A circuit and method for adjusting output power of electromagnetic coil

Abstract

The present invention provides a circuit and method for adjusting the output power of an electromagnetic coil. The circuit includes: an electromagnetic coil; an IGBT upper arm and an IGBT lower arm, each connected to one end of the electromagnetic coil and connected in parallel; a first arm capacitor and a second arm capacitor, each connected to the other end of the electromagnetic coil and connected in parallel. The IGBT upper arm and the IGBT lower arm each receive and execute an on / off drive signal, thereby changing the alternating conduction frequency of the IGBT upper arm and the IGBT lower arm, thereby adjusting the output power of the electromagnetic coil. This circuit solves the technical problems of inaccurate electromagnetic coil output power, inability to achieve stepless power regulation, and a large control power span in the prior art.

Description

Technical Field

[0001] The present invention relates to the field of electromagnetic control, and in particular to a circuit and method for adjusting the output power of an electromagnetic coil. Background Art

[0002] With the development of society and the economy, electromagnetic heating cookware has become an essential part of the kitchen, including typical household appliances such as induction cookers, electric hot pots, and rice cookers. Compared to traditional open-flame cookers, electromagnetic heating cookware is faster, safer, and more intelligent, leading to its increasing popularity. Electromagnetic heating technology injects a high-frequency alternating current into an induction coil, creating an alternating magnetic field. The alternating magnetic field creates eddy currents in the metal cookware, generating heat that heats the food inside.

[0003] Most existing electric cookers regulate their output power primarily by adjusting the pulse width of the inverter circuit's switches. The electromagnetic coil operates at a quasi-resonant frequency. However, this control method has a narrow output power range, cannot achieve stepless power regulation, and cannot output high power. Low-power operation requires intermittent operation, and the cooking effect is unlikely to surpass open-flame cooking. Summary of the Invention

[0004] The present invention provides a circuit and method for adjusting the output power of an electromagnetic coil, so as to solve the technical problems in the prior art of inaccurate output power of the electromagnetic coil, inability to achieve stepless power regulation, and large control power span.

[0005] According to a first aspect of the present invention, a circuit for adjusting the output power of an electromagnetic coil is provided, the adjustment circuit comprising: an electromagnetic coil; an IGBT upper bridge arm and an IGBT lower bridge arm, each connected to one end of the electromagnetic coil, the IGBT upper bridge arm and the IGBT lower bridge arm being connected in parallel; a first bridge arm capacitor and a second bridge arm capacitor, each connected to the other end of the electromagnetic coil, the first bridge arm capacitor and the second bridge arm capacitor being connected in parallel; wherein the IGBT upper bridge arm and the IGBT lower bridge arm respectively receive and execute an on-off drive signal, thereby changing the alternating conduction frequency of the IGBT upper bridge arm and the IGBT lower bridge arm, thereby adjusting the output power of the electromagnetic coil.

[0006] Furthermore, the alternating conduction frequency of the IGBT upper bridge arm and the IGBT lower bridge arm changes so that the oscillation frequency of the first bridge arm capacitor and the second bridge arm capacitor changes, thereby adjusting the resonant frequency of the electromagnetic coil.

[0007] Furthermore, the adjustment circuit also includes: a drive circuit, connected to the IGBT upper bridge arm and the IGBT lower bridge arm respectively, for generating the on-off drive signal according to the received pulse broadband modulation signal and sending it to the IGBT upper bridge arm and the IGBT lower bridge arm.

[0008] Furthermore, the adjustment circuit further includes: a digital signal processor connected to the driving circuit, configured to generate the pulse wideband modulation signal according to the received target power.

