Stable Control Method, System and Electronic Device for Electric Vehicle V2G Charging Pile

Abstract

The present invention relates to the technical field of electric vehicles, and particularly relates to a stable control method, system and electronic device for an electric vehicle V2G charging pile. After obtaining state variables and control variables, the method inputs the state variables and control variables into a passivity-based controller to obtain a switching function, and controls the on-off of switches of a three-phase four-wire bidirectional converter of the electric vehicle V2G charging pile based on the LCL filter according to the switching function; the passivity-based controller is obtained based on an improved port-controlled dissipative Hamiltonian equation of the three-phase four-wire bidirectional converter of the electric vehicle V2G charging pile and a state variable desired trajectory equation, and the state variable desired trajectory equation is used to dynamically adjust the injection damping parameter of the passivity-based controller. Compared with the prior art, the present invention has the advantages of simple structure, fast response, good stability, and being easy to solve practical engineering problems, etc.

Description

Technical Field

[0001] The present invention relates to the technical field of electric vehicles, and particularly to a stable control method, system and electronic device for an electric vehicle V2G charging pile. Background Art

[0002] The three-phase four-wire converter of the electric vehicle V2G charging pile can realize the bidirectional power exchange between the electric vehicle and the power grid, and has the advantages of high utilization rate of the DC bus voltage and compensation of unbalanced voltage. Among them, the LCL filter can effectively suppress the high-frequency current harmonics of the power grid. Therefore, the stable control of the electric vehicle V2G charging pile is the key to realizing the power grid harmonic suppression function.

[0003] The traditional control methods of the electric vehicle V2G charging pile mainly include vector control and repetitive control. The vector control method has a simple structure, but the design of the controller depends on the linearization premise near the stable operating point of the nonlinear system. Therefore, the stable region is narrow and the engineering application is limited. The repetitive control method can effectively suppress the periodic harmonic signals with known frequencies of the power grid, but when the frequency of the harmonic signal fluctuates, the control accuracy drops significantly. Therefore, how to ensure that the required structure of the control method is simple, the response is fast, and the stability is good, so as to enable the electric vehicle V2G charging pile to achieve low-harmonic and high-quality stable control of the grid current has become a problem to be solved in this field. Summary of the Invention

[0004] The purpose of the present invention is to overcome the above-mentioned defects existing in the prior art, and provide a stable control method, system and electronic device for an electric vehicle V2G charging pile. The passivity control method is applied to the three-phase four-wire converter of the electric vehicle V2G charging pile based on the LCL filter to realize the accurate and fast tracking of the expected trajectory of the grid-connected current, and can effectively eliminate the adverse effects of the power grid harmonics. The stable control method of the electric vehicle V2G charging pile has a simple structure, a fast response and good stability, and is easy to solve engineering practical problems.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] According to a first aspect of the present invention, a stable control method for an electric vehicle V2G charging pile is provided. The control method is implemented based on a preset control system, and specifically includes the following steps: obtaining state variables and control variables; inputting the state variables and the control variables into a preset passivity controller to obtain a switching function; based on the switching function, controlling the on-off of the switches of the three-phase four-wire bidirectional converter of the electric vehicle V2G charging pile based on the LCL filter; wherein, the passivity controller is obtained based on the improved port-controlled dissipative Hamiltonian equation of the three-phase four-wire bidirectional converter of the electric vehicle V2G charging pile and the expected trajectory equation of the state variables, and the expected trajectory equation of the state variables is used to dynamically adjust the injection damping parameter of the passivity controller.

[0007] As a preferred technical solution, the acquisition process of the passivity controller specifically includes: constructing a state - space equation of a three - phase four - wire bidirectional converter for an electric vehicle V2G charging pile based on an LCL filter; defining state variables and obtaining a global energy function of the three - phase four - wire bidirectional converter according to the state variables; defining control variables and obtaining a port - controlled dissipative Hamiltonian equation of the three - phase four - wire bidirectional converter according to the state - space equation and the global energy function; defining an expected equilibrium point of the state variables and obtaining an expected global energy function according to the equilibrium point; defining an expected trajectory tracking error of the state variables and obtaining an expected trajectory equation of the state variables according to the port - controlled dissipative Hamiltonian equation and the expected global energy function; and obtaining a passivity controller according to the port - controlled dissipative Hamiltonian equation and the expected trajectory equation of the state variables.

