Capacitive wireless transmission power control system and method based on fuzzy control

Abstract

The invention relates to a capacitive wireless power transmission power control system based on fuzzy control. The capacitive wireless power transmission power control system comprises a transmitting end, a transmitting end capacitive coupling plate, a receiving end capacitive coupling plate, a receiving end, an output load circuit, a current detection circuit, a voltage detection circuit, a direct current bias circuit and a fuzzy controller, the invention further comprises a control method of the capacitive wireless transmission power control system based on fuzzy control. The invention has the beneficial effects that the requirement on the precision of a high-frequency element is reduced, the system is ensured to always work under the condition of efficient zero voltage switching (ZVS), the switching loss is obviously reduced, and the energy transmission efficiency is improved; the self-adaptive adjustment of a nonlinear and strong-coupling system is realized; alternating-current noise interference can be avoided, and the design of a detection circuit is further simplified; the system is suitable for miniaturization and low-cost application, and can be applied to electric vehicle wireless charging, portable medical equipment power supply, unmanned aerial vehicle power supply and other scenes.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of wireless energy transmission, and particularly relates to a capacitive wireless power transmission power control system and method based on fuzzy control. BACKGROUND

[0002] Capacitive Power Transfer (CPT) is a technology for realizing wireless energy transmission by using electric field coupling, and has the advantages of simple structure, low cost, no ferromagnetic material, small size, and the ability to penetrate metal barriers, and can be applied to electric vehicle charging, medical device power supply and other fields.

[0003] However, in the prior art, the power of the existing CPT system is mainly adjusted by changing the frequency, duty cycle or switching circuit parameters, and these power adjustment methods are easy to destroy the zero voltage switching (ZVS) condition, reduce the efficiency, and easily cause chattering and instability in high frequency and high power occasions; in addition, the power control response speed of the existing CPT system is slow, the efficiency is low, and the system is easy to be unstable.

[0004] Among them, the sliding mode control method is suitable for power regulation of strong nonlinear systems, but due to the switching characteristics possessed by the sliding mode control method, chattering is easily caused when power regulation is performed.

[0005] Therefore, it is particularly important to develop a system and method that can adjust the power of the CPT system, improve the regulation speed and system stability, and reduce the design difficulty and cost, while ensuring the ZVS condition. SUMMARY

[0006] The purpose of the application is to overcome the problems of slow power control response, low efficiency and instability of the existing CPT system, and to provide a capacitive wireless power transmission power control system and method based on fuzzy control, which innovatively combines fuzzy control algorithm with dynamic phase compensation mechanism, effectively solving the problems of power regulation destroying the zero voltage switching (ZVS) condition, slow response speed, low efficiency and system instability in the existing CPT technology.

[0007] The capacitive wireless power transmission power control system based on fuzzy control comprises a transmitting end, a transmitting end capacitive coupling plate, a receiving end capacitive coupling plate, a receiving end, an output load circuit, a current detection circuit, a voltage detection circuit, a direct current bias circuit and a fuzzy controller.

[0008] The transmitting end is electrically connected with the transmitting end capacitive coupling plate, the receiving end is electrically connected with the receiving end capacitive coupling plate, the transmitting end capacitive coupling plate is opposite to the receiving end capacitive coupling plate, and the transmitting end capacitive coupling plate is used for transmitting high-frequency electric field to the receiving end capacitive coupling plate; the receiving end is electrically connected with the output load circuit, the output load circuit is also electrically connected with the current detection circuit and the voltage detection circuit, the current detection circuit and the voltage detection circuit are both electrically connected with the direct current bias circuit, and the direct current bias circuit is electrically connected with the fuzzy controller;

[0009] The transmitting end is provided with a direct current power supply, a high-frequency inverter and a transmitting end LC resonant circuit, the transmitting end LC resonant circuit comprising a compensation circuit; the receiving end is also provided with a rectifier filter and a receiving end LC resonant circuit; in the transmitting end, the direct current power supply is electrically connected with the high-frequency inverter, and the high-frequency inverter is electrically connected with the transmitting end LC resonant circuit; in the receiving end, the rectifier filter is electrically connected with the receiving end LC resonant circuit; the receiving end LC resonant circuit is electrically connected with the output load circuit, and the fuzzy controller is electrically connected with the compensation circuit;

[0010] The direct current power supply is used for sending a direct current voltage to the high-frequency inverter; the high-frequency inverter is used for converting the direct current voltage into an alternating current voltage with high-frequency square waves and sending the alternating current voltage with high-frequency square waves to the transmitting end LC resonant circuit; the transmitting end LC resonant circuit is used for performing resonant matching processing on the alternating current voltage with high-frequency square waves and sending the resonant matching processed alternating current voltage to the transmitting end capacitive coupling plate; the receiving end capacitive coupling plate is used for forwarding the resonant matching processed alternating current voltage to the rectifier filter; the rectifier filter is used for converting the resonant matching processed alternating current voltage into a direct current voltage and filtering out ripples, and sending the ripple filtered direct current voltage to the receiving end LC resonant circuit; the receiving end LC resonant circuit is used for performing impedance matching and noise suppression processing on the ripple filtered direct current voltage, and sending the ripple filtered, impedance matched and noise suppressed direct current voltage to the output load circuit; and the output load circuit is used for supplying power to the load.

