# US 2019/0356171 A1 · System and method for actively controlling output voltage of a wireless power transfer system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0356171 A1 - Document ID: US20190356171A1 - Status: Published application - Kind: A1 - Application number: 16/528,306 - Filed: 2019-07-31 - Published: 2019-11-21 - Earliest claimed: 2016-10-28 - Assignees: General Electric Company - Applicants: General Electric Company - Inventors: Kapil Jha; Arun Kumar Raghunathan; Arvind Kumar Tiwari; Deepak Aravind - Web page: https://patentgrep.com/patent/US20190356171A1 ## CPC - H02J 50/12: of the resonant type - H02M 3/33573: {Full-bridge at primary side of an isolation transformer} - H02J 50/80: involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices - H02M 3/01: {Resonant DC/DC converters} - 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 - Y02T 10/70: Energy storage systems for electromobility, e.g. batteries - Y02T 10/7072: Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors - Y02T 90/14: Plug-in electric vehicles - 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) - Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract A wireless power transfer system is disclosed. The wireless power transfer system includes a first converting unit for converting a first DC voltage of an input power to a first AC voltage, a contactless power transfer unit for transmitting the input power having the first AC voltage, and a second converting unit for transmitting the power having a second DC voltage corresponding to the first AC voltage to an electric load. Additionally, the wireless power transfer system includes an active voltage tuning unit for controlling the second DC voltage based on a difference between the second DC voltage and a reference voltage and at least one among a difference between the resonant frequency and the constant operating frequency and a difference between a phase angle of the first AC voltage and a phase angle of an AC current. ## Claims ### Claim at position 1 1-21. (canceled) ### Claim 22 A wireless power receiver for use with a wireless power transmitter having a first power exchange coil coupled to a first converting unit that converts an input power having a first DC voltage to a transmitted power having a first AC voltage based on a constant operating frequency, the wireless power receiver comprising: a second power exchange coil configured to receive a received power from the first power exchange coil of the wireless power transmitter, the received power having a second AC voltage corresponding to the first AC voltage of the transmitted power; a second converting unit configured to convert the second AC voltage of the received power to a second DC voltage, and provide the received power having the second DC voltage to an electric load; and an active voltage tuning unit coupled to the second power exchange coil and configured to control the second DC voltage based on a difference between the second DC voltage and a reference voltage and at least one among a difference between a resonant frequency of the second power exchange coil and the constant operating frequency of the first converting unit and a difference between a phase angle of the first AC voltage and a phase angle of an AC current. ### Claim 23 (depends on 22) The wireless power receiver of claim 22, wherein the second power exchange coil is configured to magnetically couple to the first power exchange coil. ### Claim 24 (depends on 22) The wireless power receiver of claim 22, wherein the active voltage tuning unit comprises: a switching sub-unit coupled in parallel to an impedance element which is coupled in series with one of the first power exchange coil and the second power exchange coil; a controller coupled to the switching sub-unit and configured to: vary a duty cycle of a switching signal based on the difference between the second DC voltage and the reference voltage, and at least one among the difference between the resonant frequency and the constant operating frequency and the difference between the phase angle of the first AC voltage and the phase angle of the AC current; and provide the switching signal having the varied duty cycle to the switching sub- unit to control the second DC voltage across the electric load. ### Claim 25 (depends on 24) The wireless power receiver of claim 24, wherein the controller is configured to increase the duty cycle of the switching signal if the second DC voltage is less than the reference voltage and if at least one of the resonant frequency is less than the constant operating frequency and the phase angle of the AC current is less than the phase angle of the first AC voltage. ### Claim 26 (depends on 24) The wireless power receiver of claim 24, wherein the controller is configured to increase the duty cycle of the switching signal to increase the second DC voltage so that the second DC voltage matches with the reference voltage. ### Claim 27 (depends on 24) The wireless power receiver of claim 24, wherein the controller is configured to decrease the duty cycle of the switching signal if the second DC voltage is greater than the reference voltage and if at least one of the resonant frequency is less than the constant operating frequency and the phase angle of the AC current is less than the phase angle of the first AC voltage. ### Claim 28 (depends on 27) The wireless power receiver of claim 27, wherein the controller is configured to decrease the duty cycle of the switching signal to decrease the second DC voltage so that the second DC voltage matches with the reference voltage. ### Claim 29 (depends on 24) The wireless power receiver of claim 24, wherein the controller is configured to decrease the duty cycle of the switching signal if the second DC voltage is less than the reference voltage and if at least one of the resonant frequency is greater than the constant operating frequency and the phase angle of the AC current is greater than the phase angle of the first AC voltage. ### Claim 30 (depends on 29) The wireless power receiver of claim 29, wherein the controller is configured to decrease the