CN109861405B - Load self-adaptive EC-WPT system based on stacked coupling mechanism and parameter design method - Google Patents

Abstract

The invention discloses a load self-adaptive EC-WPT system based on a stacked coupling mechanism and a parameter design method ₁ 、P ₂ 、P ₃ 、P ₄ The laminated coupling mechanism composed of four polar plates is used as an energy transmission channel, and the polar plate P ₁ And a polar plate P ₂ At the transmitting end, plate P ₃ And a polar plate P ₄ The transmitting end is arranged at the receiving end, the structures of the transmitting end and the receiving end in the laminated coupling mechanism are mutually symmetrical, and the transmitting end is also provided with a direct-current power supply, a high-frequency inverter circuit and an inductor L ₁ Capacitor C ₁ And an inductance L ₂ The T-shaped LCL compensation network is provided with a compensation inductor L at the receiving end ₃ A rectifying and filtering circuit and an equivalent load resistance. The effect is as follows: the system is guaranteed to provide required power for the load after the load is moved in, keep in a low input power state (standby mode) after the load is removed, and do not cause voltage and current overshoot on the inverter switch tube in the processes of moving in and removing.

Description

Load Adaptive EC-WPT System and Parameter Design Based on Laminated Coupling Mechanism method

technical field

The invention relates to a wireless power transmission technology, in particular to a load adaptive EC-WPT system based on a stacked coupling mechanism and a parameter design method.

Background technique

Wireless Power Transfer (WPT) technology is a technology that comprehensively utilizes power electronics technology and modern control theory to realize wireless power transmission through soft media. This technology has become a research hotspot at home and abroad. For the second year in a row, wireless power transfer technology has also been listed as one of the top ten emerging technologies that have the greatest impact on the world and are most likely to provide answers to global challenges. It solves various problems brought about by the direct electrical contact of traditional wires, and has wide application prospects. Among them, the research on Magnetic-field Coupled Wireless Power Transfer (MC-WPT) technology is the most popular, and many theoretical and practical achievements have also been obtained, and are gradually popularized and applied.

In recent years, a wireless power transfer (Electric-Field Coupled Wireless Power Transfer, EC-WPT) technology based on electric field coupling has also been proposed, and an electric field is used as an energy transmission medium. The electric field coupling mechanism is simple, light and thin, with low cost and variable shape; in the working state, most of the electric flux of the electric field coupling mechanism is distributed between the electrodes, and the electromagnetic interference to the surrounding environment is very small; when the electric field coupling mechanism is between or around In the presence of metal conductors, no eddy current losses are caused in the conductors. From the above characteristics of EC-WPT technology, it can be seen that it has complementary advantages with MC-WPT technology, so it has attracted more and more attention from domestic and foreign experts and scholars. At present, for the EC-WPT system, many experts and scholars have carried out research on LED lighting, wireless mouse, mobile phone, bioelectric measurement and electric vehicle charging, etc., and achieved many research results.

In the application of EC-WPT system to supply power for movable load equipment, movable load equipment, such as electric vehicle wireless charging system, its power receiving end (including receiving plate, power adjustment circuit and equivalent load resistance, etc.) The moving in and out of the wireless power supply system, the above working conditions can be regarded as the change process of the load of the system between no-load and full load. The coupling mechanism of the traditional EC-WPT system consists of two pairs of plates placed in parallel to form an energy transmission channel. When the load is moved out, the two plates at the receiving end need to be moved out at the same time. When the load is moved in, the two plates at the receiving end and the transmitting end need to be moved out. The two polar plates are exactly facing each other, which greatly limits the spatial freedom and also limits the practical application of the EC-WPT system. In recent years, an EC-WPT system with a stacked coupling mechanism has attracted attention. For example, the applicant once proposed a stacked coupling mechanism and an ECPT system and system parameter design method composed thereof. Patent application number: 201810566079.2, compared to Parallel coupling mechanism, stacked coupling mechanism The four plates are arranged side by side in parallel, which greatly reduces the floor space. When supplying power to movable equipment, it is more convenient to move the load in and out, which is more conducive to practical applications.

For the current EC-WPT system with a stacked coupling mechanism, the process of moving in and out of the load usually leads to overshoot of the voltage and current of the switch tube of the inverter, and even damages the switch tube. Moreover, after the load is removed, there is still a large input power in the system, resulting in a serious waste of system energy.