[0011] The current detection circuit is used for detecting the current of the output load circuit and sending the current of the output load circuit to the fuzzy controller; the voltage detection circuit is used for detecting the voltage of the output load circuit and sending the voltage of the output load circuit to the fuzzy controller; the DC bias circuit is used for providing DC bias for the fuzzy controller, avoiding AC noise interference, ensuring that the fuzzy controller obtains accurate feedback signals, thereby realizing accurate control and improving the stability of signal transmission; the fuzzy controller is used for calculating power deviation and required PWM phase shift angle and generating control instructions according to the current of the output load circuit, the voltage of the output load circuit and the DC bias, and sending the control instructions to the compensation circuit; the compensation circuit is used for adjusting the phase of the input voltage of the high-frequency inverter according to the control instructions, reducing or eliminating the impedance introduced by the capacitive coupling plate, thereby changing the equivalent capacitance so that the voltage and power of the capacitive wireless power transmission power control system remain stable, or making the capacitive wireless power transmission power control system operate under the condition of high-efficiency zero-voltage switching (ZVS).

[0012] As preferred:

[0013] The compensation circuit is composed of a secondary capacitor array and an inductor, forming a plurality of switch tubes and a capacitor series array. The secondary capacitor array is easy to integrate and does not occupy volume; the fuzzy controller is used for dynamically adjusting the voltage phase of the switch in parallel on the secondary capacitor array, thereby adjusting the input voltage of the high-frequency inverter, so that the voltage and power of the capacitive wireless power transmission power control system remain stable, or making the capacitive wireless power transmission power control system operate under the condition of high-efficiency zero-voltage switching (ZVS).

[0014] As preferred: the compensation circuit is composed of a parallel capacitor array and an inductor, forming a plurality of switch tubes and a parallel capacitor array; the fuzzy controller is used for dynamically adjusting the voltage phase of the switch in parallel on the parallel capacitor array, thereby adjusting the input voltage of the high-frequency inverter, so that the voltage and power of the capacitive wireless power transmission power control system remain stable, or making the capacitive wireless power transmission power control system operate under the condition of high-efficiency zero-voltage switching (ZVS).

[0015] The control method of the capacitive wireless power transmission power control system based on fuzzy control comprises the following steps:

[0016] Step 1, the direct current power supply sends a direct current voltage to the high frequency inverter, the high frequency inverter converts the direct current voltage into an alternating current voltage with high frequency square wave, the transmitting end LC resonant circuit performs resonant matching processing on the alternating current voltage with high frequency square wave, and the transmitting end capacitive coupling board transmits the high frequency alternating current voltage after the resonant matching processing to the receiving end capacitive coupling board through the air; the rectifier filter converts the high frequency alternating current voltage after the resonant matching processing into a direct current voltage and removes the ripple, the receiving end LC resonant circuit performs impedance matching and noise suppression processing on the direct current voltage after the ripple removal, and the output load circuit supplies the direct current voltage after the impedance matching and noise suppression processing to the load;

[0017] Step 2, the current detection circuit detects the current of the output load circuit and sends it to the fuzzy controller, and the voltage detection circuit detects the voltage of the output load circuit and sends it to the fuzzy controller; the direct current bias circuit provides the direct current bias for the fuzzy controller;

[0018] Step 3, the output voltage error and the output power error are calculated according to the measured value of the voltage and the measured value of the current; the fuzzy controller fuzzifies the output voltage error and the output power error to obtain the corresponding membership degree; the fuzzy controller maps the membership degree to obtain the fuzzy language variable and the fuzzy language variable subset; the fuzzy rule library and the database are formulated to obtain the fuzzy control quantity; the fuzzy controller converts the fuzzy control quantity into a clear numerical value driving signal, and the compensation circuit dynamically adjusts the voltage phase according to the numerical value driving signal, stabilizes the voltage and power of the capacitive wireless power control system, and makes the capacitive wireless power control system run under the condition of high efficiency zero voltage switching (ZVS).

