Rapid maximum efficiency tracking control method and system for wireless charging system

Abstract

The invention provides a rapid maximum efficiency tracking control method and system for a wireless charging system, and solves the problems of high time complexity, low solving speed and low maximum tracking speed of an existing maximum efficiency tracking control method. According to the method adopted by the invention, firstly, a current solution is compared with a previous solution and a latter solution, and if the current solution is superior to the previous solution and the latter solution at the same time, an interval in which an optimal solution is located can be determined; secondly, maximum efficiency tracking is carried out through a golden section search algorithm; the time complexity of the golden section search algorithm is generally O (log n), and n is the dimension of a solution space. The solution space dimension is generally greater than 1, and O (log n) is less than O (n) at the moment, so that the maximum efficiency tracking speed can be improved to a certain extent by adopting the perturbation observation-golden section method.

Description

Technical Field

[0001] The present invention belongs to the technical field of underwater wireless charging, and in particular relates to a method and system for fast maximum efficiency tracking control of a wireless charging system. Background Art

[0002] Wireless charging technology is a contactless charging technology. The system consists of two parts: the transmitter and the receiver. It is currently widely used in the fields of smartphones, smart home appliances and electric vehicles. In wireless charging technology, pursuing maximum charging efficiency is an important direction. If the maximum efficiency of the system is to be achieved, maximum efficiency tracking and control is required. Most of the existing technical solutions currently send the operating parameters of the receiver (such as voltage and current) to the transmitter through a wireless communication network. The transmitter calculates the optimal DC / DC voltage value through a series of derived formulas to achieve maximum efficiency. This calculation method can obtain accurate maximum efficiency, but it requires wireless communication, which is prone to interference in a strong magnetic field environment such as wireless charging, resulting in problems such as packet loss and connection interruption.

[0003] Chinese patent CN111509865B provides a maximum efficiency tracking control method and system for a wireless charging system, and Chinese patent application CN110571899A provides a constant current output control and efficiency improvement method for a wireless power transmission system based on a variable step size perturbation observation method. The above schemes can perform maximum efficiency tracking without the need for wireless communication. However, the above maximum efficiency tracking control methods are all based on the perturbation observation method, which is a greedy algorithm, that is, starting from a point in the solution space, moving to adjacent points until a local optimal solution that cannot be moved is reached. Both methods are greedy algorithms because they only compare with the previous solution. The time complexity of a typical greedy algorithm is usually linear or nearly linear, that is, O(n), where n is the dimension of the solution space. It has a high time complexity, a slow solution speed, and a low maximum tracking speed. Summary of the invention

[0004] The purpose of the present invention is to solve the shortcomings of the existing maximum efficiency tracking control method, such as high time complexity, slow solution speed and low maximum tracking speed, and to provide a wireless charging system fast maximum efficiency tracking control method and system.

[0005] To achieve the above purpose, the technical solution provided by the present invention is:

[0006] A wireless charging system fast maximum efficiency tracking control method and system, which is special in that it includes the following steps:

[0007] 1) Optimal solution existence judgment stage

[0008] According to the phase shift angle range of the primary side inverter, from the maximum phase shift angle θ inmax Start by decreasing the minimum resolution twice and taking the phase shift angle θ(1) = θ inmax , phase shift angle θ(2) = θ(1) - Δθ, phase shift angle θ(3) = θ(2) - Δθ, and calculate the corresponding input power P respectively in (1) P in (2) and P in (3); where Δθ is the minimum resolution of the primary-side inverter phase shift angle;

[0009] If P in (1) <P in (2) <P in (3), then the maximum phase shift angle θ of the primary side inverter is inmax The optimal phase shift angle value is selected for system efficiency, the maximum efficiency tracking is completed, and step 4 is entered;

[0010] Otherwise, go to step 2);

