# US 2019/0357320 A1 · Induction heating device having improved control algorithm and circuit structure > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0357320 A1 - Document ID: US20190357320A1 - Status: Published application - Kind: A1 - Application number: 16/180,593 - Filed: 2018-11-05 - Published: 2019-11-21 - Earliest claimed: 2018-05-16 - Assignees: LG Electronics Inc. - Applicants: LG Electronics Inc. - Inventors: Younghwan KWACK; Seongho SON; Jaekyung YANG; Yongsoo LEE - Web page: https://patentgrep.com/patent/US20190357320A1 ## CPC - H05B 6/065: {using coordinated control of multiple induction coils} - H05B 6/1209: {induction cooking plates or the like and devices to be used in combination with them} - H05B 2213/05: Heating plates with pan detection means - H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL ## Abstract An induction heating device includes: a first board including a first working coil, a first inverter configured to apply a resonant current to the first working coil, a first current transformer configured to adjusting a magnitude of the first resonant current, a first control unit configured to control the first inverter; and a second board including a second working coil, a second inverter configured to apply a resonant current to the second working coil, a second current transformer configured to adjust a magnitude of the second resonant current, a first relay configured to selectively connect the second working coil to the second current transformer or to the first working coil, a second relay configured to selectively connect the second working coil to the first working coil or to the second resonant capacitor, and a second control unit configure to control the second inverter, the first relay, and the second relay. ## Claims ### Claim 1 An induction heating device comprising: a first board that comprises: a first working coil, a first resonant capacitor connected to the first working coil, a first inverter configured to perform a first switching operation and to apply a first resonant current to the first working coil based on the first switching operation, a first current transformer configured to adjust a magnitude of the first resonant current output from the first inverter and to transmit the first resonant current having the adjusted magnitude to the first working coil, a first control unit configured to control operation of the first inverter; and a second board that comprises: a second working coil, a second resonant capacitor connected to the second working coil, a second inverter configured to perform a second switching operation and to apply a second resonant current to the second working coil based on the second switching operation, a second current transformer configured to adjust a magnitude of the second resonant current output from the second inverter and to transmit the second resonant current having the adjusted magnitude to the second working coil, a first relay configured to selectively connect a first end of the second working coil to the second current transformer or to a first end of the first working coil, a second relay configured to selectively connect a second end of the second working coil to a second end of the first working coil or to the second resonant capacitor, and a second control unit configured to control operation of each of the second inverter, the first relay, and the second relay. ### Claim 2 (depends on 1) The induction heating device of claim 1, further comprising a main control unit that is configured to: receive an input from a user through an input interface; and provide the input to at least one of the first control unit or the second control unit. ### Claim 3 (depends on 2) The induction heating device of claim 2, wherein the first control unit is configured to control operation of the first inverter based on the input received from the main control unit, and wherein the second control unit is configured to control operation of each of the second inverter, the first relay, and the second relay based on the input received from the main control unit. ### Claim 4 (depends on 3) The induction heating device of claim 3, wherein the main control unit is further configured to, in response to reception of an input indicating a concurrent operation of the first working coil and the second working coil: perform a first object detection to determine, based on a measure related to a set of the first working coil and the second working coil, whether one or more objects are located at an area of the induction heating device corresponding to at least one of the first working coil or the second working coil; control each of the first control unit and the second control unit to perform a second object detection to determine, based on a measure related to each of the first working coil and the second working coil, whether an object is located at an area of the induction heating device corresponding to each of the first working coil and the second working coil; and determine performance of the concurrent operation of the first working coil and the second working coil (i) based on a result from the first object detection and (ii) based on results from the second object detection. ### Claim 5 (depends on 3) The induction heating device of claim 3, wherein the first control unit is further configured to, in response to reception of an input indicating an individual operation of the first working coil or the second working coil: perform an object detection to determine whether a first object is located at a first area of the induction heating device corresponding to the first working coil; and determine performance of the individual operation of the first working coil based on a result from the object detection indicating that the first object is located at the first area of the induction heating device corresponding to the first working coil, and wherein the second control unit is further configured to, in response to reception of the input indicating the individual operation of the first working coil or the second working coil: perform the object detection to determine whether a second object is located at a second area of the induction heating device corresponding to the second working coil, and determine performance of the individual operation of the second working coil based on a result from the object detection indicating that the second object is located at the second area of the induction heating device corresponding to the second working coil. ### Claim 6 (depends on 2) The induction heating device of claim 