LLC resonant converter control method and device and storage medium

Abstract

The application provides an LLC resonant converter control method, device and storage medium, and belongs to the technical field of converter control.The method comprises the following steps: constructing an LLC resonant circuit through an LLC resonant converter, and obtaining a model parameter group through fitting of the LLC resonant circuit; and performing estimation value updating on the model parameter group, a controller closed-loop bandwidth angular frequency, a first voltage estimation value of a previous control period, a second voltage estimation value of the previous control period, an external disturbance of the previous control period, an output voltage of the previous control period and a switching frequency control signal of the previous control period, to obtain a first voltage estimation value of a current control period, a second voltage estimation value of the current control period and an external disturbance of the current control period. The application solves the problems of inherent chattering of traditional first-order sliding mode control and excessive dependence of traditional active disturbance rejection control on high observation bandwidth, which is easy to introduce high-frequency switching noise.

Description

Technical Field

[0001] This invention relates to the field of converter control technology, specifically to a control method, device, and storage medium for an LLC resonant converter. Background Technology

[0002] LLC resonant converters are widely used in various power electronics applications, including server power supply intermediate stages, due to their ability to achieve soft switching across the entire load range and their excellent electrical isolation performance. However, in actual operation, these converters exhibit slow dynamic response when faced with severe load fluctuations or input voltage jumps, which can easily cause significant overshoot or drop in output voltage, thereby affecting the stable operation of downstream electrical equipment.

[0003] Existing linear active disturbance rejection control (LADRC) simplifies the parameter tuning process, but its algorithm is limited by the linear error feedback law, resulting in limited ability to suppress complex nonlinear disturbances. While simply introducing sliding mode control (SMC) can improve response speed, traditional first-order sliding mode control inherently exhibits chattering, which increases steady-state output voltage ripple. Furthermore, high-frequency LLC systems are sensitive to the computational overhead of the controller; excessively high observer bandwidth amplifies high-frequency switching noise, affecting system stability. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide an LLC resonant converter control method, device and storage medium to address the shortcomings of the prior art.

[0005] The technical solution of this invention to solve the above-mentioned technical problems is as follows: A control method for an LLC resonant converter, comprising the following steps: An LLC resonant circuit is constructed using an LLC resonant converter, and the LLC resonant circuit is fitted to obtain a set of model parameters. Import the controller closed-loop bandwidth angular frequency, obtain the first voltage estimate, the second voltage estimate, the external disturbance, the output voltage, and the switching frequency control signal of the previous control cycle, and update the estimated values ​​of the model parameter group, the controller closed-loop bandwidth angular frequency, the first voltage estimate, the second voltage estimate, the external disturbance, the output voltage, and the switching frequency control signal of the previous control cycle to obtain the first voltage estimate, the second voltage estimate, and the external disturbance of the current control cycle. Import the reference voltage, and perform sliding surface analysis on the reference voltage, the first voltage estimate of the current control cycle, and the second voltage estimate of the current control cycle to obtain the sliding surface of the current control cycle; The switching frequency control signal of the current control cycle is analyzed based on the sliding surface of the current control cycle and the external disturbance of the current control cycle to obtain the switching frequency control signal of the current control cycle, and the LLC resonant converter is controlled according to the switching frequency control signal of the current control cycle.

[0006] Another technical solution of the present invention to solve the above-mentioned technical problems is as follows: An LLC resonant converter control device, comprising: The fitting module is used to construct an LLC resonant circuit through an LLC resonant converter, fit the LLC resonant circuit, and obtain a set of model parameters. The estimation update module is used to import the controller closed-loop bandwidth angular frequency, obtain the first voltage estimate, the second voltage estimate, the external disturbance, the output voltage, and the switching frequency control signal of the previous control cycle, and update the model parameter group, the controller closed-loop bandwidth angular frequency, the first voltage estimate, the second voltage estimate, the external disturbance, the output voltage, and the switching frequency control signal of the previous control cycle to obtain the first voltage estimate, the second voltage estimate, and the external disturbance of the current control cycle. The sliding surface analysis module is used to import a reference voltage, perform sliding surface analysis on the reference voltage, the first voltage estimate of the current control cycle, and the second voltage estimate of the current control cycle, and obtain the sliding surface of the current control cycle. The control module is used to analyze the sliding surface of the current control cycle and the external disturbance of the current control cycle to obtain the switching frequency control signal of the current control cycle, and to control the LLC resonant converter according to the switching frequency control signal of the current control cycle.

