Induction heating device and control method thereof

Abstract

An induction heating device according to an aspect of the disclosed invention may include: a first heating part including one heating coil; the second heating part comprises an internal heating coil and an external heating coil; and a control unit for controlling the operation of the first heating unit and the second heating unit, the maximum output frequency of the one heating coil may be set to be higher than the maximum output frequency when the internal heating coil is operated singly and lower than the maximum output frequency when the internal heating coil and the external heating coil are operated simultaneously.

Description

Induction heating device and its control method Technical Field

[0001] The disclosed invention relates to an induction heating device and its control method, specifically an induction heating device comprising dual heating coils and its control method. Background Technology

[0002] Typically, an induction heating device is a cooking device that uses the principle of induction heating to heat and cook food. An induction heating device includes a cooking plate for placing the cooking container and a heating coil that generates a magnetic field when an electric current is applied.

[0003] If a current is applied to the heating coil to generate a magnetic field, a secondary current is induced in the cooking container, and Joule heat is generated by the resistive component of the cooking container itself. Therefore, the cooking container is heated by a high-frequency current, and the food contained in the cooking container is cooked.

[0004] This induction heating device uses the cooking container itself as a heat source, thus offering advantages over gas stoves or kerosene stoves that burn fossil fuels and heat the cooking container through their combustion heat. It also has the advantages of high heat transfer rate, no harmful gases produced, and no risk of fire.

[0005] However, when multiple heating coils of such an induction heating device are operated simultaneously, noise may be generated due to their different output frequencies. Technical problems of the invention

[0006] One aspect of the disclosed invention provides an induction heating device and its control method as follows: the maximum output frequency of each heating coil is set to be different and the maximum output frequency is made consistent by duty cycle control when operating simultaneously, thereby reducing noise.

[0007] The technical problems to be solved in this article are not limited to those mentioned above. Those skilled in the art will clearly understand other technical problems not mentioned from the following description. Technical Solution

[0008] An induction heating device according to one aspect of the disclosed invention may include: a first heating unit including a heating coil; a second heating unit including an internal heating coil and an external heating coil; and a control unit for controlling the operation of the first heating unit and the second heating unit, wherein the maximum output frequency of the heating coil can be set to be higher than the maximum output frequency of the internal heating coil during single operation and lower than the maximum output frequency of the internal heating coil and the external heating coil during simultaneous operation. Attached Figure Description

[0009] Figure 1 shows the appearance of an induction heating device according to one embodiment.

[0010] Figures 2 and 3 are diagrams illustrating the heating principle of an induction heating device according to one embodiment.

[0011] Figure 4 shows an example of a resonant circuit according to one embodiment.

[0012] Figure 5 is a diagram showing an induction heating device including a dual heating coil according to an embodiment.

[0013] Figure 6 is a diagram illustrating the principle of driving a dual heating coil according to one embodiment.

[0014] Figure 7 is a diagram showing the maximum output frequency of the heating coils according to one embodiment, with different settings.

[0015] Figure 8 is a control block diagram illustrating an induction heating device according to an embodiment.

[0016] Figure 9 is a diagram showing how the maximum output frequency is consistent through duty cycle control according to one embodiment.

[0017] Figure 10 is a diagram illustrating how to make the different maximum output frequencies of the heating coils according to one embodiment consistent.

[0018] Figures 11 and 12 are flowcharts illustrating a control method for an induction heating device according to an embodiment. Detailed Implementation

[0019] The embodiments and configurations described in this specification and the accompanying drawings are merely preferred examples of the disclosed invention. At the time of filing this application, there may be various modifications that can replace the embodiments and drawings in the specification.

[0020] Furthermore, the same reference numerals or symbols shown in the various figures of this specification indicate parts or components that perform substantially the same function.

[0021] Furthermore, the terminology used in this specification is for illustrative purposes and is not intended to limit or restrict the disclosed invention. Unless the context clearly specifies otherwise, singular expressions include plural expressions. In this specification, terms such as "comprising" or "having" are used to specify the presence of features, numbers, steps, operations, constituent elements, components, or combinations thereof described in the specification, and do not preclude the presence or additional possibilities of one or more other features or numbers, steps, operations, constituent elements, components, or combinations thereof.