2, wherein the first control unit and the second control unit are further configured to, based on the input received from the main control unit, determine whether to heat a first region of the induction heating device located between the first working coil and the second working coil. ### Claim 7 (depends on 6) The induction heating device of claim 6, wherein the first control unit is further configured to, in response to reception of an input indicating that the first region of the induction heating device does not correspond to a target heating region, drive the first inverter, and wherein the second control unit is further configured to, in response to reception of the input indicating that the first region of the induction heating device does not correspond to the target heating region: drive the second inverter; control the first relay to connect the first end of the second working coil to the second current transformer; and control the second relay to connect the second end of the second working coil to the second resonant capacitor. ### Claim 8 (depends on 6) The induction heating device of claim 6, wherein the first control unit is further configured to, in response to reception of an input indicating that the first region of the induction heating device corresponds to a target heating region, drive the first inverter, and wherein the second control unit is further configured to, in response to reception of the input indicating that the first region of the induction heating device corresponds to the target heating region: control the first relay to connect the first end of the second working coil to the first end of the first working coil; and control the second relay to connect the second end of the second working coil to the second end of the first working coil. ### Claim 9 (depends on 6) The induction heating device of claim 6, wherein the main control unit is further configured to: set the first region of the induction heating device as a non-target region; and based on control signals having a same frequency, drive the first working coil and the second working coil in an in-phase state to heat second regions of the induction heating device corresponding to edges of the first working coil and the second working coil, the second regions being outside of the first region. ### Claim 10 (depends on 6) The induction heating device of claim 6, wherein the main control unit is further configured to: set the first region of the induction heating device to a target heating region; and based on control signals having a same frequency, drive the first working coil and the second working coil in an out-of-phase state by 180 degrees to heat the target heating region. ### Claim 11 (depends on 9) The induction heating device of claim 9, wherein the first control unit is configured to control the first working coil based on a first control signal having a first frequency and a first phase, and wherein the second control unit is configured to, in the in-phase state, control the second working coil based on a second control signal having the first frequency and the first phase. ### Claim 12 (depends on 10) The induction heating device of claim 10, wherein the first control unit is configured to control the first working coil based on a first control signal having a first frequency and a first phase, and wherein the second control unit is configured to, in the out-of-phase state, control the second working coil based on a second control signal having the first frequency and a second phase that is out of phase from the first phase by 180 degrees. ### Claim 13 (depends on 1) The induction heating device of claim 1, wherein the first end of the first working coil is connected to the first resonant capacitor, and wherein the second end of the first working coil is connected to the first current transformer. ### Claim 14 (depends on 1) The induction heating device of claim 1, further comprising: a first power supply configured to provide power to the first working coil; and a second power supply configured to provide power to the second working coil, the second power supply being independent of the first power supply. ### Claim 15 (depends on 14) The induction heating device of claim 14, further comprising: a first rectifier connected to the first power supply and configured to convert power supplied from the first power supply to a first direct current; and a second rectifier connected to the second power supply and configured to convert power supplied from the second power supply to a second direct current, wherein the first inverter is configured to generate the first resonant current from the first direct current, and wherein the second inverter is configured to generate the second resonant current from the second direct current. ### Claim 16 (depends on 1) The induction heating device of claim 1, wherein the first inverter comprises a plurality of switching elements that are configured to generate an alternating current corresponding to the first resonant current, and wherein the first current transformer is connected to a node between the plurality of switching elements of the first inverter. ### Claim 17 (depends on 16) The induction heating device of claim 16, wherein the first resonant capacitor is connected to an end of the plurality of switching elements of the first inverter. ### Claim 18 (depends on 1) The induction heating device of claim 1, wherein the second inverter comprises a plurality of switching elements that are configured to generate an alternating current corresponding to the second resonant current, and wherein the second current transformer is connected to a node between the plurality of switching elements of the second inverter. ### Claim 19 (depends on 18) The induction heating device of claim 18, wherein the second resonant capacitor is connected to an end of the plurality of switching elements of the second inverter. ### Claim 20 (depends on 4) The induction heating device of claim 4, wherein the measure related to the set of the first working coil and the second working coil comprises at least one of (i) an amount of total power consumption by the first working coil and the second working coil or (ii) a sum of the first resonant current and the second resonant current, and wherein the measure related to each of the first working coil and the second working coil comprises at least one of (i) an amount of power consumption by each of the first working coil and the second working coil or (ii) each of the first resonant current and the second resonant current.