Optical storage and charging integrated station system and control method thereof

Abstract

The invention relates to an optical storage and charging integrated station system and a control method thereof.The system comprises a photovoltaic power generation unit, a hybrid energy storage unit, a photovoltaic converter and a hybrid energy storage converter, the photovoltaic power generation unit is connected with a direct-current bus through the photovoltaic converter, and the hybrid energy storage unit is connected with the direct-current bus through the hybrid energy storage converter; the charging pile is connected with the direct current bus through the DC / DC converter, and the direct current bus of the optical storage and charging integrated station system is connected with a grid-connected position of a power grid through a VIENNA rectifier. According to the invention, the dynamic response speed, the robustness, the anti-interference capability and the like of the optical storage and charging integrated station can be improved.

Description

Technical Field

[0001] The present application relates to the field of photovoltaic storage and charging control, and specifically to a photovoltaic storage and charging integrated station system and a control method thereof. Background Art

[0002] Against the backdrop of rapid global economic development and expanding population, the number of fuel vehicles has continued to rise, leading to a sharp increase in demand for fossil energy. However, the large-scale exploitation and consumption of fossil energy has not only exacerbated the global energy crisis, but also caused serious damage to the environment, such as increased greenhouse gas emissions, deteriorating air quality, and imbalanced ecosystems. Electric vehicles are regarded as an ideal substitute for fuel vehicles due to their zero emissions, low noise, and high energy efficiency. In recent years, with the continuous advancement of battery technology, drive systems, and charging facilities, the range of electric vehicles has continued to increase, and the convenience of charging has also increased, which has promoted the rapid development of the electric vehicle market. With the proposal of the "dual carbon" goal, my country's electric vehicle industry has ushered in unprecedented development opportunities, but the charging demand of a large number of electric vehicles has also brought huge load pressure to the power grid.

[0003] The integrated photovoltaic, storage and charging station can supply green electricity to electric vehicles, realize auxiliary service functions such as power peak shaving and valley filling, and promote the development of green transportation. Compared with traditional charging stations, the integrated photovoltaic, storage and charging technology is a comprehensive energy solution formed by the comprehensive utilization of modern photovoltaic technology, advanced energy storage technology and intelligent charging technology. It is an important basic supporting facility for the new energy vehicle industry. On the one hand, the integrated photovoltaic, storage and charging station provides a green and low-carbon energy supply for charging new energy vehicles, which can serve as an important guarantee for the development of the new energy vehicle field; on the other hand, the integrated photovoltaic, storage and charging station can effectively overcome the problems of instability and intermittency of photovoltaic power generation, and alleviate the load pressure brought by the grid connection of a large number of electric vehicles. As a new idea for charging stations, the integrated photovoltaic, storage and charging charging station urgently needs to analyze and study its system composition and control strategy. Summary of the invention

[0004] The purpose of the embodiments of the present application is to provide a photovoltaic storage and charging integrated station system and a control method thereof, so as to improve the performance of the photovoltaic storage and charging integrated station, such as dynamic response speed, robustness and anti-interference ability.

[0005] To achieve the above objectives, this application provides the following technical solutions:

[0006] In a first aspect, an embodiment of the present application provides an integrated photovoltaic energy storage and charging station system, including a photovoltaic power generation unit, a hybrid energy storage unit, a photovoltaic converter, and a hybrid energy storage converter. The photovoltaic power generation unit is connected to a DC bus through the photovoltaic converter, the hybrid energy storage unit is connected to the DC bus through the hybrid energy storage converter, a charging pile is connected to the DC bus through a DC / DC converter, and the DC bus of the integrated photovoltaic energy storage and charging station system is connected to the grid connection point of the power grid by a VIENNA rectifier.

