An electric vehicle charging pile control method and device

Abstract

The application discloses a kind of electric vehicle charging pile control method and device, comprising: the establishment of traditional double-loop PI control model of T-type VIENNA rectifier, traditional double-loop PI control model includes current inner loop control and voltage outer loop control;Weak chattering superhelix second-order sliding mode algorithm is used to improve the current inner loop control in traditional double-loop PI control model;Linear active disturbance rejection controller LADRC is designed based on the operating condition of T-type VIENNA rectifier, and the voltage outer loop control in traditional double-loop PI control model is improved according to linear active disturbance rejection controller LADRC;According to the improved traditional double-loop PI control model, electric vehicle charging pile is controlled.The application improves the dynamic performance of electric vehicle charging pile control system when load changes, can ensure faster dynamic response after rectifier is disturbed by outside, while also can reduce the harmonic distortion rate of grid-side current.

Description

Technical Field

[0001] This invention relates to the field of rectifier control technology for electric vehicle charging piles, and in particular to a control method and device for electric vehicle charging piles. Background Technology

[0002] The existing electric vehicle charging piles use a dual closed-loop control strategy, which includes voltage outer loop control and current inner loop control. The voltage outer loop control mainly ensures the stability of the output DC voltage, and its output value serves as the reference value for the current inner loop control. The current inner loop control compares the sampled current value with the reference value and outputs the duty cycle, thereby ensuring low distortion rate of the grid-side current and timely tracking of the voltage outer loop output.

[0003] However, when the traditional PI dual-loop control strategy is applied to the control system of electric vehicle charging piles, the linear control method cannot fully adapt to the nonlinear system. Therefore, when the system is subjected to disturbances, the dynamic response performance deteriorates, the DC voltage fluctuates greatly, and the recovery speed is slow, especially when the load changes, resulting in poor dynamic characteristics. Research on disturbance suppression in the control system of electric vehicle charging piles can improve the transient performance of the charging pile device and reduce the distortion rate of grid-side current harmonics, which is of great significance for improving the charging efficiency of the charging pile. Summary of the Invention

[0004] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0005] In view of the aforementioned existing problems, the present invention is proposed.

[0006] Therefore, the present invention provides a method and device for controlling electric vehicle charging piles to solve the problems mentioned in the background art.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0008] In a first aspect, embodiments of the present invention provide a method for controlling an electric vehicle charging station, comprising:

[0009] A traditional dual-closed-loop PI control model for a T-type VIENNA rectifier is established, which includes an inner current loop control and an outer voltage loop control.

[0010] The current inner loop control in the traditional dual-closed-loop PI control model is improved by using a weak chattering super-spiral second-order sliding mode algorithm.

[0011] Based on the operating conditions of the T-type VIENNA rectifier, a linear active disturbance rejection controller (LADRC) is designed, and the voltage outer loop control in the traditional dual closed-loop PI control model is improved based on the LADRC.

[0012] The electric vehicle charging station is controlled according to the improved traditional dual closed-loop PI control model.

[0013] As a preferred embodiment of the electric vehicle charging pile control method of the present invention, wherein:

[0014] The current inner loop control in the traditional dual-closed-loop PI control model is improved by utilizing a weak chattering superspiral second-order sliding mode algorithm, including:

[0015] A mathematical model of the T-type VIENNA rectifier in the dq coordinate system is established; the mathematical model includes the KVL equations for the inductor current input side and the KVL equations for the capacitor voltage input side.

[0016] By improving the traditional second-order sliding mode control law with a hyperbolic tangent function, a weak chattering superspiral second-order sliding mode control law is obtained;

[0017] The current tracking error between the current reference and the current sampling is used as the sliding surface of the current inner loop control. The DC side voltage in the dq coordinate system is used to represent the voltage vector. The current inner loop is controlled by a weak chattering super-spiral second-order sliding mode control law, thus completing the improvement of the current inner loop control.

[0018] As a preferred embodiment of the electric vehicle charging pile control method of the present invention, wherein:

[0019] The weak chattering superspiral second-order sliding mode control law is expressed as:

[0020]

[0021] Where s1 is the sliding surface, α1 and α2 are positive real control parameters, tanh(·) is the hyperbolic tangent function, u1 is the continuous function of the differentiable sliding variable s, and u2 is the integral of the discontinuous first-order time differential.