[0019] As preferred, step 3 specifically includes the following steps:

[0020] Step 3.1, according to the measured value of the voltage and the measured value of the current, the output power is calculated, the measured value of the voltage, the output power and the reference value corresponding to the direct current bias are compared, and the output voltage error e v and the output power error e p are calculated; the output voltage error e v and the output power error e p are taken as the input of the fuzzy controller;

[0021] Step 3.2, the fuzzy controller fuzzifies the output voltage error e v and the output power error e p according to the triangular membership function in the following formula to obtain the corresponding membership degree;

[0022]

[0023] In the above formula, a, b and c are constants, wherein a and c represent the interval value of the membership function μ A (x i ), and c represents the midpoint value of the membership function μ A (x i ), x i represents the ith error value, μ A (x i ) represents the corresponding membership of x i ;

[0024] Step 3.3, the fuzzy controller maps the membership to obtain fuzzy language variables {NB, NM, NS, ZE, PS, PM, PB}, and the fuzzy mapping refers to dividing the control according to the region to correspond to the situation and the desired effect, selecting the corresponding fuzzy subset according to different situations to adjust the actual circuit, and facilitating rule reasoning; the fuzzy language variables are divided into seven fuzzy subsets according to the actual experience of the system working condition, wherein NB represents a negative large fuzzy language variable subset, NM represents a negative medium fuzzy language variable subset, NS represents a negative small fuzzy language variable subset, ZE represents a zero fuzzy language variable subset, PS represents a positive small fuzzy language variable subset, PM represents a positive medium fuzzy language variable subset, and PB represents a positive large fuzzy language variable subset;

[0025] Step 3.4, a fuzzy rule base and a database are established according to the fuzzy language variables and the fuzzy language variable subsets, the rule base defines the relationship between the error and the output (for example, if the error is PB, the controller output takes PB); the fuzzy controller uses the inference engine to infer the membership of the output voltage error e v and the output power error e p and the rule base, and finds the pre-set control rule through the membership and the rule base to infer the fuzzy control amount;

[0026] Step 3.5, the fuzzy controller converts the fuzzy control amount into a clear numerical value driving signal, and then sends the numerical value driving signal to the compensation circuit;

[0027] Step 3.6, the compensation circuit dynamically adjusts the voltage phase of the switch connected in parallel on the secondary capacitor array or dynamically adjusts the voltage phase of the switch connected in parallel on the parallel capacitor array (controls the switch state of the capacitor array) according to the numerical value driving signal, changes the effective value of the equivalent capacitance of the secondary capacitor array or the parallel capacitor array; wherein the relationship between the equivalent capacitance and the voltage phase is as follows:

[0028]

[0029] In the above formula, C eThe equivalent capacitance value adjusted by the fuzzy controller in the transmitting end LC resonant circuit is C1, the original capacitance value in the transmitting end LC resonant circuit is C1, and alpha is the phase difference between the current of the equivalent capacitance and the numerical value driving signal; so that the voltage and power of the capacitive wireless power transmission power control system remain stable, or the capacitive wireless power transmission power control system is kept in the high-efficiency zero-voltage switching (ZVS) condition.

[0030] As preferred: the inference engine in step 3.4 is an inference engine using Mamdani inference or using minimum-maximum method.

[0031] As preferred: the way that the fuzzy controller converts the fuzzy control quantity into a clear numerical value driving signal in step 3.5 is: the fuzzy controller obtains a clear actual control quantity by defuzzification method (such as barycenter method), and then calculates the required PWM phase shift angle according to the triangular membership function and the actual control quantity, and the numerical value driving signal contains the PWM phase shift angle.

[0032] The beneficial effects of the present application are:

[0033] The present application dynamically adjusts the voltage phase of the switch through the compensation circuit (secondary side capacitor array or parallel capacitor array, easy to integrate and does not increase the volume), combines the frequency selection filtering and noise suppression function of the LC resonant circuit, reduces the precision requirement of high-frequency components, combines the PWM phase shift angle output by the fuzzy controller to accurately control the equivalent capacitance value, ensures that the system always works in the high-efficiency ZVS condition, significantly reduces the switching loss, and improves the energy transmission efficiency.

[0034] The fuzzy controller of the present application takes the output voltage error and the output power error as input, maps them into seven-level language variables through triangular membership function, and generates control rules based on Mamdani inference or minimum-maximum method, to realize adaptive adjustment of the nonlinear and strongly coupled system. The method of the present application does not require an accurate mathematical model, can quickly suppress power fluctuations caused by load mutations or changes in coupling distance, and effectively eliminates the chattering phenomenon of traditional sliding mode control.

[0035] The DC bias circuit of the present application provides a stable reference for the fuzzy controller, avoids AC noise interference, and further simplifies the design of the detection circuit; the present application is suitable for miniaturization and low-cost application, and can be applied to electric vehicle wireless charging, portable medical device power supply, unmanned aerial vehicle power supply and other scenes; especially suitable for metal barrier penetration or space limited environment, providing a reliable solution for miniaturized and low-cost wireless energy transmission. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 It is a schematic diagram of the capacitive wireless power transmission power control system based on fuzzy control of the present application.