[0008] As a preferred technical solution, the state - space equation is:

[0009]

[0010] In the formula, i 1d 、 i 1q are respectively the d - axis and q - axis components of the input current of the LCL filter, i 2d 、 i 2q are respectively the d - axis and q - axis components of the output current of the LCL filter, u Cd 、 u Cq are respectively the d - axis and q - axis components of the capacitor voltage of the LCL filter, u dc is the capacitor voltage on the DC side of the three - phase four - wire converter, u gd 、 u gq are respectively the d - axis and q - axis components of the grid voltage, S d 、 S q are respectively the d - axis and q - axis components of the switching function of the three - phase four - wire converter, L 1 、 L 2 are respectively the output - side inductors of the three - phase four - wire converter and the LCL filter, C, R are respectively the capacitor and resistor of the LCL filter, ω is the grid angular frequency, is the differential symbol.

[0011] As a preferred technical solution, the state variable is defined as:

[0012]

[0013] The global energy function is:

[0014]

[0015] In the formula, x is the state variable, L 1 and L 2 are the inductances on the output sides of the three-phase four-wire converter and the LCL filter respectively, i 1d and i 1q are the d-axis and q-axis components of the input current of the LCL filter respectively, i 2d and i 2q are the d-axis and q-axis components of the output current of the LCL filter respectively, u Cd and u Cq are the d-axis and q-axis components of the capacitor voltage of the LCL filter respectively, C is the capacitor of the LCL filter.

[0016] As a preferred technical solution, the control variable is defined as:

[0017]

[0018] In the formula, S d and S q are the d-axis and q-axis components of the switching function of the three-phase four-wire converter respectively, u dc is the capacitor voltage on the DC side of the three-phase four-wire converter, u gd and u gq are the d-axis and q-axis components of the grid voltage respectively;

[0019] The port-controlled dissipative Hamilton equation is:

[0020]

[0021] In the formula, is the derivative of the state variable , y is the output variable, J(x) is the matrix characterizing the internal structure of the control system,R(x) is a positive semi - definite symmetric matrix characterizing the dissipativity of the control system, g(x) is a matrix characterizing the internal and external correlations of the control system.

[0022] As a preferred technical solution, the desired equilibrium point of the state variable is defined as:

[0023]

[0024] wherein, x is the state variable, and the superscript * represents the corresponding desired equilibrium point, L 1 and L 2 are the output - side inductances of the three - phase four - wire converter and the LCL filter respectively, i 1d and i 1q are the d - axis and q - axis components of the input current of the LCL filter respectively, i 2d and i 2q are the d - axis and q - axis components of the output current of the LCL filter respectively, u Cd and u Cq are the d - axis and q - axis components of the capacitor voltage of the LCL filter respectively, C is the capacitor of the LCL filter;

[0025] The desired global energy function is:

[0026]

[0027] where:

[0028]

[0029] wherein, H ( x ) is the global energy function, H a ( x ) is the energy injected into the system through the passivity - based control law.

[0030] As a preferred technical solution, the tracking error of the desired trajectory of the state variable is defined as:

[0031]

[0032] The desired trajectory equation of the state variable is:

[0033]

[0034] Wherein:

[0035]

[0036]

[0037] In the formula, is the state variable is the derivative of J d ( x ) is the desired interconnection matrix of the control system, J a ( x ) is the injected dissipation matrix, R d ( x ) is the desired damping matrix of the control system, R a ( x ) is the injected damping matrix, J(x) is the matrix representing the internal structure of the control system, R(x) is a positive semi - definite symmetric matrix representing the dissipativity of the control system, g(x) is the matrix representing the internal and external correlation of the control system.

[0038] As a preferred technical solution, the control variable, i.e., the passivity controller u is expressed as:

[0039] .