[0022] Furthermore, in this specification, when referring to a part as being "connected" or "combined" with another part, this includes not only cases of direct connection or combination, but also cases of indirect connection or combination with another constituent element.

[0023] Furthermore, in this specification, ordinal terms such as "first," "second," etc., are used to describe various constituent elements, but the constituent elements are not limited to the terms described above; these terms are only used to distinguish one constituent element from other constituent elements. For example, without departing from the scope of the claims of this invention, a first constituent element may be named a second constituent element, and similarly, a second constituent element may be named a first constituent element. The term "and / or" includes a combination of multiple related constituent elements or a single constituent element among multiple related constituent elements.

[0024] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0025] Figure 1 shows the appearance of an induction heating device according to an embodiment, and Figures 2 and 3 are diagrams illustrating the heating principle of the induction heating device according to an embodiment.

[0026] Figure 1 is a top view of an induction heating device 1 according to an embodiment. As shown in Figure 1, the induction heating device 1 according to an embodiment may include a plate 110 disposed on the upper part of a main body 101, cooking zones 111, 112, 113 formed on the plate 110, and user interfaces 120, 130 serving as input / output devices. For example, the plate 110 may be made of ceramic.

[0027] Cooking zones 111, 112, and 113 indicate the locations where cooking containers are placed, and can be represented by a circular shape as shown in the attached reference numeral "111" or by straight boundary lines as shown in the attached reference numerals "112" and "113", to guide the proper arrangement of the cooking containers.

[0028] However, the shapes described above are merely examples used to represent the shapes of the cooking zones 111, 112, and 113. Even if they are not circular or straight, they can be applied to embodiments of the induction heating device 1 as long as they can guide the user to the location of the cooking zone.

[0029] Furthermore, although this example shows three cooking zones formed on plate 110, the embodiment of the induction heating device 1 is not limited to this. Of course, only one cooking zone may be formed on plate 110, or more than four cooking zones may be formed.

[0030] A display 120 and an input device 130 may be provided in a region of the board 110. The display 120 may include a display device such as an LCD or an LED, and the input device 130 may include at least one of a variety of input devices such as a touchpad, buttons, a jog shuttle, etc. Alternatively, the display 120 and the input device 130 may also be implemented as a touch screen.

[0031] In this example, the display 120 and input device 130 are provided in a position spaced apart from the cooking zones 111, 112, 113 on the plate 110. However, the arrangement in FIG1 is only an example applicable to the induction heating device 1, and the display 120 or input device 130 may also be provided in other locations besides the plate 110, such as the front surface of the induction heating device 1.

[0032] Referring to Figures 2 and 3, a heating coil 240 for heating the container 10 placed on the plate 110 can be arranged at the lower part of the plate 110. For ease of explanation, only one heating coil 240 is shown in Figures 2 and 3, but the number of heating coils 240 can correspond to the number of cooking zones.

[0033] As shown in the example of Figure 1, in the case of three cooking zones 111, 112, and 113, three heating coils 240 can also be provided, and each heating coil 240 can be arranged at the bottom of each cooking zone 111, 112, and 113.

[0034] The heating coil 240 can be connected to the resonant circuit 2 (see Figure 4) described later, and a high-frequency current can be applied from the resonant circuit 2. As an example, the frequency of the high-frequency current can be from 20 kHz to 35 kHz.

[0035] If a high-frequency current is supplied to the heating coil 240, magnetic field lines ML can be formed in the heating coil 240. If the container 10 with resistance is located within the area affected by the magnetic field lines ML, the magnetic field lines ML around the heating coil 240 pass through the bottom of the container 10 and generate an induced current in the form of eddy currents (i.e., eddy current EC) according to the law of electromagnetic induction.

[0036] Heat can be generated in the container 10 by the interaction between the eddy current EC and the resistance of the container 10, and the food inside the container 10 can be heated by the generated heat.

[0037] In the induction heating device 1 shown above, since the container 10 itself is used as a heat source, iron, stainless steel, nickel, or other metals with a resistance of a predetermined level or higher can be used as the material of the container 10.

[0038] In addition, the specifications of the heating coil 240 can be designed differently depending on the rated voltage of the country where the induction heating device 1 is sold.

