A frequency tracking control method and system for wireless power transmission system based on fuzzy PI control

Abstract

The present invention provides a frequency tracking control method and system for a wireless power transmission system based on fuzzy PI control. The method of the present invention includes: a current detection circuit detects a current signal at a transmitting end, and sends the current signal at the transmitting end to a frequency tracking controller at the transmitting end; a control circuit obtains a phase difference signal between a voltage signal and a current signal through a multiplication phase detector and a filter circuit according to the detected current frequency; the phase difference signal outputs a frequency signal with the same frequency as the sampled current signal through fuzzy PI control; a pulse signal is generated according to the frequency signal to control the conduction of the MOS tube of the inverter to control the voltage frequency to be the same as the current frequency to reach a resonant state. The present invention mainly uses current detection to analyze the position of the receiving end, and uses frequency tracking control based on fuzzy PI control to control the voltage frequency of the transmitting end, so that the system enters a resonant state and improves transmission efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of wireless power transmission, and in particular to a frequency tracking control method and system for a wireless power transmission system based on fuzzy PI control. Background Art

[0002] At present, in magnetic coupling resonant wireless power transmission systems, automatic tuning technology is a method. The key is to ensure that the system always works in a resonant state by automatically adjusting relevant parameters when system parameters change. Changing the size of inductance and capacitance to make the system reach a resonant state is an important means of tuning, but the adjustment of inductance and capacitance is a passive process. Only by adding some control means to achieve active control can the continuity of tuning be guaranteed.

[0003] The phase-controlled inductor tuning system controls the current flowing through the inductor by changing the conduction angle by controlling the on-off time of the bidirectional controllable switch tube, thereby achieving continuous regulation. Because the switch tube connected to the circuit will affect the maximum power that the system can withstand, this tuning method can only be applied to WPT systems with lower power.

[0004] The tuning strategy based on the compensation capacitor matrix is ​​to use the compensation capacitor matrix method to return the detuned system to a resonant state. The compensation capacitor is used to eliminate the inductive impedance caused by the self-inductance effect of the coupling coil. When the number of capacitor matrices is sufficient, the control requirements can be fully met, but a large number of capacitor structures will make the system too large and the number of connected switch tubes will be greater. Since strong electromagnetic interference will be generated during wireless power transmission, the switch tube may be mis-conducted, which is prone to danger. Summary of the invention

[0005] According to the technical problems raised above, a frequency tracking control method and system of a wireless power transmission system based on fuzzy PI control is provided. The present invention mainly uses current detection to analyze the position of the receiving end, and uses frequency tracking control based on fuzzy PI control to control the voltage frequency of the transmitting end, so that the system enters a resonant state to improve the transmission efficiency.

[0006] The technical means adopted by the present invention are as follows:

[0007] A frequency tracking control method for a wireless power transmission system based on fuzzy PI control comprises the following steps:

[0008] S1, the current detection circuit detects the current signal of the transmitting end, and sends the current signal of the transmitting end to the transmitting end frequency tracking controller;

[0009] S2, the control circuit obtains the phase difference signal between the voltage signal and the current signal through the multiplication phase detector and the filter circuit according to the detected current frequency;

[0010] S3, the phase difference signal outputs a frequency signal with the same frequency as the sampled current signal through fuzzy PI control;

[0011] S4. Generate a pulse signal according to the frequency signal to control the conduction of the MOSFET of the inverter to control the voltage frequency to be the same as the current frequency to achieve a resonant state.

[0012] Furthermore, the multiplication phase detector in step S2 is a circuit for performing phase comparison, and is used to reflect the phase difference θ(t) between the input signal phase θ1(t) and the feedback signal θ2(t).

[0013] Furthermore, the specific implementation process of step S2 is as follows:

[0014] S21, let the coefficient of the multiplier be K m , calculate the input signal U i (t), the calculation formula is as follows:

[0015] U i (t) = U i sin[ω0+θ1(t)]

[0016] In the above formula, ω0 is the natural frequency of the voltage-controlled oscillator, and θ1(t) is the instantaneous phase of the input signal;

[0017] S22, calculate feedback output signal U 0(t) , the calculation formula is as follows:

[0018] U0(t)=U0sin[ω0+θ2(t)]

[0019] In the above formula, θ2(t) is the instantaneous phase of the output signal;

[0020] S23, multiply the two calculation formulas in step S21 and step S22, and then filter out the high-frequency components to obtain the output voltage U d (t) is:

[0021] U d (t)=0.5K m U0U i cos[θ1(t)-θ2(t)]=0.5K m U0U i cosθ(t)

[0022] U d (t)≈V d θ(t)

[0023] V d =0.5K m U0U i

[0024] In the above formula, U0 is the feedback output signal amplitude, U i is the input signal amplitude, V d is the output voltage amplitude.