[0040] According to the second aspect of the present invention, there is provided a stable control system for an electric vehicle V2G charging pile. The system is used to implement the control method, and at least includes a state variable sensor, a control variable sensor, and a passivity controller. The state variable sensor is used to obtain the state variable, the control variable sensor is used to obtain the control variable, and the passivity controller is used to receive the state variable and the control variable, obtain a switching function, and based on the switching function, control the on - off of the switches of the three - phase four - wire bidirectional converter of the electric vehicle V2G charging pile based on the LCL filter; wherein, the passivity controller is obtained based on the improved port - controlled dissipative Hamiltonian equation of the three - phase four - wire bidirectional converter of the electric vehicle V2G charging pile and the state variable desired trajectory equation, and the state variable desired trajectory equation is used to dynamically adjust the injected damping parameter of the passivity controller.

[0041] According to the third aspect of the present invention, there is provided an electronic device, including a memory, a processor, and a program stored in the memory. When the processor executes the program, the control method is implemented.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] 1. The passivity controller of the present invention is obtained based on the improved port-controlled dissipative Hamiltonian equation and the state variable desired trajectory equation of the three-phase four-wire bidirectional converter of the electric vehicle V2G charging pile. Based on this passivity controller, the three-phase four-wire bidirectional converter and the LCL filter are controlled as a whole. Without considering the internal resonance of the LCL filter, only according to the desired trajectory of the grid-connected current, the switching function of the three-phase four-wire bidirectional converter can be obtained. The calculation is simple and the response is fast. At the same time, according to the dynamic response characteristics of the state variable desired trajectory tracking, the damping parameter injected by the passivity controller can be adjusted, which can avoid the deficiency that the controller parameter tuning in the traditional control method is easily affected by the model parameter perturbation;

[0044] 2. In the process of obtaining the passivity controller of the present invention, through the shaping of the global energy function, while realizing the asymptotic tracking of the state variable desired trajectory, the global asymptotic stability of the closed-loop control system can be ensured, and the stability domain is wider. Based on this, this simple-form passivity controller can accurately and quickly track the state variable desired trajectory, stably control the grid-connected current of the three-phase four-wire converter of the electric vehicle V2G charging pile, effectively suppress the grid harmonics, and the closed-loop control system is globally asymptotically stable. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 is a schematic flow chart of the method provided by the present invention;

[0046] Figure 2 is a schematic structural diagram of the three-phase four-wire converter of the electric vehicle V2G charging pile in Embodiment 1 of the present invention;

[0047] Figure 3 is the grid-connected current of the electric vehicle V2G charging pile when the passivity control method is adopted under the condition that the grid current amplitude drops suddenly by 1 / 3 and contains uncertain harmonics in the control method of Embodiment 1 of the present invention i 2a 、 i 2b 、 i 2c waveform diagram;

[0048] Figure 4 is the harmonic analysis diagram of the grid-connected current of the electric vehicle V2G charging pile when the passivity control method is adopted under the condition that the grid current amplitude drops suddenly by 1 / 3 and contains uncertain harmonics in the control method of Embodiment 1 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0049] The present invention will be described in detail below with reference to the drawings and specific embodiments. This embodiment is implemented on the premise of the technical solution of the present invention, and the detailed implementation manner and specific operation process are given, but the protection scope of the present invention is not limited to the following embodiments.

[0050] Example 1

[0051] The passivity - based control method provided by the present invention starts from the energy perspective and designs a globally stable controller, enabling the electric vehicle V2G charging pile to still operate stably at the desired operating point when the amplitude of the grid current suddenly changes and contains uncertain harmonics, achieving zero - steady - state error tracking of the desired trajectory of the grid - connected current, having excellent grid harmonic suppression ability, and being of great practical significance for expanding the engineering application of electric vehicle V2G charging piles.

[0052] This embodiment provides a stable control method and control system for an electric vehicle V2G charging pile. Among them, the control system includes a passivity - based controller, a state - variable sensor, and a control - variable sensor. Based on this control system, as Figure 1 shown, the implementation process of the foregoing method specifically includes: the state - variable sensor and the control - variable sensor detect the state variables and control variables in real - time, input the state variables and control variables into the passivity - based controller, and the passivity - based controller outputs the switching function of the three - phase four - wire bidirectional converter (i.e., S d , S q )), and controls the on - off of the switches of the three - phase four - wire bidirectional converter of the electric vehicle V2G charging pile based on the LCL filter according to the switching function.