[0011] 2) Improve the disturbance observation phase

[0012] Within the phase shift angle range of the primary side inverter, (θ inmax -θ inmin ) / 10 as the step size Δθ' (thereby, the optimal solution interval can be determined in 10 times at most), and the phase shift angle value is gradually reduced in order from large to small, and the corresponding input power P is calculated when the phase shift angle is θ(k-1)=θ(k-2)-Δθ', θ(k)=θ(k-1)-Δθ', θ(k+1)=θ(k)-Δθ' in (k-1), P in (k) and P in (k+1); the value of k ranges from 2 to 9. During the iteration process:

[0013] If P in (k+1)>P in (k) <P in (k-1), then the optimal phase shift angle selection range for system efficiency is [θ(k+1), θ(k-1)], and proceed to step 3);

[0014] If P in (k+1)>P in (k)≥P in (k-1), then the optimal phase shift angle selection range for system efficiency is [θ(k), θ(k-1)], and proceed to step 3);

[0015] If there is always P in (k+1) <P in (k) <P in(k-1), until θ(k+1)≤θ inmin (In actual situations, the minimum phase shift angle of the primary side inverter is θ inmin , but in the judgment, it is also possible to perform the next iteration to obtain the calculated value. Therefore, in the judgment process, θ(k+1) can be less than θ inmin ), then the minimum phase shift angle θ of the primary side inverter inmin The optimal phase shift angle value is selected for system efficiency, the maximum efficiency tracking is completed, and step 4 is entered;

[0016] In the method of the present invention, in order to avoid more judgments, P is not considered. in (k+1)=P in (k) In this way, the judgment logic and process can be simplified;

[0017] 3) Golden section search phase

[0018] Use the golden section search algorithm to select the best phase shift angle selection value within the best phase shift angle selection range selected in step 2), and proceed to step 4);

[0019] 4) The selected optimal phase shift angle value is used as the phase shift angle of the primary-side inverter to achieve maximum efficiency control of the wireless charging system.

[0020] Meanwhile, the present invention provides a wireless charging system, which is special in that it includes a transmitting end and a receiving end;

[0021] The transmitting end includes a power supply battery, a primary side controller, a primary side inverter, a primary side compensation network and a primary side coupler;

[0022] The positive and negative electrodes of the power supply battery are connected to the positive and negative input ports of the primary side inverter, the output port of the primary side inverter is connected to the input port of the primary side compensation network, and the output port of the primary side compensation network is connected to the primary side coupler; wherein the primary side controller controls the phase shift angle of the primary side inverter through four-way PWM, thereby controlling the effective value of the output AC voltage of the primary side inverter;

[0023] The receiving end includes a rechargeable battery, a secondary side controller, a secondary side controlled rectifier, a secondary side compensation network and a secondary side coupler;

[0024] The secondary side coupler is connected to the input port of the secondary side compensation network, the output port of the secondary side compensation network is connected to the input port of the secondary side controlled rectifier, and the output positive and negative ports of the secondary side controlled rectifier are connected to the positive and negative electrodes of the rechargeable battery;

[0025] The primary side coupler and the secondary side coupler are coupled after the transmitting end and the receiving end are connected, and the two wirelessly transmit electric energy through electromagnetic induction generated by high-frequency alternating current;

[0026] The secondary-side controlled rectifier controls the output current and voltage according to the load requirements of the rechargeable battery, that is, the secondary-side controlled rectifier generates the voltage or current required by the battery to supply energy to the rechargeable battery under the control of the secondary-side controller;

[0027] The primary side inverter adopts the above-mentioned wireless charging system fast maximum efficiency tracking control method under the control of the primary side controller in the phase angle range [θ inmin ,θ inmax ] is used to search for the maximum efficiency tracking of the wireless charging system, and the optimal phase shift angle corresponding to the optimal output AC voltage effective value is found by controlling the phase shift angle between the two phases.

