JP5600438B2 - Overvoltage protection device for power converter - Google Patents

Description

  The present invention relates to an overvoltage protection device for a power converter that protects a power converter of a vehicle from overvoltage.

  The conventional power converter overvoltage detection method compares the voltage of the filter capacitor with a preset overvoltage set value, and when the filter capacitor voltage exceeds the overvoltage set value, the filter capacitor is connected in parallel to the filter capacitor. It is controlled to turn on the semiconductor switch and discharge the filter capacitor. As a result, the filter capacitor voltage exceeds the overvoltage set value, and the power converter can prevent destruction. The processor compares the filter capacitor voltage with the overvoltage set value and outputs the overvoltage detection signal. The overvoltage detection condition and the output condition of the overvoltage detection signal can be changed arbitrarily according to the data in the memory. ing.

JP-A-8-126101

  Such a conventional overvoltage detection method is used when the overvoltage detection means has failed, for example, when there is a problem in the processing of the processor and the processor is stopped, or when data in the memory is changed due to disturbance such as noise. When the filter capacitor voltage rises, there is a problem that the filter capacitor overvoltage cannot be detected and the power converter is destroyed. The conventional technique described in Patent Document 1 is a method in which a short-circuit semiconductor switch is turned on when the filter capacitor voltage exceeds an overvoltage set value, and when the voltage falls below a specified value, the short-circuit semiconductor switch is turned off. When the overvoltage detection means configured by the above fails, there is a problem that the filter capacitor overvoltage cannot be detected, and that the filter capacitor voltage has fallen below the specified value cannot be detected.

Above-mentioned problems, a breaker, and a filter capacitor, wherein the shorting is connected in parallel to the filter capacitor and the semi-conductor switches, when detecting an overvoltage on the filter capacitor, preset signal retention time line breaker outputting an open signal and overvoltage protection signal, the line breaker opening signal output to open the breaker to disconnect and a source power converter, before Symbol semiconductor for the short and outputs the over-voltage protection signal In the power converter comprising overvoltage protection means for turning on the switch and discharging the filter capacitor, the overvoltage protection means compares the overvoltage set value preset in the memory with the voltage of the filter capacitor and compares the overvoltage of the filter capacitor. The overvoltage detection means for detecting the overvoltage detection reference voltage set in advance with a circuit constant and the voltage of the filter capacitor. A logical sum circuit for aggregating overvoltage and configured overvoltage detection means by both of the detecting means, the overvoltage detection signal alone overvoltage detection signal detected from the both overvoltage detection means for detecting an overvoltage of the filter capacitor and, the type of overvoltage detection signal from the over-voltage detection means of the both through oR circuit, the overvoltage outputs the breaker opening signal from the time one is the output of the detection signal and the overvoltage protection signal, the both overvoltage overvoltage protection for a power converter and a, and a signal holding circuit for outputting the breaker opening signal and the overvoltage protection signal only prolonged constant signal holding time the output is set time whether we pre Me eliminated detection signal It can be solved by the device.

  According to the present invention, by providing a plurality of filter capacitor overvoltage detection means, even if a part of the overvoltage detection means fails, the other sound overvoltage detection means detects an increase in the filter capacitor voltage and the power converter It is possible to protect.

  Overvoltage detection conditions can be changed without changing the circuit by changing the data in the memory by comparing the filter capacitor voltage with the overvoltage setting value set in the memory in advance using a processor. is there.

  By performing overvoltage detection by comparing the reference voltage for overvoltage detection set by the circuit constant using a comparator and the filter capacitor voltage, it is possible to detect overvoltage without fragility such as memory problems peculiar to processor processing.

  Overvoltage detection method that has the effects of both the flexibility of changing the conditions of processor processing and the overvoltage detection excluding the vulnerability of processor processing by adopting a configuration with both overvoltage detection by processor processing and overvoltage detection by a comparator Is possible.