[0007] Based on the above-mentioned LLC resonant converter control method, the present invention also provides an LLC resonant converter control system.

[0008] Another technical solution of the present invention to solve the above-mentioned technical problems is as follows: an LLC resonant converter control system, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the LLC resonant converter control method described above is implemented.

[0009] Based on the above-described LLC resonant converter control method, this invention also provides a computer-readable storage medium.

[0010] Another technical solution of the present invention to solve the above-mentioned technical problems is as follows: a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the LLC resonant converter control method as described above.

[0011] The beneficial effects of this invention are as follows: An LLC resonant circuit is constructed using an LLC resonant converter. A model parameter set is obtained by fitting the LLC resonant circuit. The model parameter set, the controller closed-loop bandwidth angular frequency, the first voltage estimate of the previous control cycle, the second voltage estimate of the previous control cycle, the external disturbance of the previous control cycle, the output voltage of the previous control cycle, and the estimated value of the switching frequency control signal of the previous control cycle are updated to obtain the first voltage estimate of the current control cycle, the second voltage estimate of the current control cycle, and the external disturbance of the current control cycle. Sliding surface analysis of the reference voltage, the first voltage estimate of the current control cycle, and the second voltage estimate of the current control cycle yields... The sliding surface of the current control cycle is analyzed, and the switching frequency control signal of the current control cycle is obtained by analyzing the sliding surface of the current control cycle and the switching frequency control signal of the external disturbance of the current control cycle. The LLC resonant converter is controlled according to the switching frequency control signal of the current control cycle. This solves the problems of inherent chattering in traditional first-order sliding mode control and the problem of traditional active disturbance rejection control relying too much on high observation bandwidth and easily introducing high-frequency switching noise. It significantly accelerates the error convergence speed and greatly reduces the fluctuation amplitude of dynamic voltage, effectively enhances the disturbance rejection performance and parameter robustness, and has the advantages of effectively suppressing switching noise amplification under high-frequency operation, no sliding mode chattering in steady state and extremely fast dynamic recovery, and minimal overshoot. Attached Figure Description

[0012] Figure 1 A flowchart illustrating the LLC resonant converter control method provided in an embodiment of the present invention; Figure 2 The main circuit diagram of the half-bridge LLC resonant converter for the LLC resonant converter control method provided in the embodiments of the present invention; Figure 3 The extended description function method modeling circuit diagram of the LLC resonant converter control method provided in the embodiments of the present invention; Figure 4 A block diagram of a super-spiral sliding mode self-disturbance rejection composite control method for controlling LLC resonant converters provided in this embodiment of the invention; Figure 5 The disturbance rejection waveform diagram of the output load jump of the LLC resonant converter control method provided in the embodiment of the present invention is shown. Figure 6 The disturbance rejection waveform diagram of the LLC resonant converter control method provided in the embodiment of the present invention during input voltage jumps; Figure 7 A block diagram of an LLC resonant converter control device provided in an embodiment of the present invention. Detailed Implementation

[0013] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0014] Figure 1 This is a flowchart illustrating an LLC resonant converter control method provided in an embodiment of the present invention.

[0015] like Figures 1 to 3 As shown, a control method for an LLC resonant converter includes the following steps: S1: Construct an LLC resonant circuit using an LLC resonant converter, and fit the LLC resonant circuit to obtain a set of model parameters; S2: Import the controller closed-loop bandwidth angular frequency, obtain the first voltage estimate, the second voltage estimate, the external disturbance, the output voltage, and the switching frequency control signal of the previous control cycle, and update the estimated values ​​of the model parameter group, the controller closed-loop bandwidth angular frequency, the first voltage estimate, the second voltage estimate, the external disturbance, the output voltage, and the switching frequency control signal of the previous control cycle to obtain the first voltage estimate, the second voltage estimate, and the external disturbance of the current control cycle. S3: Import the reference voltage, perform sliding surface analysis on the reference voltage, the first voltage estimate of the current control cycle, and the second voltage estimate of the current control cycle to obtain the sliding surface of the current control cycle; S4: Analyze the sliding surface of the current control cycle and the external disturbance of the current control cycle to obtain the switching frequency control signal of the current control cycle, and control the LLC resonant converter according to the switching frequency control signal of the current control cycle.

