorbed as a regenerative current i2 by the load 24 of another electric vehicle via the overhead wire 3 and the pantograph 11a and the line breaker 12a. However, this state does not always continue, and the load 24 of another vehicle may be lost regardless of the operation of the inverter-controlled vehicle. For example, this case corresponds to a case where another vehicle turns off while notching and enters coasting. FIG. 4 shows the state at this time. At this time, the current i2 consumed by the load 24 rapidly decreases, and the other load disappears accordingly, so that the current i1 from the inverter-controlled vehicle loses its place. Since the regenerative current generated from the inverter is not rapidly attenuated due to the delay in control, the regenerative current that has lost its place flows into the filter capacitor 17 as i3. Therefore, the voltage of the filter capacitor 17 increases. If the voltage rises, it will be dangerous due to the breakdown voltage of the circuit. Note that i
1'i2 'indicates the regenerative current at this time. Therefore, this voltage is monitored, and when the voltage rises above a certain value, the voltage detector 18 detects it and the sequence control device 30 fires the overvoltage suppressing thyristor 16. As a result, the protection system for reducing the voltage is adopted by discharging the electric charge of the capacitor 17 through the overvoltage suppressing resistor 15. Then, the sequence controller 30 causes the line breaker 12,
The circuit breaker 13 is turned off, the circuit is opened, and the regenerative operation is completed.
After that, the electric car switched to mechanical brakes,
As a vehicle, braking continues. A conventional sequence control block diagram for this purpose is shown in FIG. The filter capacitor voltage signal 33 detected by the voltage detector 18 is compared by the comparator 44, and when it becomes a certain value or more,
A signal 32 for firing the overvoltage suppressing thyristor 16 is output to discharge the electric charge of the capacitor 17, and at the same time, a command 31 for shutting off the breaker 12 and the breaker 13 is output. In addition, the gate signal 3 from the inverter gate pulse generator 42 that fires each semiconductor element 21 forming the inverter.
Stop the 4 to 4 and stop the inverter. However, since the breaker 12 and the breaker 13 are mechanical devices, there is a delay of about 70 to 100 ms with respect to the command, and the breaker cannot be cut off immediately. Therefore, even after discharging the capacitor, as shown in FIG.
As shown in, the current continues to flow from the power supply side through the overvoltage suppressing thyristor 16 and the overvoltage suppressing resistor 15.
Therefore, for the substation, this current i4 apparently suddenly appears. Then, the protective device 2 of the substation interprets this rapid current change as a fault current and trips the circuit breaker 1. Then, the section where power is supplied from this substation will have a power outage, which will hinder train operation. That is, there is a problem that this section is blocked even though it is not an accident.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide an inverter control device for an electric vehicle, which is suitable for avoiding unnecessary operation of a ground protection device that occurs when the regenerative load is cut off in an electric vehicle that performs regenerative operation. To do.

[0004]

The above object is to insert an AC motor for driving an electric vehicle, an inverter device having a function of performing propulsion and regenerative operation, and a positive and negative pole on the DC side of the inverter device. In a controller for an electric vehicle having a capacitor, a reactor inserted in series to the power source side of the capacitor, and a circuit breaker connected to the power source side of the reactor, the voltage of the capacitor is compared at least in two levels. Then, when the voltage of the lower side is exceeded, the inverter device is stopped, the circuit breaker is shut off, and when the voltage of the capacitor exceeds the higher voltage, the semiconductor switch of the discharge circuit of the capacitor is turned on. It is achieved by In addition, when the electric vehicle control device is set as one unit and a plurality of sets of this unit are provided in the same train set and the voltage of the capacitor of any unit exceeds a predetermined threshold value, the inverter device of the own unit This is achieved by stopping the operation of the device and simultaneously interrupting the circuit breaker, and at the same time, notifying this information to another unit via the signal transmission means, and forcibly stopping and interrupting them in the other unit.