[0022] As a preferred embodiment of the electric vehicle charging pile control method of the present invention, it further includes: the improved current inner loop control is expressed as:

[0023] Represented as:

[0024]

[0025] Among them, e gd e gq It is the grid-side input voltage in the dq coordinate system, i gd i gqU is the grid-side input current in the dq coordinate system. dc ε is the DC-side output voltage, and ε is a switching parameter that determines the rate of change of the inflection point of the hyperbolic tangent function.

[0026] As a preferred embodiment of the electric vehicle charging pile control method of the present invention, it includes: the linear active disturbance rejection controller (LADRC) is a second-order LADRC; the second-order LADRC includes: the LESO control equation, the control equation composed of LTD and LSEF;

[0027] The LESO governing equations are expressed as follows:

[0028]

[0029] Where z1 is the estimated value of y, z2 is the disturbance estimate of the voltage outer loop control, and β1 and β2 are the adjustable control parameters;

[0030] The governing equations composed of LTD and LSEF are expressed as follows:

[0031]

[0032] Where, k p For adjustable control parameters, U LTD is the output value of the transient process, and b is the high-frequency gain.

[0033] As a preferred embodiment of the electric vehicle charging pile control method of the present invention, the method includes: improved voltage outer loop control based on the Linear Active Disturbance Rejection Controller (LADRC), comprising:

[0034] The poles of the LESO control equation are placed at -ω0, and the poles of the control equation composed of LTD and LSEF are placed at -ω0. c The location is represented as:

[0035]

[0036] Where ω0 is the bandwidth of the observer, ω c It is the controller's bandwidth;

[0037] The voltage outer loop control is improved by using the LESO control equation and the control equation composed of LTD and LSEF. The improved voltage outer loop control is expressed as:

[0038]

[0039] In a second aspect, the present invention provides an electric vehicle charging pile control device, comprising:

[0040] The model building module is used to establish a traditional dual-closed-loop PI control model for a T-type VIENNA rectifier, which includes an inner current loop control and an outer voltage loop control.

[0041] The first improvement module is used to improve the current inner loop control in the traditional dual closed-loop PI control model by using a weak chattering super spiral second-order sliding mode algorithm.

[0042] The second improvement module is used to design a linear active disturbance rejection controller (LADRC) based on the operating conditions of a T-type VIENNA rectifier, and to improve the voltage outer loop control in the traditional dual closed-loop PI control model based on the LADRC.

[0043] The control module is used to control the electric vehicle charging pile according to the improved traditional dual closed-loop PI control model.

[0044] As a preferred embodiment of the electric vehicle charging pile control device of the present invention, the first improved module includes:

[0045] The model building module is used to build a mathematical model of the T-type VIENNA rectifier in the dq coordinate system; the mathematical model includes the KVL equations for the inductor current input side and the KVL equations for the capacitor voltage input side.

[0046] The second-order sliding mode control law improvement module is used to improve the traditional second-order sliding mode control law with the hyperbolic tangent function to obtain a weak chattering super-spiral second-order sliding mode control law.

[0047] The current inner loop control module is used to take the current tracking error between the current reference and the current sampling as the sliding surface of the current inner loop control, let the DC side voltage in the dq coordinate system represent the voltage vector, and combine the weak chattering super spiral second-order sliding mode control law to control the current inner loop, thus completing the improvement of the current inner loop control.

[0048] Thirdly, the present invention provides a computing device, comprising:

[0049] Memory and processor;

[0050] The memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions, which, when executed by the processor, implement the steps of the electric vehicle charging pile control method.

[0051] Fourthly, the present invention provides a computer-readable storage medium storing computer-executable instructions that, when executed by a processor, implement the steps of the electric vehicle charging pile control method.

[0052] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention improves the traditional current inner loop control by utilizing a weak chattering superspiral second-order sliding mode algorithm, which can weaken the chattering phenomenon in the voltage inner loop control and greatly simplify the design structure of the superspiral algorithm of the sliding mode surface of the current inner loop control; it improves the voltage outer loop control by using LADRC instead of PI control, which can improve the dynamic recovery speed of the system when disturbances occur and reduce the fluctuations in the recovery process. Combined with linearized active disturbance rejection control, it can not only solve the shortcomings of PID control, but also reduce the complexity of the controller, making it easier to implement in practical engineering applications; this invention can improve the dynamic performance of the electric vehicle charging pile control system under load changes, and can ensure a faster dynamic response after the rectifier is subjected to external disturbances. At the same time, it can also reduce the harmonic distortion rate of the grid-side current, which is of great significance for improving the charging efficiency of the charging pile. Attached Figure Description

[0053] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0054] Figure 1 This is a flowchart illustrating a method and apparatus for controlling an electric vehicle charging pile according to an embodiment of the present invention.