[0016] In the above embodiments, an LLC resonant circuit is constructed using an LLC resonant converter. A model parameter set is obtained by fitting the LLC resonant circuit. The model parameter set, the controller closed-loop bandwidth angular frequency, the first voltage estimate of the previous control cycle, the second voltage estimate of the previous control cycle, the external disturbance of the previous control cycle, the output voltage of the previous control cycle, and the estimated value of the switching frequency control signal of the previous control cycle are updated to obtain the first voltage estimate of the current control cycle, the second voltage estimate of the current control cycle, and the external disturbance of the current control cycle. Sliding surface analysis of the reference voltage, the first voltage estimate of the current control cycle, and the second voltage estimate of the current control cycle yields the current... The sliding mode surface of the previous control cycle is analyzed, and the switching frequency control signal of the current control cycle is obtained by analyzing the sliding mode surface of the current control cycle and the switching frequency control signal of the external disturbance of the current control cycle. The LLC resonant converter is controlled according to the switching frequency control signal of the current control cycle. This solves the problems of inherent chattering in traditional first-order sliding mode control and the problem of traditional active disturbance rejection control relying too much on high observation bandwidth and easily introducing high-frequency switching noise. It significantly accelerates the error convergence speed and greatly reduces the fluctuation amplitude of dynamic voltage, effectively enhances the disturbance rejection performance and parameter robustness, and has the advantages of effectively suppressing switching noise amplification under high-frequency operation, no sliding mode chattering in steady state and extremely fast dynamic recovery, and minimal overshoot.

[0017] Optionally, as an embodiment of the present invention, the process of fitting the LLC resonant circuit to obtain the model parameter set includes: The LLC resonant circuit is fitted using the extended description function algorithm to obtain the first model parameters and the second model parameters. A set of model parameters is then obtained using the first model parameters and the second model parameters.

[0018] Specifically, based on the working principle of the half-bridge LLC resonant circuit, the large-signal nonlinear equations for the resonant inductor current, resonant capacitor voltage, and magnetizing current in the circuit can be written using the extended describing function method (i.e., the extended describing function algorithm). Then, a small-signal disturbance is introduced into the average state equation at the static operating point, and it is linearized. After simplification, the small-signal transfer function between the system's output voltage and switching frequency is obtained as follows: , The above transfer function is a high-order mathematical model. Its high-frequency poles and zeros are caused by the complex resonant network elements of the circuit itself. Considering that the digital controller mainly operates in the low-frequency domain, the influence of high-frequency poles and zeros on the closed-loop control circuit can be ignored. Therefore, to simplify the controller design and analysis, the difference-frequency dynamic characteristics of the system are extracted, and a second-order reduced-order mathematical model is used to fit the low-frequency domain of the system. The fitted second-order transfer function is as follows: , The controlled object arrangement, for a general second-order controlled object, can be written in the following form: .in, For the system output voltage variable, This is the switching frequency control signal. This is due to an unknown external disturbance. and For system model parameters, To control the gain.

[0019] In the above embodiments, the LLC resonant circuit is fitted to obtain the model parameter set, which solves the problems of inherent chattering in traditional first-order sliding mode control and the excessive reliance on high observation bandwidth in traditional active disturbance rejection control, which easily introduces high-frequency switching noise.