SUMMARY OF THE INVENTION

Aiming at the defects in the prior art, the present invention proposes an EC-WPT system with a stacked coupling mechanism. The system has a load adaptive characteristic through the rational design of parameters, that is, the moving in/removal of the load at any time will not affect the load. The inverter switch tube causes obvious voltage and current overshoot; when the load is moved in, the system can efficiently and stably provide the required power to the load; when the load is removed, the system can automatically enter a low input power mode (standby mode).

In order to achieve the above purpose, the present invention first provides a load adaptive EC-WPT system based on a stacked coupling mechanism, the key of which is that it includes a transmitter and a receiver, and a P ₁ is used between the transmitter and the receiver. , P ₂ , P ₃ , P ₄ four polar plates composed of stacked coupling mechanism as the energy transmission channel, the polar plate P ₁ and the polar plate P ₂ are located at the transmitting end, the polar plate P ₃ and the polar plate P ₄ are located at the receiving end, Moreover, the structures of the transmitting end and the receiving end in the stacked coupling mechanism are symmetrical with each other, and the transmitting end is also provided with a DC power supply, a high-frequency inverter circuit, and a T-type LCL compensation network composed of an inductance L ₁ , a capacitor C ₁ and an inductance L ₂ . , and a compensation inductance L ₃ , a rectifying filter circuit and an equivalent load resistance are also arranged at the receiving end.

Optionally, the layered coupling mechanism adopts a grooved layered coupling mechanism, four pole plates are placed in layers, the inner pole plate is embedded in the outer pole plate, and an insulating medium material is filled between the inner and outer pole plates.

Based on the above system, the present invention also proposes a parameter design method for a load adaptive EC-WPT system, comprising the following steps:

S1: Determine the size and spatial position of each pole plate in the stacked coupling mechanism according to the application, and at the same time determine the equivalent load resistance R _L and the system operating frequency f;

S2: The initial value E of the system input voltage is given according to the required power level;

S3: Set the constant N according to the required input power index requirements of the ECPT system in the standby mode;

层叠式耦合机构中各个极板之间的端口电容值C_Tij(i,j＝1,2,3,4；i≠j)以及负载移出后极板P₁和极板P₂之间的耦合电容C₁₂ ^*，且通过各个极板之间的端口电容值C_Tij(i,j＝1,2,3,4；i≠j)推导得出交叉耦合电容C_ij(i,j＝1,2,3,4；i≠j)；S4: Inductor quality factor _QL and capacitor dielectric loss angle are obtained by bridge measurement

The port capacitance value C _Tij (i,j=1,2,3,4; i≠j) between each pole plate in the stacked coupling mechanism and the coupling between the pole plate P ₁ and the pole plate P ₂ after the load is removed capacitance C ₁₂ ^* , and the cross-coupling capacitance C _ij ( _i ,j=1, 2,3,4; i≠j);

S5: According to the circuit topology, it is derived from the equivalent load resistance R _L , the compensation inductance L ₃ and the cross-coupling capacitance C _ij (i,j=1,2,3,4; i≠j) in the stacked coupling mechanism The functional expression of the output impedance Z ₄ of the output port of the inductor L ₂ when the load is not removed;

确定接收端补偿电感L₃的感抗值，其中系统工作角频率ω＝2πf，Im(Z₄)为电感L₂输出端口的输出阻抗Z₄的虚部；S6: According to

Determine the inductive reactance value of the compensating inductor L ₃ at the receiving end, wherein the system operating angular frequency ω=2πf, Im(Z ₄ ) is the imaginary part of the output impedance Z ₄ of the output port of the inductor L ₂ ;

S7: Determine the sum R _x of the equivalent series resistance of the inductor L ₂ and the coupling capacitor C ₁₂ ^* according to Re(Z ₄ )=NR _x , and Re(Z ₄ ) is the real part of the output impedance Z ₄ of the output port of the inductor L ₂ ;

S8 _: Determine the inductance value of the inductance L2 according to the sum _Rx of the equivalent series resistance _of the inductance L2 and the coupling capacitor C12 ^* _;

确定电感L₁的电感值和电容C₁的电容值；S9: According to the resonance condition

Determine the inductance value of inductor L ₁ and the capacitance value of capacitor C ₁ ;

S10: Judge whether the inequality constraints are satisfied: Z _in >NηU _p ² /P _out , if satisfied, determine the final system parameters, if not, adjust the size of the constant N, and return to step S4 for redesign, where:

Z _in is the input impedance of the input end of the inductor L ₁ ; η is the transmission efficiency, P _out is the output power required by the system, and U _p is the effective value of the fundamental component of the input voltage.