[0055] Figure 2 This is a control block diagram of the dq-axis current inner loop weak chattering-super Twisting Sliding Mode Control (WC-STSMC) algorithm of a control method and device for electric vehicle charging piles according to an embodiment of the present invention.

[0056] Figure 3 This is a VIENNA rectifier simulation model of an electric vehicle charging pile control method and device according to an embodiment of the present invention;

[0057] Figure 4 This is a block diagram of a dual closed-loop control system based on LADRC+WC-STSMC for an electric vehicle charging pile control method and device according to an embodiment of the present invention.

[0058] Figure 5 This is a simulation output waveform diagram of the PI+PI dual closed-loop control strategy of the electric vehicle charging pile control method and device according to an embodiment of the present invention to resist output voltage setpoint disturbance.

[0059] Figure 6This is a simulation output waveform diagram of the PI+PI dual closed-loop control strategy of an electric vehicle charging pile control method and device according to an embodiment of the present invention to resist load disturbance.

[0060] Figure 7 The output waveform diagram is a simulation diagram of the LADRC+WC-STSMC dual closed-loop control strategy for resisting output voltage setpoint disturbances in an embodiment of the electric vehicle charging pile control method and device of the present invention.

[0061] Figure 8 The output waveform diagram of the LADRC+WC-STSMC dual closed-loop control strategy for the electric vehicle charging pile control method and device according to an embodiment of the present invention is shown in the simulation output waveform diagram against load disturbance.

[0062] Figure 9 This is a waveform diagram of the d-axis current output under load disturbance according to the PI+PI dual closed-loop control strategy of the electric vehicle charging pile control method and device according to an embodiment of the present invention.

[0063] Figure 10 This is a waveform diagram of the d-axis current output under load disturbance according to the LADRC+STASMC dual closed-loop control strategy of an electric vehicle charging pile control method and device according to an embodiment of the present invention.

[0064] Figure 11 The LADRC+WC-STSMC dual closed-loop control strategy of an electric vehicle charging pile control method and device according to an embodiment of the present invention is shown in the d-axis current output waveform under load disturbance. Detailed Implementation

[0065] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0066] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0067] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0068] This invention is described in detail with reference to the schematic diagrams. When detailing the embodiments of this invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not adhering to the usual scale. Furthermore, the schematic diagrams are merely examples and should not be construed as limiting the scope of protection of this invention. In actual fabrication, the three-dimensional spatial dimensions of length, width, and depth should be included.

[0069] Furthermore, in the description of this invention, it should be noted that the terms "upper," "lower," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are used solely for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. In addition, the terms "first," "second," or "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0070] Unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" in this invention should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; similarly, they can refer to mechanical connections, electrical connections, or direct connections, or indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0071] Example 1

[0072] Reference Figures 1-2 As one embodiment of the present invention, this embodiment provides a method for controlling an electric vehicle charging station, including:

[0073] S1: Establish the traditional dual-closed-loop PI control model for the T-type VIENNA rectifier. The traditional dual-closed-loop PI control model includes the inner current loop control and the outer voltage loop control.

[0074] Optionally, a traditional dual-closed-loop PI control model for the T-type VIENNA rectifier can be established using Kirchhoff's laws, Laplace transform, or other methods. It should be noted that the establishment of the traditional dual-closed-loop PI control model for the T-type VIENNA rectifier is existing technology and will not be described in detail here.

[0075] S2: Improving the current inner loop control in the traditional dual-closed-loop PI control model using a weak chattering super-spiral second-order sliding mode algorithm; further, improving the current inner loop control using a weak chattering super-spiral second-order sliding mode algorithm, including:

[0076] A mathematical model of the T-type VIENNA rectifier in the dq coordinate system is established; the mathematical model includes the KVL equations for the inductor current input side and the KVL equations for the capacitor voltage input side.