[0005]

The present invention compares the voltage of the capacitor inserted between the positive and negative poles on the DC side of the inverter device in at least two-step levels so that when the regenerative load is cut off, the substation shifts to the overvoltage suppressing circuit of the inverter control device. An inflow of current prevents the unnecessary operation of the protective device of the ground substation caused by this current. In addition, even in the case of multiple units where there is a higher possibility that the substation will trip when the regenerative load is cut off, when the voltage of the capacitor of one of the units exceeds the specified threshold value, the inverter device of its own unit is stopped. At the same time, the circuit breaker is cut off, and at the same time, this information is notified to the other unit via the signal transmission means, so that the current flowing into the overvoltage suppressing circuit is avoided and the trip to the ground substation is prevented in advance. Also, even if the voltage of the capacitor temporarily rises due to voltage oscillations due to causes other than regenerative load cutoff, such as instability of the control system, unnecessary operation of the protective device at the ground substation is obviated. In addition, the overvoltage suppression circuit is operated to prevent a failure due to the breakdown voltage.

[0006]

Embodiments of the present invention will be described with reference to the drawings. Figure 1
FIG. 4 is a control block diagram of an inverter control device according to an embodiment of the present invention. In this embodiment, the basic circuit components of the inverter control device are the same as those in the known example, but the control method of the overvoltage suppressing thyristor is different. In FIG.
The voltage detector 18 detects the voltage of the filter capacitor 17, and outputs the filter capacitor voltage signal 33 to the first comparator 44 and the second comparator 45. These comparators 4
4 and 45 compare the filter capacitor voltage signal 33 with the respective set voltage. As a result of the comparison, the first comparator 4
Reference numeral 4 denotes a gate signal 34a from an inverter gate pulse generator 42 that outputs a circuit breaker and circuit breaker control signal 31 that blocks the circuit breaker 12 and the circuit breaker 13 and that fires each semiconductor element 21 of the inverter. ~ Stop the operation and stop the inverter. On the other hand, the second comparator 45 outputs the overvoltage suppressing thyristor gate signal 3 for firing the overvoltage suppressing thyristor 16.
2 is output. Here, the set voltage of the first comparator 44 is a conventional overvoltage detection level, for example, about 1800V to 2000V in a system with a nominal 1500V overhead line, and this value depends on the parts used, such as capacitors and thyristors. A margin is included to the extent that it does not cause a problem in insulation coordination. Further, the set voltage of the second comparator 45 is set higher than the set voltage of the first comparator 44, and is a conventional overvoltage detection level, for example, about 2000V to 2100V in a system of 1500V overhead line, and this value is different. The margin is set to a value smaller than that of the first comparison level within a range that does not cause a problem in the insulation coordination of the device. When a regenerative load cutoff occurs in the electric vehicle, the filter capacitor voltage signal 33 is output from the voltage detector 18 that detects the filter capacitor voltage, and the first comparator 44 and the second comparator 45 respectively output the filter capacitor voltage signal 33. It is compared with the set voltage. When the voltage of the filter capacitor 17 exceeds the set voltage of the first comparator 44, the first comparator 44
Generates a circuit breaker and circuit breaker control signal 31 to disconnect the circuit breaker 12,
The circuit breaker 13 is cut off, the gate signals 34a to 34f of the semiconductor elements 21 of the inverter are stopped, and the inverter is stopped. Then, when the voltage of the filter capacitor 17 rises and exceeds the set voltage of the second comparator 45, the second comparator 45 does not trigger the overvoltage suppression thyristor 16 until the overvoltage suppression thyristor gate signal 32. Is output. Due to the ignition of the overvoltage suppressing thyristor 16, the electric charge of the filter capacitor 17 is discharged to the overvoltage suppressing resistor 15 and the regenerative energy is consumed. According to the present embodiment, the overvoltage suppressing thyristor 16 is ignited after the breaker 12 and the circuit breaker 13 are completely opened, so that the current does not flow from the substation into the overvoltage suppressing circuit, and the electric power is changed as in the conventional case. It is possible to prevent unnecessary trips. In addition, even if the voltage of the capacitor is temporarily increased due to causes other than regenerative load cutoff, such as instability of the control system, the unnecessary trip of the substation is prevented,
The overvoltage suppressing thyristor 16 can be ignited to prevent a failure due to the breakdown voltage.

