JPH03285515A - Protective system for electric vehicle - Google Patents

Abstract

PURPOSE:To detect abnormality in a CT by logically operating a relation between externally provided operating conditions and detection values of CT when the output of the CT exceeds a predetermined value in a high speed interruptor for isolating the power supply side from the control side. CONSTITUTION:A start command 23 provided from a main controller 15 to a controller 5 and a signal representing throw-in of a main circuit switch LB3 are inputted to an AND gate 11 to produce an AND signal 26. On the other hand, a current value detected through a CT 6 is compared with a threshold at a comparing section 7b, and a signal 27 is outputted if the threshold is larger and a logical product signal 28 of the signals 27, 28 is produced from an AND gate 12. Duration of the signal 28 is measured by means of a timer 13 and when it reaches a predetermined time, a fault signal 24 is outputted and transmitted to a monitor or an operating desk in the upstream so that a target relay 18 is operated to display an alarm. The LB 3 is interrupted by that signal. Consequently, under output due to fault of the CT 6 is detected and dangerous trouble is avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a protection system for a power circuit of an electric vehicle included in a high-speed circuit breaker.

[Conventional technology]

An example of the power supply circuit of a general electric car is shown in FIG. Pantograph 2 Furthermore, a main circuit switch (LS) 3 for switching on and off the circuit under normal conditions and a high-speed circuit breaker (HB) 4 for cutting off the rapidly increasing current in a short time in the event of an accident are installed on the power supply side of the control device. inserted in series.

The high-speed circuit breaker 4 is equipped with a current detector, and has a function of automatically opening the main contact and interrupting the current when the main circuit current becomes excessive. Note that in this configuration, the current flowing through the power supply is detected as the main circuit current.

In conventional high-speed circuit breakers, the main circuit current is passed through the coil, and the electromagnetic force generated by the current operates the plunger, mechanically opening (tripping) the main contact.
It has become a mechanism.

Recently, as an alternative to the above-mentioned mechanical high-speed circuit breaker, a semiconductor circuit breaker that interrupts current using a semiconductor has been developed with the aim of achieving benefits such as arc-free operation and ultra-high speed. A known example of this type of device is (Journal of Cybernetics in Railways 198
There is something mentioned in the article (published in November 1988, p. 234~).

It is theoretically impossible to use the conventional mechanical tripping method for this type of high-speed circuit breaker, so the main circuit current is detected by a current sensor, compared and detected by an electronic circuit, and then , gives an off command to the semiconductor and cuts off the main circuit current.

The operation of the above device will be explained with reference to FIG.

The main circuit current flows through the current sensor 6 and the semiconductor cut-off section 9. During normal operation, an ON command 22 is given from the gate control section 8 to keep the semiconductor cut-off section 9 in a conductive state. The output of the current sensor 6 is input to a current comparator 7a, which constantly monitors the value of the main circuit current, and if the current value exceeds a preset value, an overcurrent detection signal is sent. 2
Outputs 1. In the gate control section 8 that receives this signal,
Immediately stop the ON command to the cutoff section and cut off the main circuit current.

[Problem to be solved by the invention]

In the above-mentioned conventional technology, there is no consideration as to whether or not the current sensor etc. are operating normally. It is also possible to continue using it.

If an accident occurs and an overcurrent flows, the critical high-speed circuit breaker may not operate, potentially exacerbating the accident.

An object of the present invention is to provide a control method that avoids dangerous operations in advance.

[Means to solve the problem]

In order to achieve the above object, the present invention focuses on the fact that this high-speed circuit breaker is rarely used alone, but is usually used in combination with a control device that should be protected by this high-speed circuit breaker. A function to monitor whether the function of the current sensor is normal or not is provided inside the control device provided in combination with the control device, or in another third place, and as a result, if there is an abnormality, This is a sequence in which an abnormality signal is output, a notification is sent to a crew member or a higher-level monitoring device, and the main circuit switch is immediately opened as necessary.

〔Example〕

FIG. 1 shows an embodiment of the present invention.

There are two possible failure modes for current detectors. That is, there are cases where current cannot be detected even though current is flowing, and cases where it is mistakenly determined that there is current even though no current is flowing.

In the latter case, there is no particular problem in terms of safety, but in the former case, there is a problem in that the interrupting operation is not performed even though an overcurrent is flowing. In order to check this, it is conceivable to monitor the output of the current sensor with reference to the operation command and operation mode of the control device.

In FIG. 1, a start command 23 given to the control device 5 from the main controller 15 and a signal 25 indicating that the main circuit switch (LB) 3 is turned on are input, and the logical product of these two signals is input. Take 26.

This output 26 means that conditions have been met for the power supply current to flow. That is, if a start command is given to the control device and the control device is normal, the main circuit switch on the power supply side is always turned on.

Power supply current should flow.

On the other hand, the current value detected by the current sensor 6 is compared with a certain threshold value in the comparison part 7b, and if it is smaller than the certain value,
Output a signal. Then, this signal and the signal 26 are ANDed.

