Three-phase rectifier circuit control method and charging pile based on sliding mode predictive control

Abstract

The present application relates to the field of rectifier circuit control technology, and in particular to a three-phase rectifier circuit control method and charging pile based on sliding mode predictive control, comprising: in the outer loop voltage regulation, a super-helical sliding mode control algorithm is used to obtain a sliding mode control law, and the sliding mode control law is used as an active power reference value; in the inner loop current control, the voltage component and current component of the three-phase AC voltage in a two-phase rotating coordinate system are obtained by transforming the coordinate system, and then the active power and reactive power at the future moment are obtained by a discretized prediction model; the optimal switching state at the current moment is obtained by rolling optimization using a cost function, and the controller is updated according to the optimal switching state, and each switching device of the three-phase rectifier circuit is predictively controlled by the updated controller. The three-phase rectifier circuit control method based on sliding mode predictive control of the present application can provide a stable reference voltage, stable output, strong disturbance suppression capability, and achieve fast response and multivariable optimization control.

Description

Technical Field

[0001] The present application relates to the technical field of rectifier circuit control, and in particular to a three-phase rectifier circuit control method and a charging pile based on sliding mode predictive control. Background Art

[0002] In electric vehicle charging applications, AC mains power needs to be converted into DC power for charging the electric vehicle. This is typically achieved using an AC-DC three-phase rectifier circuit. In a three-phase rectifier circuit, the outer loop (voltage regulation loop) is responsible for regulating the output voltage, while the inner loop (current tracking loop) is responsible for regulating the system's active and reactive currents.

[0003] Typically, PI or sliding-mode control is used in both the outer and inner loops to achieve precise control of the rectifier circuit output. Traditional PI control is a linear controller. Using PI control in both the outer and inner loops makes it difficult to simultaneously optimize response speed and overshoot performance in a constantly changing operating environment. Furthermore, PI controllers are designed based on fixed parameters. Changes in system parameters or external disturbances can affect PI control performance, leading to reduced control effectiveness and, therefore, poor robustness. The core of sliding-mode control is the switching control law. Using sliding-mode control in both the outer and inner loops results in high-frequency switching that can lead to chattering. The introduction of high-order harmonics into the current can also affect power quality and system stability.

[0004] Therefore, the above-mentioned rectifier circuit control methods all have problems and cannot simultaneously meet the requirements of dynamic performance and steady-state response, and are not suitable for controlling the three-phase rectifier circuit in the charging pile. Summary of the Invention

[0005] Based on this, it is necessary to provide a three-phase rectifier circuit control method and charging pile based on sliding mode predictive control, which can provide a stable reference voltage, have global stability and a wide range of disturbance suppression capabilities, and achieve fast response and multivariable optimization control.

[0006] The above-mentioned purpose of this application is achieved through the following technical solutions.

[0007] The present invention provides a three-phase rectifier circuit control method based on sliding mode predictive control, including:

[0008] According to the topological structure of the three-phase rectifier circuit, a rectifier circuit model in a three-phase stationary coordinate system is constructed;

[0009] Based on the rectifier circuit model, obtaining the three-phase AC voltage and three-phase AC current on the AC side, obtaining the DC output voltage across the DC side capacitor, and determining a corresponding target voltage reference value;

[0010] In outer loop voltage regulation, the DC output voltage and the target voltage reference value are used as inputs of a super-spiral sliding mode control model, a super-spiral sliding mode control algorithm is used to obtain a sliding mode control law, and the sliding mode control law is used as an active power reference value. The sliding mode surface of the super-spiral sliding mode control algorithm is designed based on integral terms and power terms, and the reaching law of the super-spiral sliding mode control algorithm is designed based on a high-frequency switching sign function, so that the sliding mode control law can suppress chattering.

[0011] In the inner loop current control, the three-phase AC voltage and the three-phase AC current are used as inputs of the rectifier circuit model, and the rectifier circuit model is converted into a rectifier circuit model in a two-phase rotating coordinate system to obtain the voltage component of the three-phase AC voltage in the two-phase rotating coordinate system and the current component of the three-phase AC current in the two-phase rotating coordinate system. Then, the active power and reactive power at the future time are obtained through a discretized prediction model.