[0053] The foregoing passivity - based controller is obtained based on the improved port - controlled dissipative Hamiltonian equation (i.e., the port - controlled dissipative Hamilton equation) of the three - phase four - wire converter of the electric vehicle V2G charging pile and the desired trajectory equation of the state variables, where the desired trajectory equation of the state variables is used to dynamically adjust the injection damping parameter of the passivity - based controller. Exemplarily, the acquisition of the passivity - based controller includes two parts:

[0054] The first part is to establish the port - controlled dissipative Hamilton equation of the three - phase four - wire converter of the electric vehicle V2G charging pile in the dq coordinate system;

[0055] The second part is to design a passivity - based controller from the energy perspective to make the tracking error of the desired trajectory of the state variables tend to zero steady - state error, achieve stable grid - connected current control, and effectively suppress grid harmonics.

[0056] The specific implementation processes of the two parts are as follows:

[0057] In the dq coordinate system, construct the state - space equation of the three - phase four - wire bidirectional converter of the electric vehicle V2G charging pile based on the LCL filter. Specifically, the state - space equation is:

[0058] (1)

[0059] In the formula, i 1d and i 1q are the d-axis and q-axis components of the input current of the LCL filter respectively; i 2d and i 2q are the d-axis and q-axis components of the output current of the LCL filter respectively; u Cd and u Cq are the d-axis and q-axis components of the capacitor voltage of the LCL filter respectively; u dc is the capacitor voltage on the DC side of the three-phase four-wire converter; u gd and u gq are the d-axis and q-axis components of the grid voltage respectively; S d and S q are the d-axis and q-axis components of the switching function of the three-phase four-wire converter respectively; L 1 and L 2 are the output-side inductors of the three-phase four-wire converter and the LCL filter respectively; C, R are the capacitor and resistor of the LCL filter respectively; ω is the grid angular frequency; is the differential symbol.

[0060] Define the state variables of the three-phase four-wire converter of the electric vehicle V2G charging pile, and obtain the global energy function of the three-phase four-wire converter of the electric vehicle V2G charging pile according to the state variables. Specifically, the state variables are defined as:

[0061] (2)

[0062] Based on this, the global energy function H ( x ) is:

[0063] (3)

[0064] In the formula, x is the state variable.

[0065] Define the control variable u , and obtain the port-controlled dissipative Hamilton equation of the three-phase four-wire bidirectional converter according to the state space equation and the global energy function. Specifically, the control variable is defined as:

[0066] (4)

[0067] Based on this and according to Eqs. (1) and (3), the port-controlled dissipative Hamiltonian equation of the three-phase four-wire converter of the electric vehicle V2G charging pile is established as follows:

[0068] (5)

[0069] where: is the derivative of the state variable , y is the output variable, J(x) is the matrix characterizing the internal structure of the control system, R(x) is the positive semi-definite symmetric matrix characterizing the dissipativity of the control system, g(x) is the matrix characterizing the internal and external connection of the control system, specifically expressed as:

[0070] (6)

[0071] (7)

[0072] (8)

[0073] Define the expected equilibrium point of the state variable and obtain the expected global energy function according to the equilibrium point. Specifically, from the energy perspective, the expected equilibrium point of the state variable is defined as:

[0074] (9)

[0075] where: x is the state variable, and the superscript * represents the corresponding expected equilibrium point.

[0076] To make the energy of the closed-loop control system reach the minimum value at the expected equilibrium point x * , that is, the closed-loop control system can asymptotically converge to the expected equilibrium point, the expected global energy function is expressed as:

[0077] (10)

[0078] where:

[0079] (11)

[0080] where: H a ( x ) is the energy injected into the system through the passivity control law.