[0077] Specifically, the KVL equation for the inductor current input side is expressed as:

[0078]

[0079] Where L is the three-phase input filter inductance, R is the equivalent resistance of the three-phase inductance, ω is the fundamental angular frequency of the power grid, and i gd i gq It is the grid-side input current in the dq coordinate system, e gd e gq It is the grid-side input voltage in the dq coordinate system, u d u q It is the dq axis voltage on the grid-connected side.

[0080] Specifically, the KVL equation for the capacitor voltage input side is expressed as:

[0081]

[0082] Where C d1 =C d2 =C is the DC-side output filter capacitor, U Cd1 =U Cd2 =U dc / 2,S dP S dN S qP S qN It is a switching function in the dq coordinate system, R L This is the load resistance.

[0083] It should be noted that, due to the high switching frequency of the T-type VIENNA rectifier, high-speed switching at the critical point inevitably produces high-frequency chattering, which affects the dynamic characteristics of the inner current loop and causes problems such as increased transition time and increased transition fluctuations. Using the hyperbolic tangent function instead of the sign function of the traditional second-order sliding mode control law can solve the inherent chattering problem of the switching function and ensure the continuity of the switching function, thus avoiding the inability to differentiate it.

[0084] Furthermore, the traditional second-order sliding mode control law is improved using the hyperbolic tangent function to obtain a weak chattering superspiral second-order sliding mode control law, including:

[0085] The second-order sliding mode control law for weak chattering supersonic spiral is expressed as:

[0086]

[0087] Where s1 is the sliding surface, α1 and α2 are positive real control parameters, tanh(·) is the hyperbolic tangent function, u1 is the continuous function of the differentiable sliding variable s, and u2 is the integral of the discontinuous first-order time differential.

[0088] Specifically, the hyperbolic tangent function is expressed as:

[0089]

[0090] It should be noted that the purpose of the current loop of the T-type VIENNA rectifier is to achieve unity power factor operation of the rectifier, enable fast tracking when the system is disturbed, and reduce the harmonic distortion rate of the grid-side current. Based on the sliding mode control theory and the control objective of the inner current loop, the difference e between the current reference and the current sampling is defined as the current tracking error, which is the sliding surface of the current loop design.

[0091] Furthermore, the current tracking error between the current reference and the current sampling is used as the sliding surface of the current inner loop control. The DC side voltage in the dq coordinate system is used to represent the voltage vector. The current inner loop is controlled by a weak chattering super-spiral second-order sliding mode control law, thus completing the improvement of the current inner loop control.

[0092] Furthermore, the sliding surface of the current loop is represented as:

[0093]

[0094] Differentiating both sides, we get:

[0095]

[0096] Furthermore, let the DC-side voltage in the dq coordinate system represent the voltage vector, U Cd1 =U Cd2 =U dc / 2, in this embodiment, C d1 =C d2 =C,U Cd1 +U Cd2 =U dc S d =S dP -S dN S q =S qP -S qN The input-side KVL equations are simplified to:

[0097]

[0098] Specifically, substituting the simplified KVL equations for the capacitor voltage input side and the differentiated current slip mode into the KVL equations for the inductor current input side, we get:

[0099]

[0100] Furthermore, the improved current inner loop control is expressed as follows:

[0101]

[0102] Where e gd e gq It is the grid-side input voltage in the dq coordinate system, i gd i gq U is the grid-side input current in the dq coordinate system. dc ε is the DC-side output voltage, and ε is a switching parameter that determines the rate of change of the inflection point of the hyperbolic tangent function.

[0103] like Figure 2 As shown, in an optional embodiment, to verify the stability of the designed controller, the direct method of the Lyapunov method is used. A scalar function V1 is constructed, its derivative is calculated, and the stability of the motion is determined by judging the sign of the derivative. In this embodiment, the Lyapunov function is constructed as follows:

[0104]

[0105] Substituting the above current inner loop control formula into the Lyapunov function and taking the derivative, we get the following expression:

[0106]

[0107] According to Lyapunov's criterion theorem, if the control parameters α1 and α2 take a certain range of values, such that... If α1 and α2 are always true, then the controller is asymptotically stable. Therefore, α1 and α2 need to be positive to meet the requirements of the controller design.

[0108] S3: Design a linear active disturbance rejection controller (LADRC) based on the operating conditions of a T-type VIENNA rectifier, and improve the voltage outer loop control in the traditional dual-closed-loop PI control model based on the LADRC.

[0109] Furthermore, the linear active disturbance rejection controller (LADRC) is a second-order LADRC; the second-order LADRC includes: the LESO control equation, the control equation composed of LTD and LSEF;

[0110] The LESO governing equations are expressed as follows:

[0111]

[0112] Where z1 is the estimated value of y, z2 is the disturbance estimate of the voltage outer loop control, and β1 and β2 are the adjustable control parameters;

[0113] Specifically, the transition process designed with the first-order LTD as a given value is expressed as:

[0114]

[0115] Among them, U LTD This is the output value of the transient process, and r is the adjustment coefficient of this transient process. The larger the value, the faster the tracking speed. Specifically, for a first-order LTD, only a proportional adjustment element is needed, so the structure is as follows:

[0116] u0 = k p (U LTD -z1)

[0117] Furthermore, by combining the linearized structural equations of LSEF,

[0118] The governing equations composed of LTD and LSEF are expressed as follows:

[0119]

[0120] Where, k p For adjustable control parameters, U LTD is the output value of the transient process, and b is the high-frequency gain.

[0121] It should be noted that, based on the established LESO, LTD, and LSEF formulas, the voltage outer loop LADRC system only requires adjustment of three control parameters: β1, β2, and k. P Furthermore, the process of adjusting the control parameters can be simplified; in practice, only the observer bandwidth ω0 and the controller bandwidth ω need to be adjusted. c Two parameters are needed to achieve the desired dynamic response effect.

[0122] Furthermore, the voltage outer loop control is improved based on the Linear Active Disturbance Rejection Controller (LADRC), including:

[0123] The poles of the LESO control equation are placed at -ω0, and the poles of the control equation composed of LTD and LSEF are placed at -ω0. c The location is represented as:

[0124]

[0125] Where ω0 is the bandwidth of the observer, ω c It is the controller's bandwidth;

[0126] The voltage outer loop control is improved by using the LESO control equation and the control equation composed of LTD and LSEF. The improved voltage outer loop control is expressed as:

[0127]

[0128] S4: Control the electric vehicle charging station according to the improved traditional dual closed-loop PI control model.

[0129] The above is an illustrative scheme of an electric vehicle charging pile control method according to this embodiment. It should be noted that the technical solution of this electric vehicle charging pile control device belongs to the same concept as the technical solution of the above-described electric vehicle charging pile control method. Details not described in detail in the technical solution of the electric vehicle charging pile control device in this embodiment can be found in the description of the technical solution of the above-described electric vehicle charging pile control method.

[0130] This embodiment provides an electric vehicle charging pile control device, comprising:

[0131] The model building module is used to build a traditional dual-closed-loop PI control model for the T-type VIENNA rectifier. The traditional dual-closed-loop PI control model includes an inner current control and an outer voltage control.

[0132] The first improvement module is used to improve the current inner loop control in the traditional dual closed-loop PI control model by using a weak chattering super-spiral second-order sliding mode algorithm.

[0133] The second improvement module is used to design a linear active disturbance rejection controller (LADRC) based on the operating conditions of a T-type VIENNA rectifier, and to improve the voltage outer loop control in the traditional dual closed-loop PI control model based on the LADRC.

[0134] The control module is used to control the electric vehicle charging station according to the improved traditional dual closed-loop PI control model.

[0135] Furthermore, the first improved module includes:

[0136] The model building module is used to build a mathematical model of the T-type VIENNA rectifier in the dq coordinate system; the mathematical model includes the KVL equations for the inductor current input side and the KVL equations for the capacitor voltage input side.

[0137] The second-order sliding mode control law improvement module is used to improve the traditional second-order sliding mode control law with the hyperbolic tangent function to obtain a weak chattering super-spiral second-order sliding mode control law.

[0138] The current inner loop control module is used to take the current tracking error between the current reference and the current sampling as the sliding surface of the current inner loop control, let the DC side voltage in the dq coordinate system represent the voltage vector, and combine the weak chattering super spiral second-order sliding mode control law to control the current inner loop, thus completing the improvement of the current inner loop control.

[0139] This embodiment also provides a computing device applicable to the control method of electric vehicle charging piles, including:

[0140] The system includes a memory and a processor. The memory stores computer-executable instructions, and the processor executes these instructions to implement the electric vehicle charging pile control method proposed in the above embodiments.

[0141] This embodiment also provides a storage medium storing a computer program that, when executed by a processor, implements the electric vehicle charging pile control method proposed in the above embodiments.

[0142] The storage medium proposed in this embodiment belongs to the same inventive concept as the electric vehicle charging pile control method proposed in the above embodiments. Technical details not described in detail in this embodiment can be found in the above embodiments, and this embodiment has the same beneficial effects as the above embodiments.

[0143] Based on the above description of the implementation methods, those skilled in the art can clearly understand that the present invention can be implemented using software and necessary general-purpose hardware, and of course, it can also be implemented using hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as a computer floppy disk, read-only memory (ROM), random access memory (RAM), flash memory, hard disk, or optical disk, etc., including several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods of the various embodiments of the present invention.

[0144] Example 2

[0145] Reference Figures 3-8 As an embodiment of the present invention, specific simulations are used to verify the beneficial effect of the improved T-type VIENNA rectifier dual closed-loop PI control model on improving dynamic performance under load variations.

[0146] like Figure 3 As shown in the figure, in this embodiment, an improved simulation model of the T-type VIENNA rectifier with dual closed-loop PI control is built based on PLECS software, and the block diagram of the dual closed-loop structure is as follows. Figure 4 As shown. The phase-locked loop (PLL) provides the angle θ for transforming the abc coordinate system into the dq coordinate system. The modulation method adopts a space vector pulse width modulation (SVM) strategy to obtain the required drive signals for each switching device. The LADRC control parameters are r = 1000, β1 = 11660, β2 = 3.39889 × e 7 k P =530; WC-STSMC control parameters α1=30, α2=800, ε=0.08.

[0147] The rectifier simulation parameters are shown in Table 1:

[0148] Table 1 Simulation parameters of the T-type VIENNA rectifier

[0149]

[0150]

[0151] In this embodiment, two operating conditions—load disturbance and output voltage setpoint disturbance—are selected for simulation. The simulation results of the LADRC+WC-STSMC dual closed-loop control strategy and the PI+PI dual closed-loop control strategy in this example are as follows: Figures 5-8 As shown, through Figures 5-8 It can be seen that by introducing WC-STSMC into the control of the current inner loop, compared with the traditional PI dual closed-loop control strategy, the controller designed by this method can achieve fast tracking when the system is disturbed, and the good performance can also reduce the harmonic distortion rate of the grid-side current. Replacing the original PI control of the voltage outer loop with LADRC can improve the dynamic recovery speed when the system is disturbed and reduce the fluctuation of the recovery process.

[0152] Example 3

[0153] Reference Figures 9-11 This is an embodiment of the present invention. This embodiment selects two operating conditions: load disturbance and output voltage setpoint disturbance, to verify the beneficial effects of our invention.

[0154] 1. Load disturbance resistance: The output voltage is set to remain constant at 800V, and the total simulation time is 1s. At 0.7s, the load resistance changes from 85.3Ω to 42.7Ω.

[0155] 2. Resistance to output voltage setpoint disturbance: Set the total simulation time to 1s and the load resistance to 42.7Ω without changing. The output voltage setpoint switches from 800V to 900V at 0.5s.

[0156] This invention utilizes a weak-chattering superspiral second-order sliding mode algorithm, which weakens system chattering while greatly simplifying the design structure of the superspiral algorithm. Replacing the original PI control of the voltage outer loop with LADRC improves the dynamic recovery speed and reduces fluctuations during the recovery process when the system is disturbed. Combining it with linearized active disturbance rejection control not only solves the shortcomings of PID control but also reduces the complexity of the controller, making it easier to implement in practical engineering applications. This invention can improve the dynamic performance of the electric vehicle charging pile control system under load changes, ensuring a faster dynamic response after the rectifier is subjected to external disturbances. It can also reduce the harmonic distortion rate of the grid-side current, which is of great significance for improving the charging efficiency of the charging pile.

[0157] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A control method for an electric vehicle charging station, characterized in that, include: A traditional dual-closed-loop PI control model for a T-type VIENNA rectifier is established, which includes an inner current loop control and an outer voltage loop control. The current inner loop control in the traditional dual-closed-loop PI control model is improved by using a weak chattering super-spiral second-order sliding mode algorithm. Based on the operating conditions of the T-type VIENNA rectifier, a linear active disturbance rejection controller (LADRC) is designed, and the voltage outer loop control in the traditional dual closed-loop PI control model is improved based on the LADRC. The electric vehicle charging pile is controlled according to the improved traditional dual closed-loop PI control model. The current inner loop control in the traditional dual-closed-loop PI control model is improved by utilizing a weak chattering superspiral second-order sliding mode algorithm, including: A mathematical model of the T-type VIENNA rectifier in the dq coordinate system is established; the mathematical model includes the KVL equations for the inductor current input side and the KVL equations for the capacitor voltage input side. By improving the traditional second-order sliding mode control law with a hyperbolic tangent function, a weak chattering superspiral second-order sliding mode control law is obtained; The current tracking error between the current reference and the current sampling is used as the sliding surface of the current inner loop control. The DC side voltage in the dq coordinate system is used to represent the voltage vector. The current inner loop is controlled by a weak chattering super-spiral second-order sliding mode control law to complete the improvement of the current inner loop control. The linear active disturbance rejection controller (LADRC) is a second-order LADRC; the second-order LADRC includes: the LESO control equation, the control equation composed of LTD and LSEF; The LESO governing equations are expressed as follows: in, yes y The estimated value, It is the disturbance estimate for the voltage outer loop control. , These are adjustable control parameters; The governing equations composed of LTD and LSEF are expressed as follows: in, k p For adjustable control parameters, U LTD The output value of the transition process. b For high-frequency gain; Improved voltage outer loop control based on Linear Active Disturbance Rejection Controller (LADRC), including: The poles of the LESO governing equations are placed at At this point, the poles of the governing equations composed of LTD and LSEF are placed at... The location is represented as: in, For the bandwidth of the observer, It is the controller's bandwidth; The voltage outer loop control is improved by using the LESO control equation and the control equation composed of LTD and LSEF. The improved voltage outer loop control is expressed as: 。 2. The electric vehicle charging pile control method as described in claim 1, characterized in that, The weak chattering superspiral second-order sliding mode control law is expressed as: in, s 1 is the sliding surface. α 1, α 2 is a positive real number control parameter. It is the hyperbolic tangent function. u 1 is a differentiable sliding mode variable s Continuous functions, u 2 is the integral of the discontinuous first-order time differential.

3. The electric vehicle charging pile control method as described in claim 2, characterized in that, Also includes: The improved current inner loop control is expressed as: in, e gd , e gq It is the grid-side input voltage in the dq coordinate system. i gd , i gq The grid-side input current is in the dq coordinate system. U dc ε is the DC-side output voltage, and ε is a switching parameter that determines the rate of change of the inflection point of the hyperbolic tangent function.

4. An electric vehicle charging pile control device, implementing the method as described in any one of claims 1 to 3, characterized in that, include: The model building module is used to establish a traditional dual-closed-loop PI control model for a T-type VIENNA rectifier, which includes an inner current loop control and an outer voltage loop control. The first improvement module is used to improve the current inner loop control in the traditional dual closed-loop PI control model by using a weak chattering super spiral second-order sliding mode algorithm. The second improvement module is used to design a linear active disturbance rejection controller (LADRC) based on the operating conditions of a T-type VIENNA rectifier, and to improve the voltage outer loop control in the traditional dual closed-loop PI control model based on the LADRC. The control module is used to control the electric vehicle charging pile according to the improved traditional dual closed-loop PI control model.

5. The electric vehicle charging pile control device as described in claim 4, characterized in that, The first improved module includes: The model building module is used to build a mathematical model of the T-type VIENNA rectifier in the dq coordinate system; the mathematical model includes the KVL equations for the inductor current input side and the KVL equations for the capacitor voltage input side. The second-order sliding mode control law improvement module is used to improve the traditional second-order sliding mode control law with the hyperbolic tangent function to obtain a weak chattering super-spiral second-order sliding mode control law. The current inner loop control module is used to take the current tracking error between the current reference and the current sampling as the sliding surface of the current inner loop control, let the DC side voltage in the dq coordinate system represent the voltage vector, and combine the weak chattering super spiral second-order sliding mode control law to control the current inner loop, thus completing the improvement of the current inner loop control.

6. An electronic device, comprising: Memory and processor; The memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions, which, when executed by the processor, implement the steps of the electric vehicle charging pile control method according to any one of claims 1 to 3.

7. A computer-readable storage medium storing computer-executable instructions that, when executed by a processor, implement the steps of the electric vehicle charging pile control method according to any one of claims 1 to 3.

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