When the regenerative load is cut off, the voltage of the filter capacitor 17 exceeds the set voltage of the first comparator 44 but does not reach that of the second comparator 45. That is, the circuit breaker and circuit breaker control signal 31 is issued to block the circuit breaker 12 and the circuit breaker 13, and the gate signals 34a to 34b of the semiconductor elements 21 constituting the inverter are connected.
However, the overvoltage suppressing thyristor 16 is in a state where it is not ignited. At this time, as shown in FIG. 7, the regenerative current ib flows into the filter capacitor 17 from the load side 25, and a current ia flows in the filter reactor 14 at the moment when the regenerative load is cut off. It has the effect of discharging the electric charge of 17. Therefore, it can be said that the voltage of the filter capacitor 17 does not always increase, but is determined by the magnitude relation between the energy stored in the filter reactor 14 and the energy supplied from the load side 25. Therefore, even if the overvoltage suppressing thyristor 16 is not ignited, that is, even if the overvoltage suppressing circuit is deactivated, no problem occurs in circuit protection.

FIG. 8 shows a detailed circuit diagram of the sequence control block section of this embodiment. The voltage of the filter capacitor 17 is detected by the voltage detector 18, and is input to the sequence controller 30 as the filter capacitor voltage signal 33. In the operational amplifier (op amp) 52, the capacitor voltage signal 33 and a set voltage level applied independently thereof are connected to the positive and negative input terminals. This operational amplifier 5
2 is built to operate as a comparator,
When the voltage of the capacitor 17 exceeds the set level, the output 73 becomes negative, so that no current flows through the base of the transistor 56 and the transistor 56 is turned off. Then, the signal line 74 becomes H level, and the signal 75 via the inverting gate 57 becomes L level. On the other hand, a block 41 is a logic circuit that outputs a signal for turning on and off the circuit breaker 12 and the circuit breaker 13 according to the operation command and the state of the circuit, and the AND gate 58 takes the logical product of this signal and the signal 75. . As mentioned above, if the voltage on capacitor 17 rises, the output of gate 58 goes low regardless of block 41, turning off transistor 60. As a result, the solenoid valve coil 43 becomes unpressurized, and the disconnector 12,
Circuit breaker 13 is turned off. The signal 75 is further input to the other AND gates 59 a to 59. The gate signal given to each thyristor from the gate pulse generator 42 is input to the other terminal of this gate. When the voltage of the capacitor 17 rises, the gates 59 a to 59
To the L level, the gate signals 34a to 34 are at the L level regardless of the output of the gate pulse generator 42, and each semiconductor element 21 of the inverter is turned off. The filter capacitor voltage signal 33 is also input to another operational amplifier 51. This operational amplifier 5
Similarly, 1 also has a signal of a set level input to the other terminal, and operates as a comparator like the operational amplifier 52 described above. The set level is set to be higher than the signal given to the operational amplifier 52 described above. When the voltage of the capacitor 17 exceeds the comparison level of the operational amplifier 51, the output 71 becomes negative, and as a result, no current flows through the base of the transistor 53 and the transistor 53 is turned off. Then, the signal line 72 becomes H level,
The transistor 54 turns on. Then, a current flows through the transformer 55, and as a result, a current also flows through the secondary side of the transformer 55. The output of the transformer 55 is connected to the gate of the overvoltage suppressing thyristor 16. Therefore, when the capacitor voltage 33 becomes higher than the set level of the operational amplifier 51, the gate current is given to the overvoltage suppressing thyristor 16, and the overvoltage suppressing thyristor 16 is turned on.