[0081] Define the expected trajectory tracking error of the state variable, and obtain the expected trajectory equation of the state variable according to the port-controlled dissipative Hamilton equation and the expected global energy function. Specifically, the expected trajectory tracking error of the state variable is defined as:

[0082] (12)

[0083] Based on this, to achieve the asymptotic tracking of the expected trajectory of the state variable, that is , according to Eqs. (5) and (10), the expected trajectory equation of the state variable can be obtained as:

[0084] (13)

[0085] where:

[0086] (14)

[0087] (15)

[0088] , (16)

[0089] In the formula, J d ( x ) is the expected interconnection matrix of the control system, J a ( x ) is the injected dissipative matrix, R d ( x ) is the expected damping matrix of the control system, R a ( x ) is the injected damping matrix, and R1, R2, R3, R4, R5, and R6 are the damping parameters injected by the passivity controller. Adjusting R a (x) can achieve the speed control of tracking the expected trajectory of the state variable.

[0090] According to the port-controlled dissipative Hamilton equation and the expected trajectory equation of the state variable, a passivity controller is obtained. Specifically, according to Eqs. (5) and (13), the control variable, that is, the passivity controller u is:

[0091] (17)

[0092] Adopting this passivity controller can make the expected trajectory tracking error of the state variable tend to zero steady-state error, maintain the stability of the grid-connected current, and effectively suppress grid harmonics; selecting an appropriate R a( x ) It can ensure the accurate and rapid tracking of the expected trajectory of the grid-connected current. This passivity controller has a simple form, small computational load, good dynamic response, and a wide stability region.

[0093] To verify the dynamic response performance and harmonic suppression performance of the designed stable control method for the electric vehicle V2G charging pile, the simulation conditions are set as follows: At t = 20 ms, the amplitude of the grid current suddenly drops by 1 / 3 and contains uncertain harmonics, and the dynamic response of the grid-connected current of the electric vehicle V2G charging pile and the harmonic content are analyzed.

[0094] Figure 2 This is the schematic diagram of the three-phase four-wire converter structure of the electric vehicle V2G charging pile in this embodiment. Among them, i 1a , i 1b , i 1c are the a phase, b phase, c phase currents on the input side of the LCL filter respectively. After Park transformation, i 1d , i 1q ; i 2a , i 2b , i 2c are the a phase, b phase, c phase currents on the output side of the LCL filter respectively. After Park transformation, i 2d , i 2q ; u dc is the DC-side capacitor voltage of the three-phase four-wire converter, S 1 ~S 8 are the IGBT devices of each bridge arm of the three-phase four-wire converter respectively, v ga , v gb , v gc are the a phase, b phase, c phase voltages of the power grid respectively; Figure 3Grid current amplitude drops suddenly by 1 / 3 in the control method of this embodiment, and at the same time, there are uncertain harmonics. The grid-connected current of the electric vehicle V2G charging pile when using the passivity control method i 2a , i 2b , i 2c waveform diagram; Figure 4 It is the harmonic analysis diagram of the grid-connected current of the electric vehicle V2G charging pile when the grid current amplitude drops suddenly by 1 / 3 in the control method of this embodiment, and at the same time, there are uncertain harmonics, and the passivity control method is used.

[0095] From Figure 3 and Figure 4 analysis shows that when using the passivity control method designed in this embodiment, when the effective value of the grid current suddenly drops from 15 A to 10 A and there are uncertain harmonics at the same time, the grid-connected current of the electric vehicle V2G charging pile quickly tracks the desired trajectory within 1 ms, and the harmonic THD is effectively controlled within 2%; the passivity control method realizes small overshoot and fast tracking speed in the transient process of the grid-connected current of the electric vehicle V2G charging pile, has good dynamic response performance, and achieves the purpose of stable control of the grid-connected current and harmonic suppression; the electric vehicle V2G charging pile operates stably, and the closed-loop control system has good stability. The simulation results show that the designed stable control method of the electric vehicle V2G charging pile has the characteristics of fast response and good stability.