Optionally, when the constant N is set in step S3, if it is defined that the input power in the standby mode is less than x% of the output power in the system working state with load, then

Optionally, when the system operating frequency f is set empirically, its range is selected between (500kHz, 1.5MHz).

Optionally, the range of the compensation inductance L ₃ is selected to be between (10 μH, 100 μH) according to experience.

表示耦合电容C₁₂ ^*的等效串联电阻。Optionally, the sum of the equivalent series resistances in step S7 is R _x =R ₂ +R ₁₂ ^* , where R ₂ =ωL ₂ /QL represents the equivalent series resistance of the inductor _{L 2} ,

represents the equivalent series resistance _of the coupling capacitance C12 ^* .

The remarkable effect of the present invention is:

The invention is based on the EC-WPT system of the stacked coupling mechanism as the research object, and proposes a topology in which LCL compensation is used at the transmitting end and single inductance compensation is used at the receiving end. In this way, the system can provide the required power to the load after the load is moved in, maintain a low input power state (standby mode) after the load is removed, and will not cause voltage to the inverter switch during the process of moving in and removing. and current overshoot.

Description of drawings

In order to illustrate the specific embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that are required to be used in the description of the specific embodiments or the prior art. Similar elements or parts are generally identified by similar reference numerals throughout the drawings. In the drawings, each element or section is not necessarily drawn to actual scale.

1 is a cross-sectional view of a laminated coupling mechanism with grooves in a specific embodiment of the present invention;

2 is a schematic diagram of an EC-WPT system of a stacked coupling mechanism in a specific embodiment of the present invention;

Fig. 3 is the port capacitance distribution diagram between each pole plate in the stacked coupling structure in Fig. 1;

FIG. 4 is a cross-capacitive coupling model diagram of the stacked coupling structure in FIG. 1;

Figure 5 is the equivalent circuit after the load is removed;

Figure 6 is the equivalent circuit when the load is not removed;

Figure 7 is the equivalent circuit of the π-type coupling structure of the EC-WPT system;

FIG. 8 is a graph showing the variation relationship of Re(Z ₄ ) with f and L ₃ in a specific embodiment of the present invention;

Fig. 9 is the parameter design flow chart of the specific embodiment of the present invention;

Figure 10 is the output waveform diagram of the system inverter with load in the simulation experiment;

Figure 11 is the input current waveform during the load moving out and moving in process in the simulation experiment;

Figure 12 is the load voltage and current waveform diagrams in the simulation experiment;

Fig. 13 is the waveform diagram of inverter output voltage and current in the specific verification experiment;

FIG. 14 is a current waveform diagram of the load moving out and moving in process in the specific verification experiment.

Detailed ways

Embodiments of the technical solutions of the present invention will be described in detail below with reference to the accompanying drawings. The following examples are only used to more clearly illustrate the technical solutions of the present invention, and are therefore only used as examples, and cannot be used to limit the protection scope of the present invention.

It should be noted that, unless otherwise specified, the technical or scientific terms used in this application should have the usual meanings understood by those skilled in the art to which the present invention belongs.

