JPH0654401A - Controller for electric railcar - Google Patents

Abstract

PURPOSE:To continuously operate with sound converters by switching protective operation reference of overload protecting means for inverters from that at a normal time to that at a safe side if any of a plurality of converters becomes defective. CONSTITUTION:If a switch 4b is opened, for example, due to a trouble of a converter 5b, a detecting contact 10b is closed, and a switching signal is output from an OR circuit 11 to an inverter controller 8 and a switch 14 of a malfunction detector 9. A controller 8 switches a current set value to a value lower than that at the time of a normal operation, and the input current of an inverter 6 is limited. Further, the detector 9 switches the switch 14 from a current reference REF1 side at the normal time to a lower current reference REF2. Accordingly, when the input current of the inverter 6 to be detected by a current detector 12 becomes larger than the reference REF2, a trip signal is applied from a comparator 13 to a breaker 2.

Description

Detailed Description of the Invention

[Object of the Invention]

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric vehicle controller.

[0003]

2. Description of the Related Art Conventionally, an electric vehicle control device having a converter and an inverter has a structure as shown in FIG. This conventional electric vehicle controller includes a current collector 1, a circuit breaker 2, and a transformer 3 and a transformer 3 for converting the AC power voltage taken in from the current collector 1 into a voltage having a magnitude corresponding to the controller. Switch 4 provided at the next output, the transformer 3
Converters 5a, 5b for converting AC power from the DC power into DC power, an inverter 6 for converting DC power connected to a common DC bus together with DC outputs of the converters 5a, 5b into desired AC power, and Inverter 6
The AC electric motor 7 is driven to rotate by the AC electric power.

Further, an inverter control circuit 8 for controlling the output power by controlling the opening / closing timing of a switching element which is a circuit element of the inverter 6, and an abnormality detection circuit 9 for detecting an abnormality of the inverter 6.
When the abnormality detection circuit 9 detects an abnormality, the circuit breaker 2 is turned off to protect the circuit. An abnormality detection method for the inverter 6 by the abnormality detection circuit 9 is a method in which a current or voltage of the circuit is detected and compared with an abnormality detection reference value, and an abnormality is detected when the detected value exceeds the reference value. It is common.

In the conventional electric vehicle control device having such a structure, the AC power obtained through the current collector 1, the circuit breaker 2, the transformer 3 and the switch 4 during the power running of the electric vehicle is converted by the converter 5.
Converted to DC power by a and 5b. Then, the DC output power of the converters 5a and 5b is used as the DC input power of the inverter 6 through the common bus, is converted into the AC power of the variable voltage variable frequency in the inverter 6, and drives the AC motor 7. When an abnormality occurs in the inverter 6, it is detected by the abnormality detection circuit 9 and a trip command is given to the circuit breaker 2 to cut off the input AC power of the circuit to protect the circuit.

[0006]

However, such a conventional electric vehicle controller has the following problems. That is, when one of the converters 5a and 5b fails, the circuit breaker 2 is used to shut off the power, or the electric power for another load (not shown) connected to the transformer 3 is secured. In order to keep the circuit breaker 2 open, the switch 4 is opened without being opened, and the converters 5a and 5b are disconnected from the power supply. However, in this way, due to the failure of one of the converters 5a and 5b, the remaining Even if the electric power for driving the electric motor can be secured to some extent because the other converter can operate normally, there is a problem that the entire device is stopped.

Therefore, by the switch 4, for example, only the failed converter 5a is opened, and the healthy converter 5b is opened.
And the inverter 6 can be improved to continue the operation. However, in this case, there is a problem that the converter 5b is overloaded in a large power region and the failure may spread. Further, there is a problem in that the function of the inverter control circuit 8 and the abnormality detection circuit 9 for circuit protection may be abnormal due to the decrease in output.

The present invention has been made in view of such conventional problems. Even if one of a plurality of converters fails, the remaining healthy converters can be continuously operated, and further, the failure can occur. It is an object of the present invention to provide an electric vehicle control device that does not cause an abnormality in the circuit even during continuous operation during time.

[Constitution of Invention]

[0010]

SUMMARY OF THE INVENTION An electric vehicle controller according to the present invention includes a plurality of converters for converting AC power into DC power, and DC power connected to a common DC bus together with all of the converters. An inverter for converting to electric power and an overload protection means for interrupting the input of AC power to the converter when the inverter is overloaded, and an overload standard for normal operation and lower than that. A safety side overload reference that can be used by switching, and an opening means for individually opening each of the plurality of converters from AC power;
Detection means for detecting the opening operation of the opening means,
Reference switching means for switching the overload reference of the overload protection means to the safe side when the detection means detects the opening operation of the opening means.

[0011]

In the electric vehicle controller of the present invention, during power running,
It is possible to supply the DC power output from each of the plurality of converters to the inverter, convert the AC power into desired AC power, and drive the AC motor. Then, when the inverter is overloaded, the overload protection means detects the overload, and the opening means stops the supply of the AC power to each of the plurality of converters.

Further, when any one of the converters fails, the reference switching means switches the protection operation reference of the overload protection means for the inverter from the normal operation to the safety operation reference, and the inverter is lowered. The overload criterion is used for protection operation, the AC motor can continue to be driven by the remaining healthy converter and inverter, and the overload is caused by requesting the remaining healthy converter to output power with abnormal capacity. Can be prevented.

[0013]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 shows a circuit configuration of an embodiment of the present invention. Like the conventional example shown in FIG. 2, a current collector 1 for taking in electric power from an AC overhead wire and a unit for interrupting the taking of AC electric power. Circuit breaker 2, Transformer 3 for transforming high-voltage input into voltage power suitable for the device, Switches 4a, 4b for individually applying secondary power of transformer 3 to each of a plurality of converters, respectively. It is provided with two voltage type pulse width control (PWM) converters 5a and 5b constituted by a turn-off thyristor G and a diode D.

