An electromagnetic induction heating control circuit, control method and heating device

Abstract

The application discloses an electromagnetic induction heating control circuit, a control method and a heating device, and relates to the technical field of electromagnetic heating. The control circuit comprises: an electromagnetic induction heating circuit, which is used for heating a workpiece to be heated; an adder, an input end of the adder being used for receiving a first capacitor voltage and a second capacitor voltage in the electromagnetic induction heating circuit; a multiplier, an input end of the multiplier receiving the first capacitor voltage and an output voltage of the adder; and an adjusting circuit, an input end of the adjusting circuit receiving an output voltage of the multiplier, an output end of the adjusting circuit being connected with a control end of the electromagnetic induction heating circuit, and the adjusting circuit adjusting a working state of the electromagnetic induction heating circuit according to the output voltage of the multiplier. When the voltage of the electromagnetic induction heating circuit changes due to working conditions, the adjusting circuit can automatically adjust the working state of the electromagnetic induction heating circuit, so that the electromagnetic induction heating circuit works in an ideal state, and the power loss of the electromagnetic induction heating circuit is reduced.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic heating technology, and in particular to an electromagnetic induction heating control circuit, control method, and heating device. Background Technology

[0002] Electromagnetic induction heating utilizes eddy currents to heat the workpiece. When an alternating current is passed through the induction coil, an alternating magnetic field is generated around the coil according to the law of electromagnetic induction. This magnetic field passes through the workpiece, generating eddy currents within it, which heat the workpiece from the inside. Therefore, electromagnetic heating is highly efficient and widely used in the steel metallurgy and metal heat treatment industries. One of the core aspects of electromagnetic induction heaters is how to generate or manufacture a frequency-controllable alternating power supply. Currently, there are two main types of devices for generating alternating electromagnetic fields: parallel resonance and series resonance. Parallel resonance, due to its large output current (eddy current), is highly efficient and widely used in high-power electromagnetic induction heating power supplies. High-power induction heating power supplies are mostly used in industrial settings such as steel, metallurgy, and metal heat treatment, where the operating conditions are complex, and the operating voltage of the electromagnetic induction heating circuit is affected by these conditions. The power supply and the electromagnetic induction heating circuit are an integral part of the system; changes in the voltage of the electromagnetic induction heating circuit directly affect the operating frequency, efficiency, and reliability of the power supply. Summary of the Invention

[0003] The purpose of this invention is to provide an electromagnetic induction heating control circuit, control method, and heating device. When the voltage of the electromagnetic induction heating circuit changes due to operating conditions, the regulating circuit can automatically adjust the operating state of the electromagnetic induction heating circuit so that the electromagnetic induction heating circuit works in an ideal state and reduces the power consumption of the electromagnetic induction heating circuit.

[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0005] One aspect of this invention provides an electromagnetic induction heating control circuit, the control circuit comprising: an electromagnetic induction heating circuit for heating a workpiece to be heated; an adder, the input terminal of which receives a first capacitor voltage and a second capacitor voltage in the electromagnetic induction heating circuit; a multiplier, the input terminal of which receives the first capacitor voltage and the output voltage of the adder; and an adjustment circuit, the input terminal of which receives the output voltage of the multiplier, the output terminal of which is connected to the control terminal of the electromagnetic induction heating circuit, the adjustment circuit adjusting the operating state of the electromagnetic induction heating circuit according to the output voltage of the multiplier, so that the electromagnetic induction heating circuit operates in an ideal state and reduces the power consumption of the electromagnetic induction heating circuit.

[0006] In some embodiments, the electromagnetic induction heating circuit includes a heating circuit and an inverter. The input terminal of the inverter receives a DC power supply, the control terminal of the inverter is connected to the output terminal of the regulating circuit, and the output terminal of the inverter is connected to the input terminal of the heating circuit.

[0007] In some embodiments, the heating circuit includes a first capacitor, a second capacitor, a third capacitor, an inductor, and a resistor. One end of the first capacitor is connected to one end of the second capacitor and a first output terminal of the inverter. The other end of the first capacitor is connected to one end of the third capacitor and a second output terminal of the inverter. The other end of the second capacitor is connected to the resistor through the inductor. The other end of the third capacitor is connected to the inductor through the resistor.

