# US 12,603,581 B2 · Power conversion circuit, and method for producing power converter > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,603,581 B2 - Document ID: US12603581B2 - Status: Granted - Kind: B2 - Application number: 18/273,982 - Filed: 2021-02-03 - Published: 2024-12-26 - Granted: 2026-04-14 - Earliest claimed: 2021-02-03 - Assignees: Sumitomo Electric Industries, Ltd.; Autonetworks Technologies, Ltd.; Sumitomo Wiring Systems, Ltd. - Applicants: Sumitomo Electric Industries, Ltd.; AutoNetworks Technologies, Ltd.; Sumitomo Wiring Systems, Ltd. - Inventors: Yuusuke Okagawa; Tomoaki Ujimaru - Web page: https://patentgrep.com/patent/US12603581B2 ## CPC - H02M 3/28: using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate AC - H02M 3/33576: {having at least one active switching element at the secondary side of an isolation transformer} - H02M 1/44: Circuits or arrangements for compensating for electromagnetic interference in converters or inverters - H02M 3/01: {Resonant DC/DC converters} - H02M 3/33573: {Full-bridge at primary side of an isolation transformer} - 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) ## Abstract Provided is a power conversion circuit capable of suppressing noise with fewer components, and a method for producing a power converter. A power conversion circuit (50) includes: a transformer (64) having first and second terminals (100, 102) on a primary side, and third and fourth terminals (104, 106) on a secondary side; a first circuit (60) connected to the first and second terminals; a second circuit (62) connected to the third and fourth terminals; and first and second inductors (66, 68) respectively connected in series to two terminals (100, 106) constituting a combination, the combination being either one of a combination of the first terminal (100) and the third terminal (104) and a combination of the first terminal (100) and the fourth terminal (106), a minimum impedance between the two terminals constituting the combination being higher than that of the other combination. ## Claims ### Claim 1 A power conversion circuit, comprising: a transformer having first and second terminals on a primary side, and third and fourth terminals on a secondary side; a first circuit connected to the first and second terminals; a second circuit connected to the third and fourth terminals; a first inductor connected in series to the first terminal; and a second inductor connected in series to one of the third terminal and the fourth terminal which provides a highest minimum impedance between the first terminal and the one of the third terminal and the fourth terminal relative to a minimum impedance between the first terminal and another one of the third terminal and the fourth terminal. ### Claim 2 (depends on 1) The power conversion circuit according to claim 1, further comprising: a third inductor connected in series to the second terminal; and a fourth inductor connected in series to one of the third terminal and the fourth terminal to which the second inductor is not connected. ### Claim 3 (depends on 2) The power conversion circuit according to claim 2, wherein the first inductor is magnetically coupled to the third inductor, or the second inductor is magnetically coupled to the fourth inductor. ### Claim 4 (depends on 1) The power conversion circuit according to claim 1, wherein no inductor is connected to any one of the second terminal and one of the third terminal and the fourth terminal to which the second inductor is not connected. ### Claim 5 (depends on 1) The power conversion circuit according to claim 1, wherein the first circuit includes a full bridge circuit. ### Claim 6 (depends on 5) The power conversion circuit according to claim 5, wherein the second circuit includes another full bridge circuit. ### Claim 7 (depends on 1) The power conversion circuit according to claim 1, wherein the transformer has a first coil and a second coil on the secondary side, the third terminal and the fourth terminal are connection terminals to the first coil, and the power conversion circuit further includes a third circuit connected to the second coil. ### Claim 8 (depends on 7) The power conversion circuit according to claim 7, wherein the transformer has fifth and sixth terminals as terminals of the second coil, and the power conversion circuit includes third and fourth inductors, the third inductor is connected in series with the first terminal, and the fourth inductor is connected to one of the fifth terminal and the sixth terminal which provides one of a highest minimum impedance or a lowest minimum resonance frequency between the first terminal and the one of the fifth terminal and the sixth terminal relative to a minimum impedance or minimum resonance frequency between the first terminal and another one of the fifth terminal and the sixth terminal. ### Claim 9 A power conversion circuit, comprising: a transformer having first and second terminals on a primary side, and third and fourth terminals on a secondary side; a first circuit connected to the first and second terminals; a second circuit connected to the third and fourth terminals; a first inductor connected in series to the first terminal; and a second inductor connected in series to one of the third terminal and