  By setting the time for turning on the short-circuiting semiconductor switch at the time of overvoltage detection to a predetermined time, it is possible to prevent the short-circuiting semiconductor switch from being kept on and stopping the control of the power converter.

  By consolidating overvoltage detection signals from a plurality of overvoltage detection means into a single overvoltage detection signal by logical sum, it is possible to consolidate circuits used for protection during overvoltage detection, and it is possible to omit components.

FIG. 1 shows an overvoltage detection method for a power converter according to an embodiment of the present invention. FIG. 2 is a diagram for explaining the overvoltage protection means of the present invention. FIG. 3 is a time chart showing the operation of each part of the present invention.

  Hereinafter, embodiments of the invention will be described with reference to the drawings.

  FIG. 1 shows a control device for a power converter according to an embodiment of the present invention. In the present embodiment, a case will be described in which the vehicle motor drive inverter device is driven by a power converter having two overvoltage detection means.

  In this embodiment, the power converter includes an inverter device 1, a current breaker 2, a filter capacitor 3, a filter switch short-circuiting semiconductor switch 4, a limiting resistor 5, a voltage detection unit 6, and an overvoltage protection unit 7. When accelerating, the circuit breaker 2 is short-circuited to charge the filter capacitor 3, and the inverter device 1 is switched to supply an AC voltage to the motor 8. When the electric motor 8 is decelerated, the electric motor 8 is operated as a generator, and the AC voltage generated from the electric motor 8 is converted into a DC voltage by the inverter device 1 and regenerated on the overhead line.

  The overvoltage protection unit 7 includes overvoltage detection units 10 a and 10 b and a control signal output unit 11. The filter capacitor voltage 9 is input to the overvoltage detection means 10a and 10b through the voltage detection means 6.

  The overvoltage detection means 10a, 10b compares the preset overvoltage set value with the filter capacitor voltage 9, and outputs the overvoltage detection signals 12a, 12b to the control signal output means 11 when the filter capacitor voltage 9 exceeds the overvoltage set value. .

  The control signal output means 11 performs an overvoltage protection operation when at least one of the overvoltage detection signals 12a and 12b is input. When the overvoltage detection signals 12a and 12b are input, the control signal output means 11 outputs the inverter stop signal 13 to stop the control of the inverter device 1 and outputs the circuit breaker open signal 14 to output the circuit breaker 2 Is opened, the power converter and the power source are disconnected, an overvoltage protection signal 15 is output, the short-circuit semiconductor switch 4 is turned on, and the filter capacitor 3 is discharged via the limiting resistor 5.

  Here, as an operation when one of the overvoltage detection means fails, it is assumed that a failure has occurred in the overvoltage detection means 10a, and the overvoltage protection operation in that case will be described below.

  When the filter capacitor voltage 9 exceeds the overvoltage set value, even if an event occurs in which the overvoltage detection means 10a does not output the overvoltage detection signal 12a, the overvoltage detection signal 12b is transmitted from the sound overvoltage detection means 10b to the control signal output means 11. Is output and the overvoltage protection operation is executed.

  Hereinafter, the detailed configuration of the overvoltage protection means 7 will be described. FIG. 2 shows an overvoltage protection means according to an embodiment of the invention. In the present embodiment, the overvoltage detection means 10a is a system in which the processor compares the filter capacitor voltage with the overvoltage set value set in the memory in advance, and the overvoltage detection means 10b detects the overvoltage set value set by the circuit constant and the filter. A description will be given of a method of performing overvoltage detection by comparing capacitor voltages with a comparator.

  The overvoltage detection means 10a is constituted by an analog-digital conversion circuit 16, a processor 17, and a memory 18. The filter capacitor voltage 9 is converted into a digital value by the analog-digital conversion circuit 16 and input to the processor 17. The processor 17 compares the overvoltage set value set in the memory 18 with the filter capacitor voltage converted into a digital value, and outputs the overvoltage detection signal 12a when the filter capacitor voltage exceeds the overvoltage set value.

