Phase shift angle control method, non-singular sliding mode controller, and wireless power transmission system

Abstract

Disclosed in the present application are a phase shift angle control method, a non-singular sliding mode controller, and a wireless power transmission system. The method comprises: on the basis of a non-singular sliding mode surface equation, a state-space average equation and circuit data, obtaining an equivalent control rate; on the basis of the non-singular sliding mode surface equation and the circuit data, obtaining a sliding mode surface; on the basis of the sliding mode surface, obtaining a switching control rate; on the basis of the equivalent control rate and the switching control rate, obtaining a total control rate; and on the basis of the total control rate, adjusting a phase shift angle between driving signals of switching tubes of a wireless power transmission system. In the present application, non-singular sliding mode control of a wireless power transmission system is realized, the non-singular sliding mode control is combined with the principle of chattering elimination for a sliding mode, and a mathematical model of a control system is reconstructed while the order of the system is not increased, such that variables of actual control and measurement are reduced, thereby reducing the system complexity, and the chattering of the system is inhibited while the response speed and the steady state of the system are improved and steady-state errors are reduced, thereby improving the response speed and the anti-interference capability.

Description

Phase shift angle control method, non-singular sliding mode controller and wireless power transmission system Technical Field

[0001] The present application relates to the field of wireless power transmission technology, and in particular to a phase shift angle control method, a non-singular sliding mode controller, and a wireless power transmission system. Background Art

[0002] The power transmission circuit consists of an input power supply, an inverter circuit, a transmitting coil, a receiving coil, a rectifier circuit, a filtering circuit, and a load. The inverter H-bridge consists of multiple switching transistors with integrated anti-parallel diodes, with the two switches in the same bridge arm in complementary conduction. Traditional control methods use PI control to adjust the output voltage deviation so that the power transmission voltage reaches the desired value. However, while traditional PI control is simple, it can lead to slow voltage response and poor steady-state characteristics in the power output.

[0003] Summary of the Invention

[0004] The main purpose of this application is to provide a phase shift angle control method, a non-singular sliding mode controller and a wireless power transmission system, which can solve the technical problems of low voltage response speed and poor steady-state of traditional PI control to the converter output in the prior art.

[0005] To achieve the above objectives, the present application provides, in a first aspect, a phase shift angle control method based on non-singular sliding mode control, which is applied to a non-singular sliding mode controller. The method comprises:

[0006] An equivalent control rate is obtained based on the established non-singular sliding surface equation, the state-space average equation, and the acquired circuit data of the wireless power transmission system. The state variables of the non-singular sliding surface equation include the voltage error and the voltage error differential, the state variables of the state-space average equation include the current value flowing through the filter inductor of the wireless power transmission system and the output voltage feedback, and the circuit data includes sampled data and circuit parameters.

[0007] The sliding surface is calculated based on the non-singular sliding surface equation and circuit data;

[0008] According to the sliding surface, the switching control rate is obtained;

[0009] According to the equivalent control rate and the switching control rate, the total control rate is obtained;

[0010] The phase shift angle between the switch drive signals of the wireless power transmission system is adjusted according to the total control rate.

[0011] To achieve the above-mentioned object, the second aspect of the present application provides a non-singular sliding mode controller, the non-singular sliding mode controller comprising:

[0012] an equivalent control rate calculation module, configured to obtain an equivalent control rate based on an established non-singular sliding surface equation, a state-space average equation, and acquired circuit data of the wireless power transmission system, wherein the state variables of the non-singular sliding surface equation include a voltage error and a voltage error differential, the state variables of the state-space average equation include a current value flowing through a filter inductor of the wireless power transmission system and an output voltage feedback value, and the circuit data includes sampled data and circuit parameters;

[0013] A sliding surface calculation module is used to calculate the sliding surface based on the non-singular sliding surface equation and circuit data;

[0014] A switching control rate calculation module is used to obtain the switching control rate according to the sliding surface;

[0015] A total control rate calculation module is used to obtain the total control rate according to the equivalent control rate and the switching control rate;

[0016] The phase shift angle calculation module is used to adjust the phase shift angle between the switch tube drive signals of the wireless power transmission system according to the total control rate.

[0017] To achieve the above-mentioned object, the third aspect of the present application provides a wireless power transmission system, which includes a non-singular sliding mode controller, a wireless power transmission circuit module, a driving module and a sampling module;

[0018] A sampling module, used for collecting sampling data and providing it to the non-singular sliding mode controller;

[0019] A non-singular sliding mode controller, configured to obtain a phase shift angle between switch drive signals of a wireless power transmission system according to any of the above-mentioned phase shift angle control methods based on non-singular sliding mode control;

[0020] A driving module, configured to generate a switch tube driving signal corresponding to each switch tube according to a phase shift angle, wherein the phase difference between the two switch tube driving signals corresponding to the two switch tubes on the same bridge arm is the phase shift angle;

[0021] The wireless power transmission circuit module is used to control the on and off of the corresponding switch tube according to the switch tube driving signal and perform wireless power transmission.

[0022] To achieve the above-mentioned object, the fourth aspect of the present application provides a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, the processor performs the following steps:

[0023] An equivalent control rate is obtained based on the established non-singular sliding surface equation, the state-space average equation, and the acquired circuit data of the wireless power transmission system. The state variables of the non-singular sliding surface equation include the voltage error and the voltage error differential, the state variables of the state-space average equation include the current value flowing through the filter inductor of the wireless power transmission system and the output voltage feedback, and the circuit data includes sampled data and circuit parameters.

[0024] The sliding surface is calculated based on the non-singular sliding surface equation and circuit data;

[0025] According to the sliding surface, the switching control rate is obtained;

[0026] According to the equivalent control rate and the switching control rate, the total control rate is obtained;

[0027] The phase shift angle between the switch drive signals of the wireless power transmission system is adjusted according to the total control rate.

[0028] To achieve the above-mentioned object, the fifth aspect of the present application provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor performs the following steps:

[0029] An equivalent control rate is obtained based on the established non-singular sliding surface equation, the state-space average equation, and the acquired circuit data of the wireless power transmission system. The state variables of the non-singular sliding surface equation include the voltage error and the voltage error differential, the state variables of the state-space average equation include the current value flowing through the filter inductor of the wireless power transmission system and the output voltage feedback, and the circuit data includes sampled data and circuit parameters.

[0030] The sliding surface is calculated based on the non-singular sliding surface equation and circuit data;

[0031] According to the sliding surface, the switching control rate is obtained;

[0032] According to the equivalent control rate and the switching control rate, the total control rate is obtained;

[0033] The phase shift angle between the switch drive signals of the wireless power transmission system is adjusted according to the total control rate.

[0034] The embodiments of the present application have the following beneficial effects:

[0035] Based on the pre-established non-singular sliding surface equation and state-space average equation, this application calculates the sliding surface based on the sampled data and the circuit parameters of the wireless power transmission system, and then calculates the equivalent control rate and switching control rate to obtain the total control rate. The phase difference between the switch tube drive signals is adjusted according to the total control rate, thereby realizing non-singular sliding mode control of the wireless power transmission system. This application combines the concept of non-singular sliding mode control with the de-bouncing principle of sliding mode control. Without increasing the system order, the mathematical model of the control system is reconstructed, reducing the actual control and measurement variables, reducing the complexity of the wireless power transmission system, and suppressing the jitter of the wireless power transmission system while improving the system response speed and steady state and reducing the steady-state error. It improves the response speed of the wireless power transmission system and improves its anti-interference ability. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0037] in:

[0038] FIG1 is a flow chart of a phase shift angle control method based on non-singular sliding mode control in an embodiment of the present application;

[0039] FIG2 is a comparison diagram of output voltage curves of PI control and non-singular sliding mode control under load changes in an embodiment of the present application;

[0040] FIG3 is a comparison diagram of output voltage curves of the second-order sliding mode control and the non-singular sliding mode control of the present application under load changes in an embodiment of the present application;

[0041] FIG4 is a partial enlarged diagram of a comparison diagram of output voltage curves of the second-order sliding mode control and the non-singular sliding mode control of the present application under load changes in an embodiment of the present application;

[0042] FIG5 is a structural block diagram of a non-singular sliding mode controller according to an embodiment of the present application;

[0043] FIG6 is a structural block diagram of a wireless power transmission system according to an embodiment of the present application;

[0044] FIG. 7 is a circuit diagram of a wireless power transmission circuit module according to an embodiment of the present application. DETAILED DESCRIPTION

[0045] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0046] With reference to FIG1 , the present application provides a phase shift angle control method based on non-singular sliding mode control, the method comprising:

[0047] S100: Obtain an equivalent control rate based on an established non-singular sliding surface equation, a state-space average equation, and acquired circuit data of the wireless power transmission system, wherein the state variables of the non-singular sliding surface equation include a voltage error and a voltage error differential, the state variables of the state-space average equation include a current value flowing through a filter inductor of the wireless power transmission system and an output voltage feedback amount, and the circuit data includes sampled data and circuit parameters.

[0048] Specifically, a phase shift angle control method based on non-singular sliding mode control is applied to the non-singular sliding mode controller.

[0049] The nonsingular sliding surface equation and state-space average equation are pre-established. The state variables of the nonsingular sliding surface equation include the voltage error and the voltage error differential. The voltage error is the difference between the desired output voltage and the actual output voltage or the output voltage feedback; the voltage error differential is the derivative of the voltage error with respect to time t.

[0050] Compared with the second-order sliding mode, the non-singular sliding mode has a faster response speed and is more conducive to achieving the sliding mode control effect without increasing the detection state variables. Therefore, this embodiment chooses to construct a non-singular sliding mode surface to implement sliding mode control.

[0051] The state variables of the state space average equation include the current value flowing through the filter inductor of the wireless power transmission system and the output voltage feedback amount.

[0052] The actual output voltage, that is, the output voltage feedback amount, is a variable.

[0053] The sampled data in the circuit data includes the sampled output voltage feedback amount and the current value flowing through the filter inductor of the wireless power transmission system.

[0054] The circuit parameters in the circuit data include, but are not limited to: expected output voltage value, filter capacitance value, load resistance value, filter inductance value, input voltage value, and the ratio of the number of turns of the receiving coil to the number of turns of the transmitting coil.

[0055] The equivalent control rate is the control rate that forces the system state to work on the sliding surface motion. The function of the equivalent control rate is to control the system to move stably on the sliding surface.

[0056] The equivalent control rate is related to the circuit parameters of the wireless power transmission system and the output voltage feedback amount.

[0057] S200: Calculate the sliding surface based on the non-singular sliding surface equation and circuit data.

[0058] Specifically, substituting some of the circuit data into the non-singular sliding surface equation can calculate the sliding surface. Because the non-singular sliding surface equation includes the variable output voltage feedback, changes in the output voltage feedback will also change the sliding surface.

[0059] S300: Obtain a switching control rate according to the sliding surface.

[0060] Specifically, the switching control rate is used to allow the state variables of the system to approach the sliding surface at two speeds: the variable speed term and the exponential term, which allows the system to enter the sliding surface motion faster.

[0061] The switching control rate is related to the sliding surface. As the sliding surface changes, the switching control rate also changes. Based on the functional relationship between the switching control rate and the sliding surface, the switching control rate can be calculated.

[0062] S400: Obtaining a total control rate according to the equivalent control rate and the switching control rate.

[0063] Specifically, according to the sliding mode equivalent control principle, the total control rate is the sum of the equivalent control rate and the switching control rate.

[0064] S500: Adjusting the phase shift angle between the switch drive signals of the wireless power transmission system according to the total control rate.

[0065] Specifically, the phase shift angle is the phase difference, specifically the phase difference between the switch tube driving signals of two switch tubes in the same bridge arm of the wireless power transmission system.

[0066] The traditional PI control output voltage deviation makes the power transmission voltage reach the expected value. However, although the traditional control is simple, it will lead to the problem of low voltage response speed of power output and poor steady-state characteristics. The introduction of second-order sliding mode control can greatly speed up the system response speed and reduce overshoot. However, the second-order sliding mode control will have a certain steady-state error, and the response speed and anti-interference ability are still lacking. This embodiment improves the system response speed and anti-interference ability, and reduces the steady-state error through non-singular sliding mode control. It effectively solves the problems of low voltage response speed, poor steady-state and steady-state error of the output of the wireless power transmission device (converter) in the system caused by the existing PI control and second-order sliding mode control methods.

[0067] This embodiment, based on pre-established nonsingular sliding mode surface equations and state-space average equations, calculates the sliding mode surface based on sampled data and the circuit parameters of the wireless power transmission system. This calculation then calculates the equivalent control rate and switching control rate to obtain the total control rate. The phase difference between the switch drive signals is adjusted based on the total control rate, thus achieving nonsingular sliding mode control of the wireless power transmission system. This embodiment combines the concept of nonsingular sliding mode control with the principle of sliding mode debounce. This restructures the mathematical model of the control system without increasing the system order, reducing the actual control and measurement variables and reducing the complexity of the wireless power transmission system. This suppresses the chattering of the wireless power transmission system while improving the system response speed and steady-state, and reducing steady-state error, thereby improving the response speed and anti-interference capability of the wireless power transmission system.

[0068] In one embodiment, the phase shift angle is calculated according to the following formula 1: θ = π - πu Formula 1

[0069] Among them, θ is the phase shift angle, and u is the total control rate.

[0070] Specifically, θ represents the phase shift angle between the drive signals for the switches in the wireless power (electric energy) transmission system. The drive signal is generated by the drive module of the wireless power transmission system, and the drive module controls the four switches S1, S2, S3, and S4, each with an integrated anti-parallel diode, to operate the wireless power transmission system.

[0071] In one embodiment, the switching control rate is calculated according to the following formula 2-4: n =-ε|s|sat(s)-ηs Formula 2

[0072] Among them, u n is the switching control rate, s is the sliding surface, ε is a constant greater than 0, η is a constant greater than 0; δ is a constant used to limit the range of the sliding surface s, and k is a constant.

[0073] Specifically, the traditional exponential approach rate causes the system to chatter at the equilibrium point, whereas the new approach rate of Formula 2 used in this embodiment can reduce chattering when the system approaches the equilibrium state.

[0074] ε can be adaptively adjusted according to different systems, for example, ε=10, which is not limited in this application.

[0075] η can be adaptively adjusted according to different systems, for example, η=0.5, and this application does not impose any limitation on this.

[0076] δ is used to limit the interval of the sliding mode surface s and is a constant value. For example, δ = 0.56, and this application does not limit it.

[0077] According to this embodiment, the switching control rate can be dynamically adjusted according to the actual sliding mode surface, and then the phase difference between the driving signals can be adaptively adjusted, reducing the chattering of the wireless power transmission system and enhancing the stability of the system.

[0078] In one embodiment, the non-singular sliding mode surface equation is shown in the following formula 5-7: 1 < p / q < 2 Formula 6

[0079] Among them, s(x) is the sliding mode surface function used to calculate the sliding mode surface s, β is a fixed coefficient, both p and q are odd numbers, x1 is the voltage error, x2 is the differential of the voltage error; α is the voltage sampling coefficient; V0 is the output voltage feedback of the wireless power transmission system, V ref is the expected output voltage value, C is the filter capacitance value of the wireless power transmission system, i c is the current value flowing through the filter capacitor.

[0080] Specifically, β is a fixed coefficient in the mathematical expression. For example, β takes 100, and this application does not limit it.

[0081] α is the voltage sampling coefficient. For example, α takes 1 / 110, and this application does not limit it.

[0082] p and q need to satisfy 1 < p / q < 2. For example, p / q takes 5 / 3, and this application does not limit it.

[0083] Since the non-singular sliding mode has a faster response speed than the second-order sliding mode and is more conducive to the realization of the sliding mode control effect without increasing the detected state variables, this embodiment selects to construct a non-singular sliding mode surface to implement the sliding mode control. The voltage error x1 and the differential of the voltage error x2 are used as the state variables of the non-singular sliding mode surface function. The sliding mode surface is constructed through the state variables. The physical meaning of the sliding mode surface is equivalent to the total error. By controlling the variables, the error is reduced or even approaches 0, thereby reducing the actual system error and making the output voltage reach the expected value as much as possible.

[0084] In one embodiment, the state-space averaging equation is shown in the following formula 8:

[0085] V0 is the output voltage feedback of the wireless power transmission system, i L is the current value flowing through the filter inductor of the wireless power transmission system, C is the filter capacitance value of the wireless power transmission system, R is the load resistance value of the wireless power transmission system, L is the filter inductor value of the wireless power transmission system, Vin is the input voltage value of the wireless power transmission system, and n is the ratio of the number of turns of the receiving coil to the number of turns of the transmitting coil.

[0086] Specifically, a mathematical model of the wireless power transmission device is established. To further simplify and analyze the wireless power (electric energy) transmission system, a mathematical model is established. Here, the state space average equation is used to construct the mathematical model, as shown in Formula 8.

[0087] Assuming that the load of the wireless power transmission system is a linear load, according to Kirchhoff's law, the current i flowing through the filter inductor L is L and the output voltage V0 as state variables, construct the state space average equation of Formula 8.

[0088] Among them, the input voltage V in For direct current.

[0089] This embodiment implements a nonsingular sliding mode control method based on the average state model of the wireless power transmission system. This method combines the concept of nonsingular sliding mode control with the anti-bounce principle of sliding mode control. This method restructures the mathematical model of the control system without increasing the system order, reducing the actual control and measurement variables and system complexity. This method suppresses system chatter while improving system response speed and reducing steady-state error.

[0090] In one embodiment, the equivalent control rate is calculated according to the following formula 5-9: 1<p / q<2 Formula 6

[0091] According to the above formulas 5-8, the following formula 9 is obtained:

[0092] Where s(x) is the sliding surface function or equation used to calculate the sliding surface s, β is a fixed coefficient, p and q are both odd numbers, x1 is the voltage error, x2 is the voltage error differential; α is the voltage sampling coefficient; V0 is the output voltage feedback of the wireless power transmission system, V ref is the expected output voltage value, C is the filter capacitance value of the wireless power transmission system, i c is the current value flowing through the filter capacitor;

[0093] i L is the current value flowing through the filter inductor of the wireless power transmission system, R is the load resistance value of the wireless power transmission system, L is the filter inductor value of the wireless power transmission system, V in is the input voltage value of the wireless power transmission system, and n is the ratio of the number of turns of the receiving coil to the number of turns of the transmitting coil;

[0094] u eq is the equivalent control rate.

[0095] Specifically, in the mathematical expression, β is a fixed coefficient. For example, β takes 100, and this application does not limit this.

[0096] α is the voltage sampling coefficient. For example, α takes 1 / 110, and this application does not limit this.

[0097] p and q need to satisfy 1 < p / q < 2. For example, p / q takes 5 / 3, and this application does not limit this.

[0098] Since the nonsingular sliding mode has a faster response speed than the second-order sliding mode and is more conducive to the realization of the sliding mode control effect without increasing the detected state variables, this embodiment selects to construct a nonsingular sliding mode surface to implement the sliding mode control. The voltage error x1 and the voltage error derivative x2 are used as the state variables of the nonsingular sliding mode surface function. A sliding mode surface is constructed through the state variables. The physical meaning of the sliding mode surface is equivalent to the total error. By controlling the variables, the error is reduced or even approaches 0, thereby reducing the actual system error and making the output voltage reach the expected value as much as possible.

[0099] Establish a mathematical model of the wireless power transmission device. To further simplify and analyze the wireless power (electric energy) transmission system, a mathematical model is established. Here, the state-space averaging equation is used to construct the mathematical model, as shown in Equation 8.

[0100] Assume that the load of the wireless power transmission system is a linear load. According to Kirchhoff's law, with the current i flowing through the filter inductor L L and the output voltage V0 as the state variables, the state-space averaging equation of Equation 8 is constructed.

[0101] Among them, the input voltage V of the wireless power transmission system in is DC.

[0102] Taking the derivative of Equation 7, the derivative values of the state variables x1 and x2 can be obtained, as shown in the following Equation 17:

[0103] x'1 and x'2 are the derivative results of x1 and x2 respectively. V in is the input voltage value of the wireless power transmission system, V ref is the expected output voltage value, L is the value of the filter inductor, C is the value of the filter capacitor, and u is the total control rate. u = u eq + u n

[0104] Among them, u eq is the equivalent control rate, u nis the switching control rate, u is a value greater than 0 and less than 1, which is the duty cycle in physical terms. By adjusting the size of u, the output voltage can be adjusted.

[0105] Derivative Formula 5 and set the derivative result to 0. The derivative result contains x'1 and x'2 in Formula 17. Substitute Formula 17 into the derivative result and combine it with Formula 8 to obtain the specific solution of u in Formula 17. The specific solution of u is u in Formula 9. eq .

[0106] This embodiment implements a nonsingular sliding mode control method based on the average state model of the wireless power transmission system. This method combines the concept of nonsingular sliding mode control with the anti-bounce principle of sliding mode control. This method restructures the mathematical model of the control system without increasing the system order, reducing the actual control and measurement variables and system complexity. This method suppresses system chatter while improving system response speed and reducing steady-state error.

[0107] In one embodiment, adjusting the phase shift angle between the switch drive signals of the wireless power transmission system according to the total control rate in step S500 includes:

[0108] Calculate the limit range of the time spent on the sliding surface in the first stage and the limit range of the time spent in the second stage;

[0109] According to the time limit of the first stage and the second stage, determine whether the total time of the first stage and the second stage does not exceed the preset time;

[0110] If the total duration of the first stage and the second stage does not exceed the preset duration, the phase shift angle between the switch drive signals of the wireless power transmission system is adjusted according to the total control rate.

[0111] Specifically, in order to ensure the stability of the system, the switching control rate u n The accessibility of the switch is judged. n The state variables of the system are allowed to approach the sliding surface at two speeds: the variable speed term and the exponential term. When approaching the sliding surface, -ε|s|sat(s) plays a major role, while when far away from the sliding surface, -ηs plays a major role. n The purpose of is to allow the system to enter the sliding surface motion faster, so the total time t0 reached cannot be infinite. Based on this, this embodiment first determines whether the actual total time t0 is within the preset time before adjusting the phase shift angle (phase difference).

[0112] The total duration of the first and second stages is the sum of the duration of the first stage and the duration of the second stage.

[0113] By determining the limit range of the time used in the first stage and the limit range of the time used in the second stage, the limit range of the total time can be determined, and then it can be determined whether the total time exceeds the preset time.

[0114] If the total duration of the first phase and the second phase does not exceed the preset duration, the phase shift angle between the switch drive signals of the wireless power transmission system is adjusted according to the total control rate.

[0115] If the total duration of the first stage and the second stage exceeds the preset duration, the phase shift angle between the switch drive signals of the wireless power transmission system is not adjusted in the current cycle, that is, the phase shift angle of the previous cycle is kept unchanged.

[0116] In this embodiment, the switching control rate u n The accessibility is judged to meet the stability requirements of the system.

[0117] In one embodiment, in the first stage, the sliding surface reaches s = δ from s(0) in a time period of t1; in the second stage, the sliding surface reaches s = 0 from s = δ in a time period of t2; t0 ≤ a Formula 10 t0 = t1 + t2 Formula 11

[0118] In the first stage, far away from the sliding surface, the effect of -ε|s|sat(s) is much greater than that of -ηs.

[0119] From the initial state s=s(0), the limit range of the duration of the first stage is shown in the following formula 13:

[0120] In the second stage, close to the sliding surface, the effect of -ε|s|sat(s) is much smaller than that of -ηs.

[0121] The limit range of the duration of the second stage obtained from the final state s=0 is shown in the following formula 15:

[0122] From the above formulas 10-15, if the total duration of the first and second stages does not exceed the preset duration, the following formula 16 must be satisfied:

[0123] Among them, t0 is the total duration of the first and second stages, and a is the preset duration.

[0124] Specifically, in order to ensure the stability of the system, the switching control rate u n The accessibility of the switch is judged. nThe state variables of the system are allowed to approach the sliding surface at two speeds: the variable speed term and the exponential term. When approaching the sliding surface, -ε|s|sat(s) plays a major role, while when far away from the sliding surface, -ηs plays a major role. n The purpose of is to allow the system to enter the sliding surface motion faster, so the total time t0 reached cannot be infinite. Based on this, this embodiment first determines whether the actual total time t0 is within the preset time before adjusting the phase shift angle (phase difference), that is, it satisfies formula 10.

[0125] The total duration t0 can be obtained by the sum of the duration used in the first stage and the duration used in the second stage.

[0126] Since the sliding mode is symmetrical when moving away from and approaching the sliding surface, the analysis here is based on the approaching state. The first stage is when the system state reaches δ from s(0), and the time taken is t1; the second stage is when the system state reaches s=0 from δ, and the time taken is t2.

[0127] Formula 10-16 can be used to determine whether the total duration t0 is within the preset duration a.

[0128] FIG2 is a comparison diagram of the output voltage curves of the PI control and the non-singular sliding mode control of the present application under load changes in the embodiment of the present application; FIG3 is a comparison diagram of the output voltage curves of the second-order sliding mode control and the non-singular sliding mode control of the present application under load changes in the embodiment of the present application; FIG4 is a partial enlarged view of the comparison diagram of the output voltage curves of the second-order sliding mode control and the non-singular sliding mode control of the present application under load changes in the embodiment of the present application. Referring to FIG2-FIG4, the sliding mode control method of wireless power transmission in the present application is simulated and compared with the PI control algorithm and the second-order sliding mode control algorithm commonly used in the current prior art. It can be seen that the non-singular sliding mode control method in this community can achieve robust control of the output voltage of wireless power transmission, eliminate the chattering problem, and converge within a limited time. It is more robust and faster than the control method of the prior art PI algorithm and the second-order sliding mode. Among them, FIG4 is specifically a partial enlarged view of the mark a in FIG3.

[0129] FIG5 is a block diagram of a non-singular sliding mode controller according to an embodiment of the present application. Referring to FIG5 , the present application further provides a non-singular sliding mode controller, the non-singular sliding mode controller 10 comprising:

[0130] An equivalent control rate calculation module 100 is configured to obtain an equivalent control rate based on an established non-singular sliding surface equation, a state-space average equation, and acquired circuit data of the wireless power transmission system, wherein the state variables of the non-singular sliding surface equation include a voltage error and a voltage error differential, the state variables of the state-space average equation include a current value flowing through a filter inductor of the wireless power transmission system and an output voltage feedback value, and the circuit data includes sampled data and circuit parameters;

[0131] A sliding surface calculation module 200 is used to calculate the sliding surface according to the non-singular sliding surface equation and circuit data;

[0132] A switching control rate calculation module 300 is used to obtain a switching control rate according to a sliding surface;

[0133] A total control rate calculation module 400 is used to obtain a total control rate based on the equivalent control rate and the switching control rate;

[0134] The phase shift angle calculation module 500 is used to adjust the phase shift angle between the switch drive signals of the wireless power transmission system according to the total control rate.

[0135] Specifically, the non-singular sliding mode controller 10 of this embodiment is used to control or adjust the phase difference between two switch tube driving signals corresponding to two switch tubes on the same bridge arm of the wireless power transmission system.

[0136] This embodiment, based on pre-established nonsingular sliding mode surface equations and state-space average equations, calculates the sliding mode surface based on sampled data and the circuit parameters of the wireless power transmission system. This calculation then calculates the equivalent control rate and switching control rate to obtain the total control rate. The phase difference between the switch drive signals is adjusted based on the total control rate, thus achieving nonsingular sliding mode control of the wireless power transmission system. This embodiment combines the concept of nonsingular sliding mode control with the principle of sliding mode debounce. This restructures the mathematical model of the control system without increasing the system order, reducing the actual control and measurement variables and reducing the complexity of the wireless power transmission system. This suppresses the chattering of the wireless power transmission system while improving the system response speed and steady-state, and reducing steady-state error, thereby improving the response speed and anti-interference capability of the wireless power transmission system.

[0137] In one embodiment, the phase shift angle calculation module 500 calculates the phase shift angle according to the following formula 1: θ = π - πu Formula 1

[0138] Among them, θ is the phase shift angle, and u is the total control rate.

[0139] In one embodiment, the handover control rate calculation module 300 calculates the handover control rate according to the following formula 2-4: n =-ε|s|sat(s)-ηs Formula 2

[0140] Among them, u n is the switching control rate, s is the sliding surface, ε is a constant greater than 0, η is a constant greater than 0; δ is a constant used to limit the range of the sliding surface s, and k is a constant.

[0141] In one embodiment, the non-singular sliding surface equation is as shown in the following formula 5-7: 1<p / q<2 Formula 6

[0142] Where s(x) is the sliding surface function used to calculate the sliding surface s, β is a fixed coefficient, p and q are both odd numbers, x1 is the voltage error, x2 is the voltage error differential; α is the voltage sampling coefficient; V0 is the output voltage feedback of the wireless power transmission system, V ref is the expected output voltage value, C is the filter capacitance value of the wireless power transmission system, i c is the current flowing through the filter capacitor.

[0143] In one embodiment, the state space average equation is shown in Equation 8 below:

[0144] V0 is the output voltage feedback of the wireless power transmission system, i L is the current value flowing through the filter inductor of the wireless power transmission system, C is the filter capacitance value of the wireless power transmission system, R is the load resistance value of the wireless power transmission system, L is the filter inductor value of the wireless power transmission system, V in is the input voltage value of the wireless power transmission system, and n is the ratio of the number of turns of the receiving coil to the number of turns of the transmitting coil.

[0145] In one embodiment, the equivalent control rate calculation module 100 calculates the equivalent control rate according to the following formulas 5-9: 1<p / q<2 Formula 6

[0146] According to the above formulas 5-8, the following formula 9 is obtained:

[0147] Where s(x) is the sliding surface function used to calculate the sliding surface s, β is a fixed coefficient, p and q are both odd numbers, x1 is the voltage error, x2 is the voltage error differential; α is the voltage sampling coefficient; V0 is the output voltage feedback of the wireless power transmission system, V ref is the expected output voltage value, C is the filter capacitance value of the wireless power transmission system, i c is the current value flowing through the filter capacitor;

[0148] i L is the current value flowing through the filter inductor of the wireless power transmission system, R is the load resistance value of the wireless power transmission system, L is the filter inductor value of the wireless power transmission system, V inis the input voltage value of the wireless power transmission system, and n is the ratio of the number of turns of the receiving coil to the number of turns of the transmitting coil;

[0149] u eq is the equivalent control rate.

[0150] In one embodiment, the phase shift angle calculation module 500 specifically includes:

[0151] The unit for calculating the range of duration used in each stage is used to calculate the limit range of duration used by the sliding surface in the first stage and the limit range of duration used in the second stage;

[0152] A timeout determination unit, configured to determine whether the total duration of the first and second stages does not exceed a preset duration based on a limit range of the durations used in the first and second stages;

[0153] The phase shift angle calculation unit is used to adjust the phase shift angle between the switch drive signals of the wireless power transmission system according to the total control rate if the total duration of the first stage and the second stage does not exceed the preset duration.

[0154] In one embodiment, in the first stage, the sliding surface reaches s = δ from s(0) in a time period of t1; in the second stage, the sliding surface reaches s = 0 from s = δ in a time period of t2; t0 ≤ a Formula 10 t0 = t1 + t2 Formula 11

[0155] In the first stage, far away from the sliding surface, the effect of -ε|s|sat(s) is much greater than that of -ηs.

[0156] From the initial state s=s(0), the limit range of the duration of the first stage is shown in the following formula 13:

[0157] In the second stage, close to the sliding surface, the effect of -ε|s|sat(s) is much smaller than that of -ηs.

[0158] The limit range of the duration of the second stage obtained from the final state s=0 is shown in the following formula 15:

[0159] From the above formulas 10-15, if the total duration of the first and second stages does not exceed the preset duration, the following formula 16 must be satisfied:

[0160] Among them, t0 is the total duration of the first and second stages, and a is the preset duration.

[0161] The working principle of the non-singular sliding mode controller of the present application is referred to the frequency control method of the wireless power transmission system mentioned above, which will not be repeated here.

[0162] The present application also provides a wireless power transmission system, which includes a non-singular sliding mode controller 10, a wireless power transmission circuit module 20, a driving module 30 and a sampling module 40;

[0163] A sampling module 40, for collecting sampling data and providing it to the non-singular sliding mode controller;

[0164] A non-singular sliding mode controller 10, configured to control the phase shift angle between the switch drive signals of the wireless power transmission system according to any of the above-mentioned phase shift angle control methods based on non-singular sliding mode control;

[0165] A driving module 30 is configured to generate a switch tube driving signal corresponding to each switch tube according to a phase shift angle, wherein the phase difference between the two switch tube driving signals corresponding to the two switch tubes on the same bridge arm is the phase shift angle;

[0166] The wireless power transmission circuit module 20 is used to control the on and off of the corresponding switch tube according to the switch tube driving signal and perform wireless power transmission.

[0167] Specifically, the sampling module 40 is a voltage and current acquisition module of the wireless power transmission system. The voltage and current acquisition module is used to acquire the voltage and current of the wireless power transmission system to obtain sampling data.

[0168] The sampled data includes but is not limited to the output voltage feedback amount and the current value flowing through the filter inductor of the wireless power transmission system. The sampled data may also include the current value flowing through the filter capacitor of the wireless power transmission system.

[0169] The output end of the sampling module 40 is connected to the input end of the non-singular sliding mode controller 10, the output end of the non-singular sliding mode controller 10 is connected to the input end of the driving module 30, the output end of the driving module 30 is connected to the input end of the wireless power transmission circuit module 20, and the sampling module 40 is connected to the wireless power transmission circuit module 20 to collect the voltage and current of the wireless power transmission circuit module 20.

[0170] The output end of the wireless power transmission system is connected to a power receiving device, and can supply power or charge the power receiving device, etc. This application does not impose any restrictions on this.

[0171] This embodiment, based on pre-established nonsingular sliding mode surface equations and state-space average equations, calculates the sliding mode surface based on sampled data and the circuit parameters of the wireless power transmission system. This calculation then calculates the equivalent control rate and switching control rate to obtain the total control rate. The phase difference between the switch drive signals is adjusted based on the total control rate, thus achieving nonsingular sliding mode control of the wireless power transmission system. This embodiment combines the concept of nonsingular sliding mode control with the principle of sliding mode debounce. This restructures the mathematical model of the control system without increasing the system order, reducing the actual control and measurement variables and reducing the complexity of the wireless power transmission system. This suppresses the chattering of the wireless power transmission system while improving the system response speed and steady-state, and reducing steady-state error, thereby improving the response speed and anti-interference capability of the wireless power transmission system.

[0172] The working principle of the non-singular sliding mode controller of the present application is referred to the frequency control method of the wireless power transmission system mentioned above, which will not be repeated here.

[0173] FIG7 is a circuit diagram of a wireless power transmission circuit module in an embodiment of the present application. Referring to FIG7 , the wireless power transmission circuit module 20 includes a DC power supply, an inverter circuit, a transmitting coil, a receiving coil, a rectifier circuit, a filter circuit, and a load R.

[0174] DC power supply U1 provides a DC input voltage Vin for the wireless power transmission system. The inverter circuit includes four switching transistor modules, each of which includes a switch S1, S2, S3, and S4. Specifically, the inverter circuit H-bridge consists of four switches S1, S2, S3, and S4 with integrated antiparallel diodes. The two switches in the same bridge arm are in complementary conduction. Switches S1 and S3 belong to the same bridge arm, and switches S2 and S4 also belong to the same bridge arm. The phase difference between the drive signals for switches S1 and S3 is controlled by the aforementioned non-singular sliding mode device; the phase difference between the drive signals for switches S2 and S4 is also controlled by the aforementioned non-singular sliding mode device. The phase difference between the two groups of switches S1 and S3 and S2 and S4 is the same, and the switching frequencies of the four switch drive signals are the same.

[0175] The turns ratio of the receiving coils (W21 and W22) to the transmitting coil W1 is n.

[0176] The rectifier circuit includes rectifier diodes VD1 and VD2.

[0177] The filter circuit includes a filter inductor L and a filter capacitor C.

[0178] In one embodiment, a computer device is provided. The computer device includes a non-singular sliding mode controller, a memory, and a processor. The memory stores a computer program. When the computer program is executed by the processor, the processor performs the following steps:

[0179] An equivalent control rate is obtained based on the established non-singular sliding surface equation, the state-space average equation, and the acquired circuit data of the wireless power transmission system. The state variables of the non-singular sliding surface equation include the voltage error and the voltage error differential, the state variables of the state-space average equation include the current value flowing through the filter inductor of the wireless power transmission system and the output voltage feedback, and the circuit data includes sampled data and circuit parameters.

[0180] The sliding surface is calculated based on the non-singular sliding surface equation and circuit data;

[0181] According to the sliding surface, the switching control rate is obtained;

[0182] According to the equivalent control rate and the switching control rate, the total control rate is obtained;

[0183] The phase shift angle between the switch drive signals of the wireless power transmission system is adjusted according to the total control rate.

[0184] In one embodiment, a computer-readable storage medium is provided, storing a computer program. When the computer program is executed by a processor, the processor performs the following steps:

[0185] An equivalent control rate is obtained based on the established non-singular sliding surface equation, the state-space average equation, and the acquired circuit data of the wireless power transmission system. The state variables of the non-singular sliding surface equation include the voltage error and the voltage error differential, the state variables of the state-space average equation include the current value flowing through the filter inductor of the wireless power transmission system and the output voltage feedback, and the circuit data includes sampled data and circuit parameters.

[0186] The sliding surface is calculated based on the non-singular sliding surface equation and circuit data;

[0187] According to the sliding surface, the switching control rate is obtained;

[0188] According to the equivalent control rate and the switching control rate, the total control rate is obtained;

[0189] The phase shift angle between the switch drive signals of the wireless power transmission system is adjusted according to the total control rate.

[0190] The technical solution adopted in this application is based on the average state model of the wireless power transmission topology structure, introduces a non-singular sliding mode control method, combines the non-singular sliding mode control concept with the sliding mode debounce principle, restructures the control system without increasing the system order, reduces the actual control and measurement variables, and reduces system complexity. While improving the system response speed and reducing the steady-state error, it suppresses the system's chattering.

[0191] Those skilled in the art will appreciate that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program. The program can be stored in a non-volatile computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0192] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0193] The above embodiments merely illustrate several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art could make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A phase shift angle control method based on non-singular sliding mode control, applied to a non-singular sliding mode controller, characterized in that: The method comprises: According to the established non-singular sliding surface equation, the state space average equation and the acquired circuit data of the wireless power transmission system, an equivalent control rate is obtained, wherein the state variables of the non-singular sliding surface equation include a voltage error and a voltage error differential, the state variables of the state space average equation include a current value flowing through a filter inductor of the wireless power transmission system and an output voltage feedback amount, and the circuit data include sampling data and circuit parameters; Calculate the sliding surface according to the non-singular sliding surface equation and the circuit data; According to the sliding surface, a switching control rate is obtained; According to the equivalent control rate and the switching control rate, a total control rate is obtained; The phase shift angle between the switch tube driving signals of the wireless power transmission system is adjusted according to the total control rate.

2. The method according to claim 1, characterized in that: The phase shift angle is calculated according to the following formula 1: θ = π - πu Formula 1 Among them, θ is the phase shift angle and u is the total control rate.

3. The method according to claim 1, characterized in that The switching control rate is calculated according to the following formula 2-4: n =-ε|s|sat(s)-ηs Formula 2 Among them, u n is the switching control rate, s is the sliding surface, ε is a constant greater than 0, and η is a constant greater than 0. number; δ is a constant used to limit the range of the sliding surface s, and k is a constant.

4. The method according to claim 1, characterized in that The non-singular sliding surface equation is shown in the following formula 5-7: 1<p / q<2 Formula 6 Among them, s(x) is the sliding surface function, which is used to calculate the sliding surface s, β is a fixed coefficient, p and q are both odd numbers, x1 is the voltage error, x2 is the voltage error differential; α is the voltage sampling coefficient; V0 is the output voltage feedback of the wireless power transmission system, V ref is the expected output voltage value, C is the filter capacitance value of the wireless power transmission system, i c is the current flowing through the filter capacitor.

5. The method according to claim 1, characterized in that The state space average equation is shown in the following formula 8: V0 is the output voltage feedback of the wireless power transmission system, i L is the current value flowing through the filter inductor of the wireless power transmission system, C is the filter capacitor value of the wireless power transmission system, R is the load resistance value of the wireless power transmission system, L is the filter inductor value of the wireless power transmission system, V in is the input voltage value of the wireless power transmission system, and n is the ratio of the number of turns of the receiving coil to the number of turns of the transmitting coil.

6. The method according to claim 1, characterized in that The equivalent control rate is calculated according to the following formula 5-9: 1<p / q<2 Formula 6 According to the above formulas 5-8, the following formula 9 is obtained: Among them, s(x) is the sliding surface function, which is used to calculate the sliding surface s, β is a fixed coefficient, p and q are both odd numbers, x1 is the voltage error, x2 is the voltage error differential; α is the voltage sampling coefficient; V0 is the output voltage feedback of the wireless power transmission system, V ref is the expected output voltage value, C is the filter capacitance value of the wireless power transmission system, i c is the current value flowing through the filter capacitor; i L is the current value flowing through the filter inductor of the wireless power transmission system, R is the load resistance value of the wireless power transmission system, L is the filter inductor value of the wireless power transmission system, V in is the input voltage value of the wireless power transmission system, and n is the ratio of the number of turns of the receiving coil to the number of turns of the transmitting coil; u eq is the equivalent control rate.

7. The method according to claim 3, characterized in that The step of adjusting the phase shift angle between the switch drive signals of the wireless power transmission system according to the total control rate comprises: Calculate the limit range of the time taken by the sliding surface in the first stage and the limit range of the time taken in the second stage; According to the limit range of the time used in the first stage and the second stage, determining whether the total time used in the first stage and the second stage does not exceed a preset time; If the total duration of the first stage and the second stage does not exceed the preset duration, the phase shift angle between the switch tube driving signals of the wireless power transmission system is adjusted according to the total control rate.

8. The method according to claim 7, characterized in that In the first stage, the sliding surface reaches s = δ from s(0) in a time t1; in the second stage, the sliding surface reaches s = 0 from s = δ in a time t2; t0 ≤ a Formula 10 t0 = t1 + t2 Formula 11 In the first stage, far away from the sliding surface, the effect of -ε|s|sat(s) is much greater than that of -ηs. From the initial state s=s(0), the limit range of the duration of the first stage is shown in the following formula 13: In the second stage, close to the sliding surface, the effect of -ε|s|sat(s) is much smaller than that of -ηs. The limit range of the duration of the second stage obtained from the final state s=0 is shown in the following formula 15: From the above formulas 10-15, if the total duration of the first stage and the second stage does not exceed the preset duration, the following formula 16 must be satisfied: Among them, t0 is the total duration of the first stage and the second stage, and a is the preset duration.

9. A non-singular sliding mode controller, characterized in that: The non-singular sliding mode controller comprises: an equivalent control rate calculation module, configured to obtain an equivalent control rate according to an established non-singular sliding surface equation, a state space average equation, and the acquired circuit data of the wireless power transmission system, wherein the state variables of the non-singular sliding surface equation include a voltage error and a voltage error differential, the state variables of the state space average equation include a current value and an output voltage feedback amount of a filter inductor flowing through the wireless power transmission system, and the circuit data include sampling data and circuit parameters; A sliding surface calculation module, used for calculating the sliding surface according to the non-singular sliding surface equation and the circuit data; A switching control rate calculation module, used to obtain a switching control rate according to the sliding surface; A total control rate calculation module, used for obtaining a total control rate according to the equivalent control rate and the switching control rate; The phase shift angle calculation module is used to adjust the phase shift angle between the switch tube driving signals of the wireless power transmission system according to the total control rate.

10. A wireless power transmission system, characterized in that: The wireless power transmission system includes a non-singular sliding mode controller, a wireless power transmission circuit module, a driving module and a sampling module; The sampling module is used to collect sampling data and provide it to the non-singular sliding mode controller; The non-singular sliding mode controller is used to obtain the phase shift angle between the switch tube driving signals of the wireless power transmission system according to the phase shift angle control method based on non-singular sliding mode control according to any one of 1-8 above; The driving module is used to generate a switch tube driving signal corresponding to each switch tube according to the phase shift angle, wherein the phase difference between two switch tube driving signals corresponding to two switch tubes on the same bridge arm is the phase shift angle; The wireless power transmission circuit module is used to control the on and off of the corresponding switch tube according to the switch tube driving signal, and perform wireless power transmission.

Images