the fourth terminal that results in a lowest minimum resonance frequency between the first terminal and the one of the third terminal and the fourth terminal relative to a minimum resonance frequency between the first terminal and another one of the third terminal and the fourth terminal. ### Claim 10 (depends on 9) The power conversion circuit according to claim 9, wherein no inductor is connected to any one of the second terminal and one of the third terminal and the fourth terminal to which the second inductor is not connected. ### Claim 11 (depends on 9) The power conversion circuit according to claim 9, wherein the first circuit includes a full bridge circuit. ### Claim 12 (depends on 11) The power conversion circuit according to claim 11, wherein the second circuit includes another full bridge circuit. ### Claim 13 (depends on 9) The power conversion circuit according to claim 9, wherein the transformer has a first coil and a second coil on the secondary side, the third terminal and the fourth terminal are connection terminals to the first coil, and the power conversion circuit further includes a third circuit connected to the second coil. ### Claim 14 (depends on 13) The power conversion circuit according to claim 13, wherein the transformer has fifth and sixth terminals as terminals of the second coil, and the power conversion circuit includes third and fourth inductors, the third inductor is connected in series with the first terminal, and the fourth inductor is connected to one of the fifth terminal and the sixth terminal which provides one of a highest minimum impedance or a lowest minimum resonance frequency between the first terminal and the one of the fifth terminal and the sixth terminal relative to a minimum impedance or minimum resonance frequency between the first terminal and another one of the fifth terminal and the sixth terminal. ### Claim 15 (depends on 9) The power conversion circuit according to claim 9, further comprising: a third inductor connected in series to the second terminal; and a fourth inductor connected in series to one of the third terminal and the fourth terminal to which the second inductor is not connected. ### Claim 16 (depends on 15) The power conversion circuit according to claim 15, wherein the first inductor is magnetically coupled to the third inductor, or the second inductor is magnetically coupled to the fourth inductor. ### Claim 17 A method for producing a power converter, comprising: a preparation step of preparing a transformer having first and second terminals on a primary side and third and fourth terminals on a secondary side; a measurement step of measuring first minimum impedance between the first terminal and the third terminal, measuring a second minimum impedance between the first terminal and the fourth terminal, measuring a third minimum impedance between the second terminal and the third terminal, and measuring a fourth minimum impedance between the second terminal and the fourth terminal; a determination step of determining which of the first, second, third, and fourth minimum impedances is highest; and a step of connecting a first inductor in series with the first terminal and a second inductor in series with the third terminal in a case that the first minimum impedance is highest, the first inductor in series with the first terminal and the second inductor in series with the fourth terminal in a case that the second minimum impedance is highest, the first inductor in series with the second terminal and the second impedance in series with the third terminal in a case that the third minimum impedance is highest, and the first inductor in series with the second terminal and the second inductor in series with the fourth terminal in a case that the fourth minimum impedance is highest. ### Claim 18 A method for producing a power converter, comprising: a preparation step of preparing a transformer having first and second terminals on a primary side and third and fourth terminals on a secondary side; a measurement step of measuring a first minimum resonance frequency between the first terminal and the third terminal, measuring a second minimum resonance frequency between the first terminal and the fourth terminal, measuring a third minimum resonance frequency between the second terminal and the third terminal, and measuring a fourth minimum resonance frequency between the second terminal and the fourth terminal; a determination step of determining which of the first, second, third, and fourth minimum resonance frequencies is lowest; and a step of connecting a first inductor in series with the first terminal and a second inductor in series with the third terminal in a case that the first minimum resonance frequency is lowest, the first inductor in series with the first terminal and the second inductor in series with the fourth terminal in a case that the second minimum resonance frequency is lowest, the first inductor in series with the second terminal and the second impedance in series with the third terminal in a case that the third minimum resonance frequency is lowest, and the first inductor in series with the second terminal and the second inductor in series with the fourth terminal in a case that the fourth minimum resonance frequency is lowest.