[0007] The hybrid energy storage converter is a bidirectional DC-DC circuit. The bidirectional DC-DC circuit includes a capacitor C1, a capacitor C2, a switching tube S1, a switching tube S2, anti-parallel diodes D1, D2, and an inductor L. When S1 is turned on, S2 is turned off, and the anti-parallel diodes D1 and D2 are turned off, the bidirectional DC-DC circuit operates in the Buck mode, and the bidirectional DC-DC circuit enables the energy storage system to switch between charging and discharging.

[0008] The hybrid energy storage unit includes battery energy storage and supercapacitor energy storage.

[0009] In a second aspect, an embodiment of the present application provides a control method for an integrated photovoltaic energy storage and charging station system, including photovoltaic converter-based control of the photovoltaic power generation unit according to the photovoltaic power generation power; fuzzy-auto disturbance rejection common voltage loop double closed-loop control of the hybrid energy storage converter of the hybrid energy storage unit, and double closed-loop PI control of the VIENNA rectifier.

[0010] The photovoltaic converter-based control of the photovoltaic power generation unit according to the photovoltaic power generation power is specifically as follows: when the photovoltaic power generation power is insufficient, the photovoltaic converter uses the conductance increment method to achieve maximum power point tracking; when the photovoltaic power generation power is excessive, the photovoltaic converter switches to a constant voltage control mode. The control method of the constant voltage control mode includes the following steps:

[0011] S01: Collect the actual value V of the DC bus voltage dc , compare it with the reference value V of the DC bus voltage dc_ref , and the difference between the two is input into a PI controller;

[0012] S02: After passing through the PI control link, obtain the reference value I of the current of the photovoltaic power generation unit PV_ref , compare it with the actual value I of the photovoltaic current PV , and the difference between the two is input into a PI controller, so as to control the photovoltaic converter to operate in the constant voltage mode.

[0013] The fuzzy-auto disturbance rejection common voltage loop double closed-loop control of the hybrid energy storage converter of the hybrid energy storage unit includes a fuzzy-auto disturbance rejection common voltage loop, a battery current loop, and a supercapacitor current loop. The control process is as follows:

[0014] S01: The DC bus voltage Vdc and the voltage reference value V ref Input the fuzzy-active disturbance rejection common voltage loop, and the fuzzy-active disturbance rejection common voltage loop includes a tracking differentiator TD, an extended state observer ESO, a state error nonlinear combination control law NLSEF, and a fuzzy control link.

[0015] S02: After passing through the fuzzy-active disturbance rejection common voltage loop, the original reference current I is output ref , and after passing through the low-pass filter, the low-frequency signal I is obtained ref-b and the medium-high frequency current signal I ref-s :

[0016]

[0017] In the above formula, T is the time constant of the low-pass filter; V bat is the output voltage of the battery energy storage; V SC is the output voltage of the supercapacitor energy storage;

[0018] The obtained I ref-b is the input reference current of the battery current inner loop; the obtained I ref-s is the input reference current of the supercapacitor current inner loop;

[0019] S03: After passing through the low-pass filter, the input reference current of the battery current inner loop and the input reference current of the supercapacitor current inner loop are obtained. The battery current inner loop and the supercapacitor current inner loop have the same structure and adopt an active disturbance rejection control structure, including three parts: a tracking differentiator, an extended state observer, and a nonlinear error feedback control law.

[0020] The double closed-loop PI control strategy of the VIENNA rectifier is

[0021]

[0022] In the above formula, K iP and K iI are the PI parameters of the current controller; v d , v q are the d and q axis components of the AC side voltage of the rectifier, and i dref and i qref are the d and q axis current reference values.

[0023] Compared with the prior art, the beneficial effects of the present invention are: it has the advantages of fast dynamic response speed, strong robustness, and strong anti-interference ability. By fuzzy control, the difficulty of setting the active disturbance rejection parameters is reduced, the stability of the integrated photovoltaic energy storage charging station is effectively improved, and it has certain reference value. Description of the Drawings

[0024] To more clearly illustrate the technical solutions of the embodiments of the present application, the accompanying drawings required for use in the embodiments of the present application will be briefly introduced below. It should be understood that the following accompanying drawings only show certain embodiments of the present application and should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related accompanying drawings can also be obtained based on these drawings.