[0037] Figure 2 A circuit schematic diagram of the present application;

[0038] Figure 3 A flow chart of the fuzzy control;

[0039] Figure 4 A membership function chart (in the chart, NB, NM, NS, Z, PS, PM, PB respectively represent negative big, negative medium, negative small, zero, positive small, positive medium, positive big, etc. fuzzy language variable division standards);

[0040] Figure 5 A control logic schematic diagram of the fuzzy controller;

[0041] Figure 6 A control flow chart of the fuzzy controller.

[0042] Explanation of reference numerals: DC power supply 1, first power switch 2, second power switch 3, first resonant inductor 4, first resonant capacitor 5, first coupling plate 6, second coupling plate 7, second resonant capacitor 8, second resonant inductor 9, compensation circuit 10, load 11, transmitting end 12, receiving end 13. DETAILED DESCRIPTION

[0043] The present application will be further described below in conjunction with examples. The following example is only used to help understand the present application. It should be pointed out that, for those skilled in the art, without departing from the principles of the present application, a number of modifications can be made to the present application, and these improvements and modifications also fall within the scope of protection of the claims of the present application.

[0044] Example 1

[0045] A capacitive wireless power transmission power control system based on fuzzy control, as shown in Figure 1 and Figure 2 , comprises a transmitting end, a transmitting end capacitive coupling plate, a receiving end capacitive coupling plate, a receiving end, an output load circuit, a current detection circuit, a voltage detection circuit, a DC bias circuit and a fuzzy controller;

[0046] The transmitting end is electrically connected to the transmitting end capacitive coupling plate, the receiving end is electrically connected to the receiving end capacitive coupling plate, the transmitting end capacitive coupling plate is opposite to the receiving end capacitive coupling plate, and the transmitting end capacitive coupling plate is used for transmitting high-frequency electric field to the receiving end capacitive coupling plate in space; the receiving end is electrically connected to the output load circuit, the output load circuit is further electrically connected to the current detection circuit and the voltage detection circuit, the current detection circuit and the voltage detection circuit are both electrically connected to the DC bias circuit, and the DC bias circuit is electrically connected to the fuzzy controller;

[0047] The transmitting end is provided with a direct current power supply, a high-frequency inverter and a transmitting end LC resonant circuit, the transmitting end LC resonant circuit comprising a compensation circuit; the receiving end is also provided with a rectifier filter and a receiving end LC resonant circuit; in the transmitting end, the direct current power supply is electrically connected to the high-frequency inverter, and the high-frequency inverter is electrically connected to the transmitting end LC resonant circuit; in the receiving end, the rectifier filter is electrically connected to the receiving end LC resonant circuit; the receiving end LC resonant circuit is electrically connected to an output load circuit, and a fuzzy controller is electrically connected to the compensation circuit;

[0048] The direct current power supply is used for sending a direct current voltage to the high-frequency inverter; the high-frequency inverter is used for converting the direct current voltage into an alternating current voltage with a high-frequency square wave and sending the alternating current voltage with the high-frequency square wave to the transmitting end LC resonant circuit; the transmitting end LC resonant circuit is used for performing resonant matching processing on the alternating current voltage with the high-frequency square wave and sending the alternating current voltage after the resonant matching processing to the transmitting end capacitive coupling plate; the receiving end capacitive coupling plate is used for forwarding the alternating current voltage after the resonant matching processing to the rectifier filter; the rectifier filter is used for converting the alternating current voltage after the resonant matching processing into a direct current voltage and performing ripple filtering, and sending the direct current voltage after the ripple filtering to the receiving end LC resonant circuit; the receiving end LC resonant circuit is used for performing impedance matching and noise suppression processing on the direct current voltage after the ripple filtering and sending the direct current voltage after the ripple filtering, impedance matching and noise suppression processing to the output load circuit; the output load circuit is used for supplying power to a load.

[0049] The current detection circuit is used for detecting the current of the output load circuit and sending the current of the output load circuit to the fuzzy controller; the voltage detection circuit is used for detecting the voltage of the output load circuit and sending the voltage of the output load circuit to the fuzzy controller; the direct current bias circuit is used for providing a direct current bias for the fuzzy controller, avoiding alternating current noise interference, ensuring that the fuzzy controller obtains accurate feedback signals, thereby realizing accurate control and improving the stability of signal transmission; the fuzzy controller is used for calculating a power deviation and a required PWM phase shift angle according to the current of the output load circuit, the voltage of the output load circuit and the direct current bias and generating a control instruction, and is used for sending the control instruction to the compensation circuit; the compensation circuit is composed of a secondary side capacitor array and an inductor, forming a plurality of switch tubes and a capacitor series array in series, and the secondary side capacitor array is easy to integrate and does not occupy volume; the fuzzy controller is used for dynamically adjusting the voltage phase of the switch in parallel on the secondary side capacitor array, thereby adjusting the input voltage of the high-frequency inverter, so that the voltage and power of the capacitive wireless power transmission power control system remain stable, or the capacitive wireless power transmission power control system is kept in a high-efficiency zero-voltage switching (ZVS) condition.