[0039] Figure 4 shows an example of a resonant circuit according to one embodiment.

[0040] Referring to Figure 4, the resonant circuit 2 may include a power supply section 20.

[0041] The power supply unit 20 may include a power supply ES and a rectifier 210.

[0042] The power supply ES, as an AC power supply ES, can supply power supplies corresponding to the rated voltage.

[0043] The rectifier 210 can convert the AC voltage supplied from the power supply ES into DC voltage.

[0044] Therefore, rectifier 210 may include a bridge rectifier circuit using multiple diodes. As an example, the bridge rectifier circuit may include four diodes. The diodes may form diode pairs, with each pair connected in series, and the two diode pairs may be connected in parallel with each other. The bridge diodes can convert AC voltages whose polarity changes over time into voltages with constant polarity, and can convert AC currents whose direction changes over time into currents with constant direction.

[0045] Furthermore, the rectifier 210 may include a DC link capacitor. The DC link capacitor converts a voltage that varies with time into a constant DC voltage. The DC link capacitor maintains the converted DC voltage and supplies it to the inverter circuits SW1-1 and SW1-2. In this case, the inverter circuits SW1-1 and SW1-2 may include a first switching element SW1-1 and a second switching element SW1-2 of the first switching section.

[0046] The first switching element SW1-1 and the second switching element SW1-2 of the first switching section operate complementaryly to allow alternating current to flow in the heating coil 240.

[0047] To enable high-speed switching, the first switching element SW1-1 and the second switching element SW1-2 of the first switching section can be implemented using three-terminal semiconductor switching devices with fast response speeds. For example, the first switching element SW1-1 and the second switching element SW1-2 of the first switching section can be a bipolar junction transistor (BJT), a metal-oxide-semiconductor field-effect transistor (MOSFET), an insulated gate bipolar transistor (IGBT), or a thyristor.

[0048] The first switching element SW1-1 and the second switching element SW1-2 of the first switching section can be switched on / off by a switch drive signal. At this time, the switch drive signal can be provided by the control unit 150, and the control unit 150 can make the first switching element SW1-1 and the second switching element SW1-2 of the first switching section alternately switch on / off, thereby supplying high-frequency alternating current to the heating coil 240.

[0049] The resonant circuit 2 may also include a filter to remove noise components from the power supplied from the power source ES. The filter may be constructed using a transformer and capacitors to remove noise mixed into the power supplied from the power source ES and to provide noise-removed AC power to the rectifier 210.

[0050] Figure 5 is a diagram illustrating an induction heating device including dual heating coils according to an embodiment. Figure 6 is a diagram illustrating the principle of driving the dual heating coils according to an embodiment.

[0051] The dual heating coil 250 can operate in both dual-mode and single-mode operation depending on the size of the bottom surface of the object being heated. In dual-mode, it heats a first area; in single-mode, it heats a second area that is narrower than the first area. For example, the dual heating coil 250 may include an inner heating coil 251 and an outer heating coil 252. The dual heating coil 250 can operate in both single-mode and dual-mode. In single-mode, the inner heating coil 251 heats only the inner region; in dual-mode, both the inner and outer regions are heated using the inner heating coil 251 and the outer heating coil 252. The operating mode of the dual heating coil 250 can be determined by the control unit 150.

[0052] The induction heating device 1 can sense the object to be heated placed on the cooking zone, and can determine the operating mode of the dual heating coils 250 as either a dual-mode or a single-mode based on the size of the bottom surface of the sensed object. Alternatively, it can be controlled to execute either a dual-mode or a single-mode operating mode based on input from the user or others.

[0053] The dual heating coil 250 may include an inner heating coil 251 located in an inner region and an outer heating coil 252 located in an outer region. The inner and outer regions may be annular regions with a common center point. A gap may be included between the inner and outer regions. However, the region of the dual heating coil 250 is not limited to this, and there may be no gap between the inner and outer regions.

[0054] The internal heating coil 251 and the external heating coil 252 can be connected in parallel. For example, the first node Nd1 of the internal heating coil 251 can be connected to the third node Nd3 of the external heating coil 252, and the second node Nd2 of the internal heating coil 251 can be connected to the fourth node Nd4 of the external heating coil 252 through the double switch SW.

