# US 2019/0356236 A1 · Power conversion circuit > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0356236 A1 - Document ID: US20190356236A1 - Status: Published application - Kind: A1 - Application number: 16/405,626 - Filed: 2019-05-07 - Published: 2019-11-21 - Earliest claimed: 2018-05-21 - Assignees: Fuji Electric Co., Ltd. - Applicants: Fuji Electric Co., Ltd. - Inventors: Ryuji YAMADA - Web page: https://patentgrep.com/patent/US20190356236A1 ## CPC - H02M 1/12: Arrangements for reducing harmonics from AC input or output - H02M 1/44: Circuits or arrangements for compensating for electromagnetic interference in converters or inverters - H02M 1/123: {Suppression of common mode voltage or current} - H02M 1/4225: {using a non-isolated boost converter} - Y02B 70/10: Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes - Y02P 80/10: Efficient use of energy, e.g. using compressed air or pressurized fluid as energy carrier - 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) - Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS - Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS ## Abstract In a power conversion circuit in which a grounded capacitor is connected to a main circuit that converts power through operation of a semiconductor switching device, a control IC that supplies a drive signal to the semiconductor switching device generates a cancellation voltage for canceling out a conducted emission that develops across terminals of the grounded capacitor as a result of the operation of the semiconductor switching device by using the drive signal (gate signal) to control a charge/discharge current of a compensation capacitor in a compensation circuit that is externally connected to the main circuit. ## Claims ### Claim 1 A power conversion circuit, comprising: a semiconductor switching device; a main circuit that performs power conversion through switching on and off of the semiconductor switching device, the main circuit including a controller that supplies a drive signal to the semiconductor switching device to switch on and off the semiconductor switching element, a grounded capacitor connected to the main circuit; a compensation circuit separate from the main circuit, connected to the main circuit, the compensation circuit including a compensation capacitor; and a compensation generator connected to the compensation circuit, the compensation generator charging and discharging the compensation capacitance on the basis of the drive signal so as to generate a cancellation voltage across the compensation capacitor that causes a conducted emission voltage across terminals of the grounded capacitor generated as a result of the switching on and off of the semiconductor switching device to be cancelled out, thereby eliminating conducted emission, wherein the compensation generator is included within the main circuit or within the compensation circuit. ### Claim 2 (depends on 1) The power conversion circuit according to claim 1, wherein the compensation generator is included within the controller of the main circuit, and the compensation generator includes a first current source for charging the compensation capacitor and a second current source for discharging the compensation capacitor that are alternately switched in accordance with the drive signal. ### Claim 3 (depends on 2) The power conversion circuit according to claim 2, wherein the controller is integrated with the first and second current sources into a single integrated circuit. ### Claim 4 (depends on 1) The power conversion circuit according to claim 1, wherein the compensation circuit further includes a delay time setter that adjusts timings at which the compensation capacitor is charged and discharged in accordance with delay times in ON and OFF switching of the semiconductor switching device relative to the drive signal. ### Claim 5 (depends on 4) The power conversion circuit according to claim 4, wherein the delay time setter includes a serious circuit made of a parallel circuit constituted by a diode and a resistor and a delay time setting capacitor that is connected in series to the parallel circuit, and the series circuit is connected between a ground voltage and the first and second current sources that are alternately switched in accordance with the drive signal. ### Claim 6 (depends on 1) The power conversion circuit according to claim 1, wherein a first series circuit constituted by a diode and a resistor is connected in series to the compensation capacitor for adjusting a leading edge slope of the cancellation voltage, and a second series circuit constituted by a diode and a resistor is connected in series to the compensation capacitor for adjusting a trailing edge slope of the cancellation voltage. ### Claim 7 (depends on 6) The power conversion circuit according to claim 6, wherein the first and second series circuits are included within the compensation circuit. ### Claim 8 (depends on 1) The power conversion circuit according to claim 1, wherein the compensation generator is included within the controller of the main circuit, wherein the compensation generator includes a first current source for charging the compensation capacitor and a second current source for discharging the compensation capacitor that are alternately switched in accordance with the drive signal, wherein the compensation circuit further includes a delay time setter that adjusts timings at which the compensation capacitor is charged and discharged in accordance with delay times in ON and OFF switching of the semiconductor switching device relative to the drive signal, wherein the delay time setter includes a serious circuit made of a parallel circuit constituted by a diode and a resistor and a delay time setting capacitor that is connected in series to the parallel circuit, and the series circuit is connected between a ground voltage and the first and second current sources that are alternately switched in accordance with the drive signal, and wherein the compensation circuit further includes a first series circuit constituted by a diode and a resistor connected in series to the compensation capacitor for adjusting a leading edge slope of the cancellation voltage, and a second series circuit constituted by a diode and a resistor connected in series to the compensation capacitor for adjusting a trailing edge slope of the cancellation voltage. ### Claim 9 (depends on 1) The power conversion circuit according to claim 1, wherein the compensation generator and the compensation circuit are configured to generate the cancellation voltage that has ON/OFF delay times, a leading edge slope and a trailing edge slop that respectively correspond to ON/OFF delay times, a leading edge slope and a trailing edge slope of the conducted emission voltage.