  The overvoltage detection means 10 b includes a DC power source 19, a fixed resistor 20, a variable resistor 21, and a comparator 22. The comparator 22 receives a voltage obtained by dividing the DC power source 19 using the fixed resistor 20 and the variable resistor 21 as a reference voltage for overvoltage detection. The comparator 22 compares the filter capacitor voltage 9 with the overvoltage set value, and outputs an overvoltage detection signal 12b when the filter capacitor voltage 9 exceeds the overvoltage set value.

  The control signal output means 11 includes an OR circuit 23 and a signal holding circuit 24. The overvoltage detection signals 12a and 12b are input to the signal holding circuit 24 through the OR circuit 23. The signal holding circuit 24 receives the inverter stop signal 13, the breaker release signal 14, and the overvoltage protection signal 15 for a preset signal holding time. Output.

FIG. 3 shows a time chart of each operation of the filter capacitor voltage 9, the overvoltage detection signals 12a and 12b, the overvoltage protection signal 15, and the shorting semiconductor switch 4.
Overvoltage detection signals 12a and 12b are output at t1 when the filter capacitor voltage 9 exceeds the overvoltage setting value, the short-circuit semiconductor switch 4 is turned on, and the overvoltage detection signals 12a and 12b at t2 when the filter capacitor voltage 9 falls below the overvoltage setting value. Output is lost.

  The signal holding circuit 24 outputs the overvoltage protection signal 15 from t1 output by the overvoltage detection signals 12a and 12b, and outputs the overvoltage protection signal 15 for a preset signal holding time t4 from t2 when the output of the overvoltage detection signals 12a and 12b disappears. Extend output.

  Although the present embodiment has been described with the configuration of controlling one inverter device, the present invention can also be configured when controlling a plurality of converter devices, inverter devices, and power supply devices.

DESCRIPTION OF SYMBOLS 1 Inverter apparatus 2 Circuit breaker 3 Filter capacitor 4 Filter capacitor short circuit semiconductor switch 5 Limiting resistor 6 Voltage detection means 7 Overvoltage protection means 8 Motor 9 Filter capacitor voltage 10a, 10b Overvoltage detection means 11 Control signal output means 12a, 12b Overvoltage detection Signal 13 Inverter stop signal 14 Circuit breaker open signal 15 Overvoltage protection signal 16 Analog-digital conversion circuit 17 Processor 18 Memory 19 DC power supply 20 Fixed resistor 21 Variable resistor 22 Comparator 23 OR circuit 24 Signal holding circuit

Claims (1)

Circuit breaker, filter capacitor, short-circuit semiconductor switch connected in parallel to the filter capacitor, and circuit breaker open signal and overvoltage protection for a preset signal holding time when overvoltage is detected in the filter capacitor outputs a signal, the output of the breaker opening signal to open the breaker disconnect and a source power converter, the turns on the short-circuit semiconductor switch and outputs a pre-Symbol overvoltage protection signal In a power converter comprising overvoltage protection means for discharging the filter capacitor,
The overvoltage protection means includes
The overvoltage detection means for detecting the overvoltage of the filter capacitor by comparing the overvoltage set value set in the memory in advance with the voltage of the filter capacitor, and comparing the reference voltage for overvoltage detection set in advance with a circuit constant and the voltage of the filter capacitor And an overvoltage detecting means constituted by both of the overvoltage detecting means for detecting the overvoltage of the filter capacitor;
An OR circuit that aggregates the overvoltage detection signals detected from both overvoltage detection means into a single overvoltage detection signal;
The type of overvoltage detection signal from the over-voltage detection means of the both through OR circuit, the overvoltage outputs the breaker opening signal from the time one is the output of the detection signal and the overvoltage protection signal, the both overvoltage power, characterized in that it comprises a signal holding circuit for outputting the breaker opening signal and the overvoltage protection signal only prolonged constant signal holding time the output is set time whether we pre Me eliminated detection signal Converter overvoltage protection device.

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