Self-adaptive control method for bidirectional DC-DC converter of optical storage all-in-one machine

Abstract

The invention belongs to the technical field of optical storage all-in-one machine control, and particularly relates to an adaptive control method for a bidirectional DC-DC converter of an optical storage all-in-one machine. Comprising the following steps: S1, respectively establishing mathematical models of the bidirectional DC-DC converter working in a Boost mode and a Buck mode; s2, designing a voltage loop controller, wherein the voltage loop controller is composed of a tracking differentiator (TD), an extended state observer (ESO), a linear feedback controller and a feedforward controller; s3, a controller of a current loop is designed, and the current loop adopts self-adaptive control based on loop gain measurement and is composed of a control performance monitor and a self-adaptive setting device; the control performance of the bidirectional DC-DC converter is monitored in real time by measuring the loop gain on line, and then the parameters of the current loop controller are adaptively adjusted according to the control performance index parameters monitored in real time, so that the adaptive capacity of the converter to bus voltage fluctuation is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of photovoltaic and storage integrated machine control, and in particular relates to an adaptive control method for a bidirectional DC-DC converter of a photovoltaic and storage integrated machine. Background Art

[0002] Technologies such as photovoltaic power generation, wind power generation and biomass power generation have gradually gained attention. Among them, photovoltaic power generation is widely regarded as one of the most promising new energy power generation technologies due to its abundant resources, safety, reliability and pollution-free. However, the output of photovoltaic power generation is random and intermittent, and is easily affected by the external environment. In the integrated photovoltaic and energy storage system, the energy storage unit plays a key role. It can not only alleviate the impact of unstable output of renewable energy on power quality, but also suppress voltage fluctuations in large power grids and improve the power supply reliability and power utilization of the DC bus. The DC bus is an important indicator for measuring the stability of the integrated photovoltaic and energy storage system. As an interface circuit connecting the DC bus and the energy storage medium, the bidirectional DC-DC converter plays an important role in the integrated photovoltaic and energy storage system. Therefore, the study of the control method of the bidirectional DC-DC converter has become a hot topic in power electronics technology.

[0003] In early research, bidirectional DC-DC converters usually use PI (proportional-integral) voltage and current dual closed-loop control. PI control has the advantages of simplicity, easy control, and few parameter settings. However, traditional PI controllers are difficult to achieve ideal control effects when facing large fluctuations in photovoltaic output and load. At the same time, the uncertainty disturbances caused by temperature changes and device parameter drifts also limit the performance of PI controllers.

[0004] The active disturbance rejection control (ADRC) proposed by Professor Han Jingqing, a Chinese control theorist and control engineer, can enhance the robustness of the system by estimating and compensating for disturbances without the need for an accurate model. However, traditional ADRC involves multiple parameters that need to be adjusted, with large amounts of calculations and complex adjustments. Based on this, Professor Gao Zhiqiang proposed the linear active disturbance rejection control (LADRC), which introduces the probability of stability margin and bandwidth into ADRC, and estimates and compensates for system disturbances in real time through the extended state observer (ESO), giving LADRC a significant advantage in combating internal and external disturbances in the system. However, traditional LADRC may introduce additional system overshoot and oscillations when faced with large disturbances, affecting the control effect.

[0005] In summary, although LADRC has shown significant advantages in improving the performance of bidirectional DC-DC converters, its limitations in handling large disturbances indicate the importance of further improvement. Improving the traditional LADRC can not only enhance the stability and reliability of the photovoltaic storage integrated system, but also better meet the needs of future renewable energy systems for efficient energy management and stable control. Summary of the invention

[0006] The purpose of the present invention is to overcome the shortcomings of the prior art and to provide an adaptive control method for a bidirectional DC-DC converter of a photovoltaic and storage integrated machine. The method realizes real-time monitoring of the control performance of the bidirectional DC-DC converter by online measuring the loop gain, and then adaptively adjusts the parameters of the current loop controller according to the control performance index parameters monitored in real time, so as to improve the adaptability of the converter to bus voltage fluctuations.