[0008] In some embodiments, the inverter includes a first input switch, a first output switch, a second input switch, and a second output switch. The input terminals of the first input switch and the second input switch are both connected to the positive terminal of a DC power supply, and the output terminals of the first output switch and the second output switch are both connected to the negative terminal of a DC power supply. The output terminal of the first input switch is connected to the input terminal of the second output switch, one end of the first capacitor, and one end of the second capacitor. The output terminal of the second input switch is connected to the input terminal of the first output switch, the other end of the first capacitor, and one end of the third capacitor. The control terminals of the first input switch, the first output switch, the second input switch, and the second output switch are connected to the output terminal of the regulating circuit.

[0009] In some embodiments, the first input switch, the first output switch, the second input switch, and the second output switch are all IGBTs.

[0010] In some embodiments, the regulating circuit includes a PID controller and a voltage-controlled oscillator (VCO). The input of the PID controller is connected to the output of the multiplier, the output of the PID controller is connected to the input of the VCO, and the output of the VCO is connected to the control terminal of the inverter.

[0011] In some embodiments, the adjustment circuit further includes a low-pass filter disposed between the input terminal of the PID controller and the output terminal of the multiplier.

[0012] In some embodiments, the adjustment circuit further includes a distribution circuit, the input terminal of which is connected to the output terminal of the voltage-controlled oscillator, and the output terminal of which is connected to the control terminals of the first input switch, the first output switch, the second input switch, and the second output switch, respectively.

[0013] One aspect of this invention provides a control method for an electromagnetic induction heating control circuit. The control method includes: acquiring a first voltage across a first capacitor and acquiring a second voltage across a second or third capacitor; calculating an output reference voltage using an adder to the first voltage and the second voltage; calculating an output product value using a multiplier to the reference voltage and the first voltage; inputting the product value sequentially through a low-pass filter, a PID controller, and a voltage-controlled oscillator to a distribution circuit; when the reference voltage and the first voltage are orthogonal in phase, the low-frequency range of the product value is 0, and the output of the distribution circuit remains unchanged; when there is a phase difference between the reference voltage and the first voltage, the low-frequency range of the product value is not 0; and adjusting the operating state of the inverter according to the product value until the reference voltage and the first voltage are orthogonal in phase.

[0014] One aspect of the present invention provides a heating device, the heating device including the electromagnetic induction heating control circuit described above.

[0015] According to an embodiment of the present invention, an electromagnetic induction heating control circuit, control method, and heating device have at least the following beneficial effects: An inverter controls the operation of the electromagnetic induction heating circuit. When the electromagnetic induction heating circuit operates in an ideal state, the inverter's control corresponds to the operating state of the electromagnetic induction heating circuit. When the electromagnetic induction heating circuit operates in a non-ideal state, the inverter's control does not correspond to the operating state of the electromagnetic induction heating circuit. This is because changes in operating conditions affect the operating state of the electromagnetic induction heating circuit, causing the inverter's control to fail to correspond to the operating state of the electromagnetic induction heating circuit. The electromagnetic induction heating control circuit of this application enables the inverter's control to automatically correspond to the operating state of the electromagnetic induction heating circuit that changes due to changes in operating conditions.

[0016] When the electromagnetic induction heating circuit operates in an ideal state, the reference voltage and the first voltage are orthogonal. When the reference voltage and the first voltage are orthogonal, the low-frequency range of the product value output by the multiplier is equal to 0. After the low-frequency range of the multiplier output product value is 0, the operating states of the PID controller, voltage-controlled oscillator, and distribution circuit in the subsequent circuit remain unchanged, maintaining their original operating states so that the electromagnetic induction heating circuit continues to operate in an ideal state. When the electromagnetic induction heating circuit operates in a non-ideal state, the reference voltage and the first voltage are not orthogonal. When the reference voltage and the first voltage are not in a quadrature state, the low-frequency range of the multiplier output product value is not equal to 0. After the low-frequency range of the multiplier output product value is not 0, the working states of the PID controller, voltage-controlled oscillator and distribution circuit in the subsequent circuit all change. The output of the PID controller is adjusted according to the input change, the output frequency of the voltage-controlled oscillator changes accordingly with the output of the PID controller, and the distribution circuit adjusts the output of the inverter according to the output frequency of the voltage-controlled oscillator. After several adjustment cycles, the inverter control keeps up with the changes of the electromagnetic induction heating circuit, reaches a new balance, realizes phase-locked control, and reduces the power loss of the electromagnetic induction heating circuit.