[0055] The control unit 150 can supply power to the internal heating coil 251 and / or the external heating coil 252. For example, when operating in dual mode, the control unit 150 can turn on the dual switch to operate both the internal heating coil 251 and the external heating coil 252 together. Furthermore, when operating in single mode, the control unit 150 can turn off the dual switch to operate only the internal heating coil 251.

[0056] Thus, the induction heating device 1 may include dual heating coils 250, which include an inner heating coil 251 and an outer heating coil 252.

[0057] The following describes the design changes and control operations for reducing noise in the induction heating device 1, which includes such a dual heating coil 250.

[0058] Figure 7 is a diagram showing the maximum output frequency of the heating coils according to one embodiment, with different settings.

[0059] As described above, when multiple heating coils included in the induction heating device 1 operate simultaneously, noise may be generated due to their different output frequencies.

[0060] In this invention, the simultaneous operation of the first heating unit 230 and the second heating unit 250 will be described. The first heating unit 230 includes a heating coil 240, and the second heating unit 250 includes an internal heating coil 251 and an external heating coil 252. Here, the second heating unit 250 may include dual heating coils 250, which include the internal heating coil 251 and the external heating coil 252 described above.

[0061] Referring to Figure 7(a), the maximum output frequency f1 of a heating coil can be set to be lower than the maximum output frequency f2 when the internal heating coil is operating alone and the maximum output frequency f3 when the internal heating coil and the external heating coil are operating simultaneously. Furthermore, the maximum output frequency f2 when the internal heating coil is operating alone can be set to be lower than the maximum output frequency f3 when the internal heating coil and the external heating coil are operating simultaneously.

[0062] Thus, noise may be generated when multiple heating coils operate at different output frequencies. Therefore, methods such as duty cycle control can be used to make the relatively higher frequency match the lower frequency.

[0063] However, the method of reducing frequency by duty cycle control is usually limited to a range of about 3 kHz. Therefore, when the difference between frequencies exceeds 3 kHz, it is difficult to make the frequencies consistent even by duty cycle control.

[0064] As shown in Figure 7(a), when the maximum output frequency of each heating coil is set, if one heating coil 240 and the internal heating coil 251 are operating simultaneously, the maximum output frequency f2 of the internal heating coil when it is operating alone can be reduced to the maximum output frequency f1 of one heating coil by controlling the duty cycle.

[0065] However, the maximum output frequency f3 when the internal heating coil and the external heating coil operate simultaneously is higher than the maximum output frequency f2 when the internal heating coil operates alone. Therefore, when one heating coil 240 and the internal heating coil 251 and the external heating coil 252 operate simultaneously, the difference between the maximum output frequency f3 when the internal heating coil and the external heating coil operate simultaneously and the maximum output frequency f1 of one heating coil may exceed 3kHz. Therefore, even by controlling the duty cycle, it may be difficult to make the frequencies consistent.

[0066] Accordingly, as shown in FIG7(b), in one embodiment of the present invention, the maximum output frequency f1 of a heating coil is set to be higher than the maximum output frequency f2 when the internal heating coil is operating alone and lower than the maximum output frequency f3 when the internal heating coil and the external heating coil are operating simultaneously.

[0067] Thus, by setting the maximum output frequency of each heating coil, as described below, when a heating coil 240 and an internal heating coil 251 operate simultaneously, the maximum output frequency f1 of a heating coil can be reduced to the maximum output frequency f2 when the internal heating coil operates alone. When a heating coil 240, an internal heating coil 251, and an external heating coil 252 operate simultaneously, the maximum output frequency f3 when the internal heating coil and the external heating coil operate simultaneously can be reduced to the maximum output frequency f1 of a heating coil.

[0068] As described above, the method of reducing frequency by duty cycle control is typically limited to a range of approximately 3 kHz. Therefore, the difference between the maximum output frequency f1 of a heating coil and the maximum output frequency f2 when the internal heating coil operates alone can be less than 3 kHz. Furthermore, the difference between the maximum output frequency f1 of a heating coil and the maximum output frequency f3 when both the internal and external heating coils operate simultaneously can also be less than 3 kHz.