The output of this logical product means that the current sensor could not detect a value higher than a certain value even though the current should normally flow. Furthermore, this signal is input to the timer 13, and after this state continues for a certain period of time, the failure signal 2 is output.
Outputs 4. The purpose of using a timer is to prevent malfunctions.

In response to this signal 24, the target relay 18 is operated to display a warning within the device, and the signal 24 is transmitted to a higher-level monitoring device (for example, a monitoring device or a warning indicator light in the driver's cab).

Moreover, if this signal is used to issue a command to forcibly turn off the main circuit switch 3, reliable protection can be achieved without delay.

According to this embodiment, a failure of the current sensor can be detected, and a dangerous failure can be discovered.

Next, an embodiment for a failure in the opposite mode is shown in FIG. get it. On the other hand, when the current value detected by the current sensor is compared with a certain threshold value in the comparison section 7C, and is larger than the certain value.

A signal that is logically 1 is output. The signal obtained by the AND of the two means that a current has been detected, even though it is impossible for a current to flow.
It can be determined that a malfunction of the current sensor has occurred.

Further, this signal is input to the timer 13, and when this state continues for a certain period of time or more, a signal 24 indicating that the current sensor is malfunctioning is output.

Based on this signal, the target relay 18 is operated to display a warning within the device, and a signal is output to a higher-level monitoring device.

According to this embodiment, it is possible to detect another abnormal mode of the current sensor.

Note that it is more effective to use this embodiment and the previously described embodiments simultaneously.

Next, another embodiment is shown in FIG. In the previous embodiment, only the binary determination of whether or not there is a current that should originally flow is possible.

Therefore, by using the internal control parameters of the control device, it becomes possible to continuously determine this.

That is, when the control device is a chopper device, one of the control parameters is the conduction rate. By executing the calculation shown in the formula below, it is possible to know the approximate value of the power supply current, that is, the current flowing through the high-speed circuit breaker.

Here, Is Power supply current γ Conductivity Ill Motor current E Power supply voltage The comparator 17 calculates the difference between the result calculated by the arithmetic unit 19 inside the control device and the output of the current sensor 6 in the high-speed circuit breaker.
If the difference exceeds a certain limit,
It is determined that there is a failure and outputs a failure detection signal 24, which activates the target relay 18 to display a warning within the device, and outputs a signal to a higher-level monitoring device.

According to this embodiment, more accurate failure detection of the current sensor is possible. It is clear that by similar means it is also possible to detect the opposite failure mode of the current sensor.

When the control device is an inverter device, one of the control parameters is the modulation rate. By executing the calculation shown in the formula below, it is possible to know the approximate value of the power supply current.

here Is Power supply current Vc Modulation rate φ phase ■1 Motor current E　Power supply voltage In this case as well, the same means as in the previous embodiment are used.

Abnormalities in the current sensor can be detected.

Although the embodiment is based on a semiconductor circuit breaker,
The present invention is not limited to semiconductor circuit breakers as a principle of current interruption, but can be applied to devices that detect overcurrent using a current sensor. It is also applicable to the method used.

〔Effect of the invention〕

According to the present invention, it is possible to detect an abnormality in a current sensor provided for overcurrent detection of a high-speed circuit breaker, and it is possible to prevent system danger.

[Brief explanation of the drawing]

Fig. 1 is a system diagram of an embodiment of the present invention, Fig. 2 is a power supply circuit diagram of a general electric vehicle, Fig. 3 is an internal circuit diagram of a high-speed circuit breaker, and Figs. FIG. 3 is a system diagram of another embodiment of the invention. DESCRIPTION OF SYMBOLS 1... Overhead line, 2... Pantograph, 3... Main circuit switch, 4... High speed circuit breaker, 5... Control device,
6... Current sensor, 7... Comparator, 8... Gate control section, 9... Cutoff section, 11.12... AND circuit, 13... Timer, 15... Master control Vessel, 16...
・NOT circuit, 17...Comparison section, 18...Target relay, 19...N control variables

Claims (1)

[Claims] 1. A high-speed circuit breaker that has the function of detecting current with a current sensor and interrupting the current when the current value exceeds a predetermined set value In the power supply circuit of an electric vehicle that separates the A protection system for electric vehicles that detects abnormalities in current sensors. 2. In claim 1, the conditions under which current should flow include:
A protection system for an electric vehicle, characterized in that an on/off signal of a main circuit switch, a start signal of the control device, and a timer condition are used singly or in combination. 3. A power supply circuit for electric cars that separates the power supply side and the control device side using a high-speed circuit breaker that detects the power supply current using a current sensor and shuts off when the value exceeds a predetermined set value. In this step, a calculation unit provided in the control device calculates a current value flowing as a power supply current from the parameters of the control device, compares this current value with a current value detected by the current sensor, and calculates the difference. A protection method for an electric vehicle, characterized in that an abnormality in the sensor is detected when the sensor becomes a certain value or more.