Next, another embodiment of the present invention is shown in FIG.
In the present embodiment, a case where a plurality of units having the same configuration as the control circuit described above are present in one formation will be described. In Figure 9,
The case where two identical units are included in the same composition is shown. The sequence control devices 30 and 30a having the same configuration function output signals for controlling the gates of the self-extinguishing type semiconductors constituting the breaker, the circuit breaker, the overvoltage suppressing thyristor, or the inverter of each unit. In the case of a plurality of units, the current flowing into the overvoltage suppressing circuit becomes a multiple, so that a malfunction of the protective device in the substation is more likely to occur. When the regenerative load cutoff occurs, the filter capacitor voltage rises as the regenerative load decreases because the units have the same function. Then, the set voltage of the comparator is exceeded. However, a slight difference in the characteristics of the two units causes a slight difference in the detection timing depending on the unit. The circuit breaker should be opened as early as possible to minimize the voltage rise of the capacitor.If an overvoltage is expected in advance, it is possible to open the circuit breaker and circuit breaker without stopping until the set level and stop the inverter. desirable. Therefore, in this embodiment, as shown in FIG. 9, the signal line 35 is provided between the sequence control devices 30 and 30a.
a, 35b are provided, and when an overvoltage occurs in one of the units in the knitting and that unit operates, the information is transmitted to another unit, and the unit receiving it is forced regardless of the voltage of the capacitor. Signal 31 or 31a
Is output, the line breaker and circuit breaker are opened, and the inverter is stopped.

A control block diagram of this embodiment is shown in FIG. Hereinafter, a case where an overvoltage occurs in a unit of the sequence control device 30 and the unit operates will be described. In addition, the inside of () shows the case where the overvoltage generate | occur | produced in the unit of the sequence control apparatus 30a, and the unit operated. When the regenerative load cutoff occurs, the filter capacitor voltage signal 33 (33a) detected by the filter capacitor voltage detector is compared with the set voltage of the first comparator 44, and the voltage of the filter capacitor is changed to the first comparator. 44
When the set voltage exceeds the set voltage, the first comparator 44 issues a command 31 (31a) for shutting off the breaker and the circuit breaker, and shuts off, and 6 sets of firing each semiconductor element forming the inverter. The gate signal 34 (34a) is stopped to stop the inverter. Subsequently, when the voltage of the filter capacitor rises and exceeds the set voltage of the second comparator 45, the second comparator 45 outputs the signal 32 (32a) for firing the overvoltage suppressing thyristor for the first time. On the other hand, when the command 31 (31a) for shutting off the breaker and the circuit breaker is output, this information is transmitted to the signal line 35a (35b) under the same condition. Upon receiving this signal, the sequence control device 30a (30) of each unit directly outputs the signal 3 which is its own control output.
1a (31) is forcibly output. Signal 31a (31)
Is activated by the condition that either the overvoltage of the filter capacitor of its own unit or the occurrence of the overvoltage of another unit is transmitted. The signal lines 35 and 35a between the respective sequence control devices are described as single-line signal lines in this embodiment, but a signal transmission means such as a serial transmission device may be used instead. According to the present embodiment, even in the case of a plurality of units in which the substation is more likely to trip when the regenerative load is cut off, it is possible to prevent the substation from tripping by avoiding the current flowing into the overvoltage suppression circuit. .

[0011]

According to the present invention, when the regenerative load is cut off, a current flows from the substation to the overvoltage suppressing circuit of the inverter control device, and the unnecessary operation of the protective device of the ground substation caused by this current is prevented in advance. It is possible to prevent the power transmission from being stopped. Further, even in the case of a plurality of units in which the substation is more likely to trip when the regenerative load is cut off, it is possible to prevent the ground substation from tripping by avoiding the current flowing into the overvoltage suppressing circuit. Also, even if the voltage of the capacitor temporarily rises due to voltage oscillations due to causes other than regenerative load cutoff, such as instability of the control system, unnecessary operation of the protective device at the ground substation is obviated. In addition, it is possible to prevent the failure caused by the breakdown voltage by operating the overvoltage suppressing circuit.