[0017] It should be understood that the above general description and the following detailed description are merely exemplary and do not limit this disclosure. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the electromagnetic induction heating control circuit according to an embodiment;

[0020] Figure 2 This is a schematic diagram of an electromagnetic induction heating circuit according to an embodiment.

[0021] The following are the labels in the attached diagram: 1. Adder; 2. Multiplier; 3. Adjustment circuit; 4. PID controller; 5. Voltage-controlled oscillator; 6. Low-pass filter; 7. Distribution circuit. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] The terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first," "second," or "third" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0024] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connection," "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0025] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, they are provided so that the description of this disclosure will be more complete and fully convey the concept of the exemplary embodiments to those skilled in the art. The drawings are merely illustrative of this disclosure and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted.

[0026] The electromagnetic induction heating control circuit of this application embodiment is briefly described below:

[0027] Electromagnetic heating is highly efficient and widely used in the steel metallurgy and metal heat treatment industries. Parallel resonant circuits, due to their large output current (eddy current), are highly efficient and widely used in high-power electromagnetic induction heating power supplies. High-power induction heating power supplies are mostly used in industrial settings such as steel, metallurgy, and metal heat treatment, where operating conditions are complex, and the operating voltage of the electromagnetic induction heating circuit is affected by these conditions. The power supply and the electromagnetic induction heating circuit are an integral part of the system; voltage changes in the electromagnetic induction heating circuit directly affect the power supply's operating frequency, efficiency, and reliability.

[0028] To address the above problems, according to some embodiments, such as Figure 1 As shown, this application provides an electromagnetic induction heating control circuit with the following connection structure. The control circuit includes:

[0029] An electromagnetic induction heating circuit, wherein the electromagnetic induction heating circuit is used to heat the workpiece to be heated;

[0030] Adder 1, the input terminal of which is used to receive the voltage of the first capacitor CP1 and the voltage of the second capacitor CS2 in the electromagnetic induction heating circuit;

[0031] Multiplier 2, the input terminal of which receives the voltage of the first capacitor CP1 and the output voltage of the adder 1;

[0032] The regulating circuit 3 receives the output voltage of the multiplier 2 at its input terminal and is connected to the control terminal of the electromagnetic induction heating circuit at its output terminal. The regulating circuit 3 adjusts the operating state of the electromagnetic induction heating circuit according to the output voltage of the multiplier 2 so that the electromagnetic induction heating circuit operates in an ideal state and reduces the power consumption of the electromagnetic induction heating circuit.

[0033] The working principle of the above embodiment is as follows: when the voltage of the electromagnetic induction heating circuit changes due to the influence of the operating conditions, the voltage of the first capacitor CP1 and the voltage of the second capacitor CS2 change. Adder 1 and multiplier 2 detect the change in the voltage of the first capacitor CP1 and the voltage of the second capacitor CS2. The output voltage of multiplier 2 also changes. Adjustment circuit 3 adjusts the working state of electromagnetic induction heating circuit according to the change in the output voltage of multiplier 2 so that electromagnetic induction heating circuit works in an ideal state and reduces the power loss of electromagnetic induction heating circuit.

[0034] The following is in conjunction with the appendix to this instruction manual. Figures 1 to 2 The electromagnetic induction heating control circuit of this application will be further described in detail.

[0035] According to some embodiments, such as Figures 1 to 2 As shown, the electromagnetic induction heating circuit includes a heating circuit and an inverter. The connection structure is as follows: the input terminal of the inverter receives DC power, the control terminal of the inverter is connected to the output terminal of the regulating circuit 3, and the output terminal of the inverter is connected to the input terminal of the heating circuit.

[0036] Based on the above embodiments, this application uses an inverter to convert DC power into AC power, which is then input into the heating circuit to drive its operation. The control terminal of the inverter is connected to the output terminal of the regulating circuit 3, so that the regulating circuit 3 can control the output of the inverter and further control the operating state of the heating circuit.

[0037] According to some embodiments, such as Figure 2 As shown, the heating circuit includes a first capacitor CP1, a second capacitor CS2, a third capacitor CS3, an inductor, and a resistor. Its connection structure is as follows: one end of the first capacitor CP1 is connected to one end of the second capacitor CS2 and the first output terminal of the inverter; the other end of the first capacitor CP1 is connected to one end of the third capacitor CS3 and the second output terminal of the inverter; the other end of the second capacitor CS2 is connected to the resistor through the inductor; and the other end of the third capacitor CS3 is connected to the inductor through the resistor.