[0012] A reactive power reference value is set, and the active power reference value, the reactive power reference value, the active power and the reactive power at the future moment are used as inputs of a cost function. The cost function is used to perform rolling optimization to obtain the optimal switching state at the current moment. The controller is updated according to the optimal switching state, and the updated controller is used to predictively control each switching device of the three-phase rectifier circuit.

[0013] An embodiment of the present application also provides a charging pile, including a three-phase rectifier circuit, and uses the three-phase rectifier circuit control method based on sliding mode predictive control recorded in the above embodiment to control the three-phase rectifier circuit.

[0014] This application has the following beneficial effects:

[0015] Sliding mode control is used in the outer loop voltage regulation, which has global stability and a wide range of disturbance suppression capabilities, and can provide a stable reference voltage; the optimized three-vector model predictive control is used in the inner loop current control to obtain the active power and reactive power at future moments, achieving fast response and multivariable optimization control, and can overcome the jitter problem caused by sliding mode control; the optimal switching state is determined by rolling optimization of the cost function, and event trigger conditions are introduced to reduce the calculation of model predictive control and reduce computing power, thereby solving the shortcomings of common AC-DC converter control methods that cannot simultaneously meet dynamic performance and steady-state response. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic structural diagram of a three-phase rectifier circuit provided in one embodiment of the present application.

[0017] Figure 2 A control schematic diagram of a controller of a three-phase rectifier circuit provided in one embodiment of the present application.

[0018] Figure 3 A schematic diagram of the model structure of a voltage outer loop sliding mode controller provided in one embodiment of the present application.

[0019] Figure 4 A schematic diagram of the principle of controller triggering update provided in one embodiment of the present application. DETAILED DESCRIPTION

[0020] To make the above-mentioned objects, features, and advantages of the present application more clearly understood, the specific embodiments of the present application are described in detail below. The following description sets forth many specific details to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar modifications without violating the scope of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0021] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of such features. Throughout the description of this application, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0023] An embodiment of the present application provides a three-phase rectifier circuit control method based on sliding mode predictive control, which is used to predictively control the three-phase rectifier circuit in an electric vehicle charging pile to output a stable DC voltage for the electric vehicle.

[0024] like Figure 1 As shown, the three-phase rectifier circuit is composed of a filter inductor 11, an AC-DC converter 12, a DC side capacitor 13 and a controller 14. The load carried by the three-phase rectifier circuit in the figure is a resistive load. It is used to indicate the load resistance value when the electric vehicle is charging. The filter inductor 11 includes three filter inductors, and the inductance value is , the filter inductor 11 also includes three equivalent resistors, the equivalent resistance value is , each equivalent resistor is connected in series with each filter inductor, and then connected in parallel to form three filter inductors. The AC-DC converter 12 includes a three-phase bridge arm converter composed of six switching devices, and the six switches are the first switch S1, the second switch S2, the third switch S3, the fourth switch S4, the fifth switch S5, and the sixth switch S6. The DC side capacitor 13 is connected in parallel to the output end of the three-phase bridge arm converter; the rear end of the DC side capacitor 13 is the DC output end of the three-phase rectifier circuit, and the capacitance of the DC side capacitor 13 is , the DC output voltage is .

[0025] The controller 14 collects the three-phase AC voltage on the AC side through the voltage transformer ,Right now 、 and Three AC voltage signals; three-phase AC current on the AC side is collected through current transformers ,Right now 、 、 Three AC current signals are detected by voltage sensors at both ends or rear end of the DC side capacitor to collect the DC output voltage at the output end. , and based on the three-phase rectifier circuit control method of sliding mode predictive control, three switching control signals are generated and transmitted to each phase switching circuit of the converter.

[0026] In this embodiment, combined with Figure 1 、 Figure 2 From the perspective of the present invention, the three-phase rectifier circuit control method based on sliding mode predictive control includes the following steps:

[0027] S1: Based on the topological structure of the three-phase rectifier circuit, construct a rectifier circuit model in a three-phase stationary coordinate system.