[0020] Optionally, as an embodiment of the present invention, the process of updating the estimated values ​​of the model parameter set, the controller closed-loop bandwidth angular frequency, the first voltage estimate of the previous control cycle, the second voltage estimate of the previous control cycle, the external disturbance of the previous control cycle, the output voltage of the previous control cycle, and the switching frequency control signal of the previous control cycle to obtain the first voltage estimate of the current control cycle, the second voltage estimate of the current control cycle, and the external disturbance of the current control cycle includes: The first set of equations is used to calculate the first model parameters, the second model parameters, and the closed-loop bandwidth angular frequency of the controller to obtain the first observer gain coefficient, the second observer gain coefficient, and the third observer gain coefficient. The first set of equations is as follows: , in, , in, The gain coefficient of the first observer. This is the gain coefficient of the second observer. This represents the gain coefficient of the third observer. The characteristic angular frequency of the observer, These are the parameters of the first model. For the second model parameters, The closed-loop bandwidth angular frequency of the controller; The first observer gain coefficient, the second observer gain coefficient, the third observer gain coefficient, the first model parameter, the second model parameter, the first voltage estimate of the previous control cycle, the second voltage estimate of the previous control cycle, the external disturbance of the previous control cycle, the output voltage of the previous control cycle, and the switching frequency control signal of the previous control cycle are calculated using the second set of equations to obtain the first voltage estimate of the current control cycle, the second voltage estimate of the current control cycle, and the external disturbance of the current control cycle. The second set of equations is as follows: , in, For the first The first voltage estimate for each control cycle. For the first The first voltage estimate for each control cycle. To control the total number of cycles, For the first The second voltage estimate for each control cycle The gain coefficient of the first observer. This is the gain coefficient of the second observer. This represents the gain coefficient of the third observer. For the first Output voltage per control cycle For the first The second voltage estimate for each control cycle These are the parameters of the first model. For the second model parameters, For the first External disturbances in each control cycle For control quantity gain coefficient, For the first The switching frequency control signal for each control cycle For the first External disturbances for each control cycle.

[0021] Specifically, it can be further rewritten into an extended form that includes known dynamics: , ( and The coefficients of the differential equation when fitting a second-order system; This refers to the gain of the control input of the actual system—a parameter that needs to be manually configured. (Unknown disturbances not modeled in the system) To increase the control input gain of the real system The estimated value extracts the known internal dynamics derived from the large-signal model of the system. The unmodeled dynamics and external disturbances are defined as the residual unknown total disturbance, and their rate of change is tracked. A model-aided mechanism is introduced to reduce the estimation burden on the observer by leveraging the known dynamics of the real-time feedforward system.

[0022] Will The observed values ​​are denoted as After introducing a known dynamic feedforward term, the scalar observation equation expanded by the Model-Assisted Linear Extended State Observer (MLESO) can be written as: , in, Derived from subsequent formulas; embodied in the formula , , The update process, Represents the system output voltage The estimated value, The first derivative of the system output voltage The estimated value, Unknown disturbances that represent the system not modeled The estimated value.

[0023] In the above formula, Represents the system output voltage The estimated value (i.e., the first voltage estimate). The first derivative of the system output voltage The estimated value (i.e., the second voltage estimate). This represents an unknown disturbance that is not modeled in the system. The estimated value (i.e., external disturbance); These are the observer gain coefficients (i.e., the first observer gain coefficient, the second observer gain coefficient, and the third observer gain coefficient).

[0024] To facilitate the engineering implementation of the digital control system, the forward Euler method is used to discretize the above equation. Let the digital control period be... (i.e., the total number of control cycles), the current control cycle is The next control cycle is The discrete difference equations used for real-time calculation of output voltage, first-order voltage derivative, and unknown disturbance estimate are derived as follows: , Based on the above formula, the digital controller inputs the current control cycle in each control cycle. The next control cycle can be directly calculated from the known state. The latest estimated value; at the initial moment of system startup, the initial values ​​of all observation states are set to 0, and subsequently, the estimated values ​​are obtained. and This information will be incorporated into the subsequent super-spiral sliding mode control module in real time.

[0025] In the formula The observer gain coefficient, Let be the crossover frequency of the closed loop (its upper limit is determined by the hardware system). According to the pole placement method, to ensure observer stability and uniform poles, the gain coefficient satisfies: , , By using a model-assisted linear extended state observer for real-time estimation and feedforward separation, the limit of the total system disturbance is effectively reduced.

[0026] In the above embodiments, the estimated values ​​of the model parameter set, the controller closed-loop bandwidth angular frequency, the first voltage estimate of the previous control cycle, the second voltage estimate of the previous control cycle, the external disturbance of the previous control cycle, the output voltage of the previous control cycle, and the switching frequency control signal of the previous control cycle are updated to obtain the first voltage estimate of the current control cycle, the second voltage estimate of the current control cycle, and the external disturbance of the current control cycle. This solves the problems of inherent chattering in traditional first-order sliding mode control and the excessive reliance on high observation bandwidth in traditional active disturbance rejection control, which easily introduces high-frequency switching noise. It significantly accelerates the error convergence speed and greatly reduces the fluctuation amplitude of dynamic voltage, effectively enhances the disturbance rejection performance and parameter robustness, and has the advantages of effectively suppressing switching noise amplification under high-frequency operation, no sliding mode chattering in steady state and extremely fast dynamic recovery, and minimal overshoot.