[0050] Embodiment 2

[0051] On the basis of embodiment 1, another fuzzy control-based capacitive wireless power control system, comprising: a transmitting end, a transmitting end capacitive coupling plate, a receiving end capacitive coupling plate, a receiving end, an output load circuit, a current detection circuit, a voltage detection circuit, a DC bias circuit and a fuzzy controller;

[0052] The transmitting end is electrically connected to the transmitting end capacitive coupling plate, the receiving end is electrically connected to the receiving end capacitive coupling plate, the transmitting end capacitive coupling plate is opposite to the receiving end capacitive coupling plate, and the transmitting end capacitive coupling plate is used for transmitting high-frequency electric field to the receiving end capacitive coupling plate in space; the receiving end is electrically connected to the output load circuit, the output load circuit is further electrically connected to the current detection circuit and the voltage detection circuit, the current detection circuit and the voltage detection circuit are both electrically connected to the DC bias circuit, and the DC bias circuit is electrically connected to the fuzzy controller;

[0053] The transmitting end is provided with a DC power supply, a high-frequency inverter and a transmitting end LC resonance circuit, the transmitting end LC resonance circuit comprising a compensation circuit; the receiving end is further provided with a rectifier filter and a receiving end LC resonance circuit; in the transmitting end, the DC power supply is electrically connected to the high-frequency inverter, and the high-frequency inverter is electrically connected to the transmitting end LC resonance circuit; in the receiving end, the rectifier filter is electrically connected to the receiving end LC resonance circuit; the receiving end LC resonance circuit is electrically connected to the output load circuit, and the fuzzy controller is electrically connected to the compensation circuit;

[0054] The DC power supply is used for sending a DC voltage to the high-frequency inverter; the high-frequency inverter is used for converting the DC voltage into an AC voltage with high-frequency square waves, and sending the AC voltage with high-frequency square waves to the transmitting end LC resonance circuit; the transmitting end LC resonance circuit is used for performing resonance matching processing on the AC voltage with high-frequency square waves, and sending the AC voltage after resonance matching processing to the transmitting end capacitive coupling plate; the receiving end capacitive coupling plate is used for forwarding the AC voltage after resonance matching processing to the rectifier filter; the rectifier filter is used for converting the AC voltage after resonance matching processing into a DC voltage and performing ripple filtering, and sending the DC voltage after ripple filtering to the receiving end LC resonance circuit; the receiving end LC resonance circuit is used for performing impedance matching and noise suppression processing on the DC voltage after ripple filtering, and sending the DC voltage after ripple filtering, impedance matching and noise suppression processing to the output load circuit; the output load circuit is used for supplying power to the load;

[0055] The current detection circuit is used for detecting the current of the output load circuit and sending the current of the output load circuit to the fuzzy controller; the voltage detection circuit is used for detecting the voltage of the output load circuit and sending the voltage of the output load circuit to the fuzzy controller; the direct current bias circuit is used for providing the direct current bias for the fuzzy controller, avoiding the alternating current noise interference, ensuring that the fuzzy controller obtains accurate feedback signals, and then realizing accurate control and improving the stability of signal transmission; the fuzzy controller is used for calculating the power deviation and the required PWM phase shift angle according to the current of the output load circuit, the voltage of the output load circuit and the direct current bias, and generating a control instruction, which is used for sending the control instruction to the compensation circuit; the compensation circuit is composed of a parallel capacitor array and an inductor, and forms a plurality of switch tubes and a parallel capacitor array; the fuzzy controller is used for dynamically adjusting the voltage phase of the switch parallel to the parallel capacitor array, and then adjusting the input voltage of the high-frequency inverter, so that the voltage and power of the capacitive wireless power transmission power control system remain stable, or the capacitive wireless power transmission power control system is kept in the high-efficiency zero-voltage switching (ZVS) condition.

[0056] Embodiment 3

[0057] Based on the embodiments 1 and 2, as shown in Figures 3 to 6 A control method of a capacitive wireless power transmission power control system based on fuzzy control, comprising the following steps:

[0058] Step 1, the direct current power supply sends a direct current voltage to the high-frequency inverter, the high-frequency inverter converts the direct current voltage into an alternating current voltage with high-frequency square wave, the transmitting end LC resonant circuit performs resonant matching processing on the alternating current voltage with high-frequency square wave, and the transmitting end capacitive coupling board transmits the high-frequency alternating current voltage after the resonant matching processing to the receiving end capacitive coupling board through the air; the rectifier filter converts the high-frequency alternating current voltage after the resonant matching processing into a direct current voltage and filters out the ripple, the receiving end LC resonant circuit performs impedance matching and noise suppression processing on the direct current voltage after the ripple filtering, and the output load circuit supplies the direct current voltage after the impedance matching and noise suppression processing to the load;

[0059] Step 2, the current detection circuit detects the current of the output load circuit and sends it to the fuzzy controller, and the voltage detection circuit detects the voltage of the output load circuit and sends it to the fuzzy controller; the direct current bias circuit provides the direct current bias for the fuzzy controller;

[0060] Step 3, calculate the output voltage error and the output power error according to the measured value of the voltage and the measured value of the current; the fuzzy controller fuzzifies the output voltage error and the output power error to obtain corresponding membership degrees; the fuzzy controller maps the membership degrees to obtain fuzzy language variables and fuzzy language variable subsets; formulate a fuzzy rule base and a database to obtain a fuzzy control quantity; the fuzzy controller converts the fuzzy control quantity into a clear numerical value driving signal, and the compensation circuit dynamically adjusts the voltage phase according to the numerical value driving signal, stabilizes the voltage and power of the capacitive wireless power control system, and makes the capacitive wireless power control system operate under the condition of high-efficiency zero-voltage switching (ZVS); the corresponding fuzzy rules of the embodiment are shown in Table 1 as follows:

[0061] Table 1 Fuzzy rule table corresponding to the embodiment

[0062] Activation rule Output phase adjustment NB→NB -100％ NM→NM -50％ NS→NS -25％ Z→Z 0％ PS→PS +25％ PM→PM +50％ PB→PB +100％

[0063] Step 3.1, calculate the output power according to the measured value of the voltage and the measured value of the current, compare the measured value of the voltage, the output power with the reference value corresponding to the direct current bias, and calculate the output voltage error e v and the output power error e p ; take the output voltage error e v and the output power error e p as the input of the fuzzy controller;

[0064] Step 3.2, the fuzzy controller fuzzifies the output voltage error e v and the output power error e p according to the triangular membership function in the following formula to obtain corresponding membership degrees.

[0065]

[0066] In the above formula, a, b and c are constants, wherein a and c represent the interval value of the membership function μ A (x i ), c represents the midpoint value of the membership function μ A (x i ), x i represents the i-th error value, and μ A (x i ) represents the membership degree corresponding to x i .

[0067] Step 3.3, the fuzzy controller maps the membership degree to get fuzzy language variable {NB, NM, NS, ZE, PS, PM, PB}, the fuzzy mapping means that according to the area to divide the control corresponding to the situation and the desired effect, according to the different situation to select the corresponding fuzzy subset, to adjust the actual circuit, facilitate rule-based reasoning; according to the actual experience of the system working condition, the fuzzy language variable is divided into seven fuzzy subsets, wherein NB represents the negative big fuzzy language variable subset, NM represents the negative middle fuzzy language variable subset, NS represents the negative small fuzzy language variable subset, ZE represents the zero fuzzy language variable subset, PS represents the positive small fuzzy language variable subset, PM represents the positive middle fuzzy language variable subset, and PB represents the positive big fuzzy language variable subset;

[0068] Step 3.4, according to the fuzzy language variable and the fuzzy language variable subset to make the fuzzy rule base and database, the rule base defines the relationship between the error and the output (for example, if the error is PB, the controller output takes PB); the fuzzy controller inferences the membership degree of output voltage error e v and output power error e p and rule base by using Mamdani inference method or using minimum-maximum method inference machine, the output fuzzy control amount is obtained by inquiring the pre-set control rule through the membership degree and the rule base;

[0069] Step 3.5, the fuzzy controller converts the fuzzy control amount into clear numerical value driving signal: the fuzzy controller de-fuzzies the fuzzy control amount by de-fuzzing method (such as center of gravity method) to get clear actual control amount, and then calculates the required PWM phase shift angle according to the triangular membership function and the actual control amount, the numerical value driving signal contains the PWM phase shift angle; then the numerical value driving signal is sent to the compensation circuit;

[0070] Step 3.6, the compensation circuit dynamically adjusts the voltage phase of the switch connected in parallel on the secondary capacitor array or dynamically adjusts the voltage phase of the switch connected in parallel on the parallel capacitor array (controls the switch state of the capacitor array), changes the effective value of the equivalent capacitance of the secondary capacitor array or the parallel capacitor array; wherein, the relationship between the equivalent capacitance and the voltage phase is as follows:

[0071]

[0072] In the above formula, C eThe equivalent capacitance value adjusted by the fuzzy controller in the LC resonant circuit of the transmitting end is C1, the original capacitance value in the LC resonant circuit of the transmitting end is C1, and alpha is the phase difference between the current of the equivalent capacitance and the numerical driving signal; so that the voltage and power of the capacitive wireless power transmission power control system remain stable, or the capacitive wireless power transmission power control system remains in the high-efficiency zero-voltage switching (ZVS) condition and operates.

[0073] The working method of the capacitive wireless power transmission power control system based on fuzzy control applied to the power regulation of CPT: the input variables are fuzzified, the secondary capacitance array or parallel capacitance is effectively adjusted under the ZVS condition, the control amount is output by using the rule base reasoning, the output power is accurately, quickly and stably and smoothly regulated, the controlled object does not require an accurate mathematical model, is suitable for processing nonlinear, strong coupling and uncertain systems, can improve the speed of CPT power regulation and the stability of the system, is simple to control and has strong adaptability, can suppress oscillation in the power regulation process, the power control method has high efficiency, strong robustness and is easy to implement, and can reduce the difficulty and cost of energy transmission.

Claims

1. A capacitor-based wireless power transmission control system based on fuzzy control, characterized in that, include: Transmitter, transmitter capacitor coupling plate, receiver capacitor coupling plate, receiver, output load circuit, current detection circuit, voltage detection circuit, DC bias circuit and fuzzy controller; The transmitting end is electrically connected to the transmitting end capacitive coupling plate, and the receiving end is electrically connected to the receiving end capacitive coupling plate. The transmitting end capacitive coupling plate faces the receiving end capacitive coupling plate. The transmitting end capacitive coupling plate is used to transmit a high-frequency electric field to the receiving end capacitive coupling plate without air. The receiving end is electrically connected to the output load circuit. The output load circuit is also electrically connected to the current detection circuit and the voltage detection circuit. The current detection circuit and the voltage detection circuit are both electrically connected to the DC bias circuit. The DC bias circuit is electrically connected to the fuzzy controller. The transmitting end is equipped with a DC power supply, a high-frequency inverter, and a transmitting end LC resonant circuit, the transmitting end LC resonant circuit including a compensation circuit; the receiving end is also equipped with a rectifier filter and a receiving end LC resonant circuit; in the transmitting end, the DC power supply is electrically connected to the high-frequency inverter, and the high-frequency inverter is electrically connected to the transmitting end LC resonant circuit; in the receiving end, the rectifier filter is electrically connected to the receiving end LC resonant circuit; the receiving end LC resonant circuit is electrically connected to the output load circuit, and the fuzzy controller is electrically connected to the compensation circuit; The DC power supply is used to send DC voltage to the high-frequency inverter; the high-frequency inverter is used to convert the DC voltage into AC voltage with a high-frequency square wave, and to send the AC voltage with the high-frequency square wave to the transmitting LC resonant circuit; the transmitting LC resonant circuit is used to perform resonant matching processing on the AC voltage with the high-frequency square wave, and to send the AC voltage after resonant matching processing to the transmitting capacitor coupling plate; the receiving capacitor coupling plate is used to forward the AC voltage after resonant matching processing to the rectifier filter; the rectifier filter is used to convert the AC voltage after resonant matching processing into DC voltage and perform ripple filtering, and to send the ripple-filtered DC voltage to the receiving LC resonant circuit; the receiving LC resonant circuit is used to perform impedance matching and noise suppression processing on the ripple-filtered DC voltage, and to send the DC voltage after ripple filtering, impedance matching, and noise suppression processing to the output load circuit; the output load circuit is used to supply power to the load; The current detection circuit is used to detect the current of the output load circuit and send the current of the output load circuit to the fuzzy controller; the voltage detection circuit is used to detect the voltage of the output load circuit and send the voltage of the output load circuit to the fuzzy controller; the DC bias circuit is used to provide DC bias for the fuzzy controller. The fuzzy controller is used to calculate the power deviation and the required PWM phase shift angle based on the current of the output load circuit, the voltage of the output load circuit, and the DC bias, and to generate control commands to send the control commands to the compensation circuit. The compensation circuit is used to adjust the phase of the input voltage of the transmitting end LC resonant circuit according to the control command.

2. The capacitor-based wireless power transmission control system based on fuzzy control according to claim 1, characterized in that: The compensation circuit consists of a secondary capacitor array and an inductor; the fuzzy controller is used to dynamically adjust the voltage phase of the switch connected in parallel with the secondary capacitor array.

3. The capacitor-based wireless power transmission control system based on fuzzy control according to claim 1, characterized in that: The compensation circuit consists of a parallel capacitor array and an inductor; the fuzzy controller is used to dynamically adjust the voltage phase of the switch connected in parallel with the parallel capacitor array.