[Brief description of drawings]

FIG. 1 is a control block diagram of an inverter control device according to an embodiment of the present invention.

[Fig. 2] Example of a general electric vehicle control circuit

FIG. 3 is an explanatory diagram of a load shedding operation during regeneration.

FIG. 4 is an explanatory diagram of a load shedding operation during regeneration.

FIG. 5 is a conventional control block diagram.

FIG. 6 is an explanatory diagram of a load shedding operation during regeneration.

FIG. 7 is an explanatory diagram of a load shedding operation during regeneration according to an embodiment of the present invention.

8 is a detailed circuit diagram of the control block diagram of FIG.

FIG. 9 is a block diagram of another embodiment of the present invention.

FIG. 10 is a control block diagram of another embodiment of the present invention.

[Explanation of symbols]

 1 Circuit Breaker 2 Protective Device 3 Overhead Wire 11 Pantograph 12 Breaker 13 Circuit Breaker 14 Filter Reactor 15 Overvoltage Suppression Resistor 16 Overvoltage Suppression Thyristor 17 Filter Capacitor 18 Voltage Detector 19 One Set 21 Self-extinguishing Semiconductor 22 Diode 23 AC Motor 24 Load 25 Load 30 Sequence control device 31 Breaker / Breaker control signal 32 Overvoltage suppression thyristor gate signal 33 Filter capacitor voltage signal 34 Inverter element gate signal 35 Inter-unit equipment wire 41 Circuit breaker controller 42 Inverter gate pulse generator 43 breaker closing coil 44 first comparator 45 second comparator

Claims (5)

[Claims] 1. An AC motor for driving an electric vehicle, an inverter device having a function of performing propulsion and regenerative operation, a capacitor inserted between positive and negative poles on the DC side of the inverter device, and a power source side of the capacitor. In a controller for an electric vehicle having a reactor inserted in series with a circuit breaker and a circuit breaker connected to the power source side of the reactor, the voltage of the capacitor is compared in at least two-stage levels, and the voltage of the lower side is exceeded. In this case, the inverter device is stopped, the circuit breaker is cut off, and when the capacitor voltage exceeds the higher voltage, the semiconductor switch of the discharge circuit of the capacitor is turned on. Inverter control device. 2. The inverter control device for an electric vehicle according to claim 1, wherein when the voltage of the capacitor exceeds a lower voltage, the regenerative current is absorbed by the reactor. 3. An AC electric motor for driving an electric vehicle, an inverter device having a function of performing propulsion and regenerative operation, a capacitor inserted between the positive and negative poles on the DC side of the inverter device, and a power source for the capacitor. There are multiple sets of electric vehicle control units in the same train consisting of a reactor inserted in series on the side of the reactor and a circuit breaker connected to the power supply side of this reactor, and the voltage of the capacitor of either unit is set to a predetermined value. If the threshold value of is exceeded, the inverter device of its own unit is stopped, the circuit breaker is cut off, and at the same time,
An inverter control device for an electric vehicle characterized by forcibly stopping and shutting off those of other units. 4. The electrical equipment according to claim 3, further comprising a signal transmission means for notifying the other unit of the information when the voltage of the capacitor of any unit exceeds a predetermined threshold value. Inverter control device for vehicles. 5. The circuit according to claim 4, when the other unit receives the information through the signal transmission means, the inverter device of the unit is forcibly stopped and the circuit breaker is irrelevant regardless of the voltage of the capacitor of the unit. An inverter control device for an electric vehicle, characterized in that it shuts off.