[0028] S2: Based on the rectifier circuit model, obtain the three-phase AC voltage on the AC side and three-phase AC current , get the DC output voltage across the DC side capacitor , and determine the corresponding target voltage reference value .

[0029] S3: In the outer loop voltage regulation, the DC output voltage and target voltage reference value As the input of the super spiral sliding mode control model, the super spiral sliding mode control algorithm is used to obtain the sliding mode control law, and the sliding mode control law is used as the active power reference value The sliding surface of the super-helical sliding mode control algorithm is designed based on the integral term and the power term, and the reaching law of the super-helical sliding mode control algorithm is designed based on the sign function of high-frequency switching, so that the sliding mode control law can suppress chattering. is the preset target voltage reference.

[0030] S4: In the inner loop current control, the three-phase AC voltage and three-phase AC current As the input of the rectifier circuit model, the rectifier circuit model is converted into a rectifier circuit model under a two-phase rotating coordinate system to obtain the three-phase AC voltage Voltage components in the two-phase rotating coordinate system , and three-phase AC current Current components in the two-phase rotating coordinate system , and then the active power and reactive power at future moments are obtained through the discretization prediction model.

[0031] Voltage component include and ,for Two-phase voltage in the coordinate system (grid voltage or motor back electromotive force in the synchronous rotating coordinate system) axis component); current component include and ,for The two-phase current in the coordinate system is transformed from the three-phase current by Park transformation 、 、 Converted from.

[0032] S5: Set the reactive power reference value, take the active power reference value, reactive power reference value, active power and reactive power at future moments as inputs of the cost function, perform rolling optimization using the cost function to obtain the optimal switching state at the current moment, update the controller based on the optimal switching state, and predictively control each switching device of the three-phase rectifier circuit through the updated controller.

[0033] The three-phase rectifier circuit control method based on sliding mode predictive control recorded in the above embodiment adopts sliding mode control in the outer loop voltage regulation, has global stability and a wide range of disturbance suppression capabilities, and can provide a stable reference voltage; in the inner loop current control, the optimized three-vector model predictive control is used to obtain the active power and reactive power at future times, thereby achieving fast response and multivariable optimization control, and can overcome the jitter problem caused by sliding mode control; when the optimal switching state is determined by rolling optimization of the cost function, event trigger conditions are introduced to reduce the calculation of the model predictive control, reduce the computing requirements, and solve the shortcomings of common AC-DC converter control methods that cannot simultaneously meet dynamic performance and steady-state response.

[0034] like Figure 3 As shown, in the outer loop voltage regulation of step S3, the sliding mode control law of the super spiral sliding mode control algorithm is:

[0035] ,

[0036] in, is the sliding mode control law of the super spiral sliding mode control algorithm, which is used as the active power reference value. is the DC output voltage across the DC side capacitor, is the target voltage reference value to be set, is the DC side capacitance, is the load resistance value, is the proportionality factor of the sliding surface design, and is the power term coefficient, and is the power term exponent, is the sliding surface, 、 、 、 is the control gain coefficient of the super-helical sliding mode, and is the power transformation of the sign function.

[0037] The method for determining the sliding mode control law of the super-helical sliding mode control algorithm is:

[0038] Determine the instantaneous power on the DC side: ,in, is the DC side current, is the rate of change of DC side voltage, that is ;

[0039] Based on the instantaneous power fluctuation on the DC side, a fast terminal sliding mode surface is designed by combining the integral term and the power term. The fast terminal sliding mode surface is: ,in, , ;

[0040] The reaching law designed based on the symbolic function is: ,

[0041] in, , 、 is a sign function, is the rate of change of the sliding surface (differential), Auxiliary state introduced for the superhelical algorithm to enhance robustness. is the rate of change (differential) of the auxiliary state quantity;

[0042] The sliding mode control law of the super-helical sliding mode control algorithm is obtained based on the sliding mode surface and reaching law.