[0027] Optionally, as an embodiment of the present invention, the process of performing sliding surface analysis on the reference voltage, the first voltage estimate of the current control cycle, and the second voltage estimate of the current control cycle to obtain the sliding surface of the current control cycle includes: The sliding surface of the current control cycle is obtained by calculating the reference voltage, the first voltage estimate of the current control cycle, and the second voltage estimate of the current control cycle using the first formula. The first formula is: , in, For the first Sliding surface for each control cycle For reference voltage, For the first The second voltage estimate for each control cycle This is the sliding surface weighting coefficient. For the first The first voltage estimate for each control cycle.

[0028] Specifically, the tracking error of the system output voltage is defined as... , where is the reference voltage , This is the MLESO estimate of the output voltage (i.e., the first voltage estimate). To ensure rapid error convergence, a sliding mode surface is designed. as follows: , Right now , The sliding surface weight coefficient is a parameter that needs to be manually configured. The given value for the output voltage – that is, the target value for the output voltage.

[0029] In the above embodiments, sliding surface analysis is performed on the reference voltage, the first voltage estimate of the current control cycle, and the second voltage estimate of the current control cycle to obtain the sliding surface of the current control cycle. This ensures rapid convergence of errors, effectively enhances anti-disturbance performance and parameter robustness, and also has the advantages of effectively suppressing switching noise amplification under high-frequency operation, no sliding mode chattering in steady state, extremely fast dynamic recovery, and minimal overshoot.

[0030] Optionally, as an embodiment of the present invention, the process of analyzing the sliding surface of the current control cycle and the external disturbance of the current control cycle to obtain the switching frequency control signal of the current control cycle includes: The nonlinear feedback control value for the current control cycle is obtained by calculating the sliding surface of the current control cycle using a third-party program. The third-party program is: , in, For the first The nonlinear feedback control value for each control cycle. and All are nonlinear switching gain coefficients. For the first Sliding surface for each control cycle For symbolic functions, For the first The continuous integral control value for each control cycle; The switching frequency control signal for the current control cycle is obtained by calculating the nonlinear feedback control value and the external disturbance of the current control cycle using the second equation. The second equation is: , in, For the first The switching frequency control signal for each control cycle For control quantity gain coefficient, For the first The nonlinear feedback control value for each control cycle. For the first External disturbances for each control cycle.

[0031] Specifically, the superspiral sliding mode control law (ST-SMC) is designed as follows: , , The nonlinear switching gain coefficient for the superspiral sliding mode is a parameter that needs to be manually configured, and its value range must meet certain requirements. And greater than 0, It is the defined sliding surface. , For nonlinear switching gain coefficients, The continuous integral control variable (i.e., continuous integral control value) generated by the system.

[0032] To systematically demonstrate the finite-time convergence and global asymptotic stability of the closed-loop control system under lumped residual uncertainty, this embodiment introduces a non-smooth state vector, as follows: , By adjusting the sliding surface variable Perform time derivative calculation, combining the lumped unknown perturbation rate of change, which includes the known dynamics of the system's large signals, the derivative of the given command, and the residual error of the observations. The closed-loop sliding mode dynamic equations can be rewritten in the form of state-space matrix differential equations of the standard superspiral algorithm, as follows: , Based on this state-space description, a constant symmetric positive definite matrix is ​​used. Based on this, a non-smooth quadratic strict Lyapunov candidate function is constructed, as shown in the following equation: , By taking the time derivative of the Lyapunov function along the system state trajectory, its functional differential form can be obtained as follows: , According to the algebraic Lyapunov equations The matrix mapping relationship is such that the error transfer matrix is ​​made so that... Preserving the Hurwitz property ensures the matrix It is strictly global positive definite, which makes the Lyapunov derivative satisfy the negative definite convergence / divergence condition.