[0028] Concept and principle of the present invention:

[0029] In view of the problems existing in the prior art, the research team of the present invention conducted an in-depth analysis and found that the current perturbation observation method has a high time complexity of the algorithm when executing, which is O(n), the calculation time is long, the maximum efficiency tracking speed is slow, and there will be a three-point oscillation link in the final stage, which is not conducive to the rapid tracking of the maximum efficiency point. At the same time, the theoretical optimal point finally found by the perturbation observation method is in the three-point oscillation area near the actual optimal point. Therefore, the selection of the perturbation step size Δθ requires a trade-off between the convergence speed and the oscillation, which is not conducive to the stability of the system. Figure 2 As shown in the figure, although increasing the perturbation step size Δθ can increase the maximum efficiency tracking speed, the final three-point oscillation area will be very large; although reducing the perturbation step size Δθ can reduce the three-point oscillation area, it will significantly increase the maximum efficiency tracking time; the operating mechanism of using the existing perturbation observation method for maximum efficiency tracking in the wireless charging system is as follows:

[0030] First, under the control of the controlled rectifier, the receiving end maintains the current value or voltage value required by the load unchanged. At this time, the output power P of the receiving end out Then, the phase shift angle of the primary inverter is adjusted based on the disturbance observation algorithm. When the output power of the battery (which is also the input power P of the wireless charging system) is detected, in ) reaches the minimum, the efficiency of the entire system reaches the maximum. When the system is in area A and area C, the phase shift angle of the primary inverter can be increased or decreased by the disturbance step Δθ, thereby continuously reducing the input power P in When the system enters zone B, θ in The state changes to P2, P minThe three-point oscillation stage between P1 and P4 points, that is, the optimal primary-side inverter phase shift angle for maximum efficiency is found. During operation, the change of the primary-side inverter phase shift angle is controlled by the duty cycle of the primary-side inverter, and the control method is the fixed-step disturbance observation method described in CN111509865B. It can be seen that if the amplitude of the final three-point oscillation stage is to be avoided, the disturbance step size needs to be reduced; if the speed of maximum efficiency tracking is to be increased, the disturbance step size needs to be increased. Therefore, the selection of the disturbance step size requires a trade-off between the oscillation amplitude and the tracking speed, which is not conducive to the stability of the system.

[0031] In order to improve the speed of tracking the maximum efficiency point, the present invention adopts an improved perturbation observation-golden section algorithm to achieve fast maximum efficiency tracking. First, the current solution should be compared not only with the previous solution, but also with the next solution. If the current solution is better than both the previous solution and the next solution, the interval where the optimal solution is located can be determined; secondly, the maximum efficiency tracking is performed through the golden section search algorithm. The time complexity of the golden section search algorithm is usually O(log n), where n is the dimension of the solution space. Since the dimension of the solution space is usually greater than 1, O(log n) < O(n), so the perturbation observation-golden section method can improve the speed of maximum efficiency tracking to a certain extent.

[0032] In the wireless charging method provided by the present invention, the secondary-side controlled rectifier is used to adjust the output to maintain a constant output voltage V required by the load. out Or the constant output current I required by the load out The input voltage of the primary side coupler V in Only the phase shift angle of the primary side inverter is adjusted, and the control method is to improve the disturbance detection-golden section algorithm until the output power of the input end battery (that is, the input power P of the wireless power transmission system) is in ) reaches the minimum point. For a given output voltage or output current, reaching the minimum input power operating point is equivalent to reaching the maximum energy efficiency operating point (system efficiency η=P out / P in , then when P out unchanged, P in During the whole operation, the duty cycle of the driving signal of the primary inverter is constant at 50%, but the phase shift angle θ between the two phases is controlled by the primary controller and is adjusted according to the disturbance detection-golden section search method within the phase angle range [θ inmin ,θ inmax ] to search.

