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EP-4044770-B1 - INDUCTION HEATING APPARATUS AND METHOD FOR CONTROLLING INDUCTION HEATING APPARATUS

EP4044770B1EP 4044770 B1EP4044770 B1EP 4044770B1EP-4044770-B1

Inventors

  • LEE, JUNG YOUN
  • KIM, GWANGROK

Dates

Publication Date
20260506
Application Date
20220209

Claims (12)

  1. An induction heating apparatus (10) comprising: a first working coil (132) provided in a position corresponding to a first heating region (12); a second working coil (142) provided in a position corresponding to a second heating region (14); an inverter circuit (204) configured to supply current for driving at least one of the first working coil (132) or the second working coil (142) and comprising a plurality of switching elements (SW1, SW2, SW3, SW4, SW5, SW6); a drive circuit (22) configured to supply a switching signal (S1, S2, S3, S4, S5, S6) to each of the switching elements (SW1, SW2, SW3, SW4, SW5, SW6); and a controller (2) configured to determine a driving mode of the first and/or second working coils (132, 142) when a heating start command for at least one of the first working coil (132) or the second working coil (142) is input, and supply a control signal for outputting of the switching signal (S1, S2, S3, S4, S5, S6) to the drive circuit (22) based on the determined driving mode, wherein the inverter circuit (204) comprises: a first arm circuit (SW1, SW2) connected to the first working coil (132); a second arm circuit (SW5, SW6) connected to the second working coil (142); and a shared arm circuit (SW3, SW4) connected to the first working coil (132) and the second working coil (142), wherein the controller (2) is configured to determine the driving mode of the first and/or second working coil (132, 142) to be a half-bridge mode when a required power value of the first and/or second working coil (132, 142) is equal to or less than a predetermined reference value, and to determine the driving mode of the first and/or second working coil (132, 142) to be a full-bridge mode when the required power value of the first and/or second working coil (132, 142) is greater than the reference power value; and wherein the controller (2) is configured to control switching elements (SW5, SW6) provided in the second arm circuit to be turned on and turned off when the first working coil (132) is driven in the full-bridge mode and the second working coil (142) is not driven, and is configured to control switching elements (SW1, SW2) provided in the first arm circuit to be turned on and turned off when the second working coil (142) is driven in the full-bridge mode and the first working coil (132) is not driven.
  2. The induction heating apparatus (10) of claim 1, wherein the switching elements (SW5, SW6) provided in the second arm circuit are turned on and turned off at the same timing as switching elements (SW3, SW4) provided in the shared arm circuit when the first working coil (132) is driven in the full-bridge mode and the second working coil (142) is not driven, and the switching elements (SW1, SW2) provided in the first arm circuit are turned on and turned off at the same timing as the switching elements (SW3, SW4) provided in the shared arm circuit when the second working coil (142) is driven in the full-bridge mode and the first working coil (132) is not driven.
  3. The induction heating apparatus (10) of claim 1 or 2, wherein the first arm circuit comprises a first switching element (SW1) and a second switching element (SW2) connected in series with each other, and the shared arm circuit comprises a third switching element (SW3) and a fourth switching element (SW4) connected in series with each other and in parallel with the first switching element (SW1) and the second switching element (SW2), and the second arm circuit comprises a fifth switching element (SW5) and a sixth switching element (SW6) connected in series with each other and in parallel with the third switching element (SW3) and the fourth switching element (SW4), and the first working coil (132) is connected between a connection point between the first switching element (SW1) and the second switching element (SW2) and a connection point between the third switching element (SW3) and the fourth switching element (SW4), and the second working coil (142) is connected between a connection point between the third switching element (SW3) and the fourth switching element (SW4) and a connection point between the fifth switching element (SW5) and the sixth switching element (SW6).
  4. The induction heating apparatus (10) of claim 1, 2 or 3, wherein when the first working coil (132) is driven in the full-bridge mode, the first switching element (SW1) and the fourth switching element (SW4) are alternately turned on and turned off with the second switching element (SW2) and the third switching element (SW3), and when the second working coil (142) is driven in the full-bridge mode, the third switching element (SW3) and the sixth switching element (SW6) are alternately turned on and turned off with the fourth switching element (SW4) and the fifth switching element (SW5).
  5. The induction heating apparatus (10) of claim 1, 2 or 3, wherein when the first working coil (132) is driven in the full-bridge mode and the second working coil (142) is not driven, the first switching element (SW1), the fourth switching element (SW4) and the sixth switching element (SW4) are alternately turned on and turned off with the second switching element (SW2), the third switching element (SW3) and the fifth switching element (SW5), and when the second working coil (142) is driven in the full-bridge mode and the first working coil (132) is not driven, the first switching element (SW1), the third switching element (SW3) and the sixth switching element (SW6) are alternately turned on and turned off with the second switching element (SW2), the fourth switching element (SW4) and the fifth switching element (SW5).