This embodiment provides a load-adaptive EC-WPT system based on a stacked coupling mechanism. In order to further save space, the system adopts a stacked coupling mechanism with grooves. As shown in FIG. The inner electrode plate is embedded in the outer electrode plate, and the inner and outer electrode plates are filled with insulating dielectric material to maintain insulation. The two pole plates connected with the power supply end are the power emitter plates, and the two pole plates connected with the load end are the power receiving pole plates. Since the plates of the transmitter and the receiver are of the same size, and the inner plate is embedded in the outer plate, when the load device is moved in and out, it is only necessary to ensure that the outer plates of the transmitter and the receiver are facing each other, which greatly enhances the Flexibility to move in and out of the EC-WPT system in practical applications. The schematic diagram of the load-adaptive EC-WPT system based on the stacked coupling mechanism adopted in this embodiment is shown in FIG. 2 . In the figure, E is the DC input voltage, and _ui is the inverter output voltage. The coupling mechanism is composed of four pole plates P ₁ , P ₂ , P ₃ and P ₄ arranged. The two pole plates P ₁ and P ₂ connected to the power supply end constitute the energy emitting end, and the two pole plates connected to the load end The polar plates P ₃ and P ₄ constitute the energy receiving end, and the four polar plates are cross-coupled to each other to constitute the energy transmission channel. The energy is first input into the high-frequency inverter circuit from the DC power supply, and the high-frequency inverter circuit converts the DC power into high-frequency AC power and outputs, and is provided to the coupling mechanism through the T-type LCL compensation network composed of the inductor L ₁ , the capacitor C ₁ and the inductor L ₂ for transmission. The transmitter and the receiver generate displacement current under the action of the alternating electric field to realize the transmission of energy between the plates. _The compensation inductor L3 at the receiving end further compensates the reactive power of the coupling mechanism, and finally provides power for the load through rectification and filtering.

The transmission distance of the EC-WPT system is the distance between P ₂ and P ₄ and is denoted as d ₁ , and the description of the size of the coupling mechanism is marked in FIG. 1 . 3 and 4, it can be seen that the four polar plates constitute six network ports, and the capacitance obtained from each port is called the port capacitance C _Tij (i, j=1, 2, 3, 4). In the capacitor network composed of four plates, every two plates are coupled to form a capacitor, and the four plates are cross-coupled to form six capacitors. We define this capacitor as the cross-coupling capacitor C _ij (i, j=1 , 2, 3, 4).

Considering the cross-coupling between the plates of the stacked coupling mechanism, when the quadrupole plate is fixedly placed, the capacitance value between the two pole plates actually measured is not only the capacitance value formed by the two pole plates, but should be Capacitance value for this net port. For example, in conjunction with Figure 3 and Figure 4, it can be seen that the value obtained by measuring the two boards P ₁ and P ₂ is not the capacitance formed by the two separate boards, but should be the capacitance value obtained from the network ports 1 and 2, which is The port capacitance C _T12 formed by the six capacitors shown in FIG. 4 . Similarly, it can be seen from FIG. 4 that the port capacitances obtained from other ports include C _T13 , C _T14 , C _T23 , C _T24 and C _T34 .

When the size and position of the four plates are determined, the port capacitance can be determined, and the cross-coupling capacitance can be determined accordingly. It can be seen that there is a certain functional relationship between the six-port capacitance and the cross-coupling capacitance. Through the basic theory of the circuit, C _Tij and C can be obtained. A relational expression between _ij .

This system designs circuit parameters under constant frequency control, and the system works stably under constant frequency control, which greatly reduces the complexity of system control. After the load is moved in, the input impedance of the system should be in a low-impedance state, and the system should work in the ZPA state to make it easier for the system to achieve ZVS during actual work, so as to meet the system output power and efficiency requirements; after the load is moved out, the input impedance should be It is a high-impedance state to ensure that the system works in the low-power state of the standby mode, and also makes the system work in the ZPA state without frequency drift.

C₁₂ ^*为P₁和P₂构成的耦合电容，不同于端口电容C_T12，也不同于交叉耦合电容C₁₂。考虑到实际电感和极板电容是存在等效串联电阻的，若记L₂和C₁₂ ^*的等效串联电阻为R₂和R₁₂，则图中R_x为电感L₂和C₁₂的等效串联电阻之和，且有R₂＝ωL₂/Q_L，

其中Q_L为电感品质因数，

为电容介质损耗角。When the load is removed, the energy receiving plate composed of _P3 and P4 and its subsequent circuit are removed, and the remaining part forms a new circuit, which can be equivalent to the circuit shown in Figure ₅ . In the figure, u _i is the square wave voltage obtained after DC inversion, its fundamental wave component is u _p , and its effective value is

C ₁₂ ^* is the coupling capacitance formed by P ₁ and P ₂ , which is different from the port capacitance C _T12 and also different from the cross-coupling capacitance C ₁₂ . Considering that the actual inductance and plate capacitance have equivalent series resistance, if the equivalent series resistance of L ₂ and C ₁₂ ^* is R ₂ and R ₁₂ , then R _x in the figure is the equivalent of the inductance L ₂ and C ₁₂ The sum of the effective series resistance, and R ₂ =ωL ₂ /Q _L ,

where _QL is the inductor quality factor,

is the dielectric loss angle of the capacitor.

