JPH02159902A - Protective circuit for electric vehicle controller - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a protection circuit for an electric vehicle control device.

(Prior Art) Generally, the main circuit of an electric vehicle that controls an induction motor using a variable voltage variable frequency (VVVF) inverter has a configuration as shown in FIG. Charge the filter capacitor 5 through the current interrupter 2 - high speed breaker 3 - filter reactor 4,
VV connected in parallel to this filter capacitor 5
DC power can be supplied to the VF inverter 6.

For the main circuit of such an electric vehicle control device,
Conventionally, a voltage detector 7 is connected in parallel to the filter capacitor 5 to constantly detect the voltage across the filter capacitor 5. In addition, the VVVF inverter 6 is three-phase, and each arm has a GTO as a switching element.
Thyristors 81 to 86 are arranged, and the G of each arm is
Overcurrent detectors 91 to 96 are arranged as short circuit detection means for detecting overcurrents flowing through the TO resistors 81 to 86, respectively.

The AC output of the VVVF inverter 6 is connected to an induction motor 10, and the DC power of the filter capacitor 5 is converted into AC power by the VVVF inverter 6 to control the rotation of the induction motor 10.

When the VVVF inverter 6 is normal, the GTO thyristors of the upper and lower arms of the same phase are used, for example, the GTO thyristor 81.
It is impossible for the GTO thyristor 82 and the GTO thyristor 82 to turn on at the same time, but if for some reason the GT and thyristors 81 and 82 of the upper and lower arms turn on at the same time, the discharged charge from the filter capacitor 5 will be in that phase. To avoid concentration, all three-phase GT○Zyristors 81 to 86 are turned on to disperse the discharge current of the filter capacitor 5 to six arms, and at the same time, the high-speed breaker 3 is turned off to remove the power supply current from the overhead line side. The system is designed to provide protection so that the flow of water does not occur.

In other words, the protection circuit of the conventional electric vehicle control device shown in FIG.
．． 92 ; 93.94 ; It is equipped with an AND circuit 11 which inputs the short circuit detection signals from 95 and 96, and a flip-flop circuit 12 which is inverted by the high level output of the AND circuit 11. The fault indicator light 13 lights up due to the high level output of
HB) 3 is made to trip. In addition, the driver's high-speed breaker reset button 14 is connected to the reset terminal of the flip-flop circuit 12, and even when the flip-flop circuit 12 operates in reverse, a reset signal from the reset button 14 is input. By doing so, the output of the high level signal is stopped.

Therefore, the GT of either arm of the VVVF inverter 6
If continuity breakdown occurs in the O thyristor, for example 82,
Simultaneously, short circuit detection signals are sent to the AND circuit 1 from the overcurrent detectors 91 and 92 installed in each of the vertically symmetrical arms.
1, the AND circuit 11 gives a high level signal to the flip-flop circuit 12, and the flip-flop circuit 1
2 is inverted and gives a high-level signal to the failure indicator light 13 and the high-speed breaker 3, and the failure indicator light 13 notifies the driver of the occurrence of a failure in the VVVF inverter 6,
High speed breaker 3 is tripped and the power supply voltage is VVVF
The input to the inverter 6 is cut off. When the driver inputs a reset signal to the reset terminal of the flip-flop circuit 12 by operating the reset button 14, the output of the flip-flop circuit 12 becomes low level, turning off the failure indicator light 13 and turning off the high-speed breaker. 3 is restored, and the power source power can be input to the VVVF inverter 6 again.

(Problem to be Solved by the Invention) However, in the protection circuit of such a conventional electric vehicle control device, the driver does not know whether the VVVF inverter has actually failed or if a short circuit detection signal is temporarily input due to a simple malfunction. Unable to determine whether the VV has become
If any of the GTO thyristors of the VF inverter 6 has continuity breakdown, for example, if the GTO thyristor 82 has continuity breakdown, as soon as it is restarted by operating the reset button 14. Normal GTO
Thyristor 81 turns on and causes an arm short circuit.