[0069] By setting the maximum output frequencies of multiple heating coils differently, noise can be easily reduced through duty cycle control when operating simultaneously. The following explains how to make the maximum output frequencies the same to reduce noise when heating coils with different maximum output frequencies are operating simultaneously.

[0070] Figure 8 is a control block diagram illustrating an induction heating device according to an embodiment.

[0071] The induction heating device 1 may include a first heating unit 230 and a second heating unit 250. The first heating unit 230 may include a heating coil 240, and the second heating unit 250 may include an internal heating coil 251 and an external heating coil 252. The induction heating device 1 may also include a control unit 150 for controlling the operation of the first heating unit 230 and the heating units. The control unit 150 may include a processor and a memory. Here, as described above, the second heating unit 250 may include dual heating coils 250, which include an internal heating coil 251 and an external heating coil 252.

[0072] The control unit 150 may include a memory 152 and a processor 151. The memory 152 may store control programs and control data for controlling the first heating unit 230 and the second heating unit 250. The processor 151 may generate control signals based on the control programs and control data stored in the memory. The memory 152 and the processor 151 may be integrated or separately.

[0073] The memory 152 can store programs and data for controlling the first heating unit 230 and the second heating unit 250.

[0074] The memory 152 may include volatile memory such as static random access memory (S-RAM) and dynamic random access memory (D-RAM) for temporary data storage. It may also include non-volatile memory such as read-only memory (ROM), erasable programmable read-only memory (EPROM), and electrically erasable programmable read-only memory (EEPROM) for long-term data storage.

[0075] The processor 151 may include various logic circuits and arithmetic circuits, can process data according to a program provided from memory, and can generate control signals according to the processing results.

[0076] When one heating coil 240 and the internal heating coil 251 are operating simultaneously (when one heating coil 240 and the two heating coils 250 are operating simultaneously in the single mode described above), the control unit 150 can change the maximum output frequency f1 of one heating coil so that the maximum output frequency f1 of one heating coil is the same as the maximum output frequency f2 when the internal heating coil is operating alone.

[0077] That is, as shown in Figure 7(b), the maximum output frequency f1 of a heating coil is set to be higher than the maximum output frequency f2 of the internal heating coil during single operation. Therefore, the maximum output frequency f1 of a heating coil can be changed to match the maximum output frequency f2 of the internal heating coil during single operation.

[0078] Furthermore, when one heating coil 240 and the internal heating coil 251 and the external heating coil 252 operate simultaneously (when one heating coil 240 and the two heating coils 250 operate simultaneously in the above dual mode), the control unit 150 can change the maximum output frequency when the internal heating coil 251 and the external heating coil 252 operate simultaneously, so that the maximum output frequency f1 of one heating coil is the same as the maximum output frequency f3 when the internal heating coil and the external heating coil operate simultaneously.

[0079] That is, as shown in Figure 7(b), the maximum output frequency f3 when the internal heating coil and the external heating coil operate simultaneously is set to be higher than the maximum output frequency f1 of a single heating coil. Therefore, the maximum output frequency f3 when the internal heating coil and the external heating coil operate simultaneously can be changed to match the maximum output frequency f1 of a single heating coil.

[0080] Figure 9 is a diagram showing how the maximum output frequency is made consistent by duty cycle control according to an embodiment, and Figure 10 is a diagram illustrating how the different maximum output frequencies of the heating coils according to an embodiment are made consistent.

[0081] The induction heating device 1 may also include a first switch SW1 connected to the first heating unit 230 and a second switch SW2 connected to the second heating unit 250.

[0082] The switching unit can be turned on / off by a switch drive signal. That is, the control unit 150 can supply high-frequency alternating current to the first heating unit 230 by alternately turning on / off the first switching element SW1-1 and the second switching element SW1-2 of the first switching unit.

[0083] Furthermore, the control unit 150 can supply high-frequency alternating current to the second heating unit 250 by alternately switching the first switching element SW2-1 of the second switching unit and the second switching element SW2-2 of the second switching unit on / off.

[0084] As described above, the control unit 150 can control the duty cycle of the on / off ratio of the switch unit to make the maximum output frequency consistent.

