# US 11,909,305 B2 · AC-to-DC power converter which removed a common mode component form the output current > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,909,305 B2 - Document ID: US11909305B2 - Status: Granted - Kind: B2 - Application number: 17/618,892 - Filed: 2019-08-30 - Published: 2022-08-11 - Granted: 2024-02-20 - Earliest claimed: 2019-08-30 - Assignees: Mitsubishi Electric Corporation - Applicants: Mitsubishi Electric Corporation - Inventors: Ryoji Tsuruta; Tsuguhiro Takuno; Takushi Jimichi; Kikuo Izumi - Web page: https://patentgrep.com/patent/US11909305B2 ## CPC - H02M 1/123: {Suppression of common mode voltage or current} - H02M 1/0009: {Devices or circuits for detecting current in a converter} - H02M 1/0064: {Magnetic structures combining different functions, e.g. storage, filtering or transformation} - H02M 1/007: {Plural converter units in cascade (push-pull DC/DC converters with pre-regulator H02M3/3374; DC-AC converters following a DC-DC stage including a high frequency transformer H02M7/4807; DC-AC converters following a DC-DC conversion stage generating periodically varying voltages H02M7/4826)} - H02M 1/0077: {Plural converter units whose outputs are connected in series} - H02M 1/009: {having two or more independently controlled outputs (for DC-DC converter with intermediate AC H02M3/33561)} - H02M 1/08: Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters - H02M 1/4233: {using a bridge converter comprising active switches} - H02M 3/158: including plural semiconductor devices as final control devices for a single load - H02M 7/2173: {in a biphase or polyphase circuit arrangement (H02M7/2176 takes precedence; voltage multipliers H02M7/25)} - H02M 7/219: in a bridge configuration - H02M 1/008: {Plural converter units for generating at two or more independent and non-parallel outputs, e.g. systems with plural point of load switching regulators} - H02M 1/126: {using passive filters} - H02M 3/003: {Constructional details, e.g. physical layout, assembly, wiring or busbar connections} - 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 An object is to obtain a power conversion device that can stabilize output voltage to a DC load. A power conversion device includes an AC/DC conversion unit having a power conversion circuit composed of a plurality of first semiconductor switching elements connected in a full-bridge form, and a full-bridge chopper circuit unit having a full-bridge chopper circuit composed of a plurality of second semiconductor switching elements connected in a full-bridge form, and connected to a positive terminal and a negative terminal. A neutral point of an AC filter capacitor unit and a neutral point of a DC filter capacitor unit are connected via a neutral point line. ## Claims ### Claim 1 A power conversion device which converts AC voltage from an AC power supply to DC voltage, further converts the DC voltage to desired DC voltage, and outputs the desired DC voltage to a DC load via a positive terminal and a negative terminal, the power conversion device comprising: a power conversion circuit which includes a plurality of first semiconductor switching elements connected in a bridge form, and which converts the AC voltage to DC voltage and outputs the DC voltage as DC link voltage; an AC filter capacitor unit connected between the AC power supply and the power conversion circuit, and having capacitors corresponding to respective phases of the AC voltage; a full-bridge chopper circuit including a plurality of second semiconductor switching elements connected so as to form a full-bridge circuit, the full-bridge chopper circuit having a positive leg and a negative leg respectively connected to the positive terminal and the negative terminal; a DC filter capacitor unit and a DC filter reactor unit connected between the full-bridge chopper circuit, and the positive terminal and the negative terminal; a neutral point line which connects a neutral point of the AC filter capacitor unit and a neutral point of the DC filter capacitor unit and through which a potential at the neutral point of the AC filter capacitor unit and a potential at the neutral point of the DC filter capacitor unit are made to be a common neutral point potential, the neutral point line not being connected to a ground point of which a potential is a ground potential; a controller for controlling the first semiconductor switching elements and the second semiconductor switching elements; and a current detector for detecting output current from the full-bridge chopper circuit, wherein the controller controls the plurality of second semiconductor switching elements on the basis of an output current command based on a predetermined value of output voltage, and a current detection value obtained by removing a common-mode component from the output current detected by the current detector, and the AC power supply includes a transformer of which a neutral point on an output side is grounded, and a potential of the neutral point line is equal to the ground potential. ### Claim 2 (depends on 1) The power conversion device according to claim 1, wherein the current detector includes a first current detector for detecting current between the positive leg of the full-bridge chopper circuit and the positive terminal, and a second current detector for detecting current between the negative leg of the full-bridge chopper circuit and the negative terminal, and the controller controls the