When an arm short circuit occurs, the high-speed circuit breaker 3 makes a loud noise in order to cut off the large current, but the loud noise may make passengers in the vehicle feel uneasy. In particular, if the driver repeats the reset/restart operation two or three times, all the GTO thyristors will be forced to overload the current, causing the problem that even healthy GTO thyristors may be destroyed. Ta. At the same time, if overcurrent flows repeatedly through a GTO thyristor that has already been destroyed, the damaged area becomes more rough, making it difficult to investigate the accident and cause.

The present invention has been made in view of such conventional problems, and it automatically reduces VV immediately after an arm short-circuit operation occurs.
Diagnose the failure of the GTO thyristors in each arm of the VF inverter, and if continuity breakdown has occurred in one of the GTO thyristors, make sure that the reset operation is not performed even when the driver presses the reset button. An object of the present invention is to provide a protection circuit for an electric vehicle control device that can protect the circuit.

[Structure of the Invention] (Means for Solving the Problems) A protection circuit for an electric vehicle control device of the present invention includes: a cutoff means for cutting off a power supply; a filter capacitor for a power supply current input through the cutoff means; A voltage detection means for detecting the voltage across the filter capacitor, a variable voltage variable frequency inverter that converts the DC from the filter capacitor to provide AC power to the induction motor, and a GTO thyristor in each arm of the variable voltage variable frequency inverter. a short-circuit detection means for detecting a short circuit of the filter capacitor, a current-cutting control means for operating the current-breaking means in response to a short-circuit detection signal from the short-circuit detecting means, and a voltage detection value of the voltage detection means for the filter capacitor that is equal to or less than a predetermined value. and a flow-interruption reset prohibition means for prohibiting the reset operation of the flow-interruption control means at a certain time.

(Function) In the protection circuit of the electric vehicle control device of the present invention, when a short-circuit failure occurs in the pair of upper and lower arms of the VVVF inverter, the short-circuit detection means provides a short-circuit detection signal to the cut-off control means, and the cut-off control means receives this short circuit detection signal, operates the current cutoff means, and the power supply current passes through the filter capacitor to VV.
The supply to the VF inverter is stopped.

Then, when the current interrupting means performs the current interrupting operation and the main circuit is opened, the VVVF inverter immediately shifts to the regeneration mode and starts charging the filter capacitor with the residual magnetic flux.

However, any GTO in the VVVF inverter
If continuity breakdown occurs in the thyristor, the filter capacitor will no longer be charged, the voltage detection value from the voltage detection means that detects the voltage across the filter capacitor will be below a predetermined value, and the cut-off reset prohibition means will stop the filter capacitor from being charged. Prohibits the control means from performing a reset operation. As a result, the flow cutoff control means cannot perform a reset operation of the flow cutoff means, and the flow cutoff means can be prevented from being reset even in response to a reset operation by the driver.

(Example> Hereinafter, embodiments of the present invention will be explained in detail based on the drawings.

FIG. 1 is a block diagram of one embodiment of the present invention, and the third
Portions having common configurations with those of the conventional example shown in the figure are indicated using the same reference numerals.

In this embodiment, an AND circuit 15 is newly provided between the driver reset signal from the driver's reset button 14 and the reset terminal of the flip-flop circuit 12. A product circuit 15 is provided.

The inverted output of the flip-flop circuit 16 is inputted to the AND circuit 15 via an inverter 17.

In addition, the other AND circuit 18 converts the vehicle speed comparison value VL to the actual measured vehicle speed together with the flip-flop circuit 120.
The output of the comparator 19 with C and the high speed breaker (HB) 3
The output of the AND circuit 18 is supplied to the delay circuit 20.

The output of the delay circuit 20 is the slip frequency ("S")
This slip frequency calculation circuit 2
The output of 1 serves as a gate start signal and is input to another delay circuit 22, and the output of this delay circuit 22 is input to an AND circuit 23.

The other input of the AND circuit 23 is connected to the output of a comparator 24 that compares the filter capacitor voltage detection value X from the filter capacitor voltage detector 7 with a comparison voltage (50V), and is connected to this AND circuit 23. The output of 23 serves as an input to the flip-flop circuit 16.

The delay time of the delay circuit 20 is set to 1 second, and the delay time of the other delay circuit 22 is set to 3 seconds.