[0009] Furthermore, the adjustment circuit also includes: a current phase detection module, a current peak detection module, an electromagnetic coil current acquisition module and a current sampling resistor, the current phase detection module and the current peak detection module are connected in parallel and between the digital signal processor and the electromagnetic coil current acquisition module, the current sampling resistor and the electromagnetic coil current acquisition module are respectively connected to the second bridge arm capacitor, and the current sampling resistor and the electromagnetic coil current acquisition module are connected in parallel; wherein, the digital signal processor is used to generate a phase difference between the electromagnetic coil input voltage and the electromagnetic coil current based on the signals sent by the current phase detection module, the current peak detection module, the electromagnetic coil current acquisition module and the current sampling resistor, wherein the phase difference is associated with the resonant frequency of the electromagnetic coil.

[0010] Furthermore, the digital signal processor obtains the time from the rising edge of the on-off drive signal to the zero crossing of the upper half cycle of the electromagnetic coil working current and the half-cycle time of the current in the resonant state based on the signals sent by the current phase detection module, the current peak detection module, the electromagnetic coil current acquisition module and the current sampling resistor. The digital signal processor generates the phase difference based on the time from the rising edge of the on-off drive signal to the zero crossing of the upper half cycle of the electromagnetic coil working current and the half-cycle time of the current in the resonant state.

[0011] According to a second aspect of the present invention, a method for adjusting the output power of an electromagnetic coil is provided, the method comprising: receiving a target output power of the electromagnetic coil, wherein an IGBT upper bridge arm and an IGBT lower bridge arm are respectively connected to one end of the electromagnetic coil, and the IGBT upper bridge arm and the IGBT lower bridge arm are connected in parallel; a first bridge arm capacitor and a second bridge arm capacitor are respectively connected to the other end of the electromagnetic coil, and the first bridge arm capacitor and the second bridge arm capacitor are connected in parallel; determining an on-off drive signal according to the target output power; and sending the on-off drive signal to the IGBT upper bridge arm and the IGBT lower bridge arm, wherein the IGBT upper bridge arm and the IGBT lower bridge arm execute the on-off drive signal, thereby changing the alternating conduction frequency of the IGBT upper bridge arm and the IGBT lower bridge arm, thereby adjusting the output power of the electromagnetic coil.

[0012] Furthermore, determining the on-off driving signal according to the target output power includes: calculating the current output power of the electromagnetic coil; and determining the on-off driving signal according to the difference between the target output power and the current output power.

[0013] Furthermore, calculating the current output power of the electromagnetic coil includes: collecting a half cycle of the resonant current of the electromagnetic coil, and generating the current output power according to the half cycle of the resonant current.

[0014] Furthermore, the alternating conduction frequency of the IGBT upper bridge arm and the IGBT lower bridge arm is inversely proportional to the phase difference, and the phase difference is the phase difference between the electromagnetic coil input voltage and the electromagnetic coil current.

[0015] The present invention provides a circuit and method for adjusting the output power of an electromagnetic coil. The circuit includes: an electromagnetic coil; an IGBT upper arm and an IGBT lower arm, each connected to one end of the electromagnetic coil and connected in parallel; a first arm capacitor and a second arm capacitor, each connected to the other end of the electromagnetic coil and connected in parallel. The IGBT upper arm and the IGBT lower arm each receive and execute an on / off drive signal, thereby changing the alternating conduction frequency of the IGBT upper arm and the IGBT lower arm, thereby adjusting the output power of the electromagnetic coil. This circuit solves the technical problems of inaccurate electromagnetic coil output power, inability to achieve stepless power regulation, and a large control power span in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of an adjustment circuit for electromagnetic coil output power provided by an embodiment of the present invention;

[0017] Figure 2 is a schematic diagram of an optional electromagnetic coil output power adjustment circuit provided in an embodiment of the present invention;

[0018] Figure 3 is a flow chart of a method for adjusting the output power of an electromagnetic coil provided in an embodiment of the present invention;

[0019] Figure 4 is a schematic diagram of phase difference calculation provided by an embodiment of the present invention;

[0020] Figure 5 is a flow chart of an optional method for adjusting the output power of an electromagnetic coil provided in an embodiment of the present invention; DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0022] Example 1

[0023] According to an embodiment of the present invention, a circuit for adjusting the output power of an electromagnetic coil is provided. Figure 1 , characterized in that the adjustment circuit includes: an electromagnetic coil 12; an IGBT upper bridge arm 14 and an IGBT lower bridge arm 16, respectively connected to one end of the coil, and the IGBT upper bridge arm 14 and the IGBT lower bridge arm 16 are connected in parallel; a first bridge arm capacitor 18 and a second bridge arm capacitor 20, respectively connected to the other end of the electromagnetic coil, and the first bridge arm capacitor 18 and the second bridge arm capacitor 20 are connected in parallel; wherein the IGBT upper bridge arm 14 and the IGBT lower bridge arm 16 respectively receive and execute on-off drive signals, so as to change the alternating conduction frequency of the IGBT upper bridge arm 14 and the IGBT lower bridge arm 16, thereby adjusting the output power of the electromagnetic coil 12.

[0024] Specifically, the term IGBT (Insulated Gate Bipolar Transistor) in this application is interpreted as: Insulated Gate Bipolar Transistor, the electromagnetic coil can be the electromagnetic coil of the heating component inside the electromagnetic heating cooker, combined with Figure 1 The electromagnetic coil 12, the IGBT upper bridge arm 14, the IGBT lower bridge arm 16, the first bridge arm capacitor 18, and the second bridge arm capacitor 20 constitute an inverter circuit of the electromagnetic coil. When the user needs to adjust the output power of the electromagnetic coil, this embodiment can adjust the output power of the electromagnetic coil by controlling the IGBT upper bridge arm 14 and the IGBT lower bridge arm 16 to be on and off.

[0025] It should be noted here that, combined with Figure 1 When the alternating conduction frequency of the IGBT upper arm and the IGBT lower arm changes, the oscillation frequency of the electromagnetic coil also changes, and therefore the output power also changes. Therefore, this solution can accurately control the output power of the electromagnetic coil by adjusting the alternating conduction frequency of the IGBT upper arm and the IGBT lower arm. When the alternating conduction frequency of the IGBT upper arm and the IGBT lower arm increases, the output power of the electromagnetic coil increases. When the alternating conduction frequency of the IGBT upper arm and the IGBT lower arm decreases, the output power of the electromagnetic coil decreases. Therefore, the output power of the electromagnetic coil can be accurately adjusted by driving the alternating conduction frequency of the IGBT upper arm and the IGBT lower arm. This solution adjusts the output power of the electromagnetic coil through multiple modules in the above-mentioned adjustment circuit, solving the technical problems in the prior art of inaccurate output power of the electromagnetic coil, inability to achieve stepless power regulation, and large control power span.

[0026] Optionally, the alternating conduction frequency of the IGBT upper bridge arm and the IGBT lower bridge arm is changed so that the oscillation frequency of the first bridge arm capacitor and the second bridge arm capacitor is changed, thereby adjusting the resonant frequency of the electromagnetic coil.

[0027] Optionally, the adjustment circuit further includes:

[0028] The driving circuit is connected to the IGBT upper bridge arm and the IGBT lower bridge arm respectively, and is used to generate the on-off driving signal according to the received pulse broadband modulation signal and send it to the IGBT upper bridge arm and the IGBT lower bridge arm.

[0029] Optionally, the adjustment circuit further includes:

[0030] A digital signal processor is connected to the driving circuit and is used to generate the pulse wideband modulation signal according to the received target power. The pulse wideband modulation signal can be two complementary PWM signals with a duty cycle of 50%.

[0031] Specifically, the above-mentioned target power can be the target operating power set by the user. After obtaining the above-mentioned target power, the digital signal processor can determine the matching pulse broadband modulation signal according to the target power and send it to the drive circuit. The drive circuit drives the IGBT upper bridge arm and the IGBT lower bridge arm according to the above-mentioned pulse broadband modulation signal to realize the change of the alternating conduction frequency.

[0032] Optionally, the adjustment circuit further includes: a current phase detection module, a current peak detection module, an electromagnetic coil current acquisition module, and a current sampling resistor, wherein the current phase detection module and the current peak detection module are connected in parallel and connected between the digital signal processor and the electromagnetic coil current acquisition module, the current sampling resistor and the electromagnetic coil current acquisition module are respectively connected to the second bridge arm capacitor, and the current sampling resistor and the electromagnetic coil current acquisition module are connected in parallel;

[0033] In which, the digital signal processor is used to generate the phase difference of the electromagnetic coil input voltage and the electromagnetic coil current based on the signals sent by the current phase detection module, the current peak detection module, the electromagnetic coil current acquisition module and the current sampling resistor, wherein the phase difference is associated with the resonant frequency of the electromagnetic coil.

[0034] Specifically, in this solution, when the electromagnetic coil is at different resonant frequencies, the phase difference between its input voltage and the electromagnetic coil current is different. The technical principle of this solution is to change the phase difference between the electromagnetic coil input voltage and the electromagnetic coil current by adjusting the alternating conduction frequency of the IGBT upper bridge arm and the IGBT lower bridge arm, that is, the phase difference is also related to the output power of the electromagnetic coil. Therefore, after this solution adjusts the alternating conduction frequency of the IGBT upper bridge arm and the IGBT lower bridge arm through the above circuit, the digital signal processor can be used to detect and calculate the phase difference between the electromagnetic coil input voltage and the electromagnetic coil current at any time to verify whether the power adjustment is performed correctly.

[0035] Optionally, the digital signal processor obtains the time from the rising edge of the on-off drive signal to the zero crossing of the upper half cycle of the electromagnetic coil working current and the time of a current half cycle in the resonant state based on the signals sent by the current phase detection module, the current peak detection module, the electromagnetic coil current acquisition module and the current sampling resistor. The digital signal processor generates the phase difference based on the time from the rising edge of the on-off drive signal to the zero crossing of the upper half cycle of the electromagnetic coil working current and the time of a current half cycle in the resonant state.

[0036] The following combination Figures 2 to 3 , introduces an optional embodiment of this solution:

[0037] like Figure 2 As shown in the figure, the main loop of the system inverter circuit is composed of ① upper bridge arm, ② lower bridge arm, ③ electromagnetic coil, ④ and ⑤ bridge arm capacitors, and ⑥ sampling resistor.

[0038] In the circuit, the inverter input voltage is the 400VDC output voltage of the PFC circuit. During normal operation, DSP (10) outputs two complementary PWM signals with a 50% duty cycle. These signals, controlled by the driver circuit, switch IGBTs (1) and (2). This causes electromagnetic coil (3) and bridge arm capacitors (4) and (5) to oscillate at high frequencies, achieving a control frequency of 20 to 45 kHz. Depending on the frequency of electromagnetic coil (3), the output power varies.

[0039] When the system detects that the output power needs to be changed, the current signal detection can be achieved through the sampling resistor ⑥, the coil current acquisition circuit ⑦, the current phase detection circuit ⑧ and the current peak detection circuit ⑨. After an upper bridge arm drive signal is issued, the DSP ⑩ timer starts timing by detecting the zero-crossing signal of the current signal with a phase difference, such as Figure 3 As shown, the IGBT drives square wave Vg1 and current sine wave i1, capturing half-cycle ta. The phase difference ψ between the input voltage and coil current is detected by acquiring a half-cycle tb of the current signal in the resonant state. When power needs to be increased, the alternating conduction frequency of IGBTs 1 and 2 is increased, increasing the coil oscillation frequency, reducing the phase difference ψ, and increasing output power. When power needs to be reduced, the alternating conduction frequency of IGBTs 1 and 2 is reduced, reducing the coil resonant frequency, increasing the phase difference ψ, and decreasing output power. DSP 10 simultaneously controls the oscillation circuit to always operate in an inductive state.

[0040] In summary, this solution uses two IGBTs, two resonant capacitors and a heating coil to form a half-bridge series resonant inverter. The main control chip collects the time from the rising edge of the IGBT drive signal to the zero crossing of the upper half cycle of the coil working current. Compared with the time of a current half cycle in the resonant state, the time difference is the phase angle ψ. By controlling the IGBT switching frequency to reduce or increase the oscillation frequency, the phase angle changes and the output power is precisely adjusted.

[0041] Example 2

[0042] Combine Figure 4 This solution also provides a method for adjusting the output power of an electromagnetic coil. The functions of the technical features in this method are the same as those in the first embodiment. The method includes:

[0043] Step S41, receiving the target output power of the electromagnetic coil, wherein the IGBT upper bridge arm and the IGBT lower bridge arm are respectively connected to one end of the electromagnetic coil, and the IGBT upper bridge arm and the IGBT lower bridge arm are connected in parallel; the first bridge arm capacitor and the second bridge arm capacitor are respectively connected to the other end of the electromagnetic coil, and the first bridge arm capacitor and the second bridge arm capacitor are connected in parallel.

[0044] Step S43: determining an on-off driving signal according to the target output power.

[0045] Step S45, sending the on-off drive signal to the IGBT upper bridge arm and the IGBT lower bridge arm, wherein the IGBT upper bridge arm and the IGBT lower bridge arm execute the on-off drive signal, thereby changing the alternating conduction frequency of the IGBT upper bridge arm and the IGBT lower bridge arm, thereby adjusting the output power of the electromagnetic coil.

[0046] Specifically, when the alternating conduction frequency of the IGBT upper and lower arms changes, the oscillation frequency of the electromagnetic coil also varies, and thus the output power also varies. Therefore, this solution can precisely control the output power of the electromagnetic coil by adjusting the alternating conduction frequency of the IGBT upper and lower arms. When the alternating conduction frequency of the IGBT upper and lower arms increases, the output power of the electromagnetic coil increases. When the alternating conduction frequency of the IGBT upper and lower arms decreases, the output power of the electromagnetic coil decreases. Therefore, the output power of the electromagnetic coil can be precisely adjusted by driving the alternating conduction frequency of the IGBT upper and lower arms. This solution adjusts the output power of the electromagnetic coil through multiple modules in the above-mentioned adjustment circuit, solving the technical problems in the prior art of inaccurate output power of the electromagnetic coil, which cannot achieve stepless power regulation and has a large control power span.

[0047] Optionally, determining an on-off driving signal according to the target output power includes:

[0048] Calculate the current output power of the electromagnetic coil;

[0049] The on-off driving signal is determined according to a difference between the target output power and the current output power.

[0050] Optionally, the current output power of the electromagnetic coil is calculated, including:

[0051] A half cycle of the resonant state current of the electromagnetic coil is collected, and the current output power is generated according to the half cycle of the resonant state current.

[0052] Optionally, the alternating conduction frequency of the IGBT upper bridge arm and the IGBT lower bridge arm is inversely proportional to the phase difference, where the phase difference is the phase difference between the electromagnetic coil input voltage and the electromagnetic coil current.

[0053] Combine Figure 5 , introduces an optional embodiment of this solution:

[0054] First, a half-cycle of the resonant state current is collected. Then, based on the half-cycle of the resonant state current, the real-time output power of the working power electromagnetic coil is calculated and compared with the set power. If the real-time output power is less than the set power, the operating frequency needs to be increased, and the IGBT on-off frequency is controlled to increase, so that the phase angle ψ decreases. If the real-time output power is greater than the set power, the operating frequency needs to be reduced, and the IGBT on-off frequency is controlled to decrease, so that the phase angle ψ increases. This ensures that the oscillation frequency of the coil is within the operating range.

[0055] It should be understood that the specific features, operations and details described herein above with respect to the method of the present invention may also be similarly applied to the apparatus and system of the present invention, or vice versa. In addition, each step of the method of the present invention described above may be performed by the corresponding components or units of the apparatus or system of the present invention.

[0056] It should be understood that the various modules / units of the apparatus of the present invention may be implemented in whole or in part by software, hardware, firmware, or a combination thereof. Each of the modules / units may be embedded in a processor of a computer device in the form of hardware or firmware or independent of the processor, or may be stored in a memory of a computer device in the form of software for the processor to call to execute the operations of the modules / units. Each of the modules / units may be implemented as an independent component or module, or two or more modules / units may be implemented as a single component or module.

[0057] In one embodiment, a computer device is provided, comprising a memory and a processor, wherein the memory stores computer instructions executable by the processor, and when executed by the processor, the computer instructions instruct the processor to perform the steps of the method according to an embodiment of the present invention. The computer device can be broadly defined as a server, a terminal, or any other electronic device with the necessary computing and / or processing capabilities. In one embodiment, the computer device can include a processor, memory, a network interface, a communication interface, etc. connected via a system bus. The processor of the computer device can be used to provide the necessary computing, processing, and / or control capabilities. The memory of the computer device can include a non-volatile storage medium and an internal memory. An operating system, a computer program, etc. can be stored in or on the non-volatile storage medium. The internal memory can provide an environment for the operation of the operating system and computer program in the non-volatile storage medium. The network interface and communication interface of the computer device can be used to connect to and communicate with external devices via a network. When the computer program is executed by the processor, the steps of the method according to the present invention are performed.

[0058] The present invention can be implemented as a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, causes the steps of the method of an embodiment of the present invention to be performed. In one embodiment, the computer program is distributed on a plurality of computer devices or processors coupled to a network so that the computer program is stored, accessed, and executed in a distributed manner by one or more computer devices or processors. A single method step / operation, or two or more method steps / operations, can be performed by a single computer device or processor or by two or more computer devices or processors. One or more method steps / operations can be performed by one or more computer devices or processors, and one or more other method steps / operations can be performed by one or more other computer devices or processors. One or more computer devices or processors can perform a single method step / operation, or perform two or more method steps / operations.

[0059] It will be understood by those skilled in the art that the method steps of the present invention can be performed by instructing relevant hardware such as a computer device or a processor through a computer program, and the computer program can be stored in a non-transitory computer-readable storage medium, which causes the steps of the present invention to be performed when the computer program is executed. Depending on the circumstances, any reference to memory, storage, database or other media herein may include non-volatile and / or volatile memory. Examples of non-volatile memory include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), flash memory, magnetic tape, floppy disk, magneto-optical data storage device, optical data storage device, hard disk, solid-state disk, etc. Examples of volatile memory include random access memory (RAM), external cache memory, etc.

[0060] The various technical features described above can be combined arbitrarily. Although not all possible combinations of these technical features are described, any combination of these technical features should be considered to be covered by this specification as long as such combination does not conflict.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A circuit for adjusting the output power of an electromagnetic coil, characterized in that: The adjustment circuit includes: electromagnetic coil; The IGBT upper bridge arm and the IGBT lower bridge arm are respectively connected to one end of the electromagnetic coil, and the IGBT upper bridge arm and the IGBT lower bridge arm are connected in parallel; The first bridge arm capacitor and the second bridge arm capacitor are respectively connected to the other end of the electromagnetic coil, and the first bridge arm capacitor and the second bridge arm capacitor are connected in parallel; Wherein, the IGBT upper bridge arm and the IGBT lower bridge arm respectively receive and execute the on-off drive signal, so as to change the alternating conduction frequency of the IGBT upper bridge arm and the IGBT lower bridge arm, thereby adjusting the output power of the electromagnetic coil; wherein, the alternating conduction frequency of the IGBT upper bridge arm and the IGBT lower bridge arm changes the oscillation frequency of the first bridge arm capacitor and the second bridge arm capacitor, thereby adjusting the resonant frequency of the electromagnetic coil; wherein, the adjustment circuit also includes: a digital signal processor, connected to the drive circuit, for generating a pulse broadband modulation signal according to the received target power; wherein, the adjustment circuit also includes: a current phase detection module, a current peak detection module, an electromagnetic coil current acquisition module and a current sampling resistor, the current phase detection module and the current peak detection module are connected in parallel and between the digital signal processor and the electromagnetic coil current acquisition module, the current sampling resistor and the electromagnetic coil current acquisition module are respectively connected to The second bridge arm capacitor is connected, and the current sampling resistor and the electromagnetic coil current acquisition module are connected in parallel; wherein, the digital signal processor is used to generate the phase difference between the electromagnetic coil input voltage and the electromagnetic coil current according to the signals sent by the current phase detection module, the current peak detection module, the electromagnetic coil current acquisition module and the current sampling resistor, wherein the phase difference is associated with the resonant frequency of the electromagnetic coil; wherein, the digital signal processor obtains the time from the rising edge of the on-off drive signal to the zero crossing of the upper half cycle of the electromagnetic coil working current and the half-cycle time of the current in the resonant state according to the signals sent by the current phase detection module, the current peak detection module, the electromagnetic coil current acquisition module and the current sampling resistor, and the digital signal processor generates the phase difference according to the time from the rising edge of the on-off drive signal to the zero crossing of the upper half cycle of the electromagnetic coil working current and the half-cycle time of the current in the resonant state.

2. The adjustment circuit according to claim 1, wherein: The adjustment circuit further includes: The driving circuit is connected to the IGBT upper bridge arm and the IGBT lower bridge arm respectively, and is used to generate the on-off driving signal according to the received pulse broadband modulation signal and send it to the IGBT upper bridge arm and the IGBT lower bridge arm.

3. A method for adjusting the output power of an electromagnetic coil, characterized in that: The electromagnetic coil has an adjustment circuit for adjusting the output power of the electromagnetic coil, and the adjustment circuit is the adjustment circuit described in claim 1 or 2. The method includes: Receive the target output power of the electromagnetic coil, wherein the IGBT upper bridge arm and the IGBT lower bridge arm are respectively connected to one end of the electromagnetic coil, and the IGBT upper bridge arm and the IGBT lower bridge arm are connected in parallel; the first bridge arm capacitor and the second bridge arm capacitor are respectively connected to the other end of the electromagnetic coil, and the first bridge arm capacitor and the second bridge arm capacitor are connected in parallel; determining an on-off driving signal according to the target output power; The on-off drive signal is sent to the IGBT upper bridge arm and the IGBT lower bridge arm, wherein the IGBT upper bridge arm and the IGBT lower bridge arm execute the on-off drive signal, so as to change the alternating conduction frequency of the IGBT upper bridge arm and the IGBT lower bridge arm, thereby adjusting the output power of the electromagnetic coil; wherein, the change in the alternating conduction frequency of the IGBT upper bridge arm and the IGBT lower bridge arm causes the oscillation frequency of the first bridge arm capacitor and the second bridge arm capacitor to change, thereby adjusting the resonant frequency of the electromagnetic coil.

4. The method according to claim 3, characterized in that Determining an on-off driving signal according to the target output power includes: Calculate the current output power of the electromagnetic coil; The on-off driving signal is determined according to a difference between the target output power and the current output power.

5. The method according to claim 4, characterized in that Calculate the current output power of the electromagnetic coil, including: A half cycle of the resonant state current of the electromagnetic coil is collected, and the current output power is generated according to the half cycle of the resonant state current.

6. The method according to claim 3, characterized in that The alternating conduction frequency of the IGBT upper bridge arm and the IGBT lower bridge arm is inversely proportional to the phase difference, which is the phase difference between the electromagnetic coil input voltage and the electromagnetic coil current.

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