# US 12,184,082 B2 · Contactless power transmission system capable of controlling power transmitter apparatus to stably supply load device with required power > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,184,082 B2 - Document ID: US12184082B2 - Status: Granted - Kind: B2 - Application number: 17/632,093 - Filed: 2019-08-05 - Published: 2022-09-01 - Granted: 2024-12-31 - Earliest claimed: 2019-08-05 - Assignees: OMRON Corporation - Applicants: OMRON Corporation - Inventors: Taichi Mishima; Yuki Ito; Shingo Nagaoka; Takeshi Uematsu - Web page: https://patentgrep.com/patent/US12184082B2 ## CPC - H02J 50/12: of the resonant type - B60L 53/124: Detection or removal of foreign bodies - H02J 7/64: against overvoltage - H02J 50/60: responsive to the presence of foreign objects, e.g. detection of living beings - H02J 50/80: involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices - H02M 7/06: using discharge tubes without control electrode or semiconductor devices without control electrode - H02M 7/5387: in a bridge configuration - H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY - 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 - 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 control circuit controls a power supply circuit to generate transmitting power having a frequency varying within a frequency range. The control circuit determines a stably transmitting frequency based on a detected output voltage of a power receiver apparatus, the stably transmitting frequency indicating a frequency of the transmitting power at which dependency of the output voltage on a load value of the power receiver apparatus is at least locally minimized within the frequency range. The control circuit determines a transmitting voltage based on the detected output voltage, the transmitting voltage indicating a voltage of the transmitting power at which the output voltage reaches a target voltage when generating transmitting power having the stably transmitting frequency. The control circuit controls the power supply circuit to generate transmitting power having the stably transmitting frequency and the transmitting voltage. ## Claims ### Claim 1 A contactless power transmission system including a power transmitter apparatus and a power receiver apparatus, the contactless power transmission system transmitting power in a contactless manner from the power transmitter apparatus to the power receiver apparatus, wherein the power transmitter apparatus comprises: a transmitting coil; a power supply circuit configured to generate transmitting power having a variable voltage and a variable frequency, and supply the transmitting power to the transmitting coil; and a controller apparatus, wherein the power receiver apparatus comprises: a receiving coil; a voltage detector circuit configured to detect an output voltage of the power receiver apparatus; and a power-receiver communication device communicatively connected to the power transmitter apparatus, and configured to transmit a detected value of the output voltage of the power receiver apparatus to the power transmitter apparatus, wherein the controller apparatus comprises: a power-transmitter communication device communicatively connected to the power receiver apparatus, and configured to receive the detected value of the output voltage of the power receiver apparatus from the power receiver apparatus; and a first control circuit configured to control the power supply circuit based on the detected value of the output voltage of the power receiver apparatus, wherein the first control circuit is further configured to: control the power supply circuit to generate transmitting power having a frequency varying within a predetermined frequency range, receive the detected value of the output voltage of the power receiver apparatus from the power receiver apparatus using the power-transmitter communication device, the detected value being detected in the power receiver apparatus when generating the transmitting power using the power supply circuit, determine a stably transmitting frequency based on the detected value of the output voltage of the power receiver apparatus, the stably transmitting frequency indicating a frequency of the transmitting power at which dependency of the output voltage of the power receiver apparatus on a load value of the power receiver apparatus is at least locally minimized within the frequency range, determine a transmitting voltage based on the detected value of an output voltage of the power receiver apparatus, the transmitting voltage indicating a voltage of the transmitting power at which the output voltage of the power receiver apparatus reaches a predetermined target voltage when generating transmitting power having the stably transmitting frequency, and control the power supply circuit to generate transmitting power having the stably transmitting frequency and the transmitting voltage, wherein the power receiver apparatus further comprises: a load device having a variable load value: a first load element having a first load value; a second load element having a second load value larger than the first load value; and a first switch circuit configured to selectively supply the output voltage of the power receiver apparatus to one of the load device, the first load element, and the second load element, wherein the first control circuit is further configured to: when performing normal power transmission, transmit a control signal to the power receiver apparatus using the power-transmitter communication device, the control signal being provided for switching the first switch circuit to supply the output voltage of the power receiver apparatus to the load device, and when determining a frequency of the transmitting power, transmit a control signal to the power receiver apparatus using the power-transmitter communication device, the control signal being provided for switching the first switch circuit to supply the output voltage of the power receiver apparatus to the first or second load element, and wherein the first control circuit is further configured to: obtain a first voltage indicating a frequency characteristic of the output voltage of the power receiver apparatus, based on the detected value of the output voltage of the power receiver apparatus, when the output voltage of the power receiver apparatus is supplied to the first load element, obtain a second voltage indicating a frequency characteristic of the output voltage of the power receiver apparatus, based on the detected value of the output voltage of the power