[0025] Furthermore, in step S3, fuzzy control is used to optimize the PI control, and the parameter K of the PI control is adjusted during the frequency tracking process. P and K i Adjustments are made to improve the performance of frequency tracking control systems.

[0026] Furthermore, the specific implementation process of step S3 is as follows:

[0027] S31, select the input variable of the fuzzy controller; select the impedance angle between the transmitting end current output by the multiplication phase detector and the voltage controlled oscillator feedback voltage signal as input variable E; select impedance angle change rate as another input variable EC;

[0028] S32, select the output variable of the fuzzy controller; select the adjustment amount ΔK of the proportional regulation and integral regulation of the PI controller P , ΔK i As output variable; then:

[0029]

[0030] In the above formula, K P (n+1), K i (n+1) are the parameter values ​​of the next signal respectively.

[0031] S33, set the basic domain of the input variable E of the fuzzy controller to [-10, 10], the domain of the language variable is represented by X, and it is quantized into 9 levels, namely:

[0032] X={-10,-7.5,-5,-2.5,0,2.5,5,7.5,10}

[0033] S34. The language variable domain of another input variable EC is represented by Y, and it is also quantized into 9 levels, namely:

[0034] Y={-10,-7.5,-5,-2.5,0,2.5,5,7.5,10}

[0035] S35, output variable ΔK P and ΔK i The language variable domains are represented by A and B respectively, and the 9 levels of quantization are:

[0036] A={-10,-7.5,-5,-2.5,0,2.5,5,7.5,10}

[0037] B={-20,-15,-10,-5,0,5,10,15,20}

[0038] S36. Select five language values ​​of “too negative”, “negative”, “zero”, “positive”, and “too positive”, and express the fuzzy subsets of the two input language variables as follows:

[0039]

[0040] S37. The fuzzy subsets of the two output linguistic variables are expressed as:

[0041]

[0042] S38, using a triangular membership function to process the input language variable and the output language variable to obtain a membership function image;

[0043] S39, after the membership function is determined, a control rule is set for the membership function, that is, the output language variable ΔK is obtained according to different output language variables corresponding to different input language variables. P , ΔK i Control rules table.

[0044] The present invention also provides a magnetically coupled resonant wireless power transmission system based on the above-mentioned frequency tracking control method of the wireless power transmission system based on fuzzy PI control, comprising: a frequency tracking control module based on fuzzy PI control, a DC power supply, an inverter, a compensation capacitor, a transmitting coil, a receiving coil, a rectifier bridge and a load; wherein: the DC power supply, the inverter and the compensation capacitor are connected in series, the input end of the current detection circuit is connected to the transmitting end loop, and the output end of the current detection circuit is connected to the input end of the control circuit.

[0045] Furthermore, the frequency tracking control module based on fuzzy PI control includes a multiplication phase detector, a filter, a fuzzy PI control module and a pulse generator; wherein the multiplication phase detector multiplies the collected current signal and the feedback voltage signal, filters out the impedance angle signal by using a filter, and then outputs the corresponding frequency signal through the fuzzy PI control module, and then generates a pulse signal of the same frequency through the pulse generator to control the conduction of the inverter's MOS tube, so that the voltage frequency is equal to the current frequency and reaches a resonant state.

[0046] Compared with the prior art, the present invention has the following advantages:

[0047] 1. The frequency tracking control method and system of the wireless power transmission system based on fuzzy PI control provided by the present invention mainly utilize current detection to analyze the position of the receiving end, and utilize frequency tracking control based on fuzzy PI control to control the voltage frequency of the transmitting end, so that the system enters a resonant state to improve the transmission efficiency.

[0048] 2. The frequency tracking control device based on fuzzy PI control does not require a large number of external devices, nor will it be affected by power or electromagnetic interference. It can greatly save costs and ensure the safety of the system, and also keep the system's transmission efficiency at the highest level.

[0049] Based on the above reasons, the present invention can be widely promoted in the fields of wireless power transmission and the like. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0051] Figure 1 The figure is a flow chart of the method of the present invention.

[0052] Figure 2 A schematic diagram of a multiplication phase detector provided in an embodiment of the present invention.

[0053] Figure 3 A block diagram of a fuzzy control system provided by an embodiment of the present invention.

[0054] Figure 4 The fuzzy control variable membership function image provided by the embodiment of the present invention.