[0043] Integral term: eliminates "steady-state power error" (if there is only a proportional term, power loss may persist, leading to steady-state voltage deviation; the integral term accumulates the deviation and forces regulation to balance).

[0044] Power term: Accelerates "dynamic power response" ( When , it converges quickly under small deviation; When the deviation is large, the voltage is increased under the control to correct the power imbalance quickly and return the voltage to the reference value faster).

[0045] In this embodiment, based on the DC side voltage deviation (i.e., the DC output voltage across the DC side capacitor and the set target voltage reference value The design uses a sliding surface function to quickly approach the system state, achieving robustness (anti-interference, anti-parameter change), and by introducing integral and power terms into the sliding surface design, the steady-state error of the sliding mode control is reduced and the error convergence rate is improved. Traditional reaching laws contain sign functions of discontinuous terms. Due to the lag in time and space between switches, the ideal sliding state on the sliding surface cannot be achieved, thus causing chattering. To reduce the chattering problem caused by sliding mode control, an improved super-helical sliding mode control algorithm was designed. When designing the reaching law, the sign function of the high-frequency switching is partially hidden in the high-order derivatives of the sliding mode variable, so that the control law ultimately contains the integral term of the switching part. Since the integral itself has a filtering function, it can effectively suppress the chattering phenomenon.

[0046] In the inner loop current control of step S4, the voltage component and current components The method to determine is:

[0047] The three-phase AC voltage and three-phase AC current As input to the rectifier circuit model;

[0048] The rectifier circuit model in the three-phase stationary coordinate system is converted into the rectifier circuit model in the two-phase rotating coordinate system, where the rectifier circuit model in the three-phase stationary coordinate system is:

[0049] ,

[0050] in, is the inductance value of the filter inductor in the three-phase rectifier circuit, 、 、 are the current values ​​of each phase on the AC side of the three-phase rectifier circuit, 、 、 are the voltage values ​​of each phase on the AC side of the three-phase rectifier circuit, is the load resistance, 、 、 is the three-phase switching function of the three-phase rectifier circuit, middle , is the load current;

[0051] The rectifier circuit model in the two-phase rotating coordinate system is:

[0052] ,

[0053] in, 、 for The two-phase current in the coordinate system is transformed from the three-phase current by Park transformation 、 、 Converted, 、 for Two-phase voltage in the coordinate system (grid voltage or motor back electromotive force in the synchronous rotating coordinate system) axis component), and The output voltage of the converter of the three-phase rectifier circuit is axis components, determined by the switching function 、 、 Converted from this, it is the control input quantity, and are the inductance and equivalent resistance of the AC side filter inductor respectively, is the synchronous rotation angular velocity, The angular velocity of the coordinate system is synchronized with the grid frequency or the motor electrical angular velocity;

[0054] According to the rectifier circuit model in the two-phase rotating coordinate system, determine the voltage component and current components .

[0055] Voltage component include and The three-phase AC voltage ( 、 、 ) is converted to stationary coordinates and , the conversion formula is: ; Then use Park transformation to transform the stationary Coordinate system converted to rotation Coordinate system, get and , the conversion formula is: .

[0056] The method for determining the active power and reactive power at the future time is:

[0057] A discrete power prediction model is established in a two-phase stationary coordinate system, and the active power and reactive power at future moments are calculated based on the discrete power prediction model. The discrete power prediction model is:

[0058] ,

[0059] in, and is the discrete time step during sampling, if To represent the current moment, Used to indicate the next moment. and is the instantaneous active power, and is the instantaneous reactive power, is the time sampling step after discretizing the continuous system.

[0060] and for The two-phase voltage in the coordinate system, 、 for Two-phase current in the coordinate system, and for The switching function in the coordinate system is composed of the three-phase switching function 、 、 Converted, 、 、 is the switching function of the three-phase bridge arm in the converter of the three-phase rectifier circuit, is the system angular frequency, .in, ,express The pulse width modulation (PWM) voltage component of the phase voltage relative to the DC bus midpoint (virtual neutral point) is used to generate a three-phase balanced AC output.