receiver apparatus, when the output voltage of the power receiver apparatus is supplied to the second load element, and determine a frequency of the transmitting power at which a difference between the first voltage and the second voltage is minimized, as the stably transmitting frequency. ### Claim 2 (depends on 1) The contactless power transmission system as claimed in claim 1, wherein, when the detected value of the output voltage of the power receiver apparatus changes by a value larger than a first threshold from the detected value obtained when determining the stably transmitting frequency and the transmitting voltage, the first control circuit redetermines the stably transmitting frequency and the transmitting voltage based on the detected value of the output voltage of the power receiver apparatus. ### Claim 3 (depends on 1) The contactless power transmission system as claimed in claim 1, the controller apparatus further comprising a coupling coefficient estimator configured to estimate a coupling coefficient of the transmitting coil and the receiving coil, wherein, when the coupling coefficient changes by a value larger than a second threshold from the detected value obtained when determining the stably transmitting frequency and the transmitting voltage, the first control circuit redetermines the stably transmitting frequency and the transmitting voltage based on the detected value of the output voltage of the power receiver apparatus. ### Claim 4 (depends on 3) The contactless power transmission system as claimed in claim 3, the controller apparatus further comprising: a first auxiliary coil electromagnetically coupled to the transmitting coil; a first detector configured to detect a value of a current or a voltage generated in the first auxiliary coil; and a second detector configured to detect a current flowing through the transmitting coil, wherein the coupling coefficient estimator estimates the coupling coefficient based on values detected by the first detector and the second detector. ### Claim 5 (depends on 4) The contactless power transmission system as claimed in claim 4, wherein the coupling coefficient estimator estimates a first coupling coefficient between the transmitting coil and the receiving coil based on the value of the current or voltage generated in the first auxiliary coil, and estimates a second coupling coefficient between the transmitting coil and the receiving coil based on a value of the current flowing through the transmitting coil, and wherein the first control circuit is further configured to: when a difference between the first coupling coefficient and the second coupling coefficient is equal to or less than a second threshold, control the power supply circuit to generate the transmitting power having the stably transmitting frequency and the transmitting voltage, and when the difference between the first coupling coefficient and the second coupling coefficient exceeds the second threshold, control the power supply circuit to stop transmission of the power to the power receiver apparatus. ### Claim 6 (depends on 3) The contactless power transmission system as claimed in claim 3, the controller apparatus further comprising: a first auxiliary coil electromagnetically coupled to the transmitting coil; and a detector configured to detect a value of a current or a voltage generated in the first auxiliary coil, wherein the coupling coefficient estimator estimates the coupling coefficient based on the value of the current or voltage generated in the first auxiliary coil. ### Claim 7 (depends on 3) The contactless power transmission system as claimed in claim 3, the controller apparatus further comprising a detector configured to detect a value of a current flowing through the transmitting coil, wherein the coupling coefficient estimator estimates the coupling coefficient based on the value of the current flowing through the transmitting coil. ### Claim 8 (depends on 1) The contactless power transmission system as claimed in claim 1, wherein the power supply circuit includes a full-bridge inverter or a half-bridge inverter. ### Claim 9 (depends on 1) The contactless power transmission system as claimed in claim 1, wherein at least one of the power transmitter apparatus and the power receiver apparatus further comprises a capacitor connected to and resonating with the transmitting coil or the receiving coil, and wherein capacitance of the capacitor is set such that a frequency at which the dependency of the output voltage of the power receiver apparatus on the load value of the power receiver apparatus is at least locally minimized is included within a predetermined frequency range. ### Claim 10 (depends on 9) The contactless power transmission system as claimed in claim 9, wherein the power transmitter apparatus comprises a first capacitor connected to and resonating with the transmitting coil, the first capacitor having first capacitance, and wherein the power receiver apparatus comprises a second capacitor connected to and resonating with the receiving coil, the second capacitor having second capacitance different from the first capacitance. ### Claim 11 (depends on 1) The contactless power transmission system according to claim 1, wherein the power receiver apparatus further includes a rectifier circuit configured to rectify a voltage generated in the receiving coil, and wherein the rectifier circuit is a full-wave rectifier circuit of diodes, a voltage-doubler rectifier circuit of diodes, a full-wave rectifier circuit of switching elements, or a voltage-doubler rectifier circuit of switching elements. ### Claim 12 (depends on 1) The contactless power transmission system as claimed in claim 1, wherein the power receiver apparatus further comprises: a second control circuit configured to switch the first switch circuit to supply the output voltage of the power receiver apparatus to the load element, when the output voltage of the power receiver apparatus detected by the voltage detector circuit exceeds a fourth threshold. ### Claim 13 (depends on 1) The contactless power transmission system as claimed in claim 1, wherein the power receiver apparatus further comprises: a second auxiliary coil electromagnetically coupled to the transmitting coil; a second switch circuit; a third load element connected to the second auxiliary coil via the second switch circuit; and a second control circuit configured to turn on the second switch circuit, when the output voltage of the power receiver apparatus detected by the voltage detector circuit exceeds a fourth threshold.