[0038] According to some embodiments, such as Figure 2 As shown, the inverter includes a first input switch, a first output switch, a second input switch, and a second output switch. The connection structure is as follows: the input terminals of both the first and second input switches are connected to the positive terminal of a DC power supply; the output terminals of both the first and second output switches are connected to the negative terminal of a DC power supply; the output terminal of the first input switch is connected to the input terminal of the second output switch, one end of the first capacitor CP1, and one end of the second capacitor CS2; the output terminal of the second input switch is connected to the input terminal of the first output switch, the other end of the first capacitor CP1, and one end of the third capacitor CS3; and the control terminals of the first input switch, first output switch, second input switch, and second output switch are connected to the output terminal of the regulating circuit 3.

[0039] In some embodiments, the first input switch, the first output switch, the second input switch, and the second output switch are all IGBTs. In other embodiments, the first input switch, the first output switch, the second input switch, and the second output switch may also be electronic components with switching functions such as transistors; this application does not impose any limitations.

[0040] According to some embodiments, such as Figure 1 As shown, the regulating circuit 3 includes a PID controller 4 and a voltage-controlled oscillator 5. The connection structure is as follows: the input terminal of the PID controller 4 is connected to the output terminal of the multiplier 2, the output terminal of the PID controller 4 is connected to the input terminal of the voltage-controlled oscillator 5, and the output terminal of the voltage-controlled oscillator 5 is connected to the control terminal of the inverter.

[0041] According to some embodiments, such as Figure 1 As shown, the adjustment circuit 3 also includes a low-pass filter 6, which is connected in such a way that the low-pass filter 6 is disposed between the input terminal of the PID controller 4 and the output terminal of the multiplier 2.

[0042] According to some embodiments, such as Figure 1As shown, the adjustment circuit 3 also includes a distribution circuit 7, which is connected in the following way: the input terminal of the distribution circuit 7 is connected to the output terminal of the voltage-controlled oscillator 5, and the output terminal of the distribution circuit 7 is connected to the control terminals of the first input switch, the first output switch, the second input switch, and the second output switch, respectively.

[0043] The technical problem this application aims to solve is that an inverter controls the operation of an electromagnetic induction heating circuit. When the electromagnetic induction heating circuit operates in an ideal state, the inverter's control corresponds to the circuit's operating state. However, when the electromagnetic induction heating circuit operates in a non-ideal state, the inverter's control fails to correspond to the circuit's operating state. This is because changes in operating conditions affect the electromagnetic induction heating circuit's operating state, causing the inverter's control to fail to match the circuit's operating state. The electromagnetic induction heating control circuit of this application enables the inverter's control to automatically correspond to the changing operating state of the electromagnetic induction heating circuit due to changes in operating conditions.

[0044] The working principle of this application is as follows: the first input terminal of adder 1 and the first input terminal of multiplier 2 receive the first voltage across the first capacitor CP1, and the second input terminal of adder 1 receives the second voltage across the second capacitor CS2 or the third capacitor CS3. Adder 1 outputs the reference voltage obtained by adding the first voltage and the second voltage to multiplier 2, and multiplier 2 performs a multiplication operation on the reference voltage and the first voltage.

[0045] When the electromagnetic induction heating circuit operates in an ideal state, the reference voltage and the first voltage are orthogonal. When the reference voltage and the first voltage are orthogonal, the low-frequency range of the product value output by multiplier 2 is equal to 0. After the low-frequency range of the product value output by multiplier 2 is 0, the operating states of the PID controller 4, voltage-controlled oscillator 5, and distribution circuit 7 in the subsequent circuit remain unchanged, maintaining their original operating states so that the electromagnetic induction heating circuit continues to operate in an ideal state.

[0046] When the electromagnetic induction heating circuit operates in a non-ideal state, the reference voltage and the first voltage are not orthogonal. When the reference voltage and the first voltage are not orthogonal, the low-frequency range of the product value output by multiplier 2 is not equal to 0. After the low-frequency range of the product value output by multiplier 2 is not equal to 0, the operating states of the PID controller 4, voltage-controlled oscillator 5, and distribution circuit 7 in the subsequent circuit all change. The output of PID controller 4 is adjusted according to the input change, the output frequency of voltage-controlled oscillator 5 changes accordingly with the output of PID controller 4, and distribution circuit 7 adjusts the inverter output according to the output frequency of voltage-controlled oscillator 5. After several adjustment cycles, the inverter control keeps up with the changes of the electromagnetic induction heating circuit, reaches a new equilibrium, and realizes phase-locked control.