4. A control method for a capacitor-based wireless power transmission control system based on fuzzy control as described in claim 2 or 3, characterized in that, Includes the following steps: Step 1: The DC power supply sends DC voltage to the high-frequency inverter. The high-frequency inverter converts the DC voltage into AC voltage with a high-frequency square wave. The transmitting LC resonant circuit performs resonant matching processing on the AC voltage with the high-frequency square wave. The transmitting capacitor coupling plate transmits the resonant-matched high-frequency AC voltage to the receiving capacitor coupling plate without air. The rectifier filter converts the resonant-matched high-frequency AC voltage into DC voltage and performs ripple filtering. The receiving LC resonant circuit performs impedance matching and noise suppression processing on the ripple-filtered DC voltage. The output load circuit supplies the impedance-matched and noise-suppressed DC voltage to the load. Step 2: The current detection circuit detects the current of the output load circuit and sends it to the fuzzy controller; the voltage detection circuit detects the voltage of the output load circuit and sends it to the fuzzy controller. The DC bias circuit provides DC bias for the fuzzy controller; Step 3: Calculate the output voltage error and output power error based on the measured values ​​of the voltage and current; The fuzzy controller fuzzifies the output voltage error and output power error to obtain the corresponding membership degrees; The fuzzy controller maps the membership degrees to obtain fuzzy linguistic variables and subsets of fuzzy linguistic variables; it formulates a fuzzy rule base and database to obtain fuzzified control quantities; the fuzzy controller converts the fuzzified control quantities into numerical driving signals, and the compensation circuit dynamically adjusts the voltage phase according to the numerical driving signals to stabilize the voltage and power of the capacitor-type wireless power transmission control system.

5. The control method for the capacitor-based wireless power transmission control system based on fuzzy control according to claim 4, characterized in that, Step 3 specifically includes the following steps: Step 3.1: Calculate the output power based on the measured voltage and current values. Compare the measured voltage and output power with the reference value corresponding to the DC bias to calculate the output voltage error e. v and output power error e p The output voltage error e v and output power error e p As input to the fuzzy controller; Step 3.2: The fuzzy controller determines the output voltage error e based on the triangular membership function in the following formula. v and output power error e p Perform fuzzification to obtain the corresponding membership degree; In the above formula, a, b, and c are all constants, where a and c represent the membership functions μ. A (x i The interval values ​​of ), where c represents the membership function μ. A (x i The midpoint value of x) i Let μ represent the i-th error value. A (x i ) represents x i The corresponding membership degree; Step 3.3: The fuzzy controller maps the membership degrees to obtain fuzzy linguistic variables {NB, NM, NS, ZE, PS, PM, PB}; the fuzzy linguistic variables are divided into seven fuzzy subsets, where NB represents the negative large fuzzy linguistic variable subset, NM represents the negative medium fuzzy linguistic variable subset, NS represents the negative small fuzzy linguistic variable subset, ZE represents the zero fuzzy linguistic variable subset, PS represents the positive small fuzzy linguistic variable subset, PM represents the positive medium fuzzy linguistic variable subset, and PB represents the positive large fuzzy linguistic variable subset. Step 3.4: Develop a fuzzy rule base and database based on the fuzzy linguistic variables and the subset of fuzzy linguistic variables; the fuzzy controller uses an inference engine to infer the output voltage error e. v and the output power error e p The membership degree and rule base are used to search for pre-set control rules and infer the fuzzy output control quantity. Step 3.5: The fuzzy controller converts the fuzzy control quantity into a numerical driving signal, and then sends the numerical driving signal to the compensation circuit; Step 3.6: The compensation circuit dynamically adjusts the voltage phase of the switch connected in parallel to the secondary capacitor array or dynamically adjusts the voltage phase of the switch connected in parallel to the parallel capacitor array according to the numerical driving signal, thereby changing the equivalent capacitance of the secondary capacitor array or the parallel capacitor array; wherein, the relationship between the equivalent capacitance and the voltage phase is as follows: In the above formula, C e C1 is the equivalent capacitance value in the LC resonant circuit of the transmitter, adjusted by the fuzzy controller, C1 is the original capacitance value in the LC resonant circuit of the transmitter, and α is the phase difference between the current of the equivalent capacitance and the numerical driving signal.

6. The control method for the capacitor-based wireless power transmission control system based on fuzzy control according to claim 5, characterized in that, The inference engine mentioned in step 3.4 is an inference engine that uses the Mamdani inference method or the min-max method.

7. The control method for the capacitor-based wireless power transmission control system based on fuzzy control according to claim 6, characterized in that, In step 3.5, the fuzzy controller converts the fuzzy control quantity into a numerical driving signal in the following way: the fuzzy controller defuzzifies the fuzzy control quantity to obtain the actual control quantity through a defuzzification method, and then calculates the required PWM phase shift angle based on the triangular membership function and the actual control quantity. The numerical driving signal includes the PWM phase shift angle.

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