# US 11,309,709 B2 · High-frequency current compensator and air-conditioning system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,309,709 B2 - Document ID: US11309709B2 - Status: Granted - Kind: B2 - Application number: 17/056,642 - Filed: 2018-07-18 - Published: 2021-07-01 - Granted: 2022-04-19 - Earliest claimed: 2018-07-18 - Assignees: Mitsubishi Electric Corporation - Applicants: Mitsubishi Electric Corporation - Inventors: Keisuke Ishikura; Shinsaku Kusube; Kazuyuki Mitsushima; Keiichi Yamamoto - Web page: https://patentgrep.com/patent/US11309709B2 ## CPC - H02J 3/01: Arrangements for reducing harmonics or ripples - H02M 5/458: using semiconductor devices only - F24F 11/88: Electrical aspects, e.g. circuits - H02M 1/12: Arrangements for reducing harmonics from AC input or output - H02M 1/126: {using passive filters} - H02J 2105/42: Home appliances - H02M 1/0009: {Devices or circuits for detecting current in a converter} - H02M 7/797: using semiconductor devices only - Y02B 70/3225: Demand response systems, e.g. load shedding, peak shaving - Y02E 40/40: Arrangements for reducing harmonics - Y04S 20/222: Demand response systems, e.g. load shedding, peak shaving - H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY - 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) - F24F: AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING (removing dirt or fumes from areas where they are produced B08B15/00; vertical ducts for carrying away waste gases from buildings E04F17/02; tops for chimneys or ventilating shafts, terminals for flues F23L17/02) - Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION - Y04S: SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS ## Abstract A harmonic current compensating device according to an embodiment of the present disclosure is a harmonic current compensating device including a power converter including at least a pair of arms each including a switching element, the harmonic current compensating device being configured to drive the switching element and supply compensating current to load current flowing between a system power source and a harmonic generating load, in which the switching element includes a unipolar device using a wide bandgap semiconductor. ## Claims ### Claim 1 A harmonic current compensating device comprising a power converter including at least a pair of arms each including a switching element, the harmonic current compensating device being configured to drive the switching element and supply compensating current to load current flowing between a system power source and a harmonic generating load, wherein the harmonic current compensating device comprises a compensating device side noise filter including a noise suppression capacitor and a noise suppression reactor, the compensating device side noise filter being configured to suppress noise of the compensating current, the noise of the compensating current being generated by the drive of the switching element, and a ripple filter including a ripple suppression capacitor and a ripple suppression reactor, wherein the ripple filter is configured to suppress ripple of the compensating current, the switching element is configured to operate at a frequency higher than a switching frequency of the harmonic generating load, and the noise suppression capacitor has a smaller capacity than the ripple suppression capacitor. ### Claim 2 (depends on 1) The harmonic current compensating device of claim 1, wherein the compensating device side noise filter has a higher frequency band than a bus side noise filter, and the bus side noise filter is configured to suppress noise of the load current flowing between the system power source and the harmonic generating load. ### Claim 3 (depends on 1) The harmonic current compensating device of claim 1, wherein the ripple suppression reactor has a smaller capacity than the noise suppression reactor. ### Claim 4 (depends on 1) The harmonic current compensating device of claim 1, comprising a control unit configured to control the drive of the switching element at a driving frequency higher than a driving frequency of a switching element of the harmonic generating load. ### Claim 5 (depends on 1) The harmonic current compensating device of claim 1, wherein the power converter includes a freewheeling diode connected to the switching element in parallel. ### Claim 6 (depends on 5) The harmonic current compensating device of claim 5, wherein the freewheeling diode has a forward voltage lower than a forward voltage of a parasitic diode of the switching element. ### Claim 7 (depends on 1) The harmonic current compensating device of claim 1, further comprising: a load current detector configured to detect the load current to the harmonic generating load; a compensation output command calculating unit configured to calculate a value of a compensation output command to compensate a harmonic component of the load current; a compensating current detector configured to detect the compensating current; an error amount calculating unit configured to send a signal about an error amount between the value of the compensation output command and the compensating current, based on the value of the compensation output command and the compensating current; a control amount calculating unit configured to evaluate a control amount of the power converter based on the error amount; a line voltage detecting unit configured to detect a power source voltage of the system power source and a change in the power source voltage; and a phase voltage command calculating unit configured to calculate an effective phase voltage of the system power source. ### Claim 8 (depends on 1) The harmonic current compensating device of claim 1, wherein the harmonic generating load is an electrolytic capacitor-less device that does not include an electrolytic capacitor. ### Claim 9 (depends on 1) An air-conditioning system including the harmonic current compensating device of claim 1, wherein the harmonic current compensating device is disposed between a power converting device and the system power source, and the power converting device is configured to control a driving frequency of a compressor to compress refrigerant. ### Claim 10 (depends on 1) The harmonic current compensating device of claim 1, further comprising a unipolar device in which a wide bandgap semiconductor element is used as the switching element. ### Claim 11 A harmonic current compensating device comprising a power converter including at least a pair of arms, wherein each arm includes a switching element, the harmonic current compensating device is configured to drive the switching element and supply compensating current to load current flowing between a system power source and a harmonic generating load, the harmonic current compensating device comprises a ripple filter including a ripple suppression capacitor and a ripple suppression reactor, the ripple filter being configured to suppress ripple of the compensating current, and a compensating device side noise filter including a noise suppression capacitor and a noise suppression reactor, wherein the compensating device side noise filter is configured to suppress noise of the compensating current, the noise of the compensating current is generated by the drive of the switching element, and the ripple suppression reactor has a smaller capacity than the noise suppression reactor. ### Claim 12 (depends on 11) The harmonic current compensating device of claim 11, further comprising a unipolar device in which a wide bandgap semiconductor element is used as the switching element. ### Claim 13 (depends on 11) The harmonic current compensating device of claim 11, wherein the compensating device side noise filter is configured to suppress noise of the load current flowing between the system power source and the harmonic generating load.