[0047] The control method of the electromagnetic induction heating control circuit according to the embodiments of this application is briefly described below:

[0048] According to some embodiments, this application provides a control method for an electromagnetic induction heating control circuit, the control method comprising:

[0049] Step 101: Obtain the first voltage across the first capacitor CP1, and obtain the second voltage across the second capacitor CS2 or the third capacitor CS3.

[0050] Step 102: Calculate the output reference voltage using adder 1 by combining the first voltage and the second voltage;

[0051] Step 103: Calculate and output the product value of the reference voltage and the first voltage using multiplier 2;

[0052] Step 104: The product value is sequentially input to the distribution circuit 7 through the low-pass filter 6, the PID controller 4, and the voltage-controlled oscillator 5. When the reference voltage and the first voltage are orthogonal in phase, the low-frequency band of the product value is 0, and the output of the distribution circuit 7 remains unchanged. When there is a phase difference between the reference voltage and the first voltage, the low-frequency band of the product value is not 0. The distribution circuit 7 adjusts the operating state of the inverter according to the product value until the reference voltage and the first voltage are orthogonal in phase.

[0053] The technical problem this application aims to solve is that an inverter controls the operation of an electromagnetic induction heating circuit. When the electromagnetic induction heating circuit operates in an ideal state, the inverter's control corresponds to the circuit's operating state. However, when the electromagnetic induction heating circuit operates in a non-ideal state, the inverter's control fails to correspond to the circuit's operating state. This is because changes in operating conditions affect the electromagnetic induction heating circuit's operating state, causing the inverter's control to fail to match the circuit's operating state. The electromagnetic induction heating control circuit of this application enables the inverter's control to automatically correspond to the changing operating state of the electromagnetic induction heating circuit due to changes in operating conditions.

[0054] The working principle of this application is as follows: the first input terminal of adder 1 and the first input terminal of multiplier 2 receive the first voltage across the first capacitor CP1, and the second input terminal of adder 1 receives the second voltage across the second capacitor CS2 or the third capacitor CS3. Adder 1 outputs the reference voltage obtained by adding the first voltage and the second voltage to multiplier 2, and multiplier 2 performs a multiplication operation on the reference voltage and the first voltage.

[0055] When the electromagnetic induction heating circuit operates in an ideal state, the reference voltage and the first voltage are orthogonal. When the reference voltage and the first voltage are orthogonal, the low-frequency range of the product value output by multiplier 2 is equal to 0. After the low-frequency range of the product value output by multiplier 2 is 0, the operating states of the PID controller 4, voltage-controlled oscillator 5, and distribution circuit 7 in the subsequent circuit remain unchanged, maintaining their original operating states so that the electromagnetic induction heating circuit continues to operate in an ideal state.

[0056] When the electromagnetic induction heating circuit operates in a non-ideal state, the reference voltage and the first voltage are not orthogonal. When the reference voltage and the first voltage are not orthogonal, the low-frequency range of the product value output by multiplier 2 is not equal to 0. After the low-frequency range of the product value output by multiplier 2 is not equal to 0, the operating states of the PID controller 4, voltage-controlled oscillator 5, and distribution circuit 7 in the subsequent circuit all change. The output of PID controller 4 is adjusted according to the input change, the output frequency of voltage-controlled oscillator 5 changes accordingly with the output of PID controller 4, and distribution circuit 7 adjusts the inverter output according to the output frequency of voltage-controlled oscillator 5. After several adjustment cycles, the inverter control keeps up with the changes of the electromagnetic induction heating circuit, reaches a new equilibrium, and realizes phase-locked control.

[0057] According to some embodiments, this application provides a heating device, which includes the electromagnetic induction heating control circuit described above.

[0058] In the description of the above embodiments, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0059] Although this disclosure has been described with reference to several typical embodiments, it should be understood that the terminology used is descriptive and exemplary, and not restrictive. Because this disclosure can be embodied in many forms without departing from the spirit or substance of this application, it should be understood that the above embodiments are not limited to any of the foregoing details, but should be interpreted broadly within the spirit and scope defined by the appended claims. Therefore, all variations and modifications falling within the scope of the claims or their equivalents should be covered by the appended claims.