[0085] That is, when a heating coil 240 and an internal heating coil 251 are operating simultaneously, the control unit 150 can execute the duty cycle control of the first switching unit SW1 so that the maximum output frequency f1 of the heating coil is the same as the maximum output frequency f2 when the internal heating coil is operating alone, thereby changing the maximum output frequency f1 of the heating coil.

[0086] Furthermore, when a heating coil 240, an internal heating coil 251, and an external heating coil 252 are operating simultaneously, the control unit 150 can execute the duty cycle control of the second switching unit SW2 so that the maximum output frequency f1 of a heating coil is the same as the maximum output frequency f3 when the internal heating coil and the external heating coil are operating simultaneously. Accordingly, the maximum output frequency f3 when the internal heating coil and the external heating coil are operating simultaneously can be changed.

[0087] Figure 9 shows an example of the duty cycle control of the second switch SW2. However, as shown in Figure 9(a), before the duty cycle control, the maximum output frequency f1 of a heating coil is different from the maximum output frequency f3 when the internal heating coil and the external heating coil operate simultaneously. However, through the duty cycle control, as shown in Figure 9(b), the maximum output frequency f3 when the internal heating coil and the external heating coil operate simultaneously decreases and becomes consistent with the maximum output frequency f1 of a heating coil.

[0088] That is, as shown in Figure 10(a), when a heating coil 240 and an internal heating coil 251 are operating simultaneously, the maximum output frequency f1 of a heating coil can be reduced to match the maximum output frequency f2 of the internal heating coil when it is operating alone. As shown in Figure 10(b), when a heating coil 240, an internal heating coil 251, and an external heating coil 252 are operating simultaneously, the maximum output frequency f3 of the internal heating coil and the external heating coil when they are operating simultaneously can be reduced to match the maximum output frequency f1 of a heating coil.

[0089] This duty cycle control ensures that the maximum output frequency remains consistent even when multiple heating coils are operating simultaneously, thereby reducing noise.

[0090] Figures 11 and 12 are flowcharts illustrating a control method for an induction heating device according to an embodiment.

[0091] In the case where one heating coil 240 and the internal heating coil 251 operate simultaneously (the case where one heating coil 240 and the two heating coils 250 operate simultaneously in the single mode described above (step 1101)), the maximum output frequency of one heating coil 240 can be changed so that the maximum output frequency f1 of one heating coil is the same as the maximum output frequency f2 when the internal heating coil operates alone (step 1103).

[0092] That is, as shown in Figure 7(b), the maximum output frequency f1 of a heating coil is set to be higher than the maximum output frequency f2 of the internal heating coil during single operation. Therefore, the maximum output frequency f1 of a heating coil can be changed to match the maximum output frequency f2 of the internal heating coil during single operation.

[0093] In this case, the duty cycle control of the first switching unit SW1 can be executed, thereby changing the maximum output frequency f1 of a heating coil.

[0094] Furthermore, in the case where one heating coil 240 and the internal heating coil 251 and the external heating coil 252 operate simultaneously (the case where one heating coil 240 and the two heating coils 250 operate simultaneously in the above dual mode (step 1201)), the maximum output frequency when the internal heating coil 251 and the external heating coil 252 operate simultaneously can be changed so that the maximum output frequency f1 of one heating coil is the same as the maximum output frequency f3 when the internal heating coil and the external heating coil operate simultaneously (step 1203).

[0095] That is, as shown in Figure 7(b), the maximum output frequency f3 when the internal heating coil and the external heating coil operate simultaneously is set to be higher than the maximum output frequency f1 of a single heating coil. Therefore, the maximum output frequency f3 when the internal heating coil and the external heating coil operate simultaneously can be changed to match the maximum output frequency f1 of a single heating coil.

[0096] In this case, the duty cycle control of the second switching unit SW2 can be executed, thereby changing the maximum output frequency f3 when the internal heating coil and the external heating coil are operating simultaneously.

[0097] An induction heating device according to one embodiment may include: a first heating unit including a heating coil; a second heating unit including an internal heating coil and an external heating coil; and a control unit for controlling the operation of the first heating unit and the second heating unit, wherein the maximum output frequency of the heating coil can be set to be higher than the maximum output frequency of the internal heating coil when operating alone and lower than the maximum output frequency of the internal heating coil and the external heating coil when operating simultaneously.