[0055] Figure 5 A schematic diagram of a system control circuit provided in an embodiment of the present invention.

[0056] Figure 6 A system simulation circuit diagram provided for an embodiment of the present invention.

[0057] Figure 7 This is a waveform diagram of the multiplier output provided by an embodiment of the present invention.

[0058] Figure 8 This is a waveform diagram of the impedance angle output by the filter provided in an embodiment of the present invention.

[0059] Fig. 9 This is a waveform diagram of the output frequency signal of the fuzzy PI controller provided in an embodiment of the present invention.

[0060] Fig.10This is a pulse generator output waveform diagram provided in an embodiment of the present invention.

[0061] Fig.11 The voltage and current signal waveform of the transmitting end provided by the embodiment of the present invention DETAILED DESCRIPTION

[0062] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0063] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0064] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0065] Unless otherwise specifically stated, the relative arrangement of the parts and steps described in these embodiments, the numerical expressions and numerical values ​​do not limit the scope of the present invention. At the same time, it should be clear that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be regarded as part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0066] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention: the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0067] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below their position devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0068] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0069] like Figure 1 As shown, the present invention provides a frequency tracking control method for a wireless power transmission system based on fuzzy PI control, comprising the following steps:

[0070] S1, the current detection circuit detects the current signal of the transmitting end, and sends the current signal of the transmitting end to the transmitting end frequency tracking controller;

[0071] S2, the control circuit obtains the phase difference signal between the voltage signal and the current signal through the multiplication phase detector and the filter circuit according to the detected current frequency;

[0072] S3, the phase difference signal outputs a frequency signal with the same frequency as the sampled current signal through fuzzy PI control;

[0073] S4. Generate a pulse signal according to the frequency signal to control the conduction of the MOSFET of the inverter to control the voltage frequency to be the same as the current frequency to achieve a resonant state.

[0074] In specific implementation, as a preferred embodiment of the present invention, the multiplication phase detector in step S2 is a circuit for phase comparison, which is used to reflect the phase difference θ(t) between the input signal phase θ1(t) and the feedback signal θ2(t). Its principle diagram is as follows Figure 2 shown. Figure 2 (a) is the PD and LPF circuit model, (b) is the output voltage U d (t) characteristic curve; the specific implementation process of step S2 is as follows:

[0075] S21, let the coefficient of the multiplier be K m , calculate the input signal U i (t), the calculation formula is as follows:

[0076] U i (t) = U i sin[ω0+θ1(t)]

[0077] In the above formula, ω0 is the natural frequency of the voltage-controlled oscillator, and θ1(t) is the instantaneous phase of the input signal;

[0078] S22, calculate the feedback output signal U0(t), the calculation formula is as follows:

[0079] U0(t)=U0sin[ω0+θ2(t)]

[0080] In the above formula, θ2(t) is the instantaneous phase of the output signal;

[0081] S23, multiply the two calculation formulas in step S21 and step S22, and then filter out the high-frequency components to obtain the output voltage U d (t) is:

[0082] U d (t)=0.5K m U0U i cos[θ1(t)-θ2(t)]=0.5K m U0U i cosθ(t)

[0083] U d (t)≈V d θ(t)

[0084] V d =0.5K m U0U i

[0085] In the above formula, U0 is the feedback output signal amplitude, U i is the input signal amplitude, V d is the output voltage amplitude.

[0086] In the specific implementation, as a preferred embodiment of the present invention, in step S3, fuzzy control is used to optimize the PI control, and the parameter K of the PI control is adjusted during the frequency tracking process. P and K i Adjustments are made to improve the performance of the frequency tracking control system. The control process is as follows: Figure 3 The specific implementation process of step S3 is as follows:

[0087] S31, select the input variable of the fuzzy controller; select the impedance angle between the transmitting end current output by the multiplication phase detector and the voltage controlled oscillator feedback voltage signal as input variable E; select impedance angle change rate as another input variable EC;

[0088] S32, select the output variable of the fuzzy controller; select the adjustment amount ΔK of the proportional regulation and integral regulation of the PI controller P , ΔK i As output variable; then:

[0089]

[0090] In the above formula, K P (n+1), K i (n+1) are the parameter values ​​of the next signal respectively.