Claims

1. An electromagnetic induction heating control circuit, characterized in that, The control circuit includes: An electromagnetic induction heating circuit, wherein the electromagnetic induction heating circuit is used to heat the workpiece to be heated; An adder, the input of which is used to receive the first capacitor voltage and the second capacitor voltage in the electromagnetic induction heating circuit; A multiplier, the input of which receives the voltage of the first capacitor and the output voltage of the adder; An adjustment circuit is provided, wherein the input terminal of the adjustment circuit receives the output voltage of the multiplier, and the output terminal of the adjustment circuit is connected to the control terminal of the electromagnetic induction heating circuit. The adjustment circuit adjusts the working state of the electromagnetic induction heating circuit according to the output voltage of the multiplier, so that the electromagnetic induction heating circuit works in an ideal state and reduces the power consumption of the electromagnetic induction heating circuit.

2. The control circuit according to claim 1, characterized in that, The electromagnetic induction heating circuit includes a heating circuit and an inverter. The input terminal of the inverter receives DC power, the control terminal of the inverter is connected to the output terminal of the regulating circuit, and the output terminal of the inverter is connected to the input terminal of the heating circuit.

3. The control circuit according to claim 2, characterized in that, The heating circuit includes a first capacitor, a second capacitor, a third capacitor, an inductor, and a resistor. One end of the first capacitor is connected to one end of the second capacitor and the first output terminal of the inverter. The other end of the first capacitor is connected to one end of the third capacitor and the second output terminal of the inverter. The other end of the second capacitor is connected to the resistor through the inductor. The other end of the third capacitor is connected to the inductor through the resistor.

4. The control circuit according to claim 3, characterized in that, The inverter includes a first input switch, a first output switch, a second input switch, and a second output switch. The input terminals of the first input switch and the second input switch are both connected to the positive terminal of a DC power supply, and the output terminals of the first output switch and the second output switch are both connected to the negative terminal of a DC power supply. The output terminal of the first input switch is connected to the input terminal of the second output switch, one end of the first capacitor, and one end of the second capacitor. The output terminal of the second input switch is connected to the input terminal of the first output switch, the other end of the first capacitor, and one end of the third capacitor. The control terminals of the first input switch, the first output switch, the second input switch, and the second output switch are connected to the output terminal of the regulating circuit.

5. The control circuit according to claim 4, characterized in that, The first input switch, the first output switch, the second input switch, and the second output switch all use IGBTs.

6. The control circuit according to claim 4, characterized in that, The regulating circuit includes a PID controller and a voltage-controlled oscillator. The input terminal of the PID controller is connected to the output terminal of the multiplier, the output terminal of the PID controller is connected to the input terminal of the voltage-controlled oscillator, and the output terminal of the voltage-controlled oscillator is connected to the control terminal of the inverter.

7. The control circuit according to claim 6, characterized in that, The adjustment circuit also includes a low-pass filter, which is disposed between the input terminal of the PID controller and the output terminal of the multiplier.

8. The control circuit according to claim 6, characterized in that, The adjustment circuit further includes a distribution circuit, the input terminal of which is connected to the output terminal of the voltage-controlled oscillator, and the output terminal of which is connected to the control terminals of the first input switch, the first output switch, the second input switch, and the second output switch, respectively.

9. A control method for an electromagnetic induction heating control circuit, characterized in that, The control method includes: Obtain the first voltage across the first capacitor, and obtain the second voltage across the second or third capacitor; The first voltage and the second voltage are used to calculate the output reference voltage using an adder; The reference voltage and the first voltage are multiplied by a multiplier to calculate and output the product value. The product value is sequentially input to the distribution circuit through a low-pass filter, a PID controller, and a voltage-controlled oscillator. When the reference voltage and the first voltage are orthogonal in phase, the low-frequency range of the product value is 0, and the output of the distribution circuit remains unchanged. When there is a phase difference between the reference voltage and the first voltage, the low-frequency range of the product value is not 0. The distribution circuit adjusts the operating state of the inverter according to the product value until the reference voltage and the first voltage are orthogonal in phase.

10. A heating device, characterized in that, The heating device includes the electromagnetic induction heating control circuit as described in any one of claims 1 to 8.

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