[0007] The object of the present invention is achieved by: a method for adaptively controlling a bidirectional DC-DC converter of an integrated photovoltaic and storage device, comprising the following steps:

[0008] S1. Establish mathematical models of bidirectional DC-DC converters operating in Boost mode and Buck mode respectively;

[0009] S2. Design a controller for a voltage loop, wherein the voltage loop controller is composed of a tracking differentiator (TD), an extended state observer (ESO), a linear feedback controller, and a feedforward controller;

[0010] S3. Design a controller for the current loop. The current loop adopts adaptive control based on loop gain measurement and is composed of a control performance monitor and an adaptive setter.

[0011] The step S1 of establishing the mathematical model of the bidirectional DC-DC converter working in the Boost mode and the Buck mode respectively includes:

[0012] In the Boost working mode, the state space average method is used to obtain the state space average equation of the circuit.

[0013]

[0014] Among them, D Boost is the duty cycle in boost mode; i L is the inductor current on the energy storage side; U dc is the DC bus voltage; R a is the equivalent resistance on the DC bus side; L is the filter inductor; C1 is the filter capacitor on the DC bus side; U bus is the voltage on the energy storage side;

[0015] By applying small signal modeling techniques and combining them with Laplace transform, the transfer function of the Boost circuit can be derived as follows:

[0016]

[0017] Among them, G id1 is the transfer function from the inductor current on the energy storage side to the duty cycle in boost mode; Gv1 is the transfer function from the DC bus voltage to the inductor current on the energy storage side in the boost mode; s is the complex frequency; C1 is the filter capacitor on the DC bus side;

[0018] In Buck working mode, the state space average method is used to obtain the state space average equation of the circuit.

[0019]

[0020] Where D buck is the duty cycle in buck mode;

[0021] The transfer function of the Buck circuit can be derived as follows,

[0022]

[0023] Among them, G i2 is the transfer function from the inductor current on the energy storage side to the duty cycle in the buck mode; G v2 is the transfer function from the DC bus voltage to the inductor current on the energy storage side in the buck mode; s is the complex frequency; R b is the equivalent resistance on the energy storage side; C2 is the filter capacitor on the energy storage side.

[0024] The step S2 of designing the controller of the voltage loop includes:

[0025] TD is based on numerical differentiation and filtering technology. It processes the input signal to obtain a smooth signal and its derivative, and obtains the The differential signal of is in the following discrete form:

[0026]

[0027] Where U1 and U2 are the original expected voltage bus voltage reference values ​​U dcref The dynamic expected signal and differential signal output by TD; fst is the fastest comprehensive control function; r is the speed factor; h is the filter factor; Ts is the sampling clock period of the bidirectional DC-DC converter;

[0028] ESO uses feedback mechanism to continuously adjust its internal parameters by observing output and known input to track the state and disturbance of the system in real time. Its discrete form is as follows:

[0029]

[0030] Where e1(t) is the tracking error of the system, that is, the difference between the actual output and the expected reference value; u(t) is the control input used to drive the system to reduce the error; z1(t) is the estimated value of the system output or system state; z2(t) is the estimated value of the system output; β1 and β2 are the observer gains of the ESO, which are used to adjust the response speed and dynamic performance of the observer; b0 is the proportional factor of the control input, which is used to adjust the influence of the control input in the extended state observer; sign[e1(t)] is the nonlinear part used to handle the error in the extended state observer;

[0031] In the linear feedback controller, the error signal generates the control quantity through the feedback mechanism, thereby realizing the dynamic compensation and linearization control of the system. Its discrete form is as follows:

[0032]

[0033] where e k is the current deviation of the system, that is, the difference between the actual output and the expected reference value; u0(t) is the output of the proportional controller, which means that the proportional gain k p Error e k The signal after amplification processing; U2(t) is the differential signal of the tracking differential controller; u1(t) is the control input signal after compensation; u3(t) is the actual control signal output;

[0034] The feedforward controller is beneficial to improve the response speed and control accuracy of the photovoltaic storage integrated system by pre-compensating for known disturbances and reference input changes. The specific algorithm is as follows:

[0035] I Lref =[U dcref -U dc (t)]×k vdc +u3(t)

[0036] Among them U dcref is the reference signal of DC bus voltage; U dc (t) is the measured value of DC bus voltage; k vdc is the feedforward control coefficient; I Lref is the reference signal of the inductor current on the energy storage side; u3(t) is the output of the linear feedback controller.

[0037] The step S3 of designing the controller of the current loop includes:

[0038] Given a bidirectional DC-DC converter current loop gain T i The control performance monitor injects a frequency-controlled sinusoidal small disturbance signal into the control loop as an excitation signal, and extracts the response signal X of the corresponding frequency before and after the injection point. in and Xout ; The relationship between the two response signals and the excitation signal is as follows:

[0039]

[0040] The adaptive tuner adjustment process is described as follows: c Its expected value f cref The error value adjusts the adaptive tuner proportional gain k pi , so that the cutoff frequency is maintained at f cref Nearby, to ensure the excellent dynamic performance of the loop; at the same time, according to the phase margin and its expected value The error value adjusts the adaptive tuner integral gain k ii , so that the phase margin Maintain near the expected value to ensure the stability of the loop; the adjustment process is expressed as,

[0041]

[0042] where f cref is the desired system cutoff frequency; f c is the actual cutoff frequency of the system; is the desired system phase margin; is the actual phase margin of the system; H fc and the regulator used to implement the regulation process; k p,int and k i,int is the theoretical design value of PI parameters under the optimal condition;

[0043] H fc and The integral controller is used to implement it, and the expression is as follows:

[0044]

[0045] k fc and is the control parameter of the regulator.

[0046] Beneficial effects of the present invention: An adaptive control method for a bidirectional DC-DC converter of a photovoltaic and storage integrated machine of the present invention comprises steps S1, respectively establishing mathematical models of the bidirectional DC-DC converter operating in Boost mode and Buck mode; S2, designing a controller for a voltage loop, wherein the voltage loop controller is composed of a tracking differentiator (TD), an extended state observer (ESO), a linear feedback controller, and a feedforward controller; S3, designing a controller for a current loop, wherein the current loop adopts adaptive control based on loop gain measurement, and is composed of a control performance monitor and an adaptive setter; through the above steps, an adaptive control method for a bidirectional DC-DC converter of a photovoltaic and storage integrated machine of the present invention solves the adverse effects of photovoltaic output uncertainty and load fluctuation on DC bus voltage stability, and effectively improves the adaptability of the converter to bus voltage fluctuations by introducing feedforward linear anti-interference control in the voltage loop and adopting an adaptive control strategy based on loop gain measurement in the current loop, thereby enhancing the robustness and stability of the system, which not only optimizes the overall performance of the photovoltaic and storage integrated machine, but also provides efficient energy management and stable control solutions for future renewable energy systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0048] Figure 1 It is the overall block diagram of adaptive control.

[0049] Figure 2 Voltage loop control block diagram.

[0050] Figure 3 It is the current loop control block diagram.

[0051] Figure 4 It is a block diagram of traditional voltage and current dual closed-loop control.

[0052] Figure 5 It is a topology diagram of a synchronous bidirectional DC-DC converter.

[0053] Figure 6 This is the topology diagram of the optical storage integrated machine. DETAILED DESCRIPTION

[0054] The present invention will be further described below in conjunction with the accompanying drawings.

[0055] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0056] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0057] like Figure 1-6 As shown, the present invention provides an adaptive control method for a bidirectional DC-DC converter of an integrated photovoltaic and storage device, which comprises the following steps:

[0058] S1. Establish mathematical models of bidirectional DC-DC converters operating in Boost mode and Buck mode respectively;

[0059] S2. Design a controller for a voltage loop, wherein the voltage loop controller is composed of a tracking differentiator (TD), an extended state observer (ESO), a linear feedback controller, and a feedforward controller;

[0060] S3. Design a controller for the current loop. The current loop adopts adaptive control based on loop gain measurement and is composed of a control performance monitor and an adaptive setter.

[0061] The present invention aims at the influence of factors such as uncertainty of photovoltaic output and load fluctuation on the stability of DC bus voltage in the photovoltaic storage integrated machine. Figure 1 As shown in the figure, a control method for a photovoltaic and energy storage integrated bidirectional DC-DC converter based on linear active disturbance rejection control (LADRC) and adaptive control is proposed. Figure 2 As shown in FIG, LADRC is used in the voltage loop, and feedforward control is introduced to enhance the robustness of the system; Figure 3 As shown, an adaptive control strategy based on loop gain measurement is applied in the current loop.

[0062] Furthermore, the step S1 of establishing mathematical models of the bidirectional DC-DC converter operating in the Boost mode and the Buck mode respectively includes:

[0063] In the Boost working mode, the state space average method is used to obtain the state space average equation of the circuit.

[0064]

[0065] Among them, D Boost is the duty cycle in boost mode; i L is the inductor current on the energy storage side; U dc is the DC bus voltage; R ais the equivalent resistance on the DC bus side; L is the filter inductor; C1 is the filter capacitor on the DC bus side; U bus is the voltage on the energy storage side;

[0066] By applying small signal modeling techniques and combining them with Laplace transform, the transfer function of the Boost circuit can be derived as follows:

[0067]

[0068] Among them, G id1 is the transfer function from the inductor current on the energy storage side to the duty cycle in boost mode; G v1 is the transfer function from the DC bus voltage to the inductor current on the energy storage side in the boost mode; s is the complex frequency; C1 is the filter capacitor on the DC bus side;

[0069] In Buck working mode, the state space average method is used to obtain the state space average equation of the circuit.

[0070]

[0071] Where D buck is the duty cycle in buck mode;

[0072] The transfer function of the Buck circuit can be derived as follows,

[0073]

[0074] Among them, G i2 is the transfer function from the inductor current on the energy storage side to the duty cycle in the buck mode; G v2 is the transfer function from the DC bus voltage to the inductor current on the energy storage side in the buck mode; s is the complex frequency; R b is the equivalent resistance on the energy storage side; C2 is the filter capacitor on the energy storage side.

[0075] Tracking Differentiator (TD) is a controller that uses numerical differentiation and filtering techniques to process the input signal to obtain a smooth signal and its derivative. By smoothing the signal, TD effectively reduces the noise interference in the differential calculation, so that it can still accurately track and respond to the input signal in the case of high-frequency interference. In addition, TD also plays a vital role in complex control systems, especially in situations where high precision and fast dynamic response are required.

[0076] Furthermore, the step S2 of designing the controller of the voltage loop includes:

[0077] TD is based on numerical differentiation and filtering technology. It processes the input signal to obtain a smooth signal and its derivative, and obtains the The differential signal of is in the following discrete form:

[0078]

[0079] Where U1 and U2 are the original expected voltage bus voltage reference values ​​U dcref The dynamic expected signal and differential signal output by TD; fst is the fastest comprehensive control function; r is the speed factor; h is the filter factor; Ts is the sampling clock period of the bidirectional DC-DC converter;

[0080] The extended state observer (ESO) uses a feedback mechanism to continuously adjust its internal parameters by observing the output of the system and the known input to track the state of the system and external disturbances in real time. Through this process, the ESO can dynamically compensate for unknown disturbances, thereby improving the robustness and response speed of the control system. Its discrete form is as follows,

[0081]

[0082] Where e1(t) is the tracking error of the system, that is, the difference between the actual output and the expected reference value; u(t) is the control input used to drive the system to reduce the error; z1(t) is the estimated value of the system output or system state; z2(t) is the estimated value of the system output; β1 and β2 are the observer gains of the ESO, which are used to adjust the response speed and dynamic performance of the observer; b0 is the proportional factor of the control input, which is used to adjust the influence of the control input in the extended state observer; sign[e1(t)] is the nonlinear part used to handle the error in the extended state observer;

[0083] In a linear feedback controller, the error signal generates a control quantity through a feedback mechanism, thereby achieving dynamic compensation and linear control of the system. By adjusting the feedback gain, the controller can effectively reduce the system error and enhance the stability and response speed of the system. Especially in the face of external disturbances and system uncertainties, the linear feedback controller can provide a robust control effect and ensure the stability of system performance. Its discrete form is as follows,

[0084]

[0085] where e k is the current deviation of the system, that is, the difference between the actual output and the expected reference value; u0(t) is the output of the proportional controller, which means that the proportional gain k p Error e k The signal after amplification processing; U2(t) is the differential signal of the tracking differential controller; u1(t) is the control input signal after compensation; u3(t) is the actual control signal output;

[0086] The feedforward controller can adjust the system before disturbances occur by pre-compensating for known disturbances and changes in reference inputs, thereby significantly improving the response speed and control accuracy of the photovoltaic storage integrated system. Compared with traditional feedback control, feedforward control can respond to changes in system inputs more quickly and reduce lag, especially in dynamic environments. This forward-looking control strategy plays a key role in the stable operation of photovoltaic storage systems. The specific algorithm is as follows:

[0087] I Lref =[U dcref -U dc (t)]×k vdc +u3(t)

[0088] Among them U dcref is the reference signal of DC bus voltage; U dc (t) is the measured value of DC bus voltage; k vdc is the feedforward control coefficient; I Lref is the reference signal of the inductor current on the energy storage side; u3(t) is the output of the linear feedback controller.

[0089] Furthermore, the step S3 of designing the controller of the current loop includes:

[0090] Given a bidirectional DC-DC converter current loop gain T i The control performance monitor injects a frequency-controlled sinusoidal small disturbance signal into the control loop as an excitation signal, and extracts the response signal X of the corresponding frequency before and after the injection point. in and X out ; The relationship between the two response signals and the excitation signal is as follows:

[0091]

[0092] The adaptive tuner adjustment process is described as follows: c Its expected value f cref The error value adjusts the adaptive tuner proportional gain k pi , so that the cutoff frequency is maintained at f cref Nearby, to ensure the excellent dynamic performance of the loop; at the same time, according to the phase margin and its expected value The error value adjusts the adaptive tuner integral gain k ii , so that the phase margin Maintain near the expected value to ensure the stability of the loop; the adjustment process is expressed as,

[0093]

[0094] where fcref is the desired system cutoff frequency; f c is the actual cutoff frequency of the system; is the desired system phase margin; is the actual phase margin of the system; H fc and the regulator used to implement the regulation process; k p,int and k i,int is the theoretical design value of PI parameters under the optimal condition;

[0095] H fc and The integral controller is used to implement it, and the expression is as follows:

[0096]

[0097] k fc and is the control parameter of the regulator.

[0098] In summary, an adaptive control method for a bidirectional DC-DC converter of a photovoltaic and storage integrated machine of the present invention comprises the steps of S1, respectively establishing mathematical models of the bidirectional DC-DC converter working in Boost mode and Buck mode; S2, designing a controller of a voltage loop, wherein the voltage loop controller is composed of a tracking differentiator (TD), an extended state observer (ESO), a linear feedback controller, and a feedforward controller; S3, designing a controller of a current loop, wherein the current loop adopts adaptive control based on loop gain measurement, and is composed of a control performance monitor and an adaptive setter; through the above steps, an adaptive control method for a bidirectional DC-DC converter of a photovoltaic and storage integrated machine of the present invention solves the adverse effects of photovoltaic output uncertainty and load fluctuation on DC bus voltage stability, and effectively improves the adaptability of the converter to bus voltage fluctuation by introducing feedforward linear anti-interference control in the voltage loop and adopting an adaptive control strategy based on loop gain measurement in the current loop, thereby enhancing the robustness and stability of the system, which not only optimizes the overall performance of the photovoltaic and storage integrated machine, but also provides efficient energy management and stable control solutions for future renewable energy systems.

[0099] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0100] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. A method for adaptively controlling a bidirectional DC-DC converter of a photovoltaic and storage integrated device, characterized in that: The following steps are involved: S1. Establish mathematical models of bidirectional DC-DC converters operating in Boost mode and Buck mode respectively; S2. Design a controller for a voltage loop, wherein the voltage loop controller is composed of a tracking differentiator (TD), an extended state observer (ESO), a linear feedback controller, and a feedforward controller; S3. Design a controller for the current loop. The current loop adopts adaptive control based on loop gain measurement and is composed of a control performance monitor and an adaptive setter.

2. The method for adaptively controlling a bidirectional DC-DC converter of a photovoltaic and storage integrated device as claimed in claim 1, characterized in that: The step S1 of establishing the mathematical model of the bidirectional DC-DC converter working in the Boost mode and the Buck mode respectively includes: In the Boost working mode, the state space average method is used to obtain the state space average equation of the circuit. Among them, D Boost is the duty cycle in boost mode; i L is the inductor current on the energy storage side; U dc is the DC bus voltage; R a is the equivalent resistance on the DC bus side; L is the filter inductor; C1 is the filter capacitor on the DC bus side; U bus is the voltage on the energy storage side; The transfer function of the Boost circuit is as follows, Among them, G id1 is the transfer function from the inductor current on the energy storage side to the duty cycle in boost mode; G v1 is the transfer function from the DC bus voltage to the inductor current on the energy storage side in the boost mode; s is the complex frequency; C1 is the filter capacitor on the DC bus side; In Buck working mode, the state space average method is used to obtain the state space average equation of the circuit. Where D buck is the duty cycle in buck mode; The transfer function of the Buck circuit is as follows, Among them, G i2 is the transfer function from the inductor current on the energy storage side to the duty cycle in the buck mode; G v2 is the transfer function from the DC bus voltage to the inductor current on the energy storage side in the buck mode; s is the complex frequency; R b is the equivalent resistance on the energy storage side; C2 is the filter capacitor on the energy storage side.

3. The method for adaptively controlling a bidirectional DC-DC converter of a photovoltaic and storage integrated device as claimed in claim 1, characterized in that: The step S2 of designing the controller of the voltage loop includes: TD is based on numerical differentiation and filtering technology. It processes the input signal to obtain a smooth signal and its derivative, and obtains the The differential signal of is in the following discrete form: Where U1 and U2 are the original expected voltage bus voltage reference values ​​U dcref The dynamic expected signal and differential signal output by TD; fst is the fastest comprehensive control function; r is the speed factor; h is the filter factor; Ts is the sampling clock period of the bidirectional DC-DC converter; ESO uses feedback mechanism to continuously adjust its internal parameters by observing output and known input to track the state and disturbance of the system in real time. Its discrete form is as follows: Where e1(t) is the tracking error of the system, that is, the difference between the actual output and the expected reference value; u(t) is the control input used to drive the system to reduce the error; z1(t) is the estimated value of the system output or system state; z2(t) is the estimated value of the system output; β1 and β2 are the observer gains of the ESO, which are used to adjust the response speed and dynamic performance of the observer; b0 is the proportional factor of the control input, which is used to adjust the influence of the control input in the extended state observer; sign[e1(t)] is the nonlinear part used to handle the error in the extended state observer; In the linear feedback controller, the error signal generates the control quantity through the feedback mechanism, thereby realizing the dynamic compensation and linearization control of the system. Its discrete form is as follows: where e k is the current deviation of the system, that is, the difference between the actual output and the expected reference value; u0(t) is the output of the proportional controller, which means that the proportional gain k p Error e k The signal after amplification processing; U2(t) is the differential signal of the tracking differential controller; u1(t) is the control input signal after compensation; u3(t) is the actual control signal output; The feedforward controller pre-compensates for known disturbances and reference input changes. The specific algorithm is as follows: I Lref =[U dcref -U dc (t)]×k vdc +u3(t) Among them U dcref is the reference signal of DC bus voltage; U dc (t) is the measured value of DC bus voltage; k vdc is the feedforward control coefficient; I Lref is the reference signal of the inductor current on the energy storage side; u3(t) is the output of the linear feedback controller.

4. The method for adaptively controlling a bidirectional DC-DC converter of a photovoltaic and storage integrated device as claimed in claim 1, characterized in that: The step S3 of designing the controller of the current loop includes: Given a bidirectional DC-DC converter current loop gain T i The control performance monitor injects a frequency-controlled sinusoidal small disturbance signal into the control loop as an excitation signal, and extracts the response signal X of the corresponding frequency before and after the injection point. in and X out ; The relationship between the two response signals and the excitation signal is as follows: The adaptive tuner adjustment process is described as follows: c Its expected value f cref The error value adjusts the adaptive tuner proportional gain k pi , so that the cutoff frequency is maintained at f cref Nearby, to ensure the excellent dynamic performance of the loop; at the same time, according to the phase margin and its expected value The error value adjusts the adaptive tuner integral gain k ii , so that the phase margin Maintain near the expected value to ensure the stability of the loop; the adjustment process is expressed as, where f cref is the desired system cutoff frequency; f c is the actual cutoff frequency of the system; is the desired system phase margin; is the actual phase margin of the system; H fc and the regulators used to implement the regulation process; k p,int and k i,int is the theoretical design value of PI parameters under the optimal condition; H fc and The integral controller is used to implement it, and the expression is as follows: k fc and is the control parameter of the regulator.

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