Furthermore, a pantograph down signal is connected to the reset terminal of the flip-flop circuit 16 for detecting that the pantograph has been lowered by the driver.

The operation of the protection circuit of the electric vehicle control device having the above configuration will be described next.

In the main circuit shown in FIG. 2, when a continuity breakdown occurs in any one of the GTO thyristors 81 to 86 of the VVVF inverter 6, the GTO thyristors that are the upper and lower pair of the GTO thyristor in which the failure occurred will also be At the same time, G is short-circuited and the short-circuit accident occurred among the overcurrent detectors 91 to 96.
As shown in FIG. 1, the TO thyristor simultaneously inputs a short circuit detection signal to the AND circuit 11, and the AND circuit 11 supplies a high level signal to the 7-lip, 70-tub circuit 12.

Then, the flip-flop circuit 12 is inverted and outputs a high-level signal, and the high-speed breaker 3 is tripped, immediately stopping the power supply to the power supply side of the main circuit. At the same time as this operation, the failure indicator light 13 provided in the driver's cab also lights up.

If the driver inputs a reset signal by operating the reset button 14 after the main circuit is cut off due to such a trip of the high-speed breaker 3, conventionally the reset signal would directly reset the flip-flop circuit 12. In this embodiment, the reset signal generated by the driver's operation of the reset button 14 is input to one terminal of the AND circuit 15 for the time being. will be given to the input. The other input of this AND circuit 15 has an inverting circuit 1.
However, when the output of the flip-flop circuit 16 is at a low level, the inverting circuit 17 outputs a high level output.
As will be described later, the output does not immediately become a low level, so a high level signal is not output from the AND circuit 15 to the reset terminal of the flip-flop circuit 12, and the reset operation of the reset button 14 by the driver is not necessary. Therefore, the trip of the high speed breaker 3 is not immediately released.

The reset input from the AND circuit 15 is applied to the reset terminal of the flip-flop circuit 12 in the following case.

First, the AND circuit 18 is given a trip command for the high-speed breaker 3 from the flip-flop circuit 12 due to a short-circuit fault, and a signal is given to the AND circuit 18 to confirm that the high-speed breaker 3 has tripped due to the trip command. Furthermore, when the electric vehicle is running, the actual vehicle speed X is the vehicle speed reference value V.
It outputs a high level signal only when it is larger than LC and a high level signal is given from the comparator 19.

The output of this AND circuit 18 is input to a delay circuit 20, and after a preset time (one second in this embodiment), a high level signal is output to a slip frequency calculation circuit 21, which calculates the slip frequency. The circuit 21 starts an arithmetic operation in response to this high level input, and causes the gates of each of the GTO thyristors 81 to 86 of the inverter 6 to be started.

When the protective operation is activated while the electric vehicle is running, the high-speed breaker 3 is turned OFF and the main circuit is turned OFF, but there is some residual magnetic flux in the induction motor 1110, When operating in regeneration mode, that is, operating at a slip frequency [S<0, the filter capacitor 5 begins to be recharged in a short time. However, if any of the GTo thyristors 81 to 86 of the VvVF inverter 6 is broken, the filter The voltage of capacitor 5 is approximately O
remains at v, the voltage detector 7 gives an O■ signal to the comparator 24, and the comparison base! By comparison with the $-voltage of 50V, the filter capacitor voltage detection value X is smaller, so a high level signal is given to the AND circuit 23.

Therefore, when the slip frequency calculation circuit 2.1 operates and gate starts, and a high level signal is given to the other delay circuit 22, this delay circuit 2.
is the AND circuit 2 after a predetermined set time, for example 3 seconds.
A high level signal will be input to 3.

As a result, the output of the AND circuit 23 provides a high-level output to the flip-flop circuit 16 due to the input of the high-level signal from the delay circuit 22 and the high-level signal from the comparator 24, and the flip-flop circuit 16 It is inverted and a high level signal is given to the inverting circuit 17, and the output of the inverting circuit 17 is conversely locked to a low level.

As a result, the output of the AND circuit 15 also remains at a low level, and the reset signal generated by the driver's operation of the reset button 14 is no longer accepted, thereby preventing the high-speed breaker 3 from being turned on again. Become.

