Dual-active bridge converter control method and system based on double-layer weighted active disturbance rejection

Abstract

The invention discloses a dual-active bridge converter control method and system based on double-layer weighted active disturbance rejection, and relates to the technical field of power electronics. The method comprises the following steps: constructing an input and output voltage dynamic model according to system characteristics of the dual-active bridge converter, and converting the input and output voltage dynamic model into a linear state space equation; constructing an energy function kinetic equation based on a transmission power balance relation according to the linear state space equation; constructing the energy function kinetic equation into a standard extended state-space equation according to an active-disturbance-rejection theory, and designing a double-layer observer according to the extended state-space equation; and according to the double-layer observer structure, a control law is constructed based on the state space model and the energy function, and the control law is used to solve the output voltage of the phase shift tracking dual-active bridge converter. According to the invention, quick response and high efficiency of the output voltage of the DAB converter can still be ensured under the coupling of noise and lumped interference.

Description

Technical Field

[0001] The present invention relates to the field of power electronics technology, and in particular, to a control method and system for a dual active bridge converter based on double-layer weighted auto-disturbance rejection. Background Art

[0002] The statements in this part only provide background technical information related to the present invention and do not necessarily constitute prior art.

[0003] Dual active bridge converters (DABs) play an important role in the key energy transfer process between DC buses and power batteries or energy storage systems due to their advantages such as large power transmission capacity and small filter volume. However, the practical application of DABs faces problems such as large estimation errors caused by high-frequency noise and external interference, and output voltage fluctuations caused by power fluctuations and load mutations, threatening the stability of system operation.

[0004] Although existing control methods have made progress in improving the dynamic performance of DAB converters, their ability to cope with the problem of high-frequency noise and disturbance coupling still has significant limitations. Classical linear controls (such as PI and LQR) are difficult to balance the contradiction between noise amplification and disturbance suppression due to fixed gain design; nonlinear methods (such as predictive control, sliding mode control, and fuzzy control) can improve transient response but are limited by model sensitivity, computational complexity, or empirical dependence problems. These defects lead to increased output voltage fluctuations and decreased stability, highlighting the urgent need to develop a disturbance observer with high anti-noise characteristics.

[0005] Auto-disturbance rejection control (ADRC) has received extensive attention in recent years due to its characteristics of not relying on an accurate mathematical model of the controlled object and being able to effectively handle external interference and internal uncertainties. The core component of ADRC is the extended state observer (ESO). The ESO can not only estimate the system state in real time but also estimate external interference and unknown dynamics simultaneously. However, the high gain of the ESO will amplify measurement noise and transmit it to the control signal calculated according to the observer state vector.

[0006] Therefore, how to design a reasonable and effective auto-disturbance rejection control scheme to enable the DAB control system to operate stably in the presence of high noise and lumped interference coupling has become an urgent technical research problem to be solved. Summary of the Invention

[0007] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide a control method and system for a dual active bridge converter based on double-layer weighted auto-disturbance rejection, which can still ensure the fast response and high efficiency of the output voltage of the DAB converter under the coupling of noise and lumped interference.

[0008] To achieve the above purpose, the present invention is implemented through the following technical solutions:

[0009] In the first aspect of the present invention, a control method for a dual-active-bridge converter based on double-layer weighted active disturbance rejection is provided, including the following steps:

[0010] Construct an input-output voltage dynamic model according to the system characteristics of the dual-active-bridge converter, and convert the input-output voltage dynamic model into a linear state-space equation;

[0011] Construct an energy function dynamic equation based on the transmission power balance relationship according to the linear state-space equation;

[0012] Construct the energy function dynamic equation into a standard extended state-space equation according to the active disturbance rejection theory, and design a double-layer observer according to the extended state-space equation;

[0013] Construct a control law based on the double-layer observer structure, the extended state-space equation and the energy function dynamic equation, and use the control law to solve the phase-shift ratio to track the output voltage of the dual-active-bridge converter.