[0033] It should be understood that, in the actual physical operation of the converter, the rate of change of the total residual unknown disturbance of the system has a definite upper bound in physical terms. (Setting...) As a positive real number with an upper bound constant, the absolute value of the rate of change of this disturbance is always less than or equal to... That is, satisfy To ensure the system possesses absolute robust stability when facing this upper bound of disturbance, the tuning of the nonlinear switching gain parameter of the superspiral sliding mode controller module should strictly satisfy the following sufficient condition boundary constraints, as shown in the following equation: , When the gain tuning satisfies the above inequality constraints, the state trajectory of the closed-loop system will necessarily satisfy... The negative definite condition, in the formula The coefficients of the convergence constant are set to be greater than zero. According to the finite-time stability theorem, the system error state will arrive within a defined finite time. It converges quickly and smoothly to the zero point of the sliding surface.

[0034] Furthermore, because the model-assisted linear extended state observer structurally pre-strips and feeds forward to cancel out most of the known low-frequency model dynamics of the converter, the physical upper bound of the residual total disturbance entering the sliding mode control loop is reduced. The gain has been significantly reduced. This mechanism significantly lowers the theoretical safety gain boundary of the sliding mode controller, allowing the feedback loop to use a smaller nonlinear switching gain while maintaining high-speed convergence performance. This fundamentally suppresses the switching oscillation of the high-frequency control signal at the sliding surface and solves the chattering drawback of traditional first-order sliding mode.

[0035] like Figure 2 and 3 As shown, the unknown lumped disturbance state values, ultimately estimated online by the model-assisted linear extended state observer, will be used. (i.e., external disturbances) are cascaded with the continuous nonlinear feedback control law generated by the super-spiral sliding mode control module and canceled out by dynamic feedforward compensation. This comprehensive calculation process is directly simplified at the digital processor level, yielding the final output converter comprehensive digital frequency control quantity analytical expression as follows: , For the final output of the control variable, corresponding to Figure 2 and 3 The on and off frequencies of Q1 and Q2 are specified. The mathematical simplification and derivation process of this control law fully constructs the underlying logic calculation chain of the control algorithm of this invention, from error input to the final control switching frequency output.

[0036] In the above embodiments, the switching frequency control signal of the sliding surface of the current control cycle and the external disturbance of the current control cycle are analyzed to obtain the switching frequency control signal of the current control cycle. This suppresses the switching oscillation of the high-frequency control signal at the sliding surface, solves the chattering problem of the traditional first-order sliding mode, and ensures absolute robust stability when facing the upper limit of this disturbance.

[0037] Optionally, as another embodiment of the present invention, addressing the problems of slow dynamic response, large output voltage overshoot or drop, and inherent chattering in traditional first-order sliding mode control and the over-reliance on high observation bandwidth in traditional active disturbance rejection control in existing server power supply applications, the present invention organically integrates the information of the second-order simplified reduced-order model derived by the extended describing function method (EDF) into the active disturbance rejection control framework, constructing a model-assisted linear extended state observer. By stripping and feedforward cancelling the known large-signal dynamics of the system, the observer's real-time estimation method for the system's lumped disturbances is structurally improved. At the same time, a super-spiral sliding mode control belonging to the second-order sliding mode algorithm is introduced into the feedback loop to replace the linear error feedback law in the traditional active disturbance rejection control. By utilizing its continuous nonlinear control signal output, targeted improvements are made to the feedback loop error convergence and disturbance rejection mechanism. Compared to traditional voltage outer-loop PI control methods or single first-order sliding mode control methods, this invention significantly accelerates the system error convergence speed and greatly reduces the fluctuation amplitude of dynamic voltage when facing load changes and input voltage steps.

[0038] Alternatively, as another embodiment of the present invention, such as Figure 4 As shown, the controlled object of the present invention is a gallium nitride half-bridge LLC resonant converter; the digital control device includes: a voltage reference generator, an analog-to-digital converter, a first subtractor, a super-spiral sliding mode controller module, a model-assisted linear extended state observer module, a second-order model known dynamic extraction module, a second subtractor, a proportional module, a limiter, and a digital pulse width modulation generator. The output of the gallium nitride half-bridge LLC resonant converter is connected to the input of the analog-to-digital converter (ADC); the output of the ADC is connected to the first input of the model-aided linear extended state observer module; the output of the voltage reference generator is connected to the positive input of the first subtractor; the first output of the model-aided linear extended state observer module is connected to the negative input of the first subtractor; the output of the first subtractor is connected to the input of the super-spiral sliding mode controller module; the output of the super-spiral sliding mode controller module is connected to the positive input of the second subtractor; the second output of the model-aided linear extended state observer module is connected to the negative input of the second subtractor; the output of the second subtractor is connected to the input of the proportional module; the output of the proportional module is connected to the input of the limiter, the second input of the model-aided linear extended state observer module, and the input of the second-order model known dynamic extraction module; the output of the second-order model known dynamic extraction module is connected to the third input of the model-aided linear extended state observer module; the output of the limiter is connected to the input of the digital pulse width modulation generator; the output of the digital pulse width modulation generator is connected to the drive input of the gallium nitride half-bridge LLC resonant converter.