  6. The induction heating apparatus (10) of claim 1, 2 or 3, wherein when the first working coil (132) is driven in the half-bridge mode, the first switching element (SW1) is alternately turned on and turned off with the second switching element (SW2) and the fourth switching element (SW4) is maintained in a turned-on state, and when the second working coil (142) is driven in the half-bridge mode, the fifth switching element (SW5) is alternately turned on and turned off with the sixth switching element (SW6) and the fourth switching element (SW4) is maintained in the turned-on state.
  7. A method for controlling an induction heating apparatus (10) according to any one of claims 1-6 comprising steps of receiving an input of a heating start command for at least one of a first working coil (132) or a second working coil (142); determining a driving mode of the one or more working coils (132, 142); controlling switching elements (SW1, SW2, SW3, SW4, SW5, SW6) provided in a second arm circuit to be turned on and turned off when the first working coil (132) is driven in a full-bridge mode and the second working coil (142) is not driven; and controlling switching elements (SW1, SW2, SW3, SW4, SW5, SW6) provided in a first arm circuit to be turned on and turned off when the second working coil (142) is driven in the full-bridge mode and the first working coil (132) is not driven, wherein the driving mode of the first and/or second working coil (132, 142) is determined to be a half-bridge mode when a required power value of the first and/or second working coil (132, 142) is equal to or less than a predetermined reference value, and wherein the driving mode of the first and/or second working coil (132, 142) is determined to be a full-bridge mode when the required power value of the first and/or second working coil (132, 142) is greater than the reference power value.
  8. The method for controlling the induction heating apparatus (10) of claim 7, wherein when the first working coil (132) is driven in the full-bridge mode and the second working coil (142) is not driven, the switching elements (SW5, SW6) provided in the second arm circuit are turned on and turned off at the same timing as switching elements (SW3, SW4) provided in a shared arm circuit, and when the second working coil (142) is driven in the full-bridge mode and the first working coil (132) is not driven, the switching elements (SW1, SW2) provided in the first arm circuit are turned on and turned off at the same timing as the switching elements (SW3, SW4) provided in the shared arm circuit.
  9. The method for controlling the induction heating apparatus (10) of claim 7 or 8, wherein the induction heating apparatus (10) comprises: an inverter circuit (204) configured to supply current for driving at least one of the first working coil (132) or the second working coil (142) and comprising: a plurality of switching elements (SW1, SW2, SW3, SW4, SW5, SW6), a first arm circuit (SW1, SW2) connected to the first working coil (132); a second arm circuit (SW5, SW6) connected to the second working coil (142); and a shared arm circuit (SW3, SW4) connected to the first working coil (132) and the second working coil (142), and the first arm circuit (SW1, SW2) comprises a first switching element (SW1) and a second switching element (SW2) connected in series with each other, and the shared arm circuit (SW3, SW4) comprises a third switching element (SW3) and a fourth switching element (SW4) connected in series with each other and in parallel with the first switching element (SW1) and the second switching element (SW2), and the second arm circuit (Sw5, SW6) comprises a fifth switching element (SW5) and a sixth switching element (SW6) connected in series with each other and in parallel with the third switching element (SW3) and the fourth switching element (SW4), and the first working coil (132) is connected between a connection point between the first switching element (SW1) and the second switching element (SW2) and a connection point between the third switching element (SW3) and the fourth switching element (SW4), and the second working coil (142) is connected between a connection point between the third switching element (SW3) and the fourth switching element (SW4) and a connection point between the fifth switching element (SW5) and the sixth switching element (SW6).
  10. The method for controlling the induction heating apparatus (10) of claim 7, 8, or 9, wherein when the first working coil (132) is driven in the full-bridge mode, the first switching element (SW1) and the fourth switching element (SW4) are alternately turned on and turned off with the second switching element (SW2) and the third switching element (SW3), and when the second working coil (142) is driven in the full-bridge mode, the third switching element (SW3) and the sixth switching element (SW6) are alternately turned on and turned off with the fourth switching element (SW4) and the fifth switching element (SW5).
  11. The method for controlling the induction heating apparatus (10) of claim 7, 8, or 9, wherein when the first working coil (132) is driven in the full-bridge mode and the second working coil (142) is not driven, the first switching element (SW1), the fourth switching element (SW4) and the sixth switching element (SW6) are alternately turned on and turned off with the second switching element (SW2), the third switching element (SW3) and the fifth switching element (SW5), and when the second working coil (142) is driven in the full-bridge mode and the first working coil (132) is not driven, the first switching element (SW1), the third switching element (SW3) and the sixth switching element (SW6) are alternately turned on and turned off with the second switching element (SW2), the fourth switching element (SW4) and the fifth switching element (SW5).
  12. The method for controlling the induction heating apparatus (10) of claim 7, 8, or 9, wherein when the first working coil (132) is driven in a half-bridge mode, the first switching element (SW1) is alternately turned on and turned off with the second switching element (SW2) and the fourth switching element (SW4) is maintained in a turned-on state, and when the second working coil (142) is driven in the half-bridge mode, the fifth switching element (SW5) is alternately turned on and turned off with the sixth switching element (SW6) and the fourth switching element (SW4) is maintained in the turned-on state.

Description

TECHNICAL FIELD The present disclosure relates to an induction heating apparatus and a method for controlling the induction heating apparatus. BACKGROUND An induction heating apparatus is a device that heats a container by generating an eddy current in a metal container, using a magnetic field generated around a working coil. When the induction heating apparatus is driven, an alternating current may be applied to the working coil. Accordingly, an induction magnetic field may be generated around the working coil disposed in the induction heating device. When a magnetic force line of the induced magnetic field generated in this way passes through the bottom of the container having a metal component placed on the working coil, an eddy current may be generated inside the bottom of the container. When the eddy current generated in this way flows through the container, the container itself may be heated. The induction heating apparatus includes an inverter circuit supplying current for driving a working coil. The inverter circuit includes a plurality of switching elements that are alternately turned on and off with each other. The inverter circuit may be divided into a half-bridge inverter circuit including two switching elements and a full-bridge inverter circuit including four switching elements. KR 100 204 243 B1 discloses a dual pole bridge (Dual Full Bridge) type electromagnetic induction heating device and a control method thereof. An inverter circuit to heat a plurality of heating plates, and also time-divisionally controls the switching means for supplying power to the heating means so that the plurality of heating plates are alternately heated independently. JP 2007 012482 A discloses that an output voltage of a direct current source circuit is converted to a high-frequency voltage in magnetically coupled inner/outer heating coils by a high-frequency power control means. The high-frequency voltage is applied to each of magnetically coupled inner/outer heating coils at the same frequency while controlling the phase difference. FIG. 1 is a circuit diagram of an induction heating apparatus with a full-bridge inverter circuit. Referring to FIG. 1, the induction heating apparatus 7 includes two working coils 712 and 714 (i.e., a first working coil 712 and a second working coil 714). The first working coil 712 and the second working coil 714 may be provided in respective positions corresponding to a first heating region (or heating area) and a second heating region (or heating area). The induction heating apparatus 7 includes a rectifier circuit 702, a smoothing circuit 704, a first inverter circuit 706 and a second inverter circuit 708. The rectifier circuit 702 may include a plurality of diodes. The smoothing circuit 704 may include a first inductor L1 and a first DC link capacitor C1. The first inverter circuit 706 may be a full-bridge inverter circuit including four switching elements SW1, SW2, SW3 and SW4. The second inverter circuit 708 may be a full-bridge inverter circuit including four switching elements SW5, SW6, SW7 and SW8. When the switching elements S1 to S8 are controlled by a controller, the first inverter circuit 706 and the second inverter circuit 708 may receive current through the rectifier circuit 702 and the smoothing circuit 704, respectively, and then convert the input currents to supply the converted currents to the first working coil 712 and the second working coil 714, respectively. In FIG. 1, since two inverter circuits 706, 708 supplying currents to two working coils 712, 714 are configured as the full-bridge circuits, a total of eight switching elements S1 to SW8 must be provided inside the induction heating apparatus. However, as the number of the switching elements provided in the induction heating apparatuses increases, there is a disadvantage in that the complex circuit design results in difficulties and/or increased manufacturing cost of the induction heating apparatus. SUMMARY An object of the present disclosure is to provide an induction heating apparatus and a method for controlling the induction heating apparatus that may be variably driven in a half-bridge mode or a full-bridge mode based on a required power value. A further object is to provide an induction heating apparatus including a smaller number of switching elements than the prior art. An object of the present disclosure is to provide an induction heating apparatus and a method for controlling the induction heating apparatus in which when only one of the two working coils is driven, the temperature increase rate of the remaining working coils that are not driven is reduced. Aspects of the present disclosure are not limited to the above ones, and other aspects and advantages that are not mentioned above can be clearly understood from the following description and can be more clearly understood from the embodiments set forth herein. The object is solved by the features of the independent claims. Preferred embodimen