[0014] In the second aspect of the present invention, a control system for a dual-active-bridge converter based on double-layer weighted active disturbance rejection is provided, including:

[0015] A voltage dynamic model construction module, configured to construct an input-output voltage dynamic model according to the system characteristics of the dual-active-bridge converter, and convert the input-output voltage dynamic model into a linear state-space equation;

[0016] An energy dynamic model construction module, configured to construct an energy function dynamic equation based on the transmission power balance relationship according to the linear state-space equation;

[0017] An observer design module, configured to construct the energy function dynamic equation into a standard extended state-space equation according to the active disturbance rejection theory, and design a double-layer observer according to the extended state-space equation;

[0018] An observer control module, configured to construct a control law based on the double-layer observer structure, the state-space model and the energy function, and use the control law to solve the phase-shift ratio to track the output voltage of the dual-active-bridge converter.

[0019] In the third aspect of the present invention, a medium is provided, on which a program is stored, and when the program is executed by a processor, the steps in the control method for a dual-active-bridge converter based on double-layer weighted active disturbance rejection as described in the first aspect of the present invention are implemented.

[0020] In the fourth aspect of the present invention, a device is provided, including a memory, a processor, and a program stored on the memory and executable on the processor. When the processor executes the program, the steps in the control method for a dual-active-bridge converter based on double-layer weighted active disturbance rejection as described in the first aspect of the present invention are implemented.

[0021] The above one or more technical solutions have the following beneficial effects:

[0022] The present invention discloses a control method and system for a dual active bridge converter based on double-layer weighted auto-disturbance rejection to effectively suppress noise and compensate for lumped interference and achieve accurate tracking of the DAB output voltage. By combining a double-layer observer system and a weighted auto-disturbance rejection control method, effective separation of noise and interference is achieved through weighted factors and fusion factors. The noise is filtered by a primary subsystem and the lumped interference of the system is smoothed by a secondary subsystem, which can effectively suppress the influence of noise on the converter data and compensate for the estimation error caused by lumped disturbances, and achieve the asymptotic stability of the output voltage of the DAB converter under the condition of noise and disturbance coupling.

[0023] The present invention designs a double-layer observer including weighted factors and fusion factors to compensate for interference. By combining an optimized control method with the double-layer observer, the asymptotic stability of the DAB under coupling conditions is achieved. Even in the face of variable operating conditions and disturbance changes, stable output voltage control can be maintained, which has broad application prospects and important practical value.

[0024] Advantages of additional aspects of the present invention will be partially given in the following description, partially become apparent from the following description, or be understood through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The specification drawings forming a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0026] Figure 1 It is a topological structure diagram of a dual active bridge converter according to Embodiment 1 of the present invention;

[0027] Figure 2 It is a simplified structure diagram of a dual active bridge converter according to Embodiment of the present invention;

[0028] Figure 3 It is a topological structure diagram of a double-layer observer system according to Embodiment 1 of the present invention;

[0029] Figure 4 It is a closed-loop feedback control structure diagram of a control method for a dual active bridge converter according to Embodiment 1 of the present invention;

[0030] Figure 5 It is a simulation waveform diagram of the output voltage of double-layer weighted auto-disturbance rejection control when the output voltage of a dual active bridge converter according to Embodiment 1 of the present invention changes suddenly;

[0031] Figure 6 It is a waveform diagram of relevant parameters of a DAB converter of double-layer weighted auto-disturbance rejection control when the output voltage of a dual active bridge converter according to Embodiment 1 of the present invention changes suddenly;

[0032] Figure 7 This is a comparison chart of the simulation waveforms of the output voltage of the double-layer weighted active disturbance rejection control, PI control, and traditional active disturbance rejection control in Embodiment 1 of the present invention when the load changes suddenly;

[0033] Figure 8 This is a waveform chart of the relevant parameters of the DAB converter for the double-layer weighted active disturbance rejection control in Embodiment 1 of the present invention when the load changes suddenly. Specific embodiments

[0034] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0035] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof;

[0036] Embodiment 1:

[0037] Embodiment 1 of the present invention provides a control method for a dual-active-bridge converter based on double-layer weighted active disturbance rejection, including the following steps:

[0038] Step 1: Construct an input-output voltage dynamic model according to the system characteristics of the dual-active-bridge converter, and convert the input-output voltage dynamic model into a linear state-space equation.