[0098] According to this disclosure, the maximum output frequencies of the heating coils can be set to be different, and when operating simultaneously, the maximum output frequencies can be made consistent by duty cycle control, thereby reducing noise.

[0099] When the one heating coil and the internal heating coil are operating simultaneously, the control unit can change the maximum output frequency of the one heating coil so that the maximum output frequency of the one heating coil is the same as the maximum output frequency when the internal heating coil is operating alone.

[0100] The induction heating device may further include a first switching unit connected to the first heating unit, wherein the control unit may change the maximum output frequency of the heating coil by controlling the duty cycle of the first switching unit.

[0101] When the one heating coil, the internal heating coil, and the external heating coil are operating simultaneously, the control unit can change the maximum output frequency of the internal heating coil and the external heating coil when they are operating simultaneously, so that the maximum output frequency of the one heating coil is the same as the maximum output frequency of the internal heating coil and the external heating coil when they are operating simultaneously.

[0102] The induction heating device may further include a second switching unit connected to the second heating unit, wherein the control unit may change the maximum output frequency when the internal heating coil and the external heating coil operate simultaneously by controlling the duty cycle of the second switching unit.

[0103] The difference between the maximum output frequency of the single heating coil and the maximum output frequency of the internal heating coil during single operation can be less than 3 kHz.

[0104] The difference between the maximum output frequency of the heating coil and the maximum output frequency when the internal heating coil and the external heating coil operate simultaneously can be less than 3 kHz.

[0105] According to one embodiment, a control method for an induction heating device includes a first heating section comprising a heating coil and a second heating section comprising an internal heating coil and an external heating coil. The maximum output frequency of the heating coil can be set to be higher than the maximum output frequency of the internal heating coil during single operation and lower than the maximum output frequency of the internal heating coil and the external heating coil during simultaneous operation. When the heating coil and the internal heating coil are operating simultaneously, the maximum output frequency of the heating coil can be changed so that the maximum output frequency of the heating coil is the same as the maximum output frequency of the internal heating coil during single operation.

[0106] The induction heating device may further include a first switching unit connected to the first heating unit, wherein changing the maximum output frequency of the heating coil may include changing the maximum output frequency of the heating coil by controlling the duty cycle of the first switching unit.

[0107] When the one heating coil, the internal heating coil, and the external heating coil operate simultaneously, the maximum output frequency of the internal heating coil and the external heating coil during simultaneous operation can be changed so that the maximum output frequency of the one heating coil is the same as the maximum output frequency of the internal heating coil and the external heating coil during simultaneous operation.

[0108] The induction heating device may further include a second switching unit connected to the second heating unit. Changing the maximum output frequency when the internal heating coil and the external heating coil operate simultaneously may include changing the maximum output frequency when the internal heating coil and the external heating coil operate simultaneously by controlling the duty cycle of the second switching unit.

[0109] The difference between the maximum output frequency of the single heating coil and the maximum output frequency of the internal heating coil when operating alone can be less than 3 kHz.

[0110] The difference between the maximum output frequency of the heating coil and the maximum output frequency when the internal heating coil and the external heating coil operate simultaneously can be less than 3 kHz.

[0111] According to the disclosed invention, by setting the maximum output frequency of each heating coil to be different and controlling the duty cycle to make the maximum output frequency consistent when operating simultaneously, noise can be reduced.

[0112] Furthermore, the disclosed embodiments can be implemented in the form of a recording medium storing computer-executable instructions. The instructions can be stored in the form of program code, and when executed by a processor, a program module can be generated to perform the operations of the disclosed embodiments. The recording medium can be implemented as a computer-readable recording medium.

[0113] Computer-readable recording media include all kinds of recording media that store computer-readable instructions. For example, they may include read-only memory (ROM), random access memory (RAM), magnetic tape, magnetic disk, flash memory, optical data storage devices, etc.

[0114] As described above, the disclosed embodiments have been illustrated with reference to the accompanying drawings. Those skilled in the art will understand that the invention can be implemented in forms different from the disclosed embodiments without altering the technical concept or essential features of the invention. The disclosed embodiments are exemplary and should not be construed as restrictive.