[0091] S33, set the basic domain of the input variable E of the fuzzy controller to [-10, 10], the domain of the language variable is represented by X, and it is quantized into 9 levels, namely:

[0092] X={-10,-7.5,-5,-2.5,0,2.5,5,7.5,10}

[0093] S34. The language variable domain of another input variable EC is represented by Y, and it is also quantized into 9 levels, namely:

[0094] Y={-10,-7.5,-5,-2.5,0,2.5,5,7.5,10}

[0095] S35, output variable ΔK P and ΔK i The language variable domains are represented by A and B respectively, and the 9 levels of quantization are:

[0096] A={-10,-7.5,-5,-2.5,0,2.5,5,7.5,10}

[0097] B={-20,-15,-10,-5,0,5,10,15,20}

[0098] S36. For better control, the number of elements in the language variable domain should be twice the number of language value elements in the language variable fuzzy subset. Select five language values: "overly negative", "negative", "zero", "positive", and "overly positive", and express the fuzzy subsets of the two input language variables as:

[0099]

[0100] S37. The fuzzy subsets of the two output linguistic variables are expressed as:

[0101]

[0102] S38, using the triangular membership function, processing the input language variables and the output language variables to obtain a membership function image, such as Figure 4 As shown, Figure 4 In the figure, (a) is the membership function image of the input language variable E; (b) is the membership function image of the input language variable EC; (c) is the output language variable ΔK P Membership function graph; (d) is the output language variable ΔK i Membership function graph.

[0103] S39, after the membership function is determined, a control rule is set for the membership function, that is, the output language variable ΔK is obtained according to different output language variables corresponding to different input language variables. P , ΔK i The control rule table is shown in Table 1 and Table 2 below.

[0104] Table 1 Output language variables ΔK P Control rules table

[0105]

[0106] Table 2 Output language variables ΔK i Control rules table

[0107]

[0108] The present invention also provides a magnetically coupled resonant wireless power transmission system based on the above-mentioned frequency tracking control method of the wireless power transmission system based on fuzzy PI control, comprising: a frequency tracking control module based on fuzzy PI control, a DC power supply, an inverter, a compensation capacitor, a transmitting coil, a receiving coil, a rectifier bridge and a load; wherein: the DC power supply, the inverter and the compensation capacitor are connected in series, the input end of the current detection circuit is connected to the transmitting end loop, and the output end of the current detection circuit is connected to the input end of the control circuit.

[0109] The frequency tracking control module based on fuzzy PI control includes a multiplication phase detector, a filter, a fuzzy PI control module and a pulse generator; wherein, Figure 5 As shown, the multiplication phase detector multiplies the collected current signal and the feedback voltage signal, and then uses a filter to filter out the impedance angle signal, and then outputs the corresponding frequency signal through the fuzzy PI control module. After that, the pulse generator generates a pulse signal of the same frequency to control the conduction of the inverter's MOS tube, so that the voltage frequency is equal to the current frequency and reaches a resonant state.

[0110] In order to verify the effectiveness of the method of the present invention, a simulation experiment was also carried out. The system simulation circuit diagram is shown in FIG. Figure 6 As shown in the figure, after the simulation starts, the current sampling at the transmitting end enters the multiplier and is multiplied by the voltage signal fed back. The resulting waveform image is as follows: Figure 7 As shown, the output waveform is filtered by the filter to obtain the impedance angle signal, such as Figure 8 As shown, the impedance angle signal is converted into a corresponding frequency signal through a fuzzy PI controller and input into the pulse generator. The image of the signal is shown in Fig. 9 As shown in the figure, the pulse generator outputs various signal waveforms at this frequency after calculation. The sawtooth wave output value is compared with 0.5 by the comparator to output the pulse signal as shown in the figure. Fig.10 As shown, it is used to control the switch of the inverter MOS tube, and then control the frequency of the transmitter voltage. When the signal output by the filter is equal to 0, the phase difference between the transmitter voltage frequency and the current controlled by the inverter is 0. At this time, the frequency tracking system controlled by the fuzzy PI completes the frequency tracking task, as shown in Fig.11 The simulation results show that the frequency tracking control method of the wireless power transmission system based on fuzzy PI control provided by the present invention uses current detection to analyze the position of the receiving end, and uses the frequency tracking control based on fuzzy PI control to control the voltage frequency of the transmitting end, so that the simulation system enters a resonant state, thereby improving the transmission efficiency.