Further, like the converters 5a and 5b, a voltage type pulse width control (PWM) inverter 6 which is composed of a turn-off thyristor G and a diode D and is connected to these converters by a common DC bus, and An AC electric motor 7 driven by the AC power from the inverter 6 is provided. Further, an inverter control circuit 8 for controlling the inverter 6 and an abnormality detection circuit 9 for detecting an abnormality of the inverter 6 are provided.

In the electric vehicle controller of this embodiment, the contacts 10a and 10b which output a detection signal when the switches 4a and 4b are opened in cooperation with the contacts of the switches 4a and 4b, and their detection. It is provided with an OR circuit 11 which takes the logical sum of the output signals of the contacts 10a and 10b, and a current detector 12 which is provided on the DC input line of the inverter 6.

Further, the abnormality detection circuit 9 has a comparator 13 which receives the detection signal from the current detector 12 as one input, a reference setter REF1 which gives an overload current reference during normal operation, and a lower level than that. A reference setter REF2 for providing a safety-side overload current reference and a switch 14 for switching these current references are provided. The switch 14 is connected so that the current reference REF1 and the current reference REF2 are switched by the output of the OR circuit 11 and the output of the switch 14 becomes the other input of the comparator 13. Further, the output of the comparator 13 causes the circuit breaker 2 to trip. Incidentally, 16 is a capacitor.

Next, the operation of the electric vehicle controller having the above structure will be described.

The operation when the converter 5b fails, for example, will now be described.
The switch 4b is opened due to the failure of b. Then, the contact 10b for detection interlocking with the switch 4b is turned on, and a detection signal is given to the OR circuit 11, and the OR circuit 11 switches 14 of the inverter control circuit 8 and the abnormality detection circuit 9.
A switching signal is output to and.

Therefore, the inverter control circuit 8 controls the electric motor current to a preset value according to the output of the speed detector 15. When the switch 4b is opened, the OR circuit 11 outputs the current. Depending on the output, the current setting value is switched to a value lower than that during normal operation, and the input current of the inverter 6 is limited.

On the other hand, in the abnormality detection circuit 9, the OR circuit 11
Switch signal from the side of the current reference REF1 in the normal state until then to the lower current reference REF2 corresponding to the operating capacity of the converter 5a,
The current reference REF2 is given to the comparator 13.

Therefore, when the converter 5a is not overloaded, the converter 5a alone converts the AC power into the DC power and supplies it to the inverter 6, and the inverter 6 outputs the low input current limited by the inverter control circuit 8. The conversion operation is performed on the contrary, and the AC motor 7 is continuously driven.

However, in spite of the limitation of the input current by the inverter control circuit 8, the input current of the inverter 6 detected by the current detector 12 (and therefore also the load current of the converters 5a and 5b) is the above-mentioned current reference RE.
If it is larger than F2, it is determined that the converter 5a is overloaded and a trip signal is given to the circuit breaker 2 to cut off the input power to protect the circuit.

Thus, a plurality of converters 5a, 5b
Even if one of the two fails, the operation can be continued only with a healthy converter, and in that case, the input current of the inverter 6 is limited to a low level to apply a heavy load to the converter. In addition, if there is an overload, it is detected to shut off the power to protect the circuit.

The present invention is not limited to the above-described embodiment, and the converter may be a plurality of converters of three or more. In that case, each converter is individually provided with a switch and its open / close detection. And a switching means for stepwise switching the current reference or the voltage reference to the lower one in accordance with the number of failed converters. Further, in that case, the inverter control circuit also has a function of stepwise limiting the input current according to the number of failed converters. Further, the overload reference may be a voltage reference instead of the current reference.

Further, although the circuit breaker 2 is cut off in the above embodiment, when another load is connected to the secondary side of the transformer 3, the input power to each converter is cut off at the same time. Another circuit breaker may be provided.

[0026]

As described above, according to the present invention, even if one of a plurality of converters fails, the comparison standard for the input current or the input voltage to the inverter is switched to the low side, and a sound converter is used. Since the power is cut off because the converter is overloaded when there is an input that exceeds the current or voltage reference while continuing the operation, the device is damaged by the failure of one converter as in the past. The operation can be continued without stopping the whole, and the overload of the converter can be detected and the power can be cut off by the lower overload standard on the safe side during the continuous operation to ensure the protection of the circuit. .

[Brief description of drawings]

FIG. 1 is a circuit block diagram of an embodiment of the present invention.

FIG. 2 is a circuit block diagram of a conventional example.

[Explanation of symbols]

 1 Current Collector 2 Circuit Breaker 3 Transformer 4a, 4b Switch 5a, 5b Converter 6 Inverter 7 AC Motor 8 Inverter Control Circuit 9 Abnormality Detection Circuit 10a, 10b Detection Contact 11 OR Circuit 12 Current Detector 13 Comparator 14 Switch 15 Speed Detector REF1 Normal current reference REF2 Abnormal current reference

Claims (1)

[Claims] 1. A plurality of converters for converting AC power to DC power, an inverter for converting DC power connected to a common DC bus with all of the converters to AC power, and an inverter for converting the DC power to AC power. An overload protection means for shutting off the input of AC power to the converter when a load is applied, which can be used by switching between an overload standard for normal operation and a safety side overload standard lower than that. The opening means for individually opening the plurality of converters from the AC power, the detecting means for detecting the opening operation of the opening means, and the detecting means for opening the opening operation of the opening means. An electric vehicle control device comprising a reference switching means for switching the overload reference of the overload protection means to a safe side when detected.