duty cycle of the switching signal to increase the second DC voltage so that the second DC voltage matches with the reference voltage. ### Claim 31 (depends on 24) The wireless power receiver of claim 24, wherein the controller is configured to increase the duty cycle of the switching signal if the second DC voltage is greater than the reference voltage and if at least one of the resonant frequency is greater than the constant operating frequency and the phase angle of the AC current is greater than the phase angle of the first AC voltage. ### Claim 32 (depends on 31) The wireless power receiver of claim 31, wherein the controller is configured to increase the duty cycle of the switching signal to decrease the second DC voltage so that the second DC voltage matches with the reference voltage. ### Claim 33 (depends on 24) The wireless power receiver of claim 24, wherein the switching sub-unit comprises a first electronic switch and a second electronic switch coupled antiparallel to each other, wherein the controller is configured to activate and deactivate at least one of the first electronic switch and the second electronic switch based on the varied duty cycle of the switching signal. ### Claim 34 (depends on 33) The wireless power receiver of claim 33, wherein at least one of the first electronic switch and the second electronic switch is activated and deactivated to change an impedance of the second power exchange coil so that the second DC voltage is correspondingly changed across the electric load. ### Claim 35 (depends on 22) The wireless power receiver of claim 22, further comprising: a voltage sensor electrically coupled to the electric load and configured to determine the second DC voltage across the electric load; and a first transceiver coupled to the voltage sensor and configured to receive a voltage signal representative of the second DC voltage and provide the voltage signal representative of the second DC voltage to a second transceiver communicatively coupled to the first transceiver. ### Claim 36 (depends on 35) The wireless power receiver of claim 35, wherein the controller is further configured to: receive the voltage signal representative of the second DC voltage from the voltage sensor; receive a frequency signal representative of the difference between the resonant frequency and the constant operating frequency from the first converting unit via the first transceiver and the second transceiver; and receive a phase signal representative of the difference between the phase angle of the first AC voltage and the phase angle of the AC current from the first converting unit via the first transceiver and the second transceiver. ### Claim 37 (depends on 22) The wireless power receiver of claim 22, wherein the second converting unit is configured to provide the second DC voltage controlled by the active voltage tuning unit to a battery of a vehicle. ### Claim 38 A method for operating a wireless power receiver for use with a wireless power transmitter having a first power exchange coil coupled to a first converting unit that converts an input power having a first DC voltage to a transmitted power having a first AC voltage based on a constant operating frequency, the method comprising: receiving, by a second power exchange coil, a received power from the first power exchange coil of the wireless power transmitter, the received power having a second AC voltage corresponding to the first AC voltage of the transmitted power; converting, by a second converting unit, the second AC voltage of the received power to a second DC voltage; providing the received power having the second DC voltage from the second converting unit to an electric load; and controlling, by an active voltage tuning unit, the second DC voltage based on a difference between the second DC voltage and a reference voltage and at least one among a difference between a resonant frequency of the second power exchange coil and the constant operating frequency of the first converting unit and a difference between a phase angle of the first AC voltage and a phase angle of an AC current. ### Claim 39 (depends on 38) The method of claim 38, wherein controlling the second DC voltage comprises: varying, by a controller, a duty cycle of a switching signal based on the difference between the second DC voltage and the reference voltage, and at least one of the difference between the resonant frequency and the constant operating frequency, and the difference between the phase angle of the first AC voltage and the phase angle of the AC current; and providing the switching signal having the varied duty cycle to a switching sub-unit to control the second DC voltage across the electric load. ### Claim 40 (depends on 39) The method of claim 39, wherein varying the duty cycle of the switching signal comprises: increasing the duty cycle of the switching signal if the second DC voltage is less than the reference voltage and if at least one of the resonant frequency is less than the constant operating frequency and the phase angle of the AC current is less than the phase angle of the first AC voltage; and decreasing the duty cycle of the switching signal if the second DC voltage is greater than the reference voltage and if at least one of the resonant frequency is less than the constant operating frequency and the phase angle of the AC current is less than the phase angle of the first AC voltage. ### Claim 41 (depends on 39) The method of claim 39, wherein varying the duty cycle of the switching signal comprises: decreasing the duty cycle of the switching signal if the second DC voltage is less than the reference voltage and if at least one of the resonant frequency is greater than the constant operating frequency and the phase angle of the AC current is greater than the phase angle of the first AC voltage; and increasing the duty cycle of the switching signal if the second DC voltage is greater than the reference voltage and if at least one of the resonant frequency is greater than the constant operating frequency and the phase angle of the AC current is greater than the phase angle of the first AC voltage.