[0025] Figure 1 It is a schematic diagram of the integrated optical storage and charging station system of the present invention.

[0026] Figure 2 It is the bidirectional DC-DC circuit diagram of the hybrid energy storage controller.

[0027] Figure 3 It is the auto-disturbance rejection control structure diagram of the present invention.

[0028] Figure 4 It is the fuzzy-auto-disturbance rejection control structure diagram of the present invention.

[0029] Figure 5 It is the fuzzy control input and output membership function diagram.

[0030] Figure 6 It is the output power of the photovoltaic power generation unit.

[0031] Figure 7 It is the output power of the hybrid energy storage system. Specific embodiments

[0032] Next, the technical solutions in the embodiments of the present application will be described in conjunction with the accompanying drawings in the embodiments of the present application. It should be noted that: similar reference numerals and letters denote similar items in the following accompanying drawings. Therefore, once an item is defined in one accompanying drawing, it does not need to be further defined and explained in subsequent accompanying drawings.

[0033] The term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, such that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the phrase "comprising a..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the element.

[0034] The terms "first", "second", etc. are only used to distinguish one entity or operation from another entity or operation, and cannot be construed as indicating or implying relative importance, nor can it be construed as requiring or implying any actual relationship or order between these entities or operations.

[0035] When S1 is turned on, S2 is turned off, and the anti-parallel diodes D1 and D2 are turned off, the bidirectional DC-DC circuit operates in the Buck mode. Select the inductor current i L as the state variable, and the DC-side voltage U dc , and the energy storage-side voltage U b as the input variables. Based on Kirchhoff's law, the circuit is modeled as follows:

[0036]

[0037] In the above formula, R dc and R b are the equivalent resistances of the DC bus side and the energy storage side, respectively.

[0038] When S1 and S2 are turned off, D1 is turned off, and D2 is turned on, based on Kirchhoff's law, the circuit is modeled as follows:

[0039]

[0040] Based on the small-signal method and the state-space averaging method, the state-space averaging equation in the Buck mode is obtained:

[0041]

[0042] In the above formula, d1 is the duty cycle of the Buck mode.

[0043] Based on the small-signal method for modeling and simplification, the transfer function in the Buck mode is obtained:

[0044]

[0045]

[0046] In the above formula, d(s) is the control variable.

[0047] Similarly, the mathematical model and transfer function in the Boost mode are as follows:

[0048]

[0049]

[0050]

[0051] In the above formula, d2 is the duty cycle in the Boost mode.

[0052] The VIENNA rectifier circuit model at the grid connection is as follows:

[0053]

[0054] In the above formula, e d and e q are the d-axis and q-axis components of the grid electromotive force on the AC side; v d and v q are the d-axis and q-axis components of the voltage on the AC side of the rectifier; R is the parasitic resistance of the inductor.

[0055] The double closed-loop PI control strategy of the VIENNA rectifier circuit at the grid connection point is as follows:

[0056]

[0057] In the above formula, K iP and K iI are the PI parameters of the current controller; i dref and i qref are the reference values of the d-axis and q-axis currents.

[0058] The energy storage controller adopts a fuzzy-active disturbance rejection common voltage loop double closed-loop control method, which includes a fuzzy-active disturbance rejection common voltage loop, a battery current loop, and a supercapacitor current loop.

[0059] The DC bus voltage V dc and the voltage reference value V ref are input into the fuzzy-active disturbance rejection control module, and the original reference current I ref is output. After passing through a low-pass filter, the low-frequency signal I ref-b and the medium-high frequency current signal I ref-s are obtained:

[0060]

[0061] In the above formula, T is the time constant of the low-pass filter; V bat is the output voltage of the battery energy storage; V SC is the output voltage of the supercapacitor energy storage.

[0062] The obtained I ref-b is the input reference current of the inner loop of the battery current; the obtained I ref-s is the input reference current of the inner loop of the supercapacitor current; I ref-b and I ref-s output the control quantity after passing through the inner loop of the battery current and the inner loop of the supercapacitor current, thereby controlling the converter switching tubes.

[0063] The fuzzy-active disturbance rejection common voltage loop includes a tracking differentiator (TD), an extended state observer (ESO), a nonlinear state error feedback (NLSEF), and a fuzzy control link.

[0064] The non - linear function fal function is used in the tracking differentiator TD, the state - error non - linear combination control law NLSEF, and the extended state observer ESO. Its expression is as follows:

[0065]

[0066] In the above formula, a is the tracking factor; e is the error signal; δ is the filtering factor; sign represents the step function.

[0067] The tracking differentiator TD is responsible for arranging a transition process to ensure that when the given signal changes, the controller output can track the given value in a short time without overshoot. Its expression is as follows:

[0068]

[0069] In the above formula, U ref is the reference voltage given signal value; U2(t) is the tracking signal of the voltage given signal value; r0 is the speed factor, which determines the tracking speed. Generally speaking, the larger r0 is, the faster U2(t) tracks U ref However, when r0 is too large, it will cause system oscillation at the same time.

[0070] The function of the extended state observer ESO is to expand the internal and external disturbances and uncertainties into system state variables. The expression of ESO is as follows:

[0071]

[0072] In the above formula, U dc (t) is the real - time voltage of the DC bus voltage; z1(t) and z2(t) are the state variables of ESO, which are the tracking signal of the sampled voltage feedback signal and the observed value of the total disturbance signal respectively; β1 and β2 are the error - adjustment gains of ESO; u(t) is the control signal output by the ADRC controller.

[0073] The function of the state - error non - linear combination control law NLSEF is to calculate the demand of the controlled object to meet the given requirements according to the error information of the state variables observed in the expanded state. The expression of NLSEF is as follows:

[0074]

[0075] In the above formula, β3 is the regulator gain; u0 is the non - linear control quantity calculated by NLSEF; u is the final output control quantity of the ADRC controller.

[0076] The fuzzy control link uses fuzzy logic reasoning and fuzzy set theory to solve practical engineering problems, learns the internal and external dynamic relationships of the system through fuzzy reasoning, and finally outputs the fuzzy input value as a clear value. The larger the value of β3 in the non-linear combination control law of state error NLSEF, the smaller the lag of system disturbance estimation. However, if β3 is too large, it will cause system oscillation. β1 and β2 in the extended state observer ESO can suppress voltage fluctuations. However, if β1 and β2 are too large, the system will diverge. Through the fuzzy control link, the online adjustment of β1, β2 and β3 is realized within the parameter range to make the parameters optimal.

[0077] The fuzzy control link includes the following steps:

[0078] S01: Fuzzify the input and output variables and determine the membership function;

[0079] S02: Fuzzy rules and fuzzy reasoning.

[0080] In the above S01, based on the empirical value, determine the initial value of the optimal adjustment gain, and then adjust the parameters based on the initial value of the optimal adjustment gain as follows:

[0081]

[0082] In the above S01, the input of the fuzzy controller designed by the system is the error e = V1 - Z1(t) between the voltage set value V1 and the output voltage observation value Z1(t), and its derivative Δβ1, Δβ2, Δβ3 are used as the output of the fuzzy controller. Gaussian functions are selected on both sides of the membership functions of the input and output, and a triangular function with higher sensitivity is used in the middle.

[0083] In the above S02, set 5 fuzzy subsets on the fuzzy domain: {NB, NS, ZO, PS, PB}, and the meanings of each element are: negative large, negative small, zero, positive small, positive large. According to the accumulation of professional knowledge and operation experience, and in accordance with the adjustment rules of each parameter, the fuzzy control rule selection table of e and ec can be obtained. Mamdani type reasoning is used for fuzzy reasoning, and the centroid method is used for the defuzzification process.

[0084] Embodiment 1:

[0085] See Figures 1 to 5 , Figure 1 is a schematic diagram of the integrated photovoltaic energy storage and charging station system of the present invention. It includes a photovoltaic power generation unit, a hybrid energy storage unit, a photovoltaic converter, and a hybrid energy storage converter. The photovoltaic power generation unit is connected to the DC bus through a photovoltaic converter, the hybrid energy storage unit is connected to the DC bus through a hybrid energy storage converter, the charging pile is connected to the DC bus through a DC / DC converter, a VIENNA rectifier is used at the grid connection of the integrated photovoltaic energy storage and charging station, and a double closed-loop PI control strategy is adopted.

[0086] The photovoltaic converter is based on a control method for selecting the photovoltaic power generation. When the photovoltaic power generation is insufficient, the photovoltaic converter uses the conductance increment method to achieve maximum power point tracking. When the photovoltaic power generation is excessive, the photovoltaic converter switches to the constant voltage control mode. The constant voltage control method includes the following steps:

[0087] S01: Collect the actual value V of the DC bus voltage dc , compare it with the reference value V of the DC bus voltage dc_ref , and transmit the difference between the two to the PI controller;

[0088] S02: After passing through the PI control link, obtain the reference current I of the photovoltaic power generation unit PV_ref , compare it with the actual value I of the photovoltaic current PV , and transmit the difference between the two to the PI controller, so as to control the photovoltaic converter to operate in the constant voltage mode.

[0089] The bidirectional DC-DC circuit diagram of the hybrid energy storage controller is shown in Figure 2 , and includes capacitors C1, C2, switching tubes S1, S2, anti-parallel diodes D1, D2, and inductor L. When S1 is turned on, S2 is turned off, and the anti-parallel diodes D1, D2 are turned off, the bidirectional DC-DC circuit operates in the Buck mode. This circuit can enable the energy storage system to switch between charge and discharge.

[0090] The energy storage controller adopts a fuzzy-active disturbance rejection common voltage loop double closed-loop control method, which includes a fuzzy-active disturbance rejection common voltage loop, a battery current loop, and a supercapacitor current loop. The active disturbance rejection control structure diagram of the present invention is shown in Figure 3 , and the fuzzy-active disturbance rejection control structure diagram of the present invention is shown in Figure 4 .

[0091] The fuzzy-active disturbance rejection control structure includes a fuzzy-active disturbance rejection common voltage loop, a battery current loop, and a supercapacitor current loop.

[0092] The DC bus voltage V dc and the voltage reference value V ref After being input into the fuzzy-active disturbance rejection control module, the original reference current I ref is output, and after passing through the low-pass filter, the low-frequency signal I ref-b and the medium-high frequency current signal I ref-s are obtained:

[0093]

[0094] In the above formula, T is the time constant of the low-pass filter; V bat is the output voltage of the battery energy storage; V SC is the output voltage of the supercapacitor energy storage.

[0095] The obtained I ref-b is the input reference current of the inner loop of the battery current; the obtained I ref-s is the input reference current of the inner loop of the supercapacitor current; I ref-b and I ref-s respectively pass through the inner loop of the battery current and the inner loop of the supercapacitor current, and then output control quantities to control the converter switching tubes.

[0096] The described fuzzy-active disturbance rejection common voltage loop includes a tracking differentiator (TD), an extended state observer (ESO), a nonlinear state error feedback (NLSEF), and a fuzzy control link.

[0097] The nonlinear function fal function is used in the tracking differentiator TD, the nonlinear state error feedback NLSEF, and the extended state observer ESO links. Its expression is as follows:

[0098]

[0099] In the above formula, a is the tracking factor; e is the error signal; δ is the filtering factor; sign represents the step function.

[0100] The described tracking differentiator TD is responsible for arranging a transition process to ensure that when the given signal changes, the controller output can track the given value in a short time without overshoot. Its expression is as follows:

[0101]

[0102] In the above formula, U ref is the reference voltage given signal value; U2(t) is the tracking signal of the voltage given signal value; r0 is the speed factor, which determines the tracking speed. Generally speaking, the larger r0 is, the faster U2(t) tracks U ref faster, but when r0 is too large, it will cause system oscillation at the same time.

[0103] The function of the described extended state observer ESO is to expand the internal and external disturbances and uncertainties into system state variables. The expression of ESO is as follows:

[0104]

[0105] In the above formula, U dc(t) is the real-time voltage of the DC bus; z1(t) and z2(t) are the state variables of the ESO, which are the tracking signal of the sampled voltage feedback signal and the observed value of the total interference signal respectively; β1 and β2 are the error adjustment gains of the ESO; u(t) is the control signal output by the ADRC controller.

[0106] The function of the state error nonlinear combination control law NLSEF is to calculate the demand of the controlled object to meet the given requirements according to the error information of the state variables observed in the inflated state. The expression of NLSEF is as follows:

[0107]

[0108] In the above formula, β3 is the regulator gain; u0 is the nonlinear control quantity calculated by NLSEF; u is the final output control quantity of the ADRC controller.

[0109] The fuzzy control link is shown in Figure 4 , where ε, ε0, Δβ1, Δβ2, Δβ3 are fuzzy variables. Among them, ε and ε0 are input variables, and Δβ1, Δβ2 and Δβ3 are output variables; x1 and x2 are input adjustment factors; x3, x4 and x5 are output adjustment factors; ε is the error between the bus voltage tracking signal z1 and the TD output signal; ε0 is the error change rate.

[0110] The basic domains of ε and ε0 are [-1.2, +1.2]. If the change ranges of ε and ε0 exceed the basic domain, the adjustment factors x1 and x2 can be set. The basic fuzzy domains of Δβ1, Δβ2, Δβ3 are set to [-1.2, +1.2], [-1.2, +1.2], [-0.5, +0.5] respectively.

[0111] The fuzzy-auto disturbance rejection parameters β1, β2 and β3 are set to [800, 1.6×10 3 , [6×10 5 , 10×10 5 and [0.1, 0.3] respectively.

[0112] Five fuzzy subsets are set in the fuzzy domain, and the fuzzy sets are taken as: {NB, NS, ZO, PS, PB}, and the meaning of each element is: negative high, negative low, zero, positive low, positive high. According to the engineering practice experience, the detailed table of the fuzzy control rule design is shown in Table 1.

[0113] Table 1 Fuzzy control rule design table

[0114]

[0115] The input and output membership functions in the fuzzy control are as Figure 5 .

[0116] Example 2:

[0117] Set the rated bus voltage to 700V, the rated voltage of the battery to 500V, the rated voltage of the supercapacitor to 350V, and the initial light intensity to 1000W / m 2 , and the initial temperature to 25°C. At t = 1s and t = 2s, the light intensity changes suddenly, to 550W / m 2 and 1000W / m 2 . The results of the example are as follows Figure 6 the output power of the photovoltaic power generation unit, and Figure 7 the output power of the hybrid energy storage system

[0118] See Figure 6 and Figure 7 , when t = 1s, due to the sudden decrease in light intensity, the output power of the photovoltaic power generation unit decreases, the energy storage power of the supercapacitor shows a sudden spike and then quickly returns to normal, and the energy storage power of the battery increases to maintain the power balance of the integrated photovoltaic energy storage and charging station

[0119] The above are only the embodiments of the present application and are not used to limit the protection scope of the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application

Claims

1. A photovoltaic-storage-charging integrated station system, characterized in that, It includes a photovoltaic power generation unit, a hybrid energy storage unit, a photovoltaic converter, and a hybrid energy storage converter. The photovoltaic power generation unit is connected to the DC bus through the photovoltaic converter, the hybrid energy storage unit is connected to the DC bus through the hybrid energy storage converter, the charging pile is connected to the DC bus through a DC / DC converter, and the DC bus of the integrated photovoltaic energy storage charging station system is connected to the grid connection point by a VIENNA rectifier.

2. The integrated optical storage and charging station system according to claim 1, characterized in that The hybrid energy storage converter is a bidirectional DC-DC circuit. The bidirectional DC-DC circuit includes capacitor C1, capacitor C2, switch tube S1, switch tube S2, anti-parallel diodes D1, D2, and inductor L. When S1 is turned on, S2 is turned off, and anti-parallel diodes D1 and D2 are turned off, the bidirectional DC-DC circuit operates in the Buck mode, and the bidirectional DC-DC circuit enables the energy storage system to switch between charging and discharging.

3. The integrated optical storage and charging station system according to claim 1, characterized in that, The hybrid energy storage unit includes battery energy storage and supercapacitor energy storage.

4. A control method for an integrated photovoltaic energy storage and charging station system, characterized in that, It includes the photovoltaic converter of the photovoltaic power generation unit based on photovoltaic power generation power selection control; the fuzzy-active disturbance rejection common voltage loop double closed-loop control of the hybrid energy storage converter of the hybrid energy storage unit and the double closed-loop PI control of the VIENNA rectifier. The photovoltaic converter of the photovoltaic power generation unit based on photovoltaic power generation power selection control is specifically as follows: when the photovoltaic power generation power is insufficient, the photovoltaic converter uses the conductance increment method to achieve maximum power point tracking; when the photovoltaic power generation power is excessive, the photovoltaic converter switches to the constant voltage control mode, and the control method of the constant voltage control mode includes the following steps: S01: Collect the actual value of DC bus voltage V dc , and the DC bus voltage reference value V dc_ref The difference between the two is compared and passed to the PI controller; S02: The current reference value I of the photovoltaic power generation unit is obtained after passing through the PI control link PV_ref , which is compared with the actual value I of the photovoltaic current PV . The difference between the two is fed into the PI controller, thereby controlling the photovoltaic converter to operate in the constant voltage mode.

5. The control method of an integrated photovoltaic energy storage and charging station system according to claim 4, characterized in that The fuzzy-active disturbance rejection common voltage loop double closed-loop control of the hybrid energy storage converter of the hybrid energy storage unit includes a fuzzy-active disturbance rejection common voltage loop, a battery current loop, and a supercapacitor current loop. The control flow is as follows: S01: DC bus voltage V dc and the voltage reference value V ref are input into the fuzzy-active disturbance rejection combined voltage loop, which includes a tracking differentiator TD, an extended state observer ESO, a state error nonlinear combination control law NLSEF, and a fuzzy control link. S02: After passing through the fuzzy-active disturbance rejection common voltage loop, the original reference current I is output ref , and after passing through a low-pass filter, a low-frequency signal I ref-b and a medium-high frequency current signal I ref-s are obtained: In the above formula, T is the time constant of the low-pass filter; V bat is the output voltage of the battery energy storage; V SC is the output voltage of the supercapacitor energy storage; The obtained I ref-b is the input reference current of the inner current loop of the storage battery; The obtained I ref-s is the input reference current of the inner current loop of the super capacitor; S03: After passing through the low-pass filter, the input reference current of the battery current inner loop and the input reference current of the supercapacitor current inner loop are obtained. The battery current inner loop and the supercapacitor current inner loop have the same structure and adopt an active disturbance rejection control structure, including three parts: a tracking differentiator, an extended state observer, and a nonlinear error feedback control law.

6. The control method of an integrated photovoltaic energy storage and charging station system according to claim 4, characterized in that The double closed-loop PI control strategy of the VIENNA rectifier is In the above formula, K iP and K iI are the PI parameters of the current controller; v d , v q are the d-axis and q-axis components of the voltage on the AC side of the rectifier, and i dref and i qref are the d-axis and q-axis current reference values.

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