# US 9,520,790 B2 · Interleaved LLC converters and current sharing method thereof > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,520,790 B2 - Document ID: US9520790B2 - Status: Granted - Kind: B2 - Application number: 14/206,743 - Filed: 2014-03-12 - Published: 2014-09-18 - Granted: 2016-12-13 - Earliest claimed: 2013-03-15 - Assignees: General Electric Company - Applicants: General Electric Company - Inventors: Raghothama Reddy - Web page: https://patentgrep.com/patent/US9520790B2 ## CPC - H02M 3/285: {Single converters with a plurality of output stages connected in parallel (parallel operation of a plurality of converters in DC distribution networks H02J1/10)} - H02M 1/0058: {by employing soft switching techniques, i.e. commutation of transistors when applied voltage is zero or when current flow is zero (using an auxiliary actively switched resonant commutation circuit connected to an intermediate DC voltage or between two push-pull branches of an inverter bridge H02M7/4811; in resonant inverters H02M7/4815; in inverters operating from a resonant DC source H02M7/4826)} - H02M 3/1586: {switched with a phase shift, i.e. interleaved} - H02M 3/335: using semiconductor devices only - 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 - 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 ## Abstract Methods and systems for current sharing using interleaved LLC power converters are described herein. The method provides for current sharing between a first LLC power converter interleaved with a second LLC power converter. The method includes determining an expected output voltage for at least one of the first and second LLC power converters and measuring an output voltage of at least one of the first and second LLC power converters. The method also includes increasing a dead-time of at least one of the first and second LLC power converters when the measured output voltage exceeds the expected output voltage. Finally, the method includes interleaving the first and second LLC power converters, wherein an output current of the first LLC power converter is substantially equal to an output current of the second LLC power converter. ## Claims ### Claim 1 A method of current sharing between a first inductor-inductor-capacitor (LLC) power converter interleaved with a second LLC power converter, said method comprising: operating the first and second LLC power converters at a nominal resonant frequency in an open loop during a calibration of the first and second LLC power converters; measuring an open loop output voltage of the first and second LLC power converters; determining which of the first and second LLC power converters outputs a higher measured open loop output voltage; increasing a dead-time of whichever of the first and second LLC power converters outputs the higher open loop output voltage to calibrate the first and second LLC power converters; and operating the calibrated first and second LLC power converters in a normal operating mode, wherein an output current of the first LLC power converter is substantially equal to an output current of the second LLC power converter. ### Claim 2 (depends on 1) The method according to claim 1, further comprising predicting the open loop output voltage using at least one of a predetermined input voltage, a predetermined frequency, and a known load. ### Claim 3 (depends on 1) The method according to claim 1, wherein the increasing the dead-time of whichever of the first and second LLC converters outputs the higher open loop output voltage further comprises increasing the dead-time of whichever of the first and second LLC power converters outputs the higher open loop output voltage until the measured open loop output voltage is substantially equal to an expected output voltage. ### Claim 4 (depends on 1) The method according to claim 1, further comprising: coupling the first LLC power converter to a common load; coupling the second LLC power converter to the common load; and driving the common load using output current from both the first and second LLC power converters. ### Claim 5 (depends on 1) The method according to claim 1, wherein the operating the calibrated first and second LLC power converters the normal operating mode further comprises reducing variation of a ripple current between the output current of each of the first and second LLC power converters. ### Claim 6 A system comprising: a first inductor-inductor-capacitor (LLC) power converter; and a second LLC power converter interleaved with said first LLC power converter, wherein said first and second LLC power converters are calibrated to output substantially equal output currents, the calibration comprising: operating said first and second LLC power converters at a nominal resonant frequency in an open loop; measuring an open loop output voltage of said first and second LLC power converters; determining which of said first and second LLC power converters outputs a higher measured open loop output voltage; and increasing a dead-time of whichever of said first and second LLC power converters outputs the higher open loop output voltage. ### Claim 7 (depends on 6) The system according to claim 6, wherein said first and second LLC power converters are configured to be coupled to a common load. ### Claim 8 (depends on 7) The system according to claim 7, wherein each of said first and second LLC power converters is configured to operably provide a substantially equal amount of power to drive the common load. ### Claim 9 (depends on 6) The system according to claim 6, wherein said first LLC power converter is configured to be operably coupled to a first power source and said second LLC power converter is configured to be operably coupled to a second power source. ### Claim 10 (depends on 9) The system according to claim 9, wherein said first LLC power converter comprises a first magnetic inductor, and wherein said second LLC power converter comprises a second magnetic inductor. ### Claim 11 (depends on 10) The system according to claim 10, wherein said first magnetic inductor comprises a primary winding of a first transformer, and wherein said second magnetic inductor comprises a primary winding of a second transformer. ### Claim 12 (depends on 10) The system according to claim 10, wherein said first LLC power converter comprises a first resonant inductor coupled between the first power source and said first magnetic inductor, and wherein said second LLC power converter comprises a second resonant inductor coupled between the second power source and said second magnetic inductor. ### Claim 13 (depends on 12) The system according to claim 12, wherein said first LLC power converter comprises a first resonant capacitor coupled between said first resonant inductor and said first magnetic inductor, and wherein said second LLC power converter comprises a second resonant capacitor coupled between said second resonant inductor and said second magnetic inductor. ### Claim 14 A method of interleaving a first inductor-inductor-capacitor (LLC) power converter and a second LLC power converter, said method comprising: operating the first and second LLC power converters at a nominal resonant frequency in an open loop during a calibration of the first and second LLC power converters; measuring an open loop output voltage of the first and second LLC power converters; determining which of the first and second LLC power converters outputs a higher measured open loop output voltage; increasing a dead-time of whichever of the first and second LLC power converters outputs the higher open loop output voltage; coupling the first and second LLC power converters to a common load; coupling the first LLC power converter to a first power source and the second LLC power converter to a second power source; and operating the calibrated first and second LLC power converters in a normal operating mode, wherein an output current of the first LLC power converter is substantially equal to an output current of the second LLC power converter. ### Claim 15 (depends on 14) The method according to claim 14, wherein the increasing the dead-time for whichever of the first and second LLC power converters outputs the higher open loop output voltage comprises: determining an expected output voltage for at least one of the first and second LLC power converters; measuring an output voltage of at least one of the first and second LLC power converters; and increasing the dead-time of at least one of the first and second LLC power converters when the measured output voltage exceeds the expected output voltage. ### Claim 16 (depends on 15) The method according to claim 15, wherein the measuring the open loop output voltage comprises measuring respective output voltages of each of the first and second LLC power converters, said method further comprising: comparing the measured respective output voltages of the first and second LLC power converters; wherein the increasing the dead-time of at least one of the first and second LLC power converters comprises increasing the dead-time for whichever of the first and second LLC power converters measures a higher output voltage.