[0039] Step 1.1: Construct an input-output voltage dynamic model according to the system characteristics of the dual-active-bridge converter.

[0040] Step 1.1.1: Obtain the topology of the dual-active-bridge converter.

[0041] In a specific embodiment, this embodiment is applied to the topology of the dual-active-bridge converter, and a single-phase-shift modulation strategy is adopted for square-wave control, that is, the duty cycle between two AC square-wave voltages is fixed at 50%, and the phase-shift ratio between the two H-bridges is changed.

[0042] Figure 1 Shows the circuit topology of a typical DAB converter. The dual-active-bridge converter consists of primary and secondary H-bridge arms, an energy transfer inductor L (auxiliary inductor can be externally connected or the leakage inductance of the high-frequency transformer can be used), a high-frequency transformer T, and an input-side DC power supply V inand the output-side load R (the voltage across both sides of the load R is the output voltage V out ), as well as the capacitor C in and C out which consists of the primary H-bridge arm composed of switching devices Q1-Q4, the secondary H-bridge arm composed of Q5-Q8, and the magnetic network composed of the energy transfer inductor L and the high-frequency transformer T connecting the AC ports of the two bridge arms. N:1 is the turns ratio of the transformer (i.e., the ratio of the number of turns of the primary coil to the number of turns of the secondary coil of DAB), V ab and V cd are the AC-side voltages of the primary and secondary bridge arms respectively, V L is the inductor voltage, and i L is the inductor current.

[0043] Step 1.1.2: Analyze the input-output voltage dynamic relationship according to the dual-active-bridge converter topology and construct an input-output voltage dynamic model.

[0044] In a specific embodiment, the construction of this model involves the coupling relationship between the changes in the capacitor voltages on the input and output sides and power transmission, and is derived based on the principle of capacitor charge balance.

[0045] The power transmission of DAB is determined by the phase-shift ratio and the voltage amplitude, and its steady-state power formula is:

[0046]

[0047] where P out is the steady-state power, f s is the switching frequency, L is the system inductor, an auxiliary inductor can be externally connected or the leakage inductance of the high-frequency transformer can be used, N:1 is the turns ratio of the transformer, C in and C out are the capacitances of the input and output capacitors respectively, V in represents the input voltage of DAB, V out represents the voltage across the output capacitor, and D is the phase-shift ratio between the two AC square-wave voltages.

[0048] The dynamics of the input / output capacitors are determined by power balance:

[0049]

[0050] where and are the change rates of the input voltage and the output voltage respectively, R is the load equivalent resistance, R s is the internal resistance of the DC voltage side, and V s represents the DC voltage source voltage.

[0051] Step 1.2: Convert the input-output voltage dynamic model into a linear state-space equation.

[0052] In a specific embodiment, to facilitate the intuitive analysis of the input-output voltage dynamic relationship of the DAB converter, its equivalent circuit is simplified to obtain a simplified topology diagram of the dual-active-bridge converter, as Figure 2 shown. Among them, the DAB will regulate the charging / discharging of energy storage devices such as power batteries and supercapacitors to ensure that the user load requirements are normally met.

[0053] Convert the dynamic model of the physical characteristics of the DAB converter into a system linear state-space equation, establish and simplify the linear state-space equation of the DAB system. According to the simplified topology diagram of the DAB, the linear state-space equation of the DAB system can be obtained by Kirchhoff's voltage law (KVL) as follows:

[0054]

[0055] Among them, f s is the switching frequency, L is the system inductor, an auxiliary inductor can be externally connected or the leakage inductance of the high-frequency transformer can be used, N:1 is the turns ratio of the transformer, C in and C out are the capacitances of the input and output capacitors respectively, R is the equivalent resistance of the load, R s is the internal resistance of the DC voltage side, V s represents the DC voltage source voltage, V in represents the input voltage of the DAB, V out represents the voltage across the output capacitor, and are the change rates of the input voltage and the output voltage respectively, and D is the phase shift ratio between the two AC square-wave voltages.