[0039] The Model-Aided Linear Extended State Observer (MALE) module, by using observation equations incorporating known dynamic information from the second-order model, enables accurate observation and estimation of the output voltage of the half-bridge LLC resonant converter, as well as unmodeled internal dynamics and unknown external total disturbances. The Super-Helical Sliding Mode Controller (SMT) module, by using a continuous nonlinear control law designed based on a second-order sliding mode algorithm, enables rapid nonlinear compensation and chattering suppression of the error between the reference voltage and the output observations of the MALE module. The Second-Order Model Known Dynamics Extraction module contains a converter reduced-order mathematical analytical expression derived based on the extended describing function method, enabling real-time extraction and feedforward stripping of known dynamic characteristics under the current system state. This significantly reduces the real-time estimation burden and dependence on high observation bandwidth of the MALE module.

[0040] Optionally, as another embodiment of the present invention, the present invention introduces a known dynamic extraction module for a second-order model and a super-spiral sliding mode controller module, which enables the known dynamics of the system to be stripped of feedforward in real time and the nonlinear feedback control law to be continuously output. This effectively enhances the model-assisted linear extended state observer module's ability to accurately estimate residual disturbances and the super-spiral sliding mode controller module's ability to quickly compensate for voltage tracking errors. It effectively enhances the system's anti-disturbance performance and parameter robustness in response to load abrupt changes and input voltage jumps. At the same time, it has the advantages of effectively suppressing switching noise amplification under high-frequency operation, no sliding mode chattering in steady state, extremely fast dynamic recovery, and minimal overshoot.

[0041] Alternatively, as another embodiment of the present invention, such as Figure 4As shown, the controlled object of the present invention is a gallium nitride half-bridge LLC resonant converter; the digital control device includes: a voltage reference generator, an analog-to-digital converter, a first subtractor, a super-spiral sliding mode controller module, a model-assisted linear extended state observer module, a second-order model known dynamic extraction module, a second subtractor, a proportional module, a limiter, and a digital pulse width modulation generator.

[0042] The output of the gallium nitride half-bridge LLC resonant converter is connected to the input of the analog-to-digital converter (ADC); the output of the ADC is connected to the first input of the model-aided linear extended state observer module; the output of the voltage reference generator is connected to the positive input of the first subtractor; the first output of the model-aided linear extended state observer module is connected to the negative input of the first subtractor; the output of the first subtractor is connected to the input of the super-spiral sliding mode controller module; the output of the super-spiral sliding mode controller module is connected to the positive input of the second subtractor; the second output of the model-aided linear extended state observer module is connected to the negative input of the second subtractor; the output of the second subtractor is connected to the input of the proportional module; the output of the proportional module is connected to the input of the limiter, the second input of the model-aided linear extended state observer module, and the input of the second-order model known dynamic extraction module; the output of the second-order model known dynamic extraction module is connected to the third input of the model-aided linear extended state observer module; the output of the limiter is connected to the input of the digital pulse width modulation generator; the output of the digital pulse width modulation generator is connected to the drive input of the gallium nitride half-bridge LLC resonant converter.

[0043] The model-assisted linear extended state observer module, by using observation equations that incorporate known dynamic information from the second-order model, can accurately observe and estimate the output voltage of the half-bridge LLC resonant converter, as well as the unmodeled dynamics within the system and the total unknown external disturbances. The super-spiral sliding mode controller module, by using a continuous nonlinear control law designed based on the second-order sliding mode algorithm, can achieve fast nonlinear compensation and chattering suppression of the error between the reference voltage and the output observation value of the model-assisted linear extended state observer module. The second-order model known dynamics extraction module contains a converter reduced-order mathematical analytical expression derived based on the extended describing function method, which can achieve real-time extraction and feedforward stripping of known dynamic characteristics under the current system state. The specific parameter settings of the main circuit and control system of the half-bridge LLC resonant converter are shown in Table 1.

