# US 12,015,264 B2 · Power converter > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,015,264 B2 - Document ID: US12015264B2 - Status: Granted - Kind: B2 - Application number: 17/850,167 - Filed: 2022-06-27 - Published: 2023-02-02 - Granted: 2024-06-18 - Earliest claimed: 2021-07-27 - Assignees: Mitsubishi Electric Corporation - Applicants: Mitsubishi Electric Corporation - Inventors: Hideki Yoshikawa - Web page: https://patentgrep.com/patent/US12015264B2 ## CPC - H02H 7/12: for static converters or rectifiers {(for discharge lamp power supplies using static converters H05B41/2851, H05B41/2921, H05B41/2981)} - H02H 7/1213: {for DC-DC converters} - H02H 1/0007: {concerning the detecting means (in general G01R or other subclasses of G01; reed switches H01H71/2445)} - H02H 7/222: {for switches} - H02M 1/0009: {Devices or circuits for detecting current in a converter} - 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 - H03K 17/04123: {in field-effect transistor switches} - H03K 17/0822: {in field-effect transistor switches} - H03K 2217/0027: Measuring means of, e.g. currents through or voltages across the switch - H02H: EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS (indicating or signalling undesired working conditions G01R, e.g. G01R31/00, G08B; locating faults along lines G01R31/08; emergency protective devices H01H) - 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) - H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M) ## Abstract To provide a power converter which can detect occurrence of excess current in early stage without providing a blanking time when the detection of excess current is not performed after the turn on of the switching device, and which can protect the power converter. A power converter includes a time change detection circuit that outputs a detection signal according to a time change rate of a main voltage; an excess current determination circuit that generates an excess current occurrence signal of normal current state when the detection signal is less than a first threshold value, and generates the excess current occurrence signal of excess current state when the detection signal is not less than the first threshold value; and a driving circuit that generates the driving voltage of OFF state when the drive command signal is ON state and the excess current occurrence signal is excess current state. ## Claims ### Claim 1 A power converter comprising: a semiconductor switching device that is provided with a high potential side main electrode terminal, a low potential side main electrode terminal, and a control electrode terminal, and turns on and off an electrical connection between the high potential side main electrode terminal and the low potential side main electrode terminal according to a voltage applied to the control electrode terminal; a driving circuit that generates a driving voltage according to an inputted drive command signal, and applies the driving voltage to the control electrode terminal; a time change detection circuit that is connected between the high potential side main electrode terminal and the low potential side main electrode terminal, and outputs a detection signal according to a time change rate of a main voltage which is a potential difference of the high potential side main electrode terminal with respect to the low potential side main electrode terminal; and an excess current determination circuit that, when the detection signal is less than a first threshold value, determines that a normal current flows between the high potential side main electrode terminal and the low potential side main electrode terminal, and generates an excess current occurrence signal of a normal current state showing occurrence of the normal current; and when the detection signal is not less than the first threshold value, determines that an excess current flows between the high potential side main electrode terminal and the low potential side main electrode terminal, and generates the excess current occurrence signal of an excess current state showing occurrence of the excess current, wherein the driving circuit generates the driving voltage of OFF state, when the excess current occurrence signal is the excess current state, even when the drive command signal is ON state. ### Claim 2 (depends on 1) The power converter according to claim 1, wherein the time change detection circuit is provided with a differentiation circuit which outputs the detection signal obtained by time-differentiating the main voltage. ### Claim 3 (depends on 2) The power converter according to claim 2, wherein the differentiation circuit is configured by a capacity element and a resistance element which were connected in series between the high potential side main electrode terminal and the low potential side main electrode terminal. ### Claim 4 (depends on 1) The power converter according to claim 1, wherein when, after the detection signal becomes less than a second threshold value which is a value higher than the first threshold value, the detection signal exceeds the second threshold value without being less than the first threshold value, the excess current determination circuit determines that the excess current flows, and generates the excess current occurrence signal of the excess current state; and when, in a state where the detection signal is less than the second threshold value, the detection signal becomes less than the first threshold value, the excess current determination circuit determines that the normal current flows, and generates the excess current occurrence signal of the normal current state. ### Claim 5 (depends on 1) The power converter according to claim 1, wherein when, until a preliminarily set determination period elapses after the driving voltage started to be set to ON state, the detection signal does not become less than the first threshold value, the excess current determination circuit determines that the excess current flows, and generates the excess current occurrence signal of the excess current state; and When, until the determination period elapses after the driving voltage started to be set to ON state, the detection signal becomes less than the first threshold value, the excess current determination circuit determines that the normal current flows, and generates the excess current occurrence signal of the normal current state. ### Claim 6 (depends on 1) The power converter according to claim 1, wherein when, after the driving voltage starts to be set to ON state, the driving voltage exceeds a determination voltage without the detection signal being less than the first threshold value, the excess current determination circuit determines that the excess current flows, and generates the excess current occurrence signal of the excess current state; and when, after the driving voltage starts to be set to ON state, the detection signal becomes less than the first threshold value in a state where the driving voltage is less than the determination voltage, the excess current determination circuit determines that the normal current flows, and generates the excess current occurrence signal of the normal current state. ### Claim 7 (depends on 1) The power converter according to claim 1, wherein the driving circuit makes a change speed of changing the driving voltage from ON state to OFF state when the excess current occurrence signal becomes the excess current state slower than a change speed when the excess current occurrence signal is the normal current state. ### Claim 8 (depends on 3) The power converter according to claim 3, further comprising a constant current source that is connected to a connection part between the capacity element and the resistance element, and supplies a constant current to the connection part when the driving voltage is set to ON state. ### Claim 9 (depends on 3) The power converter according to claim 3, wherein a junction capacitance of a diode is used as the capacity element. ### Claim 10 (depends on 1) The power converter according to claim 1, wherein the semiconductor switching device is a switching device made of a wideband gap semiconductor.