[0056] Step 2: Construct an energy function dynamic equation based on the transmission power balance relationship according to the linear state-space equation.

[0057] In a specific embodiment, define the total energy storage function of the system as According to the power difference, the energy expression is obtained as Define the energy change rate function as The following energy dynamic equation is obtained:

[0058]

[0059] Based on the result of the above feedback linearization (1), define as the instantaneous converter energy stored in the capacitor. The transmission power balance relationship is: the energy change rate inside the converter is equal to the difference between the input power and the output power, which has a clear physical meaning. Then the total energy storage function of the DAB system is:

[0060]

[0061] Select the energy change rate function as:

[0062]

[0063] Take its derivative, perform a coordinate transformation again, and obtain the energy dynamics equation as follows:

[0064]

[0065] Step 3: According to the active disturbance rejection control (ADRC) theory, construct the energy function dynamics equation into a standard form of the extended state space equation, and design a two-layer observer based on the extended state space equation to suppress the measurement noise during the sampling process and compensate for the lumped disturbances during the operation of the DAB system.

[0066] Step 3.1: According to the ADRC theory, construct the energy function dynamics equation into a standard form of the extended state space equation through a coordinate transformation.

[0067] In a specific implementation, take as the main state variable, u = D(1 - D) as the control variable, and define the generalized total disturbance as Define the derivative of the disturbance as Eliminate the influence of different operating points by substituting b = b0 + Δb. Describe the characteristics of the DAB energy function using the ADRC theory as follows:

[0068]

[0069] Among them, is the second-order time derivative of the total energy storage function of the DAB system, obtained according to the basic definition of ADRC. The energy dynamics equation is upgraded to a second-order system for high-order controller design. represents the input gain. Further, b = b0 + Δb can be obtained, where b0 represents a preset operating point, Δb represents the mismatched disturbance, and f is the matched disturbance.

[0070] Regard the generalized total disturbance to be estimated as a new state. Then, the extended state space equation in the controllable canonical form is obtained as follows:

[0071]

[0072] Among them, is the instantaneous converter energy function stored in the capacitor, is the energy change rate function, is the total disturbance, respectively represent The derivative, where u is the control variable, b0 represents a preset operating point, y represents the normal measured output, and h is the disturbance change rate.

[0073] Written in compact form as

[0074]

[0075] Where, is the extended state variable, A e , B e and E e represent the system matrix, input matrix, and disturbance input matrix of the extended state space equation, ξ represents the sensor noise, y ξ represents the measured output with noise, and u represents the control variable.

[0076] To estimate the total disturbance online in real time, a corresponding linear extended state observer (LESO) is designed based on (7) as follows:

[0077]

[0078] Where, is the estimated term of the extended state variable H, L e =[l e1 l e2 l e3 is the ESO feedback error gain matrix to be designed. According to the bandwidth parameterization method, all observer poles should be placed at the same location, i.e., (-ω e , 0). The observer gain can be set as l e1 =3ω e ,

[0079] Step 3.2: Design a double-layer observer according to the extended state space equation.

[0080] As Figure 3 shown, Figure 3 in, I out is the output current of the DAB, and V out is the output voltage of the DAB. According to the extended state space equation, the observer structure is improved. To accurately estimate the total disturbance in real time and effectively suppress noise, different from the single-layer ESO structure of the existing observer, this embodiment proposes a weighted double-layer fusion estimator (WDO) with two-level subsystem interconnection closely related to the performance of HWADRC based on a hybrid structure of double-layer third-order ESO and second-order ESO.

[0081] Step 3.21: To suppress the influence of output measurement noise on the estimation performance and compensate for part of the disturbance, construct the dynamic model of the first-level subsystem (WDO-1).

[0082] The dynamic model of the first - stage subsystem of the double - layer observer system is as follows:

[0083]

[0084] where, is the dynamic model of the first - stage subsystem, respectively represent the first - order derivatives of z1, z2, and z3. z1 and z2 are the final estimated values of respectively, and z3 is the estimated value of the combination of the unknown lumped disturbance pre - estimate of WDO - 1 and the measurement noise ξ. l is a constant, and the observer gain β1 = 3ω and e , represent the extended - state observer gain, and ω e represents an adjustable parameter used to determine the bandwidth of the extended - state observer.

[0085] The main function of WDO - 1 is to suppress the influence of the output measurement noise on the estimation performance and compensate for a part of the disturbance Then the remaining disturbance will establish the second - stage subsystem by WDO - 2, and draw on the UDE idea to filter the data to improve the estimation accuracy of the total disturbance.

[0086] Step 3.22: Construct the dynamic model of the second - stage subsystem to compensate for the remaining disturbance.

[0087] z3 will enter the second - stage subsystem WDO - 2 as the only input signal. The dynamic model of WDO - 2 is:

[0088]

[0089] where, is the dynamic model of the second - stage subsystem, respectively represent the first - order derivatives of z4 and z5. z4 and z5 are the estimates of the remaining disturbance and the disturbance change rate h respectively. β4 and β5 are the designed bandwidth observer gains used to smoothly compensate for the disturbance part.

[0090] Step 4: According to the double - layer observer structure, construct a control law based on the extended - state - space equation and the energy - function dynamic equation, and use the control law to solve for the output voltage of the phase - shift - ratio tracking dual - active - bridge converter.

[0091] Step 4.1: According to the observer structure, construct a control law based on the state - space model and the energy function.

[0092] Based on the filtering and estimation effect of WDO, the feedback control law u e can be designed as:

[0093]

[0094] wherein is the reference value of the internal energy of the converter, V in0 and V out0 are the reference input and reference output voltages in the steady state.

[0095] respectively represent the estimated values. k d = 2ω c are the amplification coefficients of proportional and derivative respectively, ω c is the controller bandwidth, and α is the weighting factor. Due to the different disturbance dynamics and noise characteristics, the sensitivity of WDO to measurement noise and disturbance signals is dynamically adjusted by introducing the weighting factor α.

[0096] In this embodiment, the weighting factor α is usually a preset constant. The weighting factor α is mainly used to balance the estimation weights of the double-layer observer for disturbances and noises, so that the observer shows different characteristics in the two parts of noise suppression and disturbance compensation, and strong real-time response is not required. In this embodiment, the influence of high-frequency noise and external disturbances on the output voltage is suppressed by the weighting factor α, and the object of action is the estimation accuracy of the observer for disturbances and noises, which indirectly affects the shift ratio generation.

[0097] By substituting (12) into the energy function, the dynamic characteristics of the DAB energy function with WDO are re-expressed as:

[0098]

[0099] wherein, after the system disturbance converges, it will compensate represents the fusion factor.

[0100] Through the structure of ADRC, especially the disturbance estimation and compensation of ESO, the high-order dynamics and disturbances of the system are effectively cancelled, so that the output response of the system is approximately directly determined by the control input u0. Therefore, in this embodiment, the dynamic characteristic expression formula is designed, which can simplify the design of the controller, without dealing with the complex nonlinear terms of the original system. Reducing the dependence on the accurate mathematical model, the parameter adjustment only requires the nominal gain, weighting factor and observer bandwidth.

[0101] Step 4.2: Solve the updated shift ratio according to the relationship between the control input and the shift ratio by using the control law.

[0102] In a specific embodiment, the control input obtained according to the control law; the value of the phase shift ratio is calculated using the relationship between the control input and the phase shift ratio; when the load suddenly changes, the reference voltage can be tracked to quickly adjust the phase shift ratio D, compensate for the power gap, prevent voltage dips or overshoots, and applying the solved value of the phase shift ratio in the dual-active-bridge converter can effectively track the output voltage reference value.

[0103] Specifically, to achieve the control of the DAB converter, the control signal should be modulated to the external phase shift ratio D, and its generation method can be calculated according to the existing single-phase-shift modulation strategy. According to the relationship between the control input and the phase shift ratio D(1 - D) = u, the following expression for solving the phase shift ratio is obtained:

[0104]

[0105] According to the characteristics, around D = 0.5, the relationship between the transmission power of the DAB and the absolute value of the phase shift ratio D characteristic is symmetric. According to (15), the solution of D is also symmetric around D = 0.5. In addition, to prevent damage to the DAB converter, the following constraints should also be imposed on the output of the phase shift ratio to limit the output range:

[0106] 0 ≤ D ≤ 0.5 (15).

[0107] In the DAB conversion, the most important power transmission power is jointly determined by the phase difference and the voltage amplitude. The converter controls the power transmission direction and magnitude by adjusting the phase shift ratio, thereby tracking the voltage reference value. By using the solved phase shift ratio D and substituting it into the output power of the DAB specifically, it also involves in the model:

[0108]

[0109] where the first term on the right side is the power input controlled by the phase shift ratio, and the second term is the load power consumption. By adjusting D in a closed loop, and then adjusting V through power balance out to make it converge to the reference output voltage value V out0 in the steady state.

[0110] The auto-disturbance rejection optimization control method of the dual-active converter in this embodiment is applicable to various phase-shift modes of the DAB, such as single-phase shift, extended phase shift, double phase shift, etc., and can be changed according to different phase-shift modes, with strong adaptability. Taking the simplest single-phase-shift control as an example, a double-layer weighted auto-disturbance rejection control method described in this embodiment is used to control the dual-active-bridge converter, and the control flow chart is as Figure 4 shown. In this embodiment, the MATLAB R2023b software is used to verify the control method in this embodiment.

[0111] The specific simulation parameter settings are as follows: switching frequency f s = 10 kHz, system inductor L = 50 μF, turns ratio N of the transformer = 1:1.2, input and output capacitors are C in = 100 μF and C out = 470 μF, load equivalent resistance R = 30 Ω, internal resistance R s of the DC voltage side = 1e-6 Ω, voltage V s of the DC voltage source = 300 V. The noise source uses Gaussian white noise and follows the 3σ principle.

[0112] As Figure 5 shown, this embodiment provides a simulation waveform diagram of the output voltage of the double-layer weighted active disturbance rejection control when the reference voltage suddenly changes (the voltage suddenly changes from 360 V to 740 V). It can be seen that when the working condition of the DAB converter changes, the model has a relatively fast convergence speed, and has good steady-state and dynamic following performances. The transient recovery time is 17.3 ms, and it is completely unaffected by the changes or inaccuracies of the converter parameters, and the robustness of the system is significantly improved. As Figure 6 shown, the waveform diagram of the relevant parameters of the DAB converter under the double-layer weighted active disturbance rejection control provided by this embodiment, respectively intercepts the waveform outputs of some time periods before and after the load mutation. It can be seen that the waveform output is normal under the control of the present invention.

[0113] As Figure 7 shown, this embodiment provides a comparison diagram of the simulation waveforms of the output voltages of the double-layer weighted active disturbance rejection control, PID control, and traditional active disturbance rejection control when the load suddenly changes (the output load suddenly changes from 30 Ω to 15 Ω). It can be seen that during the dynamic adjustment process, when the load suddenly changes, the voltage stabilization time of this embodiment is about 4.991 ms, and the voltage overshoot is 5.78 V, which has the characteristics of fast dynamics of predictive control. Although the PID control can stabilize relatively quickly, the amplitude fluctuation is large, and the voltage overshoot is 14.65 V for the relative error; the transient recovery time of the traditional active disturbance rejection control strategy is 20.087 ms, and the voltage overshoot is 26.92 V, which proves the superiority of the method in the present invention. Under the controller provided by this embodiment, the output voltage tracking error is about 1.23 V.

[0114] As Figure 8 shown, the waveform diagram of the relevant parameters of the DAB converter under the double-layer weighted active disturbance rejection control provided by this embodiment, respectively intercepts the waveform outputs of some time periods before and after the load mutation. It can be seen that the waveform output is normal under the control of this embodiment.

[0115] Embodiment 2:

[0116] Embodiment 2 of the present invention provides a dual-active-bridge converter control system based on double-layer weighted active disturbance rejection, including:

[0117] A voltage dynamics model construction module, configured to construct an input-output voltage dynamics model according to the characteristics of a dual-active-bridge converter system, and convert the input-output voltage dynamics model into a linear state-space equation;

[0118] An energy dynamics model construction module, configured to construct an energy function dynamics equation based on the transmission power balance relationship according to the linear state-space equation;

[0119] An observer design module, configured to construct the energy function dynamics equation into an extended state-space equation in standard form according to the active disturbance rejection theory, and design a two-layer observer according to the extended state-space equation;

[0120] An observer control module, configured to construct a control law based on the state-space model and the energy function according to the two-layer observer structure, and use the control law to solve the phase-shift ratio to track the output voltage of the dual-active-bridge converter.

[0121] Embodiment 3:

[0122] Embodiment 3 of the present invention provides a medium on which a program is stored, and when the program is executed by a processor, it implements the steps in the control method of the dual-active-bridge converter based on the two-layer weighted active disturbance rejection as described in Embodiment 1 of the present invention.

[0123] Embodiment 4:

[0124] Embodiment 4 of the present invention provides a device, including a memory, a processor, and a program stored on the memory and executable on the processor. When the processor executes the program, it implements the steps in the control method of the dual-active-bridge converter based on the two-layer weighted active disturbance rejection as described in Embodiment 1 of the present invention.

[0125] The steps involved in the above Embodiments 2, 3, and 4 correspond to those in Method Embodiment 1. For specific implementation manners, reference may be made to the relevant description part of Embodiment 1.

[0126] Those skilled in the art should understand that the above-mentioned modules or steps of the present invention can be implemented by a general-purpose computer device. Optionally, they can be implemented by program codes executable by a computing device, so that they can be stored in a storage device and executed by the computing device, or they can be separately fabricated into individual integrated circuit modules, or multiple modules or steps among them can be fabricated into a single integrated circuit module for implementation. The present invention is not limited to any specific combination of hardware and software.

[0127] Although the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not a limitation on the protection scope of the present invention. Those skilled in the art should understand that various modifications or deformations that can be made without creative efforts on the basis of the technical solution of the present invention are still within the protection scope of the present invention.

Claims

1. A control method for a dual-active-bridge converter based on double-layer weighted active disturbance rejection, characterized in that It includes the following steps: Construct an input-output voltage dynamics model according to the characteristics of the dual-active-bridge converter system, and convert the input-output voltage dynamics model into a linear state-space equation; Construct an energy function dynamics equation based on the transmission power balance relationship according to the linear state-space equation; Construct the energy function dynamics equation into an extended state-space equation in standard form according to the active disturbance rejection theory, and design a two-layer observer according to the extended state-space equation; According to the two-layer observer structure, construct a control law based on the state-space model and the energy function, and use the control law to solve the phase-shift ratio to track the output voltage of the dual-active-bridge converter.

2. The control method of the dual-active-bridge converter based on double-layer weighted active disturbance rejection according to claim 1, wherein The specific steps for constructing the input-output voltage dynamics model according to the characteristics of the dual-active-bridge converter system are as follows: Obtain the topology of the dual-active-bridge converter; Analyze the input-output voltage dynamics relationship according to the topology of the dual-active-bridge converter, and construct an input-output voltage dynamics model.

