Wireless power supply overvoltage protection circuit based on moment magnetic material and control method thereof

Abstract

The invention belongs to the technical field of wireless power supply, and provides a wireless power supply overvoltage protection circuit based on a moment magnetic material and a control method thereof.The wireless power supply overvoltage protection circuit comprises a primary side circuit, a transformer and a secondary side circuit, and energy transmission is achieved between the primary side circuit and the secondary side circuit through electromagnetic coupling of the transformer; and a moment magnetic inductor made of a moment magnetic material is connected in series in a secondary resonance network in the secondary side circuit.

Description

Technical Field

[0001] The present invention belongs to the technical field of wireless power supply, and in particular relates to a wireless power supply overvoltage protection circuit based on magnetic material and a control method thereof. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] Wireless power technology, particularly those based on electromagnetic induction or magnetic resonance, has been widely used in electronics, electric vehicles, and medical devices. In wireless power systems using common inductor-capacitor-capacitor (LCC) resonant compensation networks, the primary side typically exhibits current source characteristics. This means that if a short circuit occurs on the secondary side (for example, if the receiving device is removed or internally open-circuited) or the load impedance suddenly increases significantly, without effective protection measures, the induced voltage on the secondary side may rise unchecked, far exceeding the rated operating voltage of components in the circuit (such as rectifier diodes, filter capacitors, and the load itself), potentially causing component breakdown and damage, and even posing safety hazards such as equipment burnout and fire.

[0004] Traditional LCC wireless power supply circuits such as Figure 1 As shown in the figure, in order to achieve output voltage / current regulation, a high-frequency switch tube (such as MOSFET) and a corresponding control circuit are usually added after the secondary rectifier circuit. Based on the added high-frequency switch tube, the energy transmitted to the load is controlled by high-frequency switching, thereby indirectly stabilizing the effective value of the output voltage or current; the capacitor Cs1 (i.e. Figure 1 The capacitor connected in series before the secondary rectifier bridge participates in secondary resonance, while the filter capacitor Co after rectification provides energy storage and voltage regulation. During the on and off switching of the switch, Co helps maintain a stable output voltage. Diode Drec is added to prevent reverse charging or provide a freewheeling path.

[0005] However, this protection and regulation solution that relies on active high-frequency switching tubes has the following disadvantages: (1) Reliability issues High-frequency switching transistors and their drive circuits are susceptible to performance degradation, aging, and even failure due to factors such as heat, electrical stress, and mechanical vibration when operating for long periods of time at high frequencies. If a switching transistor or its control circuit fails, the protective function may be lost, and the system will still face the risk of overvoltage.

[0006] (2) Complexity and cost The need for additional switching tubes, drive circuits, and control logic (usually implemented by a microcontroller or dedicated chip) increases the complexity and cost of the circuit.

[0007] (3) Response speed and efficiency Active control requires detection, judgment, and execution, and its response speed may be limited by the bandwidth of the control loop. The switching process itself also causes certain energy losses.

[0008] (4) Safety hazards Switching devices have various failure modes, and partial failure (such as short circuit) may directly lead to more serious safety accidents.

[0009] Therefore, it is of great practical significance and application value to study a wireless power supply circuit with simple structure, high reliability and the ability to passively achieve overvoltage protection. Summary of the Invention

[0010] To solve the above problems, the present invention proposes a wireless power supply overvoltage protection circuit based on moment magnetic materials and a control method thereof. Overvoltage protection is achieved by introducing moment magnetic inductance into the secondary resonant network without the need for additional active control circuits, sensors or fragile switching devices. This fundamentally avoids the loss of protection function due to aging, damage or failure of the switching devices or control logic, and significantly improves the long-term stability and reliability of the protection circuit.

[0011] According to some embodiments, a first solution of the present invention provides a wireless power supply overvoltage protection circuit based on a magnetic material, which adopts the following technical solution: A wireless power supply overvoltage protection circuit based on moment magnetic material includes a primary-side circuit, a transformer, and a secondary-side circuit. Energy is transmitted between the primary-side circuit and the secondary-side circuit via electromagnetic coupling of the transformer. A moment magnetic inductor made of moment magnetic material is connected in series in a secondary resonant network in the secondary-side circuit.