[0033] The advantages of the present invention are:

[0034] 1. The transmitting end of the wireless charging system of the present invention includes a power supply battery, a primary side controller, a primary side inverter, a primary side compensation network and a primary side coupler, and the receiving end includes a rechargeable battery, a secondary side controller, a secondary side controllable rectifier, a secondary side compensation network and a secondary side coupler; and the secondary side controllable rectifier controls the output current and voltage according to the rechargeable battery load requirements, and the primary side inverter adopts the wireless charging method proposed by the present invention under the control of the primary side controller to achieve the maximum efficiency tracking of the wireless charging system, and finds the optimal phase shift angle selection value corresponding to the optimal output AC voltage effective value by controlling the phase shift angle. Conventional perturbation observation passes only need to compare the current solution with the previous solution, so there will be Figure 2 The three-point oscillation in the final stage shown in range B; and the improved disturbance observation in the present invention requires that the current solution not only be compared with the previous solution, but also with the next solution. After judging the obtained interval, the golden section method is used to optimize the interval; since the golden section method optimization is unique and has low time complexity and fast solution speed, it can quickly track the maximum efficiency and avoid three-point oscillation. In addition, the present invention not only omits the primary-side DC-DC converter, but also uses a controlled rectifier to replace the uncontrolled rectifier on the secondary side of the conventional system, so as to realize the control of the output voltage and current to match the battery requirements without the need for additional components, thereby further reducing the weight, volume and cost of the system.

[0035] 2. Compared with the simple perturbation observation method, the wireless charging method based on perturbation observation-golden section proposed in the present invention can realize the rapid maximum efficiency tracking of the system without communication conditions and avoid the three-point oscillation existing in the perturbation observation method. At the same time, because no communication is required, it also avoids the different degrees of attenuation of electromagnetic waves caused by different underwater environmental temperatures, salinity and conductivity, resulting in long delays and poor stability of the communication system, reducing the cost, volume and complexity of the underwater wireless charging system, and improving its stability. In addition, since the proposed method does not involve mutual inductance, it can be unaffected by the docking situation on the system power transmission to a certain extent, and achieves the maximum efficiency transmission in this docking state, so it is still effective when the coupler is misaligned. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 Schematic diagram of the LCC-S compensation wireless charging system without communication proposed by the present invention;

[0037] Figure 2 The operating mechanism of the fixed-step maximum efficiency tracking disturbance observation method in the current wireless charging system;

[0038] Figure 3 This is a flow chart of the disturbance observation-golden section algorithm of the present invention;

[0039] Figure 4 : is the relationship between the system efficiency of the present invention and the phase shift angle range of the primary side inverter; (a) is case A, (b) is case B, and (c) is case C;

[0040] Figure 5 To improve the optimal solution interval iteration process in the disturbance observation phase of the present invention;

[0041] Figure 6 It is the iterative calculation process of the golden section search phase;

[0042] Figure 7 To compare the system efficiency when using the perturbation observation-golden section method and when not using this method;

[0043] Figure 8 A comparison between the perturbation observation-golden section method of the present invention and the traditional perturbation observation method; wherein (a) is a load resistance R=7.5Ω; (b) is a load resistance R=10Ω; and (c) is a load resistance R=12.5Ω. DETAILED DESCRIPTION

[0044] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0045] The wireless charging system adopted by the present invention includes a transmitting end and a receiving end; the transmitting end includes a power supply battery, a primary side controller, a primary side inverter, a primary side compensation network and a primary side coupler; the positive and negative electrodes of the power supply battery are connected to the positive and negative input ports of the primary side inverter, the output port of the primary side inverter is connected to the input port of the primary side compensation network, and the output port of the primary side compensation network is connected to the primary side coupler; wherein the primary side controller controls the phase shift angle of the primary side inverter through four-way PWM, thereby controlling the effective value of the output AC voltage of the primary side inverter; the receiving end includes a rechargeable battery, a secondary side controller, a secondary side controlled rectifier, a secondary side compensation network and a secondary side coupler; the secondary side coupler is connected to the input of the secondary side compensation network. On the input port, the output port of the secondary side compensation network is connected to the input port of the secondary side controlled rectifier, and the output positive and negative ports of the secondary side controlled rectifier are connected to the positive and negative electrodes of the rechargeable battery; the primary side coupler and the secondary side coupler are coupled after being connected at the transmitting end and the receiving end, and the two are wirelessly transmitted with electric energy through electromagnetic induction generated by high-frequency alternating current; the secondary side controlled rectifier controls the output current and voltage according to the load requirements of the rechargeable battery, that is, the secondary side controlled rectifier, under the control of the secondary side controller, generates the voltage or current required by the battery to replenish the energy of the rechargeable battery; the primary side inverter, under the control of the primary side controller, adopts the above-mentioned wireless charging system fast maximum efficiency tracking control method to control the phase angle range [θ inmin ,θ inmax] to search for the maximum efficiency tracking of the wireless charging system, and find the optimal phase shift angle selection value corresponding to the optimal output AC voltage effective value by controlling the phase shift angle between the two phases. Figure 1 As shown, Vbattery is the battery supply voltage; Lp and Ls are the self-inductance of the transmitting and receiving couplers respectively; Rp and Rs are the resistances of the transmitting and receiving couplers respectively; M is the mutual inductance of the coupler; Lps, Cpp and Cps represent the transmitting compensation elements used to compensate for the leakage inductance; Css represents the receiving compensation capacitor; C1 (C3) is the filter capacitor of the rectifier; and R is the load resistor.

[0046] In order to improve the speed of tracking the maximum efficiency point, the flowchart of the disturbance observation-golden section algorithm proposed in the present invention is as follows: Figure 3 As shown, it includes the optimal solution existence judgment stage, the improved disturbance observation stage and the golden section search stage. The specific steps are as follows.

[0047] 1) Optimal solution existence judgment stage

[0048] Since the phase shift angle range of the primary-side inverter is a finite interval, the interval may be on the left side of the best efficiency point, on the right side of the best efficiency point, or include the best efficiency point, such as Figure 4 Therefore, it is necessary to determine whether the interval of the primary-side inverter phase shift angle contains the optimal solution before performing maximum efficiency tracking.

[0049] In the optimal solution existence judgment stage, the minimum resolution of the primary side inverter output voltage is used as the disturbance step Δθ, and the primary side inverter is shifted from the maximum phase shift angle θ(1) = θ inmax Start by decreasing twice with the minimum resolution, i.e. θ(2) = θ inmax -Δθ and θ(3) = θ(2) - Δθ, and calculate the corresponding input power P respectively in (1) P in (2) and P in (3). If P in (1) <P in (2) <P in (3), that is, Figure 4 In case (a) of A, the maximum phase shift angle θ of the primary inverter is inmax is the optimal point of system efficiency, the maximum efficiency tracking ends, and the process goes to step 4); otherwise, the process goes to step 2);

[0050] 2) Improve the disturbance observation phase

[0051] In the improved disturbance observation stage, the present invention improves the disturbance observation algorithm so that the current solution P in(k) Not only with the previous solution P in(k-1) Compare with the next solution Pin(k+1) In order to increase the speed of maximum efficiency tracking, the step size of the phase shift angle change can be larger, that is, θ (k) =θ (k-1) -n*Δθ, where Δθ is the minimum resolution of the primary side inverter phase shift angle, n*Δθ is Δθ', Δθ'=(θ inmax -θ inmin ) / 10, then n=[(θ inmax -θ inmin ) / 10] / Δθ, which is a positive integer.

[0052] In the improved disturbance observation stage, if the relationship between the system efficiency and the phase shift angle range of the primary side inverter belongs to Figure 4 (b) Case B. In this case, if P in (k+1)>P in (k) <P in (k-1), the interval where the optimal solution is located is [θ(k+1), θ(k-1)], and go to step 3);

[0053] If P in (k+1)>P in (k)≥P in (k-1), the interval where the optimal solution is located is [θ(k), θ(k-1)], and go to step 3);

[0054] Figure 5 The iterative process of improving the optimal solution interval in the disturbance observation phase is shown. During the search process, if there is always P in (k+1) <P in (k) <P in (k-1), until θ(k+1)≤θ inmin , that is, belongs to Figure 4 In case (c) of C, the minimum phase shift angle θ of the primary inverter is inmin The optimal phase shift angle value for system efficiency is selected, and the maximum efficiency tracking is completed, and the process goes to step 4).

[0055] 3) Golden section search phase

[0056] After improving the perturbation observation phase, the interval where the optimal solution exists is obtained. The next step is to use the golden section search algorithm to find the optimal solution.

[0057] Golden section search is an accurate line search algorithm. When using the golden section search method, the second and third points constitute the golden section points of the initial interval, such as Figure 6As shown in the figure, when the optimal solution interval is from the first point to the third point, the second point is exactly the golden section point of the new interval; when the optimal solution interval is from the second point to the fourth point, the third point is exactly the golden section point of the new interval. Therefore, the golden section point of the initial interval can be reused in the next iteration, greatly reducing the number of experiments.

[0058] The proposed perturbation observation-golden section algorithm can achieve faster maximum efficiency tracking. This is because in the improved perturbation observation stage, the step size can take a larger value, and the time complexity of the golden section search algorithm is lower than that of the perturbation observation method. In addition, the proposed perturbation observation-golden section method for maximum efficiency tracking can also effectively avoid the three-point oscillation existing in the perturbation observation method.

[0059] Figure 7 The curves showing the system efficiency changing with load resistance, coupling coefficient, and whether the perturbation observation-golden section algorithm is used. It can be seen that the system efficiency decreases with the increase of load resistance, because the efficiency of the wireless charging system is related to the load resistance. When the coupling coefficient k is 0.3 or 0.35, the system input power using the perturbation observation-golden section algorithm is lower than the system input power when it is not used, that is, the system efficiency using the perturbation observation-golden section algorithm is higher than the system efficiency when it is not used. Therefore, it can be verified that the perturbation observation-golden section algorithm improves the system efficiency. In addition, it can be proved that the proposed method is still effective when the coupling coefficient changes (i.e., coupler offset).

[0060] In the perturbation observation-golden section algorithm, in the optimal solution existence judgment stage, the phase shift angle θ in The step size of the change is the same as that of the traditional perturbation observation method, that is, Δθ, where Δθ is the minimum output resolution of the primary side inverter. In the improved ramp stage, the phase shift angle θ in The step size of the change is (θ inmax -θ inmin ) / 10 to speed up the maximum efficiency tracking.

[0061] Figure 8 The input power P of the perturbation observation-golden section and traditional perturbation observation methods is shown under the conditions of coupling coefficient k = 0.3, 0.35 and load resistance R = 7.5Ω, 10Ω, 12.5Ω in The relationship curve with the number of iterations.

[0062] from Figure 8 It can be clearly seen from (a)-(c) that the traditional perturbation observation method will have three-point oscillation in the final stage, while the perturbation observation-golden section method of the present invention can effectively avoid oscillation. Figure 8 Under the same number of iterations, the P of the perturbation observation-golden section method inThe value is smaller than that of the traditional perturbation observation method, which means it is more efficient.

[0063] In summary, the perturbation observation-golden section method proposed in the present invention can achieve rapid maximum efficiency tracking of the system without communication conditions and avoid the three-point oscillation existing in the perturbation observation method, compared with the perturbation observation method. At the same time, it avoids the different degrees of attenuation of electromagnetic waves caused by different underwater environmental temperatures, salinity and conductivity, resulting in long delays and poor stability of the communication system, reducing the cost, volume and complexity of the underwater wireless charging system, and improving its stability. In addition, since the proposed method does not involve mutual inductance, it is still effective when the coupler is misaligned.

[0064] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should be included in the protection scope of the present invention.

Claims

1. A wireless charging system fast maximum efficiency tracking control method, characterized in that: The following steps are involved: 1) Optimal solution existence judgment stage According to the phase shift angle range of the primary side inverter, from the maximum phase shift angle θ inmax Start by decreasing the minimum resolution twice and taking the phase shift angle θ(1) = θ inmax , phase shift angle θ(2) = θ(1) - Δθ, phase shift angle θ(3) = θ(2) - Δθ, and calculate the corresponding input power P respectively in (1) P in (2) and P in (3); where Δθ is the minimum resolution of the primary-side inverter phase shift angle; If P in (1) <P in (2) <P in (3), then the maximum phase shift angle θ of the primary side inverter is inmax The optimal phase shift angle value is selected for system efficiency, the maximum efficiency tracking is completed, and step 4 is entered; Otherwise, go to step 2); 2) Improve the disturbance observation phase Within the phase shift angle range of the primary side inverter, (θ inmax -θ inmin ) / 10 as the step size Δθ', and gradually reduce the phase shift angle value in order from large to small, and calculate the corresponding input power P when the phase shift angle is θ(k-1)=θ(k-2)-Δθ', θ(k)=θ(k-1)-Δθ', θ(k+1=θ(k)-Δθ' in (k-1), P in (k) and P in (k+1); the value of k ranges from 2 to 9. During the iteration process: If P in (k+1)>P in (k) <P in (k-1), then the optimal phase shift angle selection range for system efficiency is [θ(k+1), θ(k-1)], and proceed to step 3); If P in (k+1)>P in (k)≥P in (k-1), then the optimal phase shift angle selection range for system efficiency is [θ(k), θ(k-1)], and proceed to step 3); If there is always P in (k+1) <P in (k) <P in (k-1), until θ(k+1)≤θ inmin , then the minimum phase shift angle θ of the primary side inverter inmin The optimal phase shift angle value is selected for system efficiency, the maximum efficiency tracking is completed, and step 4 is entered; 3) Golden section search phase Use the golden section search algorithm to select the best phase shift angle selection value within the best phase shift angle selection range selected in step 2), and proceed to step 4); 4) The selected optimal phase shift angle value is used as the phase shift angle of the primary-side inverter to achieve maximum efficiency control of the wireless charging system.

2. A wireless charging system, characterized in that: Includes a transmitter and a receiver; The transmitting end includes a power supply battery, a primary side controller, a primary side inverter, a primary side compensation network and a primary side coupler; The positive and negative electrodes of the power supply battery are connected to the positive and negative input ports of the primary side inverter, the output port of the primary side inverter is connected to the input port of the primary side compensation network, and the output port of the primary side compensation network is connected to the primary side coupler; wherein the primary side controller controls the phase shift angle of the primary side inverter through four-way PWM, thereby controlling the effective value of the output AC voltage of the primary side inverter; The receiving end includes a rechargeable battery, a secondary side controller, a secondary side controlled rectifier, a secondary side compensation network and a secondary side coupler; The secondary side coupler is connected to the input port of the secondary side compensation network, the output port of the secondary side compensation network is connected to the input port of the secondary side controlled rectifier, and the output positive and negative ports of the secondary side controlled rectifier are connected to the positive and negative electrodes of the rechargeable battery; The primary side coupler and the secondary side coupler are coupled after the transmitting end and the receiving end are connected, and the two wirelessly transmit electric energy through electromagnetic induction generated by high-frequency alternating current; The secondary-side controlled rectifier controls the output current and voltage according to the rechargeable battery load requirements; The primary side inverter adopts the wireless charging system fast maximum efficiency tracking control method of claim 1 under the control of the primary side controller in the phase angle range [θ inmin ,θ inmax ] is used to search for the maximum efficiency tracking of the wireless charging system, and the optimal phase shift angle corresponding to the optimal output AC voltage effective value is found by controlling the phase shift angle.

3. A wireless charging system according to claim 2, characterized in that: The duty cycle of the driving signal of the primary-side inverter is constant at 50%.

Images