[0061] and for The two-phase current at the current moment in the coordinate system, and for The two-phase current at the next moment in the future in the coordinate system, and for The two-phase voltage at the current moment in the coordinate system, and for The two-phase voltage at the next moment in the future in the coordinate system.

[0062] In step S5, the controller updates in the following way:

[0063] Determine the first cost function: ,in, is the switching sequence determined by the first cost function, is the instantaneous active power on the DC side, is the output of the super-helical sliding mode control algorithm, which is the instantaneous active power reference value of the DC side. is the instantaneous reactive power on the DC side, is the output of the super-helical sliding mode control algorithm, which is the instantaneous reactive power reference value of the DC side.

[0064] The reference voltage vector is obtained by solving the first cost function and ;

[0065] Calculate the position angle of the reference voltage vector: ;

[0066] The space voltage is divided into 6 sectors using the space vector modulation principle, and the target sector is locked according to the position angle of the calculated reference voltage vector;

[0067] Determine a non-zero voltage vector corresponding to a target sector according to a mapping relationship table between sectors and voltage vectors;

[0068] An optimal switching state is solved based on the selected non-zero voltage vector, the reference voltage vector, and the second cost function, and a controller is updated based on the optimal switching state, wherein the optimal switching state is an optimal switching sequence.

[0069] The mapping relationship table between sectors and voltage vectors is shown in the following table: The table shows the correspondence between six sectors, six reference voltage vector angular positions, six non-zero voltage vectors, and six zero voltage vectors.

[0070]

[0071] Specifically, the selected non-zero voltage vector is substituted into the formula:

[0072] ,Sure and , then 、 、 、 Substitute the second cost function, solve the optimal switching state, and update the controller based on the optimal switching state to obtain the optimal controller. The expression of the optimal controller can be: .

[0073] Among them, the second cost function is: ,in, is the optimal switching sequence determined by the second cost function, that is, the optimal switching state, 、 for Reference voltage vector in the coordinate system.

[0074] Since model predictive control greatly increases the computing tasks of the system, this embodiment also introduces event trigger conditions, that is, the calculation of the optimal switching state is triggered based on preset trigger conditions. When the event trigger conditions are not met, no computing power will be generated, thereby reducing the computing requirements of the system.

[0075] Specifically, the optimal switching state is calculated based on a preset trigger condition, and the preset trigger condition is determined as follows:

[0076] The spatial state equation in the two-phase rotating coordinate system (two-phase rectifier circuit model) , rewritten as: ,in, , , ;

[0077] The measurement error is defined as: , find the event trigger adjustment value.

[0078] Specifically, if there exists a continuously differentiable function that satisfies the following conditions:

[0079] , then the closed-loop system is stable, and the triggering condition is determined as: , where by adjusting How often the value change event is triggered, The smaller the value, the easier it is to trigger the inequality, that is, the easier it is to trigger the recalculation of the optimal switching state.

[0080] like Figure 4 As shown, after the trigger condition is met, according to the current state of the system Perform model predictive control calculations to obtain the optimal switching state, update the controller based on the optimal switching state, and obtain the optimal controller. The optimal controller is maintained until the next triggering moment to reduce the number of model predictive control calculations and reduce the computational burden.

[0081] If the current trigger time is , the optimal controller is: , the next triggering moment is , For a single trigger cycle, Indicates the number of trigger cycles.

[0082] In this embodiment, sliding mode control is responsible for "macro-decision-making" and uses robustness to generate reference instructions; model predictive control is responsible for "micro-execution" and selects the optimal switching action through prediction and optimization. The combination of the two ensures that the system is resistant to interference and has a fast response (advantage of sliding mode), while also accurately tracking instructions and reducing harmonics (advantage of model prediction).

[0083] According to an embodiment of the present application, a charging pile is further provided, comprising a three-phase rectifier circuit, and the three-phase rectifier circuit is controlled by the three-phase rectifier circuit control method based on sliding mode predictive control as described above.