The system is analyzed by the fundamental wave approximation method, and the input impedance of the circuit can be obtained from Figure 5 as:

where ω is the angular frequency of the fundamental component of u _i . In order to make the system work in the low-power state of standby mode after the load is removed, when the input voltage remains unchanged, the input impedance of the system must be in a high-impedance state to reduce the system input power to a lower state. Since the system is required to work in the ZPA state, the imaginary part of the input impedance of the system should be zero at this time, that is:

Substituting (2) into (1) can simplify the input impedance to:

的值均可通过电桥测量得到。由式(3)可见，输入阻抗为纯阻性，系统理论功率因数为1。当耦合机构确定之后，则C₁₂ ^*也相应确定。为使系统工作在待机模式，需要设计合适的f和C₁使Z_in呈高阻态。where _QL and

The value of can be measured by the bridge. It can be seen from formula (3) that the input impedance is purely resistive, and the theoretical power factor of the system is 1. After the coupling mechanism is determined, C ₁₂ ^* is determined accordingly. In order to make the system work in standby mode, it is necessary to design appropriate f and C ₁ to make Z _in a high-impedance state.

分别为201和0.013。In this embodiment, combined with the layered coupling mechanism with grooves shown in FIG. 1, the coupling mechanism with the size parameters shown in Table 1 is used as a research example to analyze and design the system, and each cross-coupling capacitance is measured through experiments. , and further the cross-coupling capacitance of the coupling mechanism that can be obtained is shown in Table 2. _The C12 ^* after removal was _400pF as measured by the bridge, QL and

201 and 0.013, respectively.

Table 1 Dimensions of the coupling mechanism

Table 2 Port capacitance and cross-coupling capacitance values

When the load is not removed, the equivalent circuit of the system is shown in Figure 6. Using Kirchhoff's law to simplify the cross-coupled six-capacitor structure into a π-type three-capacitor structure, the circuit shown in FIG. 6 can be further simplified into the circuit shown in FIG. 7 . By establishing Kirchhoff's equations, it can be deduced

In practical applications, the size and position of the coupling mechanism are generally symmetrical, so C ₃₄ =C ₁₂ , C ₂₃ =C ₁₄ , and C ₁₁ , C ₂₂ and C _M can be further simplified to obtain

It can be seen from Figure 7 that:

The resonant frequency of the system keeps the same before and after the load is removed. In order to ensure that the system works in the ZPA state when the load is not removed, the imaginary part of Z ₄ must meet the following conditions:

Under the same ZPA working state, it can be concluded that the system input impedance when the load is not removed is

In the formula, Re(Z ₄ ) is the real part of Z ₄ . In order to ensure the normal power transmission of the system, the input impedance of the system with the load not removed must be in a low-impedance state, that is, Re(Z ₄ )>>R _x must be satisfied.

It can be seen from equation (6) that when the coupling mechanism and the load are constant, the variation law of Z ₄ with respect to the system operating frequency f and the inductance L ₃ can be obtained. Considering the system volume and system loss in practical applications, f is given according to experience. The ranges of and L ₃ are (500kHz, 1.5MHz) and (10μH, 100μH), respectively, and the three-dimensional relationship of the real part of Z ₄ Re(Z ₄ ) with respect to f and L ₃ is drawn when the equivalent load Re _eq is 10Ω Figure, as shown in Figure 8. After the system operating frequency is selected, the parameter L ₃ can be determined by solving equation (7), thereby further obtaining Re(Z ₄ ).

式中N为常数，根据应用中待机模式的功率要求指标而定。If it is defined that the power in standby mode is less than x% of the power in the system under load, it can be deduced:

where N is a constant, based on the power requirements of the application in standby mode.