[0096] Embodiment 2

[0097] This embodiment provides an electronic device, including a memory, a processor, and a program stored in the memory. When the processor executes the program, it implements the method provided in Embodiment 1. Exemplarily, the processor includes a central processing unit (CPU), which can execute various appropriate actions and processes according to computer program instructions stored in a read-only memory (ROM) or computer program instructions loaded from a storage unit into a random access memory (RAM). In the RAM, various programs and data required for device operation can also be stored. The CPU, ROM, and RAM are connected to each other via a bus. An input / output (I / O) interface is also connected to the bus. Multiple components in the device are connected to the I / O interface, including: an input unit, such as a keyboard, a mouse, etc.; an output unit, such as various types of displays, speakers, etc.; a storage unit, such as a disk, an optical disc, etc.; and a communication unit, such as a network card, a modem, a wireless communication transceiver, etc. The communication unit allows the device to exchange information / data with other devices through a computer network such as the Internet and / or various telecommunication networks. The processing unit executes the various methods and processes described above, such as one or more steps of the method in the aforementioned Embodiment 1. For example, in some embodiments, the method in Embodiment 1 can be implemented as a computer software program, which is tangibly contained in a machine-readable medium, such as a storage unit. In some embodiments, part or all of the computer program can be loaded and / or installed onto the device via the ROM and / or the communication unit. When the computer program is loaded into the RAM and executed by the CPU, one or more steps of the method in Embodiment 1 described above can be executed. Alternatively, in other embodiments, the CPU can be configured to execute one or more steps of the method in Embodiment 1 by any other appropriate means (e.g., by means of firmware). The functions described above can be at least partially executed by one or more hardware logic components. For example, without limitation, exemplary types of hardware logic components that can be used include: field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), systems on a chip (SOCs), complex programmable logic devices (CPLDs), and so on.

[0098] The preferred specific embodiments of the present invention have been described in detail above. It should be understood that those of ordinary skill in the art can make many modifications and variations based on the concept of the present invention without creative efforts. Therefore, all technical solutions that can be obtained by those skilled in the art in the technical field based on the concept of the present invention through logical analysis, reasoning, or limited experiments on the basis of the prior art should fall within the protection scope determined by the claims.

Claims

1. A stable control method for an electric vehicle V2G charging pile, characterized in that, The control method is implemented based on a preset control system, and specifically includes the following steps: Obtain state variables and control variables; Input the state variables and the control variables into a preset passivity controller to obtain a switching function; Based on the switching function, control the on / off of the switches of a three-phase four-wire bidirectional converter of an electric vehicle V2G charger based on an LCL filter; Among them, the passivity controller is obtained based on an improved port-controlled dissipative Hamiltonian equation of a three-phase four-wire bidirectional converter of an electric vehicle V2G charger and a state variable desired trajectory equation, and the state variable desired trajectory equation is used to dynamically adjust the injection damping parameter of the passivity controller; The obtaining process of the passivity controller specifically includes: Construct a state space equation of a three-phase four-wire bidirectional converter of an electric vehicle V2G charger based on an LCL filter; Define state variables, and obtain a global energy function of the three-phase four-wire bidirectional converter according to the state variables; Define control variables, and obtain a port-controlled dissipative Hamiltonian equation of the three-phase four-wire bidirectional converter according to the state space equation and the global energy function; Define a desired equilibrium point of the state variables, and obtain a desired global energy function according to the equilibrium point; The state variables are defined as: ， The desired equilibrium point of the state variables is defined as: ， wherein, x is the state variable, and the superscript * represents the corresponding desired equilibrium point, L 1 and L 2 are the output - side inductors of the three - phase four - wire bidirectional converter and the LCL filter respectively, i 1d and i 1q are the d - axis and q - axis components of the input current of the LCL filter respectively, i 2d and i 2q are the d - axis and q - axis components of the output current of the LCL filter respectively, u Cd and u Cq are the d - axis and q - axis components of the capacitor voltage of the LCL filter respectively, C is the capacitor of the LCL filter; The desired global energy function is: ， Where: ， wherein, H ( x ) is the global energy function, H a ( x ) is the energy injected into the system through the passivity control law; Define a state variable desired trajectory tracking error, and obtain a state variable desired trajectory equation according to the port-controlled dissipative Hamiltonian equation and the desired global energy function; According to the port-controlled dissipative Hamiltonian equation and the state variable desired trajectory equation, obtain a passivity controller.

2. The stable control method for an electric vehicle V2G charging pile according to claim 1, characterized in that The state space equation is: ， ， ， ， ， ， ， Wherein, i 1d and i 1q are the d - axis and q - axis components of the input current of the LCL filter respectively, i 2d and i 2q are the d - axis and q - axis components of the output current of the LCL filter respectively, u Cd and u Cq are the d - axis and q - axis components of the capacitor voltage of the LCL filter respectively, u dc is the capacitor voltage of the DC side of the three - phase four - wire bidirectional converter, u gd and u gq are the d - axis and q - axis components of the grid voltage respectively, S d and S q are the d - axis and q - axis components of the switching function of the three - phase four - wire bidirectional converter respectively, L 1 and L 2 are the output - side inductors of the three - phase four - wire bidirectional converter and the LCL filter respectively, C, R are the capacitor and resistor of the LCL filter respectively, ω is the grid angular frequency, is the differential symbol.

3. The stable control method for an electric vehicle V2G charging pile according to claim 1, characterized in that, The global energy function is: ， Wherein, x is a state variable, L 1 , L 2 are the inductors on the output side of the three-phase four-wire bidirectional converter and the LCL filter respectively, i 1d , i 1q are the d-axis and q-axis components of the input current of the LCL filter respectively, i 2d , i 2q are the d-axis and q-axis components of the output current of the LCL filter respectively, u Cd , u Cq are the d-axis and q-axis components of the capacitor voltage of the LCL filter respectively, C is the capacitor of the LCL filter.

4. The stable control method for an electric vehicle V2G charging pile according to claim 3, wherein The control variables are defined as: ， Wherein, S d and S q are the d-axis and q-axis components of the switching function of the three-phase four-wire bidirectional converter respectively, u dc is the DC-side capacitor voltage of the three-phase four-wire bidirectional converter, u gd and u gq are the d-axis and q-axis components of the grid voltage respectively; The port-controlled dissipative Hamiltonian equation is: ， In the formula, is the derivative of the state variable , y is the output variable, J(x) is the matrix representing the internal structure of the control system, R (x) is the positive semi - definite symmetric matrix representing the dissipativity of the control system, g(x) is the matrix representing the internal and external correlation of the control system.

5. The stable control method for an electric vehicle V2G charging pile according to claim 1, wherein The state variable desired trajectory tracking error is defined as: ， The state variable desired trajectory equation is: ， Where: ， ， In the formula, is the derivative of the state variable , J d ( x ) is the desired interconnection matrix of the control system, J a ( x ) is the injected dissipation matrix, R d ( x ) is the desired damping matrix of the control system, R a ( x ) is the injected damping matrix, J(x) is the matrix characterizing the internal structure of the control system, R(x) is the positive semi - definite symmetric matrix characterizing the dissipativity of the control system, g(x) is the matrix characterizing the internal and external correlations of the control system; represents the control variable.

6. The stable control method for an electric vehicle V2G charging pile according to claim 5, wherein The control variable, i.e., the passivity controller u is expressed as: 。 7. A stable control system for an electric vehicle V2G charging pile, characterized in that, The system is used to implement the control method described in any one of claims 1-6, and at least includes a state variable sensor, a control variable sensor, and a passivity controller. The state variable sensor is used to obtain state variables, the control variable sensor is used to obtain control variables, and the passivity controller is used to receive the state variables and the control variables, obtain a switching function, and based on the switching function, control the on / off of the switches of a three-phase four-wire bidirectional converter of an electric vehicle V2G charger based on an LCL filter; Among them, the passivity controller is obtained based on an improved port-controlled dissipative Hamiltonian equation of a three-phase four-wire bidirectional converter of an electric vehicle V2G charger and a state variable desired trajectory equation, and the state variable desired trajectory equation is used to dynamically adjust the injection damping parameter of the passivity controller.

8. An electronic device, comprising a memory, a processor, and a program stored in the memory, characterized in that, When the processor executes the program, it implements the control method described in any one of claims 1-6.

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