[0044] Table 1 Alternatively, as another embodiment of the present invention, such as Figure 5As shown, the disturbance rejection performance of three different controllers is evaluated when the input bus voltage of this invention experiences a jump. The disturbance rejection performance and dynamic characteristics of the output voltage under traditional PI control are the worst, with large voltage overshoot and slow recovery. The disturbance rejection performance of the super-spiral sliding mode active disturbance rejection control proposed in this invention is the best, with almost no significant voltage overshoot and a settling time in the range of only 10ms. Traditional linear active disturbance rejection control falls between the two.

[0045] Alternatively, as another embodiment of the present invention, such as Figure 6 As shown, this invention demonstrates the output voltage changes under three control methods during the switching of output load between sudden increases and decreases. The voltage drop and overshoot are greatest under PI control, with a long recovery time; the voltage fluctuation amplitude under the control strategy of this invention is the smallest, greatly accelerating the dynamic response time of the system. Therefore, the proposed method has stronger anti-disturbance capability and dynamic tracking effect.

[0046] Figure 7 This is a block diagram of an LLC resonant converter control device provided in an embodiment of the present invention.

[0047] Alternatively, as another embodiment of the present invention, such as Figure 7 As shown, an LLC resonant converter control device includes: The fitting module is used to construct an LLC resonant circuit through an LLC resonant converter, fit the LLC resonant circuit, and obtain a set of model parameters. The estimation update module is used to import the controller closed-loop bandwidth angular frequency, obtain the first voltage estimate, the second voltage estimate, the external disturbance, the output voltage, and the switching frequency control signal of the previous control cycle, and update the model parameter group, the controller closed-loop bandwidth angular frequency, the first voltage estimate, the second voltage estimate, the external disturbance, the output voltage, and the switching frequency control signal of the previous control cycle to obtain the first voltage estimate, the second voltage estimate, and the external disturbance of the current control cycle. The sliding surface analysis module is used to import a reference voltage, perform sliding surface analysis on the reference voltage, the first voltage estimate of the current control cycle, and the second voltage estimate of the current control cycle, and obtain the sliding surface of the current control cycle. The control module is used to analyze the sliding surface of the current control cycle and the external disturbance of the current control cycle to obtain the switching frequency control signal of the current control cycle, and to control the LLC resonant converter according to the switching frequency control signal of the current control cycle.

[0048] Optionally, as an embodiment of the present invention, the process of fitting the LLC resonant circuit to obtain the model parameter set in the fitting module includes: The LLC resonant circuit is fitted using the extended description function algorithm to obtain the first model parameters and the second model parameters. A set of model parameters is then obtained using the first model parameters and the second model parameters.

[0049] Optionally, as an embodiment of the present invention, the estimation update module updates the model parameter set, the controller closed-loop bandwidth angular frequency, the first voltage estimate of the previous control cycle, the second voltage estimate of the previous control cycle, the external disturbance of the previous control cycle, the output voltage of the previous control cycle, and the switching frequency control signal of the previous control cycle to obtain the first voltage estimate of the current control cycle, the second voltage estimate of the current control cycle, and the external disturbance of the current control cycle. The process includes: The first set of equations is used to calculate the first model parameters, the second model parameters, and the closed-loop bandwidth angular frequency of the controller to obtain the first observer gain coefficient, the second observer gain coefficient, and the third observer gain coefficient. The first set of equations is as follows: , in, , in, The gain coefficient of the first observer. This is the gain coefficient of the second observer. This represents the gain coefficient of the third observer. The characteristic angular frequency of the observer, These are the parameters of the first model. For the second model parameters, The closed-loop bandwidth angular frequency of the controller; The first observer gain coefficient, the second observer gain coefficient, the third observer gain coefficient, the first model parameter, the second model parameter, the first voltage estimate of the previous control cycle, the second voltage estimate of the previous control cycle, the external disturbance of the previous control cycle, the output voltage of the previous control cycle, and the switching frequency control signal of the previous control cