# US 12,603,580 B2 · Power conversion apparatus and power conversion system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,603,580 B2 - Document ID: US12603580B2 - Status: Granted - Kind: B2 - Application number: 18/294,780 - Filed: 2022-08-18 - Published: 2024-10-17 - Granted: 2026-04-14 - Earliest claimed: 2021-10-06 - Assignees: TDK Corporation - Applicants: TDK Corporation - Inventors: Akinori Hariya - Web page: https://patentgrep.com/patent/US12603580B2 ## CPC - H02M 3/28: using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate AC - H02M 3/33573: {Full-bridge at primary side of an isolation transformer} - 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 - H02M 1/36: Means for starting or stopping converters - H02M 3/33592: {having a synchronous rectifier circuit or a synchronous freewheeling circuit at the secondary 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 A power conversion apparatus includes: a first power terminal; a switching circuit including first switching devices configured to be turned on/off based on a first driving signal; a transformer; a rectifying circuit including second switching devices configured to be turned on/off based on a second driving signal; a smoothing circuit; a second power terminal; and a control circuit. In a first period before electric power is supplied from the first power terminal toward the second power terminal, the control circuit generates a first threshold increasing with the passage of time, and performs, when a voltage value of a voltage at the first power terminal reaches the first threshold, switching from an output state in which the second driving signal is outputted to an output stop state in which output of the second driving signal is stopped, or switching from the output stop state to the output state. ## Claims ### Claim 1 A power conversion apparatus comprising: a first power terminal; a switching circuit coupled to the first power terminal and including a plurality of first switching devices, the first switching devices being configured to be turned on and off based on a first driving signal; a transformer including a first winding and a second winding, the first winding being coupled to the switching circuit; a rectifying circuit coupled to the second winding and including a plurality of second switching devices, the second switching devices being configured to be turned on and off based on a second driving signal; a smoothing circuit coupled to the rectifying circuit; a second power terminal coupled to the smoothing circuit; and a control circuit configured to control operations of the first switching devices and the second switching devices, wherein the control circuit is configured to, in a first period before electric power is supplied from the first power terminal toward the second power terminal, generate a first threshold that increases with passage of time, and perform, when a voltage value of a voltage at the first power terminal reaches the first threshold, switching from an output state to an output stop state, or switching from the output stop state to the output state, the output state being a state in which the second driving signal is outputted, the output stop state being a state in which output of the second driving signal is stopped. ### Claim 2 (depends on 1) The power conversion apparatus according to claim 1, wherein the output state is a state in which the first driving signal and the second driving signal are outputted, and the output stop state is a state in which output of the first driving signal and the second driving signal is stopped. ### Claim 3 (depends on 1) The power conversion apparatus according to claim 1, wherein the control circuit is configured to: further generate, in the first period, a second threshold that increases with the passage of time and has a value greater than a value of the first threshold; perform, when the voltage value reaches the first threshold, the switching from the output stop state to the output state; and perform, when the voltage value reaches the second threshold, the switching from the output state to the output stop state. ### Claim 4 (depends on 3) The power conversion apparatus according to claim 3, wherein the control circuit is configured to, in a second period after the first period, set the first threshold to a first predetermined value and set the second threshold to a second predetermined value. ### Claim 5 (depends on 3) The power conversion apparatus according to claim 3, wherein the control circuit is configured to change the first threshold and the second threshold, based on a control signal supplied from outside, in a second period after the first period. ### Claim 6 (depends on 1) The power conversion apparatus according to claim 1, wherein the control circuit is configured to: perform the switching from the output stop state to the output state when the voltage value reaches the first threshold; and perform the switching from the output state to the output stop state at a timing at which a predetermined length of time elapses from a timing at which the voltage value has reached the first threshold. ### Claim 7 (depends on 1) The power conversion apparatus according to claim 1, wherein the control circuit is configured to: perform the switching from the output state to the output stop state when the voltage value reaches the first threshold; and perform the switching from the output stop state to the output state at a timing at which a predetermined length of time elapses from a timing at which the voltage value has reached the first threshold. ### Claim 8 (depends on 6) The power conversion apparatus according to claim 6, wherein the control circuit is configured to set the first threshold to a predetermined value in a second period after the first period. ### Claim 9 (depends on 6) The power conversion apparatus according to claim 6, wherein the control circuit is configured to change the first threshold, based on a control signal supplied from outside, in a second period after the first period. ### Claim 10 (depends on 1) The power conversion apparatus according to claim 1, wherein the control circuit includes: a comparator configured to make a determination as to whether the voltage value has reached the first threshold; a duty ratio generator configured to generate a duty ratio in the first period; and a driver configured to generate the second driving signal, based on the duty ratio, and to perform the switching from the output stop state to the output state, or the switching from the output state to the output stop state, based on a result of the determination made by the comparator. ### Claim 11 (depends on 1) The power conversion apparatus according to claim 1, wherein the control circuit includes: a comparator configured to make a determination as to whether the voltage value has reached the first threshold; a duty ratio generator configured to generate a duty ratio in the first period, based on a result of the determination made by the comparator; and a driver configured to generate the second driving signal, based on the duty ratio. ### Claim 12 (depends on 10) The power conversion apparatus according to claim 10, wherein the duty ratio generator is configured to, in a second period after the first period, generate the duty ratio by performing feedback control, based on a voltage at the first power terminal or a voltage at the second power terminal. ### Claim 13 A power conversion system comprising: a first battery including a first terminal and a second terminal; a capacitor including a first terminal and a second terminal; a first switch provided on a path coupling the first terminal of the first battery and the first terminal of the capacitor to each other; a second switch provided on a path coupling the second terminal of the first battery and the second terminal of the capacitor to each other; a power conversion apparatus; and a second battery, wherein the power conversion apparatus includes a first power terminal including a first coupling terminal and a second coupling terminal, the first coupling terminal being coupled the first terminal of the capacitor, the second coupling terminal being coupled to the second terminal of the capacitor, a switching circuit coupled to the first power terminal and including a plurality of first switching devices, the first switching devices being configured to be turned on and off based on a first driving signal, a transformer including a first winding and a second winding, the first winding being coupled to the switching circuit, a rectifying circuit coupled to the second winding and including a plurality of second switching devices, the second switching devices being configured to be turned on and off based on a second driving signal, a smoothing circuit coupled to the rectifying circuit, a second power terminal coupled to the smoothing circuit, and a control circuit configured to control operations of the first switching devices and the second switching devices, and the control circuit is configured to, in a first period before electric power is supplied from the first power terminal toward the second power terminal, generate a first threshold that increases with passage of time, and perform, when a voltage value of a voltage at the first power terminal reaches the first threshold, switching from an output state to an output stop state, or switching from the output stop state to the output state, the output state being a state in which the second driving signal is outputted, the output stop state being a state in which output of the second driving signal is stopped.