plurality of second semiconductor switching elements on the basis of a current detection value obtained from a difference between a current value detected by the first current detector and a current value detected by the second current detector. ### Claim 3 (depends on 2) The power conversion device according to claim 2, further comprising: a subtractor which receives the current value detected by the first current detector and the current value detected by the second current detector, and outputs the difference; and a gain unit which receives the difference outputted from the subtractor, and outputs, as the current detection value, a value obtained by multiplying the difference by a predetermined gain, to the controller. ### Claim 4 (depends on 3) The power conversion device according to claim 3, wherein the controller controls the first semiconductor switching elements so that zero-phase voltage of the AC power supply becomes zero. ### Claim 5 (depends on 3) The power conversion device according to claim 3, wherein the DC filter reactor unit includes a three-leg core having a first leg portion wound with a winding connected to the positive terminal, a second leg portion wound with a winding connected to the negative terminal, and a third leg portion. ### Claim 6 (depends on 2) The power conversion device according to claim 2, wherein the controller controls the first semiconductor switching elements so that zero-phase voltage of the AC power supply becomes zero. ### Claim 7 (depends on 2) The power conversion device according to claim 2, wherein the DC filter reactor unit includes a three-leg core having a first leg portion wound with a winding connected to the positive terminal, a second leg portion wound with a winding connected to the negative terminal, and a third leg portion. ### Claim 8 (depends on 2) The power conversion device according to claim 2, the power conversion device being a power conversion device that outputs DC voltage to each of a plurality of DC loads, wherein a plurality of the full-bridge chopper circuits, a plurality of the DC filter capacitor units, and a plurality of the DC filter reactor units are provided correspondingly for the respective plurality of DC loads. ### Claim 9 (depends on 2) The power conversion device according to claim 2, wherein the controller controls the second semiconductor switching elements so that a potential of the positive terminal and a potential of the negative terminal with respect to the neutral point potential become positive-negative symmetric. ### Claim 10 (depends on 2) The power conversion device according to claim 2, wherein in generating gate signals for controlling the second semiconductor switching elements, the controller performs modulation by using a first voltage command and a second voltage command having a polarity inverted from the first voltage command with respect to the same carrier signal. ### Claim 11 (depends on 2) The power conversion device according to claim 2, wherein the second semiconductor switching elements are incorporated in one power module. ### Claim 12 (depends on 2) The power conversion device according to claim 2, wherein the first semiconductor switching elements and the second semiconductor switching elements are made of a wide bandgap semiconductor. ### Claim 13 (depends on 1) The power conversion device according to claim 1, wherein the controller controls the first semiconductor switching elements so that zero-phase voltage of the AC power supply becomes zero. ### Claim 14 (depends on 1) The power conversion device according to claim 1, wherein the DC filter reactor unit includes a three-leg core having a first leg portion wound with a winding connected to the positive terminal, a second leg portion wound with a winding connected to the negative terminal, and a third leg portion. ### Claim 15 (depends on 1) The power conversion device according to claim 1, the power conversion device being a power conversion device that outputs DC voltage to each of a plurality of DC loads, wherein a plurality of the full-bridge chopper circuits, a plurality of the DC filter capacitor units, and a plurality of the DC filter reactor units are provided correspondingly for the respective plurality of DC loads. ### Claim 16 (depends on 1) The power conversion device according to claim 1, wherein the controller controls the second semiconductor switching elements so that a potential of the positive terminal and a potential of the negative terminal with respect to the neutral point potential become positive-negative symmetric. ### Claim 17 (depends on 1) The power conversion device according to claim 1, wherein in generating gate signals for controlling the second semiconductor switching elements, the controller performs modulation by using a first voltage command and a second voltage command having a polarity inverted from the first voltage command with respect to the same carrier signal. ### Claim 18 (depends on 1) The power conversion device according to claim 1, wherein the second semiconductor switching elements are incorporated in one power module. ### Claim 19 (depends on 1) The power conversion device according to claim 1, wherein the first semiconductor switching elements and the second semiconductor switching elements are made of a wide bandgap semiconductor. ### Claim 20 (depends on 19) The power conversion device according to claim 19, wherein the wide bandgap semiconductor is silicon carbide.