By preventing the reset input to the 7-lip flop circuit 12 in this way, the high-speed breaker 3 will not be immediately re-closed when a short-circuit failure occurs, causing a loud noise and causing a sense of anxiety to the passengers. This makes it possible to eliminate this problem and also to prevent an adverse effect on the GTO thyristor.

If a trip of the high-speed breaker 3 occurs due to malfunction, all the GTO thyristors 81 to 86 of the VVVF inverter 6 are normal, so when the gate start is performed by the slip frequency calculation circuit 21 after the trip occurs, the VVVF Inverter 6 shifts to regeneration mode operation,
The residual magnetic flux of the induction motor 10 comes to charge the filter capacitor 5, the detection value X of the voltage detector 7 becomes larger than the comparison voltage 50V, the output of the converter 24 becomes low level, and the output of the AND circuit 23 also becomes [The flip-flop circuit 16 becomes low level, and the flip-flop circuit 16 supplies a low level signal to the inverting circuit 17 without being inverted.

Therefore, the output of the inverting circuit 17 becomes high level, and the AND circuit 15 becomes able to give a reset signal to the flip-flop circuit 12 in response to the reset signal generated by the driver's operation of the reset button 14. 12 is immediately reset by inputting a reset signal by the driver's operation of the reset button 14, and can return to normal operation.

In addition, the GTO thyristor 81 of the VVVF inverter 6
86, and the high-speed circuit breaker 3 cannot be released from the trip even by the driver's reset operation of the reset button 14, in order to return to the original state, the electric vehicle must be By completely turning off the pantograph down signal, the pantograph down signal is input to the reset terminal of the 7 lip-flop circuit 16. As a result, the flip-flop circuit 16 is reset and gives a low level signal to the inverting circuit 17, and the inverting circuit 17 gives a high level signal to the AND circuit 15. This makes it possible to reset the flip-flop circuit 12 and release the high-speed circuit breaker 3 from tripping.

[Effects of the Invention] As described above, according to the present invention, when continuity breakdown occurs in one of the GTO thyristors of a VVVF inverter, failure diagnosis of the GTO thyristor is automatically performed and the GT
If a continuity breakdown occurs in one of the O thyristors, it is detected and the driver's reset operation is disabled to prevent the main circuit from being turned on again. Even after a trip, the driver's reset operation re-energized the flow cutoff means two or three times, causing no loud noises and causing passengers to feel uneasy. It is possible to prevent the negative effects caused by the overcurrent that has caused the conduction, and it is also possible to prevent the damage from becoming rougher due to re-conduction of the GTO thyristor that has caused conduction breakdown, making it easier to investigate the cause. It can be made into something.

[Brief explanation of the drawing]

FIG. 1 is a circuit block diagram of an embodiment of the present invention, FIG. 2 is a circuit diagram of a main circuit of a general electric vehicle control device, and FIG. 3 is a circuit block diagram of a conventional example. 1... Pantograph 3... High speed breaker 4...
・Filter reactor 5...Filter capacitor 6...Variable voltage variable frequency (VVVF) inverter 7...Voltage detector 81-86...GTO thyristor 91-96 Gastric overcurrent detector 10...Induction motor 11...Logic product circuit 12...
・Flip-flop circuit 13... Failure indicator light 14... Reset button 15
...AND circuit 16...Flip-flop circuit 17...Inversion circuit 18...AND circuit 19...
Comparator 20...Delay circuit 21...Slip frequency calculation circuit 22...Delay circuit 23...AND circuit 24...
··comparator

Claims (1)

[Claims] A current cutoff means for cutting off the power supply, a filter capacitor for the power supply current input through the current cutoff means, a voltage detection means for detecting the voltage across the filter capacitor, and an induction motor by converting the direct current from the filter capacitor. a variable voltage variable frequency inverter that supplies alternating current power to the variable voltage variable frequency inverter; short circuit detection means for detecting a short circuit in the GTO thyristor of each arm of the variable voltage variable frequency inverter; An electric vehicle control comprising: a current cutoff control means to operate; and a cutoff reset prohibition means for prohibiting a reset operation of the cutoff control means when a voltage detection value of the voltage detection means of the filter capacitor is below a predetermined value. Equipment protection circuit.