# US 9,882,426 B2 · Method and apparatus for detecting efficiency of wireless power transmission > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,882,426 B2 - Document ID: US9882426B2 - Status: Granted - Kind: B2 - Application number: 13/484,967 - Filed: 2012-05-31 - Published: 2012-12-06 - Granted: 2018-01-30 - Earliest claimed: 2011-06-01 - Assignees: Samsung Electronics Co., Ltd. - Applicants: Nam Yun Kim; Sang Wook Kwon; Yun Kwon Park; Young Tack Hong - Inventors: Nam Yun Kim; Sang Wook Kwon; Yun Kwon Park; Young Tack Hong - Web page: https://patentgrep.com/patent/US9882426B2 ## CPC - B60L 53/36: by positioning the vehicle - B60L 53/126: Methods for pairing a vehicle and a charging station, e.g. establishing a one-to-one relation between a wireless power transmitter and a wireless power receiver - H02J 50/12: of the resonant type - H02J 50/40: using two or more transmitting or receiving devices (H02J50/50 takes precedence) - H02J 50/80: involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices - B60L 2210/10: DC to DC converters - B60L 2210/30: AC to DC converters - B60L 2210/40: DC to AC converters - B60L 2250/16: by display - H02J 7/62: against overcurrent - H02J 7/64: against overvoltage - H02J 50/90: involving detection or optimisation of position, e.g. alignment - 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 10/72: Electric energy management in electromobility - Y02T 90/12: Electric charging stations - Y02T 90/14: Plug-in electric vehicles - B60L: PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES (arrangements or mounting of electrical propulsion units or of plural diverse prime-movers for mutual or common propulsion in vehicles B60K1/00, B60K6/20; arrangements or mounting of electrical gearing in vehicles B60K17/12, B60K17/14; preventing wheel slip by reducing power in rail vehicles B61C15/08; dynamo-electric machines H02K; control or regulation of electric motors H02P); SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES (electric coupling devices combined with mechanical couplings of vehicles B60D1/64; electric heating for vehicles B60H1/00); ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL (control or regulation of electric motors H02P); MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES - H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract Provided are a method and apparatus for detecting an efficiency of a wireless power transmission. An output power of a source device may be adjusted based on current that is flowing in a power converter of the source device. The efficiency of wireless power transmission may be calculated based on the adjusted output power, and an amount of power used by a target device. ## Claims ### Claim 1 A method of detecting an efficiency of a wireless power transmission from a source device to a target device, the method comprising: receiving, from the target device, information about power used by the target device; determining a first power of a power amplifier (PA) of the source device based on the information about the power used by the target device; transmitting, to the target device, wireless power corresponding to the first power; determining a second power of the PA in response to a current of the PA converging to a constant level, wherein the current of the PA is changed until the target device receives wireless power corresponding to the information about the power used by the target device; and calculating the efficiency of the wireless power transmission based on the second power and the information about power used by the target device. ### Claim 2 (depends on 1) The method of claim 1, further comprising: receiving, from the target device, information about power that is received by the target device, wherein the efficiency is calculated based on the information about the power that is received by the target device and the second power. ### Claim 3 (depends on 1) The method of claim 1, further comprising in response to the current of the PA increasing, increasing a power level of the PA until the current of the PA becomes constant. ### Claim 4 (depends on 1) The method of claim 1, further comprising: interrupting an operation of the source device, in response to the calculated efficiency being lower than a reference efficiency. ### Claim 5 A method of detecting an efficiency of a wireless power transmission from a source device to a target device, the method comprising: receiving, from the target device, information about power used by the target device; determining an output power of a power amplifier (PA) of the source device based on the information about power used by a target device; transmitting, to the target device, wireless power corresponding to the output power; receiving, from the target device, information about power that is received by the target device, wherein the information about the power that is received by the target device comprises information about a current flowing in a load modulator of the target device, in a state in which a connection to a load of the target device is blocked and the received power inputted to the load modulator of the target device; and calculating the efficiency of the wireless power transmission, based on the information about the power that is received by the target device and the output power. ### Claim 6 (depends on 5) The method of claim 5, further comprising: interrupting an operation of a source device, in response to the calculated efficiency being lower than a reference efficiency. ### Claim 7 A computer-readable storage medium having stored therein program instructions to cause a processor to execute a method of detecting an efficiency of a wireless power transmission from a source device to a target device, the method comprising: receiving, from the target device, information about power used by the target device; determining a first output power of a power amplifier (PA) of the source device based on the information about power used by the target device; transmitting, to the target device, wireless power corresponding to the first power; determining a second power of the PA in response to a current of the PA converging to a constant level, wherein the current of the PA is changed until the target device receives wireless power corresponding the information about the power used by the target device; and calculating the efficiency of the wireless power transmission, based on the second power and the information about the power used by the target device. ### Claim 8 A wireless power transmitter, comprising: a controller to determine a first power of a power amplifier (PA) of the wireless power transmitter based on information about power used by a target device received from the target device; and a resonator to transmit, to the target device, wireless power corresponding to the first power, wherein the controller determines a second power of the PA in response to a current of the PA converging to a constant level, wherein the current of the PA is changed until the target device receives wireless power corresponding the information about the power used by the target device, and calculates an efficiency of a wireless power transmission, based on the second power and the information about power used by the target device. ### Claim 9 (depends on 8) The wireless power transmitter of claim 8, wherein the controller receives the information about the power used by the target device from the target device. ### Claim 10 (depends on 8) The wireless power transmitter of claim 8, wherein the controller receives, from the target device, information about power that is received by the target device, and calculates the efficiency based on the information about the power that is received by the target device and the second power. ### Claim 11 (depends on 8) The wireless power transmitter of claim 8, wherein, in response to the current of the PA increasing, the controller increases a power level of the PA until the current of the PA becomes constant. ### Claim 12 (depends on 8) The wireless power transmitter of claim 8, wherein, in response to the calculated efficiency being lower than a reference efficiency, the controller interrupts an operation of a source device. ### Claim 13 A wireless power transmitter, comprising: a controller to determine an output power of a power amplifier (PA) of the wireless power transmitter based on information about power used by a target device; and a resonator to transmit, to the target device, wireless power corresponding to the output power, wherein the controller receives, from the target device, information about power that is received by the target device, wherein the information about the power that is received by the target device comprises information about a current flowing in a load modulator of the target device, in a state in which a connection to a load of the target device is blocked and the received power inputted to the load modulator of the target device, and calculates an efficiency of a wireless power transmission, based on the information about the power that is received by the target device and the output power. ### Claim 14 (depends on 13) The wireless power transmitter of claim 13, wherein, in response to the calculated efficiency being lower than a reference efficiency, the controller interrupts an operation of a source device. ### Claim 15 (depends on 13) The wireless power transmitter of claim 13, wherein, in response to a value of a current of the output power being equal to or greater than a set value determined based on the efficiency and the output power, the controller interrupts the operation of the source device.