[0084] The technical solution of the present application has the following beneficial effects: Enhanced anti-interference ability: The sliding mode control technology adopted in the voltage outer loop significantly improves the anti-interference ability of the system, so that it can still maintain stable operation in the face of complex electromagnetic environments, and therefore has high anti-interference ability; Vibration suppression and response speed improvement: The sliding surface approach law is designed as a super-helical sliding mode approach law, and the switching control quantity is obtained through integral action. Compared with the traditional exponential approach law sliding mode control, it effectively suppresses the system's chattering phenomenon and improves the system's approach speed, thereby making the system respond more quickly and having faster dynamic response capabilities; Comprehensive improvement of performance and reliability: The application of the improved model predictive sliding mode composite control strategy not only effectively improves the dynamic and static performance of the rectifier, but also enhances its anti-interference ability, reduces the amount of calculation, and ensures the high reliability and stability of the system; The current inner loop adopts three-vector model predictive control to improve the response speed and static performance, and solves the vibration problem caused by the sliding mode control used in the inner loop. At the same time, the introduction of event trigger conditions greatly reduces the amount of calculation, reduces the system computing power, and makes it feasible.

[0085] 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.

[0086] The above embodiments merely illustrate several implementation methods of the present application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the 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 application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be determined by the appended claims, and the specification may be used to interpret the content of the claims.

Claims

1. A three-phase rectifier circuit control method based on sliding mode predictive control, characterized in that: include: According to the topological structure of the three-phase rectifier circuit, a rectifier circuit model in a three-phase stationary coordinate system is constructed; Based on the rectifier circuit model, obtaining the three-phase AC voltage and three-phase AC current on the AC side, obtaining the DC output voltage across the DC side capacitor, and determining a corresponding target voltage reference value; In outer loop voltage regulation, the DC output voltage and the target voltage reference value are used as inputs of a super-spiral sliding mode control model, a super-spiral sliding mode control algorithm is used to obtain a sliding mode control law, and the sliding mode control law is used as an active power reference value. The sliding mode surface of the super-spiral sliding mode control algorithm is designed based on integral terms and power terms, and the reaching law of the super-spiral sliding mode control algorithm is designed based on a high-frequency switching sign function, so that the sliding mode control law can suppress chattering. In the inner loop current control, the three-phase AC voltage and the three-phase AC current are used as inputs of the rectifier circuit model, and the rectifier circuit model is converted into a rectifier circuit model in a two-phase rotating coordinate system to obtain the voltage component of the three-phase AC voltage in the two-phase rotating coordinate system and the current component of the three-phase AC current in the two-phase rotating coordinate system. Then, the active power and reactive power at the future time are obtained through a discretized prediction model. setting a reactive power reference value, using the active power reference value, the reactive power reference value, and the active power and reactive power at a future moment as inputs of a cost function, performing rolling optimization using the cost function to obtain an optimal switching state at a current moment, updating a controller based on the optimal switching state, and predictively controlling each switching device in the three-phase rectifier circuit using the updated optimal controller; The sliding mode control law of the super-helical sliding mode control algorithm is: ， in, is the sliding mode control law of the super-helical sliding mode control algorithm, is the DC output voltage across the DC side capacitor, is the target voltage reference value to be set, is the DC side capacitance, is the load resistance value, is the proportionality factor of the sliding surface design, and is the power term coefficient, and is the power term exponent, is the sliding surface, 、 、 、 is the control gain coefficient of the super-helical sliding mode, and is the power transformation of the sign function.

2. The three-phase rectifier circuit control method based on sliding mode predictive control according to claim 1, characterized in that: The method for determining the sliding mode control law of the super-helical sliding mode control algorithm is: Determine the instantaneous power on the DC side: ， in, is the DC side current, is the rate of change of DC side voltage; Based on the instantaneous power fluctuation on the DC side, a fast terminal sliding mode surface is designed by combining the integral term and the power term. The fast terminal sliding mode surface is: ， in, , ; The reaching law designed based on the symbolic function is: ， in, , 、 is a sign function, is the rate of change of the sliding surface, Auxiliary state introduced for the superhelical algorithm to enhance robustness. is the rate of change of the auxiliary state quantity; The sliding mode control law of the super-helical sliding mode control algorithm is obtained according to the sliding mode surface and the reaching law.

3. The three-phase rectifier circuit control method based on sliding mode predictive control according to claim 1, characterized in that: The method for determining the voltage component and the current component is: Using the three-phase AC voltage and the three-phase AC current as inputs of the rectifier circuit model; The rectifier circuit model in the three-phase stationary coordinate system is converted into a rectifier circuit model in the two-phase rotating coordinate system, wherein the rectifier circuit model in the three-phase stationary coordinate system is: ， in, is the inductance value of the filter inductor in the three-phase rectifier circuit, is a three-phase alternating current, which includes 、 、 , 、 、 are the current values ​​of each phase on the AC side of the three-phase rectifier circuit, is a three-phase AC voltage, which includes 、 、 , 、 、 are the voltage values ​​of each phase on the AC side of the three-phase rectifier circuit, is the load resistance, 、 、 is the three-phase switching function of the three-phase rectifier circuit, middle , is the load current; The rectifier circuit model in the two-phase rotating coordinate system is: ， in, is the current component, which includes 、 , 、 for The two-phase current in the coordinate system is transformed from the three-phase current by Park transformation 、 、 Converted, is the voltage component, which includes and , 、 for The two-phase voltage in the coordinate system, and The output voltage of the converter of the three-phase rectifier circuit is axis components, determined by the switching function 、 、 Converted into the control input, and are the inductance and equivalent resistance of the AC side filter inductor respectively, is the synchronous rotation angular velocity; The voltage component and the current component are determined according to a rectifier circuit model in a two-phase rotating coordinate system.

4. The three-phase rectifier circuit control method based on sliding mode predictive control according to claim 3, characterized in that: The method for determining the active power and reactive power at the future time is: Establish a discrete power prediction model in a two-phase stationary coordinate system, and calculate the active power and reactive power at future moments based on the discrete power prediction model. Wherein, the discrete power prediction model is: ， in, and is the discrete time step during sampling, if To represent the current moment, Used to indicate the next moment. and is the instantaneous active power, and is the instantaneous reactive power, is the time sampling step after discretizing the continuous system, and for The two-phase voltage in the coordinate system, 、 for Two-phase current in the coordinate system, and for The switching function in the coordinate system is composed of the three-phase switching function 、 、 Converted, is the system angular frequency, and for The two-phase current at the current moment in the coordinate system, and for The two-phase current at the next moment in the future in the coordinate system, and for The two-phase voltage at the current moment in the coordinate system, and for The two-phase voltage at the next moment in the future in the coordinate system.

5. The three-phase rectifier circuit control method based on sliding mode predictive control according to claim 4, characterized in that: The controller's update method is: Determine the first cost function: ， in, is the switching sequence determined by the first cost function, is the instantaneous active power on the DC side, is the output of the super-helical sliding mode control algorithm, which is the instantaneous active power reference value of the DC side. is the instantaneous reactive power on the DC side, is the output of the super-helical sliding mode control algorithm, which is the instantaneous reactive power reference value on the DC side; The reference voltage vector is obtained by solving the first cost function and ; Calculate the position angle of the reference voltage vector: ； The space voltage is divided into six sectors using the space vector modulation principle, and the target sector is locked according to the position angle of the calculated reference voltage vector; Determining a non-zero voltage vector and a zero voltage vector corresponding to the target sector according to a mapping relationship table between sectors and voltage vectors; Solving the optimal switching state based on the selected non-zero voltage vector, the reference voltage vector, and the second cost function, and updating the controller based on the optimal switching state, Among them, the second cost function is: ， in, 、 By substituting the selected non-zero voltage vector into the conversion formula, 、 for Reference voltage vector in the coordinate system.

6. A charging pile, comprising a three-phase rectifier circuit, characterized in that: The three-phase rectifier circuit is controlled by using the three-phase rectifier circuit control method based on sliding mode predictive control according to any one of claims 1 to 5.

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