If the effective value of the fundamental component of the input voltage is U _p , to ensure that the required output power of the system is P _out and the transmission efficiency η, the system input power must be greater than P _out /η, and the system input current should be greater than P _out /(ηU _p ), the input current in the system standby mode should not exceed P _out /(NηU _p ), so the input impedance should be higher than NηU _p ² /P _out , namely:

Z _in >NηU _p ² /P _out (10)

Based on the above analysis, the system parameter design flow chart shown in Figure 9 is given. According to the requirements in practical applications, the equivalent load resistance, coupling mechanism and system operating frequency can be determined first, and the constant N and the initial value of the input voltage can be given according to the input power requirements in standby mode and the output power requirements of the system under load. . Among them, in order to ensure that the output power can meet the application requirements, the setting of the input voltage will leave a certain margin. After the coupling mechanism is determined, the capacitance of each port can be measured, and each cross-coupling capacitance can be calculated according to the formula. After simplifying the cross-coupling model, the value of L ₃ can be obtained from equations (6) and (7), and Re(Z ₄ ) can be further determined. When the constant N is given, R _x is determined according to formula (9), L ₂ can be determined from the equivalent series resistance relationship, and finally the values of L ₁ and C ₁ are obtained from formula (2). Then it is judged whether the input impedance relationship meets the requirements. If so, the system parameters are given. If not, the size of N is further adjusted.

Based on the above parameter design method, this embodiment also provides the system parameters shown in Table 3, and builds the EC-WPT system simulation model under the MATLAB/Simulink simulation platform. Figure 10 shows the inverter output voltage and current waveforms of the EC-WPT system with the load not removed. It can be seen that the system output voltage and current are in the same phase, and the system works in the ZPA state. Figure 11 shows the waveform of the input current in the process of load moving out and moving in. It can be seen that there is no current spike during the switching process of the system, and it will not cause current impact to the switching tube. When the load is removed, the input current amplitude is reduced to about 0.016A, the system input power is about 0.51W, and the system works in standby mode. Figure 12 shows the load voltage and current waveforms. It can be seen that the output power of the system is 53W when the system is working with a load.

Table 3 EC-WPT system parameter values

In order to further verify the validity of the theories and methods in this paper, this embodiment also builds a specific experimental device based on the EC-WPT system topology shown in FIG. 2 and the system parameters shown in Table 3. The size of the coupling mechanism is generally selected according to the actual application. In this experiment, the coupling mechanism is composed of four aluminum plates. The size parameters are shown in Table 1. For the convenience of the experiment, insulating tape is used between the plates on the same side to insulate the two plates. , between the transmitting end and the receiving end, an acrylic gasket is used for electrical isolation, and the cross-coupling capacitance of the coupling mechanism is obtained through the measured "port capacitance", as shown in Table 2. The inductor is made of Litz wire wound to form an air-core inductor, the capacitor is a high-frequency high-voltage ceramic capacitor CCG81 series, the switching device of the full-bridge inverter is a silicon carbide MOSFET C2M0080120D from American CREE Company, and the rectifier bridge diode is a silicon carbide tube IDW30G65C from Infineon Company. Considering that the size of the system and the size of the air-core inductor should not be too large, the operating frequency of the system is selected as 1MHz in the experiment. Figure 13 shows the inverter output voltage and current waveforms of the system. It can be seen that the system is weakly inductive, and the system realizes ZVS work. Figure 14 shows the waveform of the system inverter output current during the process of load moving out and moving in. It can be seen that there is no current spike in the dynamic process before and after the load is moved out, which shows that this design method is beneficial to improve the system reliability. After the load is removed, the inverter current amplitude drops rapidly to about 0.01A. At this time, the output power of the system does not exceed 0.5W, and the system works in standby mode; About 51W, 82% efficiency. Due to the use of a stacked coupling mechanism with grooves, when the load is moved into the system again, there will be no obvious dislocation, and the system at this time is basically the same as the system before the load is moved out. This can be explained by the deviation of the inverter current below 0.5%.

To sum up, the specific embodiment of the present invention verifies this feature through simulation and experiments. It should be noted that the theories and methods of the present invention are not only applicable to the coupling mechanism used as an example in this paper, but also can use the same method and idea to design system parameters for coupling mechanisms of other sizes.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that it can still be Modifications are made to the technical solutions recorded in the foregoing embodiments, or some or all of the technical features thereof are equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention. It should be covered within the scope of the claims and description of the present invention.

Claims (4)

1. A parameter design method for a load-adaptive EC-WPT system based on a stacked coupling mechanism, the system includes a transmitter and a receiver, and P ₁ , P ₂ , P ₃ are used between the transmitter and the receiver , P ₄ The stacked coupling mechanism composed of four polar plates is used as an energy transmission channel, the polar plate P ₁ and the polar plate P ₂ are located at the transmitting end, the polar plate P ₃ and the polar plate P ₄ are located at the receiving end, and in the stacked coupling mechanism The structures of the transmitting end and the receiving end are symmetrical to each other. The transmitting end is also provided with a DC power supply, a high-frequency inverter circuit, and a T-type LCL compensation network composed of an inductance L ₁ , a capacitor C ₁ and an inductance L ₂ , and the receiving end is also provided with a T-type LCL compensation network. Compensation inductance L ₃ , rectifier filter circuit and equivalent load resistance are provided; It is characterized in that, the parameter design method comprises the following steps: S1: Determine the size and spatial position of each pole plate in the stacked coupling mechanism according to the application, and at the same time determine the equivalent load resistance R _L and the system operating frequency f; S2: The initial value E of the system input voltage is given according to the required power; S3: Set the constant N according to the required input power index requirements of the ECPT system in the standby mode; S4: Inductor quality factor _QL and capacitor dielectric loss angle are obtained by bridge measurement

The port capacitance value C _Tij (i, j=1, 2, 3, 4; i≠j) between each pole plate in the stacked coupling mechanism and between the pole plate P ₁ and the pole plate P ₂ after the receiving end is removed The coupling capacitance C ₁₂ ^* , and the cross-coupling capacitance C _ij ( _i , j= 1,2,3,4; i≠j); S5: According to the circuit topology, it is derived from the equivalent load resistance R _L , the compensation inductance L ₃ and the cross-coupling capacitance C _ij (i,j=1,2,3,4; i≠j) in the stacked coupling mechanism The functional expression of the output impedance Z ₄ of the output port of the inductor L ₂ in the state that the output receiving end is not removed; S6: According to

Determine the inductive reactance value of the compensating inductor L ₃ at the receiving end, wherein the system operating angular frequency ω=2πf, Im(Z ₄ ) is the imaginary part of the output impedance Z ₄ of the output port of the inductor L ₂ ; S7: Determine the sum R _x of the equivalent series resistance of the inductor L ₂ and the coupling capacitor C ₁₂ ^* according to Re(Z ₄ )=N·R _x , and Re(Z ₄ ) is the difference between the output impedance Z ₄ of the output port of the inductor L ₂ Real; S8 _: Determine the inductance value of the inductance L2 according to the sum _Rx of the equivalent series resistance _of the inductance L2 and the coupling capacitor C12 ^* _; S9: According to the resonance condition

Determine the inductance value of inductor L ₁ and the capacitance value of capacitor C ₁ ; S10: Determine whether the inequality constraints are satisfied: Z _in >NηU _p ² /P _out , if satisfied, determine the final system parameters, if not, adjust the size of the constant N, and return to step S3 to redesign the value of N, where : Z _in is the input impedance of the input end of the inductor L ₁ ; η is the transmission efficiency, P _out is the output power required by the system, and U _p is the effective value of the fundamental component of the input voltage. 2. the parameter design method of the load-adaptive EC-WPT system based on the stacked coupling mechanism according to claim 1, is characterized in that: When setting the constant N in step S3, if the input power in the standby mode is defined to be less than x% of the output power in the system under load working state, then

3. The parameter design method of the load-adaptive EC-WPT system based on the stacked coupling mechanism according to claim 1, is characterized in that: when the system operating frequency f is set, its range is selected between (500kHz, 1.5MHz) between. 4. the parameter design method of the load-adaptive EC-WPT system based on the stacked coupling mechanism according to claim 1, is characterized in that: The sum of the equivalent series resistances in step S7 is R _x =R ₂ +R ₁₂ ^* , where R ₂ =ωL ₂ /QL represents the equivalent series resistance of the inductor _{L 2} ,

represents the equivalent series resistance _of the coupling capacitance C12 ^* .

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