[0111] 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 aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned 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 frequency tracking control method for a wireless power transmission system based on fuzzy PI control, characterized in that: The steps include: S1, the current detection circuit detects the current signal of the transmitting end, and sends the current signal of the transmitting end to the transmitting end frequency tracking controller; S2, the control circuit obtains the phase difference signal between the voltage signal and the current signal through the multiplication phase detector and the filter circuit according to the detected current frequency; The specific implementation process of step S2 is as follows: S21, let the coefficient of the multiplier be K m , calculate the input signal U i (t), the calculation formula is as follows: U i (t)=U i sin[ω0+θ1(t)] In the above formula, ω0 is the natural frequency of the voltage-controlled oscillator, and θ1(t) is the instantaneous phase of the input signal; S22, calculate the feedback output signal U0(t), the calculation formula is as follows: U0(t)=U0sin[ω0+θ2(t)] In the above formula, θ2(t) is the instantaneous phase of the output signal; S23, multiply the two calculation formulas in step S21 and step S22, and then filter out the high-frequency components to obtain the output voltage U d (t) is: U d (t)=0.5K m U0U i cos[θ1(t)-θ2(t]=0.5K m U0U i cosθ(t) U d (t)≈V d θ(t) V d =0.5K m U0U i In the above formula, U0 is the feedback output signal amplitude, U i is the input signal amplitude, V d is the output voltage amplitude; S3, the phase difference signal outputs a frequency signal with the same frequency as the sampling current signal through fuzzy PI control; The specific implementation process of step S3 is as follows: S31, select the input variable of the fuzzy controller; select the impedance angle between the transmitting end current output by the multiplication phase detector and the voltage controlled oscillator feedback voltage signal as input variable E; select impedance angle change rate as another input variable EC; S32, select the output variable of the fuzzy controller; select the adjustment amount ΔK of the proportional regulation and integral regulation of the PI controller P , ΔK i As output variable; then: In the above formula, K P (n+1), K i (n+1) are the parameter values ​​of the next signal respectively; S33. Set the basic domain of the input variable E of the fuzzy controller to [-10,10], the domain of the language variable is represented by X, and quantize it into 9 levels, namely: X＝[-10，-7.5，-5，-2.5，0，2.5，5，7.5，10} S34. The language variable domain of another input variable EC is represented by Y, and it is also quantized into 9 levels, namely: Y＝[-10，-7.5，-5，-2.5，0，2.5，5，7.5，10} S35, output variable ΔK P and ΔK i The language variable domains are represented by A and B respectively, and the 9 levels of quantization are: A＝{-10,-7.5,-5,-2.5,0,2.5,5,7.5,10} B＝{-20,-15,-10,-5,0,5,10,15,20} S36. Select five language values ​​of "too negative", "negative", "zero", "positive", and "too positive", and express the fuzzy subsets of the two input language variables as follows: S37. The fuzzy subsets of the two output linguistic variables are expressed as: S38, using a triangular membership function to process the input language variable and the output language variable to obtain a membership function image; S39, after the membership function is determined, a control rule is set for the membership function, that is, the output language variable ΔK is obtained according to different output language variables corresponding to different input language variables. P , ΔK i The control rule table; S4. Generate a pulse signal according to the frequency signal to control the conduction of the MOSFET of the inverter to control the voltage frequency to be the same as the current frequency to achieve a resonant state.

2. The frequency tracking control method of wireless power transmission system based on fuzzy PI control according to claim 1 is characterized in that: The multiplication phase detector in step S2 is a circuit for performing phase comparison, and is used to reflect the phase difference θ(t) between the input signal phase θ1(t) and the feedback signal θ2(t).

3. The frequency tracking control method of wireless power transmission system based on fuzzy PI control according to claim 1 is characterized in that: In step S3, fuzzy control is used to optimize the PI control, and the parameter K of the PI control is adjusted during the frequency tracking process. P and K i Adjustments are made to improve the performance of frequency tracking control systems.

4. A magnetically coupled resonant wireless power transmission system based on the frequency tracking control method of a wireless power transmission system based on fuzzy PI control as described in any one of claims 1 to 3, characterized in that: include: A frequency tracking control module, a DC power supply, an inverter, a compensation capacitor, a transmitting coil, a receiving coil, a rectifier bridge and a load based on fuzzy PI control; wherein: the DC power supply, the inverter and the compensation capacitor are connected in series, the input end of the current detection circuit is connected to the transmitting end loop, and the output end of the current detection circuit is connected to the input end of the control circuit.

5. The magnetically coupled resonant wireless power transmission system according to claim 4, characterized in that: The frequency tracking control module based on fuzzy PI control includes a multiplication phase detector, a filter, a fuzzy PI control module and a pulse generator; wherein the multiplication phase detector performs multiplication operation on the collected current signal and the feedback voltage signal, and then uses the filter to filter out the impedance angle signal, and then outputs the corresponding frequency signal through the fuzzy PI control module, and then generates a pulse signal of the same frequency through the pulse generator to control the conduction of the MOS tube of the inverter, so that the voltage frequency is equal to the current frequency and reaches a resonant state.

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