# US 2019/0356239 A1 · Method for controlling inverter during startup and control device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0356239 A1 - Document ID: US20190356239A1 - Status: Published application - Kind: A1 - Application number: 16/525,125 - Filed: 2019-07-29 - Published: 2019-11-21 - Earliest claimed: 2017-01-30 - Assignees: Furukawa Electric Co., Ltd.; Furukawa Automotive Systems Inc. - Applicants: Furukawa Electric Co., Ltd.; Furukawa Automotive Systems Inc. - Inventors: Akihiro OKUDERA; Takezo SUGIMURA; Ryosuke TAMURA - Web page: https://patentgrep.com/patent/US20190356239A1 ## CPC - H02M 1/36: Means for starting or stopping converters - H02M 7/5387: in a bridge configuration - F02N 11/08: Circuits specially adapted for starting of engines - H02M 3/28: using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate AC - H02M 7/48: using discharge tubes with control electrode or semiconductor devices with control electrode - H02M 7/53878: {by time shifting switching signals of one diagonal pair of the bridge with respect to the other diagonal pair} - F02N 2011/0896: {Inverters for electric machines, e.g. starter-generators} - 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)} - 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) - F02N: STARTING OF COMBUSTION ENGINES; STARTING AIDS FOR SUCH ENGINES, NOT OTHERWISE PROVIDED FOR - Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS ## Abstract Provided are a control method and a control device for an inverter being capable of soft start using soft switching without causing a voltage surge or a current surge. A control method for soft start using soft switching of an inverter, the inverter being a bridge circuit with at least two upper and lower arms, the control method including: shifting phases of gate pulses for a switching element of the upper arm and a switching element of the lower arm, which are paired for current energization, from each other to form an overlap period of both the gate pulses; and changing magnitude of the shift to gradually increase the overlap period that defines an energization period to implement the soft start using the soft switching. ## Claims ### Claim 1 A method for controlling an inverter for soft start using soft switching, the inverter being a bridge circuit with at least two upper and lower arms, the control method comprising: shifting phases of gate pulses for a switching element of the upper arm and a switching element of the lower arm, which are paired for current energization, from each other to form an overlap period of both the gate pulses; and changing magnitude of the shift to increase the overlap period that defines an energization period over time thereby implementing the soft start using the soft switching. ### Claim 2 (depends on 1) The control method according to claim 1, wherein the gate pulses each have a same pulse width. ### Claim 3 (depends on 1) The control method according to claim 1, wherein each of the switching elements is a GaN-based element. ### Claim 4 (depends on 1) A method for controlling a DC/AC converter, the DC/AC converter including at least two inverters, the control method comprising: converting DC voltage of a battery to AC voltage by a first inverter; boosting by a transformer the AC voltage converted; rectifying the AC voltage boosted in order to form DC voltage; converting by a second inverter the DC voltage rectified to AC voltage; and outputting the AC voltage, wherein the first inverter is started on the basis of soft start using the control method for soft start using soft switching of an inverter according to claim 1, and the second inverter is started on the basis of soft start after a predetermined time has elapsed. ### Claim 5 A control device for soft start using soft switching of an inverter, the control device comprising the inverter that is a bridge circuit having at least two upper and lower arms, wherein phases of gate pulses for a switching element of the upper arm and a switching element of the lower arm, which are paired for current energization, are shifted from each other to form an overlap period of both the gate pulses, and then the overlap period is increased over time thereby implementing the soft start using the soft switching. ### Claim 6 (depends on 5) The control device according to claim 5, wherein the gate pulses each have a same pulse width. ### Claim 7 (depends on 5) The control device according to claim 5, wherein each of the switching elements is a GaN-based element. ### Claim 8 (depends on 5) A control device for a DC/AC converter, the DC/AC converter including at least two inverters, which are a first inverter converting DC power supply of a battery to AC voltage, the AC voltage converted being boosted by a transformer, the AC voltage boosted being rectified to form DC voltage, and a second inverter converting the DC voltage rectified to AC voltage and outputting the AC voltage, the control device comprising a control device for soft start using soft switching of the inverter according to claim 5, wherein the first inverter is started on the basis of soft start using the control device, and the second inverter is started on the basis of soft start after a predetermined time has elapsed.