Claims

1. An induction heating device, comprising: A first heating unit includes a heating coil; a second heating unit includes an internal heating coil and an external heating coil; and a control unit controls the operation of the first heating unit and the second heating unit, wherein the maximum output frequency of the heating coil is set to be higher than the maximum output frequency of the internal heating coil when operating alone and lower than the maximum output frequency of the internal heating coil and the external heating coil when operating simultaneously.

2. The induction heating device according to claim 1, wherein, When the one heating coil and the internal heating coil are operating simultaneously, the control unit changes the maximum output frequency of the one heating coil so that the maximum output frequency of the one heating coil is the same as the maximum output frequency when the internal heating coil is operating alone.

3. The induction heating device according to claim 2, further comprising: A first switching unit is connected to the first heating unit, wherein the control unit changes the maximum output frequency of the heating coil by controlling the duty cycle of the first switching unit.

4. The induction heating device according to claim 1, wherein, When the one heating coil, the internal heating coil, and the external heating coil operate simultaneously, the maximum output frequency of the internal heating coil and the external heating coil when operating simultaneously is changed so that the maximum output frequency of the one heating coil is the same as the maximum output frequency of the internal heating coil and the external heating coil when operating simultaneously.

5. The induction heating device according to claim 4, further comprising: The second switching unit is connected to the second heating unit, wherein the control unit changes the maximum output frequency when the internal heating coil and the external heating coil operate simultaneously by controlling the duty cycle of the second switching unit.

6. The induction heating device according to claim 1, wherein, The difference between the maximum output frequency of the single heating coil and the maximum output frequency of the internal heating coil during single operation is less than 3 kHz.

7. The induction heating device according to claim 1, wherein, The difference between the maximum output frequency of the heating coil and the maximum output frequency of the internal heating coil and the external heating coil when they are operating simultaneously is less than 3 kHz.

8. The induction heating device according to claim 1, wherein, The second heating unit includes: dual heating coils, including the internal heating coil and the external heating coil, wherein the internal heating coil can operate independently of the external heating coil or can operate simultaneously with the external heating coil.

9. The induction heating device according to claim 8, wherein, The second heating element further includes a gap located between the internal heating coil and the external heating coil.

10. A control method for an induction heating device, comprising a first heating section including a heating coil and a second heating section including an internal heating coil and an external heating coil, comprising the following steps: setting the maximum output frequency of the heating coil to be higher than the maximum output frequency of the internal heating coil when operating alone and lower than the maximum output frequency of the internal heating coil and the external heating coil when operating simultaneously; and changing the maximum output frequency of the heating coil to be the same as the maximum output frequency of the internal heating coil when operating alone when the heating coil and the internal heating coil are operating simultaneously.

11. The control method for the induction heating device according to claim 10, wherein, It also includes a first switching unit connected to the first heating unit, wherein changing the maximum output frequency of the heating coil includes changing the maximum output frequency of the heating coil by controlling the duty cycle of the first switching unit.

12. The control method of the induction heating device according to claim 11 further includes the following step: when the one heating coil, the internal heating coil, and the external heating coil are operating simultaneously, changing the maximum output frequency of the internal heating coil and the external heating coil during simultaneous operation, so that the maximum output frequency of the one heating coil is the same as the maximum output frequency of the internal heating coil and the external heating coil during simultaneous operation.

13. The control method for the induction heating device according to claim 12, wherein, It also includes a second switching unit connected to the second heating unit, and changing the maximum output frequency when the internal heating coil and the external heating coil operate simultaneously includes changing the maximum output frequency when the internal heating coil and the external heating coil operate simultaneously by controlling the duty cycle of the second switching unit.

14. The control method for the induction heating device according to claim 10, wherein, The difference between the maximum output frequency of the single heating coil and the maximum output frequency of the internal heating coil during single operation is less than 3 kHz.

15. The control method for the induction heating device according to claim 10, wherein, The difference between the maximum output frequency of the heating coil and the maximum output frequency of the internal heating coil and the external heating coil when they are operating simultaneously is less than 3 kHz.

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