3. The control method of the dual-active-bridge converter based on double-layer weighted active disturbance rejection according to claim 1, characterized in that, The extended state-space equation in standard form is: Among them, is the instantaneous converter energy function stored in the capacitor, is the energy change rate function, is the total disturbance, respectively represent the derivatives of, u is the control quantity, b0 represents a preset operating point, y represents the normal measured output, and h is the disturbance change rate.

4. The control method of the dual-active-bridge converter based on double-layer weighted active disturbance rejection according to claim 3, wherein The specific steps for designing a two-layer observer according to the extended state-space equation are as follows: To suppress the influence of output measurement noise on the estimation performance and compensate for part of the disturbance, construct a first-level subsystem dynamics model; Construct a second-level subsystem dynamics model to compensate for the remaining disturbance.

5. The control method of the dual-active-bridge converter based on double-layer weighted active disturbance rejection according to claim 4, characterized in that, The two-layer observer includes: The first-level subsystem dynamics model: Among them, is the first-level subsystem dynamics model, respectively represent the first-order derivatives of z1, z2, and z3. z1 and z2 are the final estimated values of respectively, and z3 is the estimated value of the combination of the unknown lumped disturbance pre-estimation value of the first-level subsystem dynamics model and the measurement noise ξ. l is a constant, and the observer gain β1 = 3ω and e 、 represent the extended state observer gain, and ω e represents an adjustable parameter used to determine the bandwidth of the extended state observer; The second-level subsystem dynamics model: Among them, is the second-level subsystem dynamics model, respectively represent the first-order derivatives of z4 and z5. z4 and z5 are the estimates of the remaining disturbance and the disturbance change rate h. β4 and β5 are bandwidth observer gains used to smoothly compensate the disturbance part.

6. The control method of the dual-active-bridge converter based on double-layer weighted active disturbance rejection according to claim 5, wherein The control law is: where u e is the control law, is the reference value of the internal energy of the converter, V in0 and V out0 are the reference input and reference output voltages in the steady state. respectively represent the estimated values of. k d = 2ω c are the amplification coefficients of proportional and differential respectively, ω c is the controller bandwidth, α is the weighting factor, C in and C out are the capacitances of the input and output capacitors respectively.

7. The control method of the dual-active-bridge converter based on double-layer weighted active disturbance rejection according to claim 1, wherein The specific steps for using the control law to solve the phase-shift ratio to track the output voltage of the dual-active-bridge converter are as follows: The control input obtained according to the control law; Calculate the value of the phase-shift ratio by using the relationship between the control input and the phase-shift ratio; Apply the solved value of the phase-shift ratio in the dual-active-bridge converter to track the output voltage reference value.

8. A control system for a dual-active-bridge converter based on a double-layer weighted active disturbance rejection, characterized in that It includes: A voltage dynamics model construction module, configured to construct an input-output voltage dynamics model according to the characteristics of the dual-active-bridge converter system, and convert the input-output voltage dynamics model into a linear state-space equation; An energy dynamics model construction module, configured to construct an energy function dynamics equation based on the transmission power balance relationship according to the linear state-space equation; An observer design module, configured to construct the energy function dynamics equation into an extended state-space equation in standard form according to the active disturbance rejection theory, and design a two-layer observer according to the extended state-space equation; An observer control module, configured to construct a control law based on the state-space model and the energy function according to the two-layer observer structure, and use the control law to solve the phase-shift ratio to track the output voltage of the dual-active-bridge converter.

9. A computer-readable storage medium, characterized in that, It stores multiple instructions, and the instructions are adapted to be loaded and executed by the processor of the terminal device to perform the control method of the dual-active-bridge converter based on double-layer weighted active disturbance rejection according to any one of claims 1-7.

10. A terminal device, characterized in that, It includes a processor and a computer-readable storage medium. The processor is used to implement each instruction; the computer-readable storage medium is used to store multiple instructions, and the instructions are adapted to be loaded and executed by the processor to perform the control method of the dual-active-bridge converter based on double-layer weighted active disturbance rejection according to any one of claims 1-7.

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