# US 10,122,299 B2 · Power conversion device

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- Number: US 10,122,299 B2
- Document ID: US10122299B2
- Status: Granted
- Kind: B2
- Application number: 15/563,964
- Filed: 2015-04-08
- Published: 2018-05-17
- Granted: 2018-11-06
- Earliest claimed: 2015-04-08
- Assignees: Hitachi, Ltd.
- Applicants: Hitachi, Ltd.
- Inventors: Takashi Ogawa; Kimihisa Furukawa; Junichi Sakano
- Web page: https://patentgrep.com/patent/US10122299B2

## CPC

- H02M 11/00: Power conversion systems not covered by the preceding groups
- G01R 31/382: Arrangements for monitoring battery or accumulator variables, e.g. SoC
- G01R 31/44: Testing lamps
- G08C 19/36: using optical means to covert the input signal {(characterised by optical transfer means G01D5/26; optical analogue digital converters G02F7/00)}
- H02M 1/08: Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
- H02M 1/32: Means for protecting converters other than automatic disconnection
- H02M 1/0003: {Details of control, feedback or regulation circuits}
- H02M 1/327: {against abnormal temperatures}
- H02M: APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF (transformers H01F; dynamo-electric converters H02K47/00; controlling transformers, reactors or choke coils, control or regulation of electric motors, generators or dynamo-electric converters H02P)
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)
- G08C: TRANSMISSION SYSTEMS FOR MEASURED VALUES, CONTROL OR SIMILAR SIGNALS (fluid pressure transmitting systems F15B; mechanical means for transferring the output of a sensing member into a different variable G01D5/00; mechanical control systems G05G)

## Abstract

The present invention relates to a power conversion device in the power electronics field. An object of the present invention is to provide a technique of determining whether a switching element operates normally or not from a gate monitor signal of a power conversion device, and predicting a sign of a failure by obtaining the temperature of the switching element from a transient state of the switching voltage of the power conversion circuit as a component of the power conversion device without using a new signal path.

## Claims

### Claim 1

A power conversion device comprising:
a power conversion circuit performing power conversion by switching operation of a semiconductor switching element;
a signal processing circuit controlling switching operation of the power conversion circuit;
a gate drive circuit applying a drive signal to a control terminal of the power conversion circuit on the basis of an output signal of the signal processing circuit;
a gate signal monitor circuit generating a monitor signal on the basis of drive voltage and drive current of the gate drive circuit;
a filter circuit shaping an output signal of the gate monitor circuit;
a voltage detection circuit detecting switching voltage of the power conversion circuit;
a temperature detection circuit calculating temperature of the semiconductor switching element from the switching voltage from the voltage detection circuit and outputting a temperature detection signal; and
an optical communication module transmitting a control signal from the signal processing circuit to the gate drive circuit and transmitting a gate monitor signal from the filter circuit to the signal processing circuit,
wherein a synthesis circuit synthesizing the gate monitor signal and the temperature detection signal is provided between the filter circuit and the optical communication module,
wherein an optical module receiving a signal from the synthesis circuit, converting the signal to an optical signal, and transmitting the optical signal, and
an optical module receiving the optical signal are provided,
wherein a separation circuit separating the optical signal to a gate monitor signal and a temperature detection signal is provided between the optical module receiving the optical signal and the signal processing circuit, and
wherein means which calculates temperature of the switching element on the basis of the temperature detection signal by the signal processing circuit is provided.

### Claim 2 (depends on 1)

The power conversion device according to claim 1, wherein the synthesis circuit and the separation circuit synthesizes the gate monitor signal and the temperature detection signal by a time-division path switching circuit.

### Claim 3

A power conversion device comprising:
a power conversion circuit performing power conversion by switching operation of a semiconductor switching element;
a signal processing circuit controlling switching operation of the power conversion circuit;
a gate drive circuit applying a drive signal to a control terminal of the power conversion circuit on the basis of an output signal of the signal processing circuit;
a gate signal monitor circuit generating a monitor signal on the basis of drive voltage and drive current of the gate drive circuit;
a filter circuit shaping an output signal of the gate monitor circuit;
a voltage detection circuit detecting switching voltage of the power conversion circuit;
a temperature detection circuit calculating temperature of the semiconductor switching element from the switching voltage from the voltage detection circuit and outputting a temperature detection signal; and
an optical communication module transmitting a control signal from the signal processing circuit to the gate drive circuit and transmitting a gate monitor signal from the filter circuit to the signal processing circuit,
wherein a synthesis circuit synthesizing the gate monitor signal and the temperature detection signal is provided between the filter circuit and the optical communication module,
wherein an optical module receiving a signal from the synthesis circuit, converting the signal to an optical signal, and transmitting the optical signal, and
an optical module receiving the optical signal are provided,
wherein a separation circuit separating the optical signal to a gate monitor signal and a temperature detection signal is provided between the optical module receiving the optical signal and the signal processing circuit, and
wherein the signal processing circuit calculates temperature of the switching element on the basis of the temperature detection signal.

### Claim 4 (depends on 3)

The power conversion device according to claim 3, wherein the synthesis circuit and the separation circuit synthesize the gate monitor signal and the temperature detection signal by a time-division path switching circuit.