[0012] As a further technical limitation, the primary side circuit includes an AC power supply and a primary resonant network, the primary resonant network includes a primary resonant inductor, a first primary resonant capacitor and a second primary resonant capacitor, the primary resonant inductor and the first primary resonant capacitor are connected in series and then arranged between the AC power supply and the primary coil of the transformer; the first primary resonant capacitor is connected in series with the primary coil of the transformer and then connected in parallel with the second primary resonant capacitor.

[0013] As a further technical limitation, the secondary side circuit also includes a rectifier circuit, a filter circuit and a load; the secondary resonant network also includes a first secondary resonant capacitor and a second secondary resonant capacitor, the first secondary resonant capacitor, the second secondary resonant capacitor and the transformer secondary coil are connected in series to form a loop, the second secondary resonant capacitor is connected in parallel with the moment magnetic inductor, and a rectifier circuit is also arranged in parallel at both ends of the moment magnetic inductor; the rectifier circuit is also connected to the filter circuit, and the filter circuit is connected in parallel with the load.

[0014] Furthermore, the first secondary resonant capacitor is connected in series with the moment magnetic inductor to realize passive overvoltage protection; when the load is normal, the wireless power supply overvoltage protection circuit operates within the normal voltage range, the moment magnetic inductor presents a preset inductance value, and participates in normal resonant energy transmission; when the load is short-circuited or the resistance increases sharply, the secondary induced voltage increases, and the voltage across the moment magnetic inductor increases.

[0015] Furthermore, as the secondary induced voltage increases, the magnetic core of the moment magnetic inductor gradually tends to a deep saturation state. When the saturation point is reached, the relative magnetic permeability of the moment magnetic inductor decreases until it approaches the magnetic permeability of air.

[0016] Furthermore, the primary side circuit of the wireless power supply overvoltage protection circuit realizes a constant current source by maintaining the constant current input into the secondary side circuit. When the inductance value of the moment magnetic inductor drops suddenly, the inductive reactance of the moment magnetic inductor at the operating frequency decreases, so that the equivalent total impedance of the secondary side circuit is reduced, and the voltage across the secondary side circuit drops, forming a clamping mechanism of the secondary side circuit.

[0017] As a further technical limitation, the inductance of the moment magnetic inductor changes nonlinearly with the increase of the voltage across the moment magnetic inductor. The lower the voltage across the moment magnetic inductor, the higher the inductance.

[0018] Furthermore, when the voltage across the moment magnetic inductor rises to the moment magnetic inductor voltage threshold, the magnetic induction intensity of the moment magnetic inductor is saturated, the magnetic permeability decreases, and the inductance value decreases; in extreme cases, the voltage across the moment magnetic inductor increases, causing the magnetic induction intensity of the moment magnetic inductor to be completely saturated, and the inductance value of the moment magnetic inductor tends to the inductance value of the air-core coil.

[0019] As a further technical limitation, when the moment magnetic inductance is in a detuned state, the inductance of the secondary resonant network decreases, the resonant frequency of the secondary resonant network shifts, and the impedance characteristics of the secondary resonant network change, so that the coupling energy between the primary side circuit and the secondary side circuit decreases, thereby suppressing the increase of the secondary side circuit.

[0020] According to some embodiments, a second solution of the present invention provides a control method for a wireless power supply overvoltage protection circuit based on a moment magnetic material, which adopts the following technical solution: A control method for a wireless power supply overvoltage protection circuit based on moment magnetic materials employs the moment magnetic material-based wireless power supply overvoltage protection circuit provided by the first solution. When the load is normal, the wireless power supply overvoltage protection circuit operates within a normal voltage range, the moment magnetic inductor exhibits a preset inductance value, and participates in normal resonant energy transmission. When the load is disconnected or its resistance increases sharply, the secondary induced voltage increases, and the voltage across the moment magnetic inductor also increases. As the secondary induced voltage increases, the magnetic core of the moment magnetic inductor gradually approaches a deep saturation state. When the saturation point is reached, the relative permeability of the moment magnetic inductor decreases until it approaches the permeability of air.

[0021] Compared with the prior art, the present invention has the following beneficial effects: The present invention achieves overvoltage protection by introducing a moment magnetic inductor into the secondary resonant network, without the need for additional active control circuits, sensors or fragile switching devices; it fundamentally avoids the loss of protection function due to aging, damage or failure of the switching device control logic, and significantly improves the long-term stability and reliability of the protection circuit.

[0022] The present invention omits the high-frequency switching tube, complex driving circuit and control unit in the traditional solution, making the secondary circuit structure simpler and reducing the hardware cost and design complexity of the overall system; it effectively limits the generation of excessive voltage in a passive manner, avoiding safety accidents such as damage and burning caused by voltage exceeding the withstand voltage limit of components, and improving the overall safety of the wireless power supply system. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings constituting a part of the specification of this embodiment are used to provide a further understanding of this embodiment. The schematic embodiments and descriptions of this embodiment are used to explain this embodiment and do not constitute an improper limitation on this embodiment.

[0024] Figure 1 Schematic diagram of the topology of a conventional LCC wireless power supply circuit in the background technology of the present invention; Figure 2 Schematic diagram of the topology of a wireless power supply overvoltage protection circuit based on magnetic materials in the first embodiment of the present invention; Figure 3 Schematic diagram of the hysteresis loop of the moment magnetic material in Example 1 of the present invention. DETAILED DESCRIPTION

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0026] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention belongs.

[0027] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0028] In the present invention, terms such as "upper", "lower", "left", "right", "front", "back", "vertical", "horizontal", "side", "bottom", etc. indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. They are relational words determined only for the convenience of describing the structural relationships of the various parts or elements of the present invention, and do not specifically refer to any part or element in the present invention, and should not be understood as limiting the present invention.

[0029] In the present invention, terms such as "fixed connection," "connected," and "connection" should be interpreted broadly to mean a fixed connection, an integral connection, or a detachable connection; a direct connection or an indirect connection through an intermediary. Relevant researchers or technicians in this field may determine the specific meanings of these terms in the present invention based on specific circumstances, and they should not be construed as limitations of the present invention.

[0030] In the absence of conflict, the embodiments of the present invention and the features thereof may be combined with each other.

[0031] Example 1 Embodiment 1 of the present invention introduces a wireless power supply overvoltage protection circuit based on magnetic material.

[0032] To address the problem of unlimited secondary voltage increase in existing wireless power supply circuits (particularly LCC circuits with current source characteristics) when the load is disconnected or the load impedance changes drastically, and to overcome the drawbacks of traditional active high-frequency switches for voltage regulation and overvoltage protection, such as easy switch device wear, low reliability, complex circuits, and potential safety hazards, this embodiment provides a wireless power supply overvoltage protection circuit based on magnetic materials.

[0033] like Figure 1The traditional LCC wireless power supply circuit shown in the figure includes an AC power source AC_Source, a primary resonant inductor Lp1, a primary series resonant capacitor Cp1, a primary parallel resonant capacitor Cp2 (Lp1, Cp1, and Cp2 form the primary LCC resonant network), a transformer (coupled by the primary coil Lp and the secondary coil Ls), a secondary series resonant capacitor Cs1, a bridge rectifier BR1, a filter inductor Lf (may be omitted in some solutions), a high-frequency switch SW (such as a MOSFET), a freewheeling diode Drec (typically the body diode of the MOSFET or an additional parallel Schottky diode), an output filter capacitor Co, and a load RL. When the load RL is disconnected or its resistance is significantly greater than normal, the secondary-side voltage rises sharply. In this case, a control circuit (not shown) controls the on-duty cycle or switching frequency of the switch SW to limit the average power output to the load, thereby indirectly controlling the output voltage. However, as described in the background, this active control method relies on the reliability of the switch SW and its control system.

[0034] like Figure 2 The wireless power supply overvoltage protection circuit shown in the figure, based on moment magnetic materials, includes a primary-side circuit, a transformer, and a secondary-side circuit. Energy transmission is achieved between the primary-side circuit and the secondary-side circuit through electromagnetic coupling of the transformer. Specifically: The primary-side circuit includes an AC power supply AC_Source and a primary resonant network. The primary resonant network includes a primary resonant inductor Lp1, a first primary resonant capacitor Cp1, and a second primary resonant capacitor Cp2. The primary resonant inductor Lp1 and the first primary resonant capacitor Cp1 are connected in series and arranged between the AC power supply AC_Source and the primary coil Lp of the transformer. The first primary resonant capacitor Cp1 is connected in series with the primary coil Lp of the transformer and then connected in parallel with the second primary resonant capacitor Cp2.

[0035] The secondary side circuit includes a secondary resonant network, a rectifier circuit, a filter circuit Co and a load RL; the secondary resonant network includes a first secondary resonant capacitor Cs1, a second secondary resonant capacitor Cs2 and a torque inductor Lvar. The first secondary resonant capacitor Cs1, the second secondary resonant capacitor Cs2 and the transformer secondary coil Ls are connected in series to form a loop, the second secondary resonant capacitor Cs2 is connected in parallel with the torque inductor Lvar, and a rectifier circuit BR1 is also provided in parallel at both ends of the torque inductor Lvar; the rectifier circuit BR1 is also connected to the filter circuit Co, and the filter circuit Co is connected in parallel with the RL load.

[0036] Compared to traditional wireless power supply circuits, the secondary circuit in this embodiment is significantly simplified, eliminating the high-frequency switch SW, its drive circuit, and any dedicated filter inductor Lf and independent freewheeling diode required in traditional solutions. Protection is primarily provided by the magnetic inductor Lvar, connected in series with the secondary resonant network.

[0037] The magnetic core of the moment magnetic inductor Lvar in this embodiment is made of moment magnetic material with steep saturation characteristics (such as Permalloy, ferrite moment magnetic material, amorphous or nanocrystalline soft magnetic alloy, etc.), and its hysteresis loop is as follows: Figure 2 As shown, the moment magnetic material has special magnetization characteristics, and the inductance value L will show a nonlinear change as the voltage U across its two ends increases.

[0038] When the voltage across (or current flowing through) a moment magnetic inductor is low, it exhibits a high inductance value. When the voltage (or current) rises to a certain level, approaching or reaching the saturation magnetic induction intensity of the moment magnetic material, its magnetic permeability drops sharply, resulting in a significant decrease in inductance value. In extreme cases, when the voltage is very high, the moment magnetic material is completely saturated, and the inductance of the inductor element approaches that of an air-core coil. Its impedance characteristics are closer to those of a low-inductance inductor, and it may even exhibit certain resistance characteristics (due to the winding resistance and the loss of the saturated magnetic core).

[0039] By integrating this torque-magnetic inductor in series within the secondary resonant network (for example, after the secondary coupling coil and before the rectifier bridge, in conjunction with the secondary resonant capacitor), passive overvoltage protection is achieved by leveraging its aforementioned characteristics. When the load is operating normally and the circuit is within the normal voltage range, the torque-magnetic inductor maintains its preset inductance value and participates in normal resonant energy transfer. However, when the load becomes disconnected or its resistance increases dramatically, the secondary induced voltage tends to rise. When this rise occurs, the current flowing through the torque-magnetic inductor, or the voltage across it, increases accordingly.

[0040] When the voltage (or magnetic flux density) on the primary side of a transformer increases and reaches a certain value, the core of the moment-magnetic material will tend to saturate. Once the core saturates, the inductance of the moment-magnetic inductor drops sharply, and its behavior becomes similar to that of an air-core inductor. This sharp drop in inductance results in a significant decrease in its inductive reactance (XL = 2πfL). Because LCC (series resonant compensation) circuits typically exhibit current source characteristics, their design goal is to maintain a relatively constant output current over a wide load range. When the moment-magnetic inductor saturates, causing its inductive reactance to drop sharply, it significantly changes the impedance characteristics of the secondary equivalent circuit. Driven by a constant output current, the equivalent impedance of the secondary side decreases, causing the secondary voltage to drop sharply, thereby clamping the voltage to a safe low value and avoiding the risk of overvoltage.

[0041] The working principle of the moment magnetic inductor in this embodiment is: (1) Normal working state When the load RL is within the normal operating range, the voltage and current in the secondary circuit are within the design's acceptable range. At this point, the voltage across (or current flowing through) the momentary magnetic inductor Lvar causes the core to operate in an unsaturated or shallowly saturated region, resulting in a relatively stable and high inductance. This inductance, along with the leakage inductance (or total inductance) of the secondary coil Ls and the secondary resonant capacitor Cs1, determines the secondary resonant frequency, enabling the system to efficiently transmit energy at the set operating frequency.

[0042] (2) Overvoltage occurrence and protection status When the load RL experiences an open circuit (infinite impedance) or a sudden increase in impedance, the open-circuit voltage on the secondary side rises rapidly due to the continuous energy input on the primary side and the current source characteristics of the LCC network. This causes the current flowing through the moment-magnetic inductor Lvar, or the voltage across it, to also increase sharply. As the voltage / current increases, the magnetic core of the moment-magnetic inductor var gradually becomes deeply saturated. Once it reaches or exceeds its saturation point, the relative permeability μr of the moment-magnetic material drops sharply to near 1 (the permeability of air). Consequently, the effective inductance Lvar of the moment-magnetic inductor Lvar decreases significantly, approaching its air-core inductance value. This dramatic reduction in inductance Lvar produces the following protective effects: (3) Detuned state The total inductance of the secondary resonant network decreases, causing the secondary resonant frequency to shift, typically increasing. If the system operates at a fixed frequency fop, a shift in the secondary resonant frequency f_s will cause the system to detune, changing the impedance characteristics of the secondary loop and significantly reducing the energy coupling efficiency from the primary to the secondary, effectively limiting further increases in the secondary voltage.

[0043] When the core of the moment-magnetic inductor L_var reaches saturation, its inductance drops dramatically, resulting in a significant reduction in its inductance at the operating frequency. This sharp decrease in inductive reactance significantly changes the total impedance of the transformer's secondary-side equivalent circuit. Because the LCC resonant converter exhibits current source characteristics during normal operation, it maintains a relatively constant output current within a certain range. When the moment-magnetic inductor saturates, causing the secondary-side equivalent impedance to drop significantly, Ohm's law causes the secondary voltage to drop sharply, creating a core mechanism for limiting excessive secondary voltage through the saturation effect. When the secondary voltage rises abnormally, the moment-magnetic inductor Lvar passively and automatically changes the characteristics of the secondary resonant network, limiting excessive energy transfer from the primary to the secondary, thereby clamping the secondary voltage to a relatively safe level and protecting the rectifier bridge BR1, filter capacitor Co, and any connected load RL from overvoltage damage.

[0044] This embodiment achieves overvoltage protection by introducing a torque magnetic inductor into the secondary resonant network, without the need for additional active control circuits, sensors, or fragile switching devices; it fundamentally avoids the loss of protection function due to aging, damage, or failure of the control logic of the switching device, significantly improving the long-term stability and reliability of the protection circuit; it omits the high-frequency switching tube, complex drive circuit, and control unit in the traditional solution, making the secondary circuit structure simpler and reducing the hardware cost and design complexity of the overall system; it effectively limits the generation of excessive voltage in a passive manner, avoiding safety accidents such as damage and burning caused by voltage exceeding the withstand voltage limit of components, thereby improving the overall safety of the wireless power supply system.

[0045] Example 2 A second embodiment of the present invention introduces a control method for a wireless power supply overvoltage protection circuit based on magnetic materials.

[0046] A control method for a wireless power supply overvoltage protection circuit based on a moment magnetic material is disclosed. The method utilizes the moment magnetic material-based wireless power supply overvoltage protection circuit described in Example 1. When the load is normal, the wireless power supply overvoltage protection circuit operates within a normal voltage range, the moment magnetic inductor exhibits a preset inductance value, and participates in normal resonant energy transmission. When the load is disconnected or its resistance increases sharply, the secondary induced voltage increases, and the voltage across the moment magnetic inductor increases. As the secondary induced voltage increases, the magnetic core of the moment magnetic inductor gradually approaches a deep saturation state. When the saturation point is reached, the relative permeability of the moment magnetic inductor decreases until it approaches the permeability of air.

[0047] The detailed steps are the same as those of the wireless power supply overvoltage protection circuit based on magnetic material provided in Example 1, and are not repeated here.

[0048] The above description is merely a preferred embodiment of this embodiment and is not intended to limit this embodiment. Those skilled in the art will readily appreciate that this embodiment may be modified and varied in various ways. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this embodiment shall be within the scope of protection of this embodiment.

Claims

1. A wireless power supply overvoltage protection circuit based on moment magnetic material, characterized in that: The invention comprises a primary side circuit, a transformer and a secondary side circuit, wherein energy is transmitted between the primary side circuit and the secondary side circuit via electromagnetic coupling of the transformer; a moment magnetic inductor made of moment magnetic material is connected in series in the secondary resonant network of the secondary side circuit.

2. A wireless power supply overvoltage protection circuit based on moment magnetic material as claimed in claim 1, characterized in that: The primary-side circuit includes an AC power supply and a primary resonant network. The primary resonant network includes a primary resonant inductor, a first primary resonant capacitor, and a second primary resonant capacitor. The primary resonant inductor and the first primary resonant capacitor are connected in series and are arranged between the AC power supply and the primary coil of the transformer. The first primary resonant capacitor is connected in series with the primary coil of the transformer and then connected in parallel with the second primary resonant capacitor.

3. The wireless power supply overvoltage protection circuit based on moment magnetic material as claimed in claim 1, characterized in that: The secondary side circuit also includes a rectifier circuit, a filter circuit and a load; the secondary resonant network also includes a first secondary resonant capacitor and a second secondary resonant capacitor, the first secondary resonant capacitor, the second secondary resonant capacitor and the secondary coil of the transformer are connected in series to form a loop, the second secondary resonant capacitor is connected in parallel with the moment magnetic inductor, and a rectifier circuit is also arranged in parallel at both ends of the moment magnetic inductor; the rectifier circuit is also connected to the filter circuit, and the filter circuit is connected in parallel with the load.

4. A wireless power supply overvoltage protection circuit based on moment magnetic material as claimed in claim 3, characterized in that: The first secondary resonant capacitor is connected in series with the moment magnetic inductor to realize passive overvoltage protection; when the load is normal, the wireless power supply overvoltage protection circuit operates within the normal voltage range, the moment magnetic inductor presents a preset inductance value, and participates in normal resonant energy transmission; when the load is short-circuited or the resistance increases sharply, the secondary induced voltage increases, and the voltage across the moment magnetic inductor increases.

5. A wireless power supply overvoltage protection circuit based on moment magnetic material as claimed in claim 4, characterized in that: As the secondary induced voltage increases, the magnetic core of the moment magnetic inductor gradually tends to a deep saturation state. When the saturation point is reached, the relative magnetic permeability of the moment magnetic inductor decreases until it approaches the magnetic permeability of air.

6. A wireless power supply overvoltage protection circuit based on moment magnetic material as claimed in claim 4, characterized in that: The primary side circuit of the wireless power supply overvoltage protection circuit realizes a constant current source by maintaining a constant current input into the secondary side circuit. When the inductance value of the moment magnetic inductor drops suddenly, the inductive reactance of the moment magnetic inductor at the operating frequency decreases, so that the equivalent total impedance of the secondary side circuit is reduced, and the voltage across the secondary side circuit drops, forming a clamping mechanism for the secondary side circuit.

7. The wireless power supply overvoltage protection circuit based on moment magnetic material as claimed in claim 1, characterized in that: The inductance of the moment magnetic inductor changes nonlinearly with the increase of the voltage across the moment magnetic inductor. The lower the voltage across the moment magnetic inductor, the higher the inductance.

8. The wireless power supply overvoltage protection circuit based on moment magnetic material as claimed in claim 7, characterized in that: When the voltage across the moment magnetic inductor rises to the moment magnetic inductor voltage threshold, the magnetic induction intensity of the moment magnetic inductor is saturated, the magnetic permeability decreases, and the inductance value decreases; in extreme cases, the voltage across the moment magnetic inductor increases, causing the magnetic induction intensity of the moment magnetic inductor to be completely saturated, and the inductance value of the moment magnetic inductor tends to the inductance value of the air-core coil.

9. The wireless power supply overvoltage protection circuit based on moment magnetic material as claimed in claim 1, characterized in that: When the moment magnetic inductance is in a detuned state, the inductance of the secondary resonant network decreases, the resonant frequency of the secondary resonant network shifts, and the impedance characteristics of the secondary resonant network change, so that the coupling energy between the primary side circuit and the secondary side circuit decreases, thereby suppressing the increase of the secondary side circuit.

10. A control method for a wireless power supply overvoltage protection circuit based on a moment magnetic material, using the wireless power supply overvoltage protection circuit based on a moment magnetic material according to any one of claims 1 to 9, characterized in that: When the load is normal, the wireless power supply overvoltage protection circuit operates within the normal voltage range, the moment magnetic inductor presents a preset inductance value, and participates in normal resonant energy transmission; when the load is disconnected or the resistance increases sharply, the secondary induced voltage increases, and the voltage across the moment magnetic inductor increases; as the secondary induced voltage increases, the magnetic core of the moment magnetic inductor gradually tends to a deep saturation state. When the saturation point is reached, the relative magnetic permeability of the moment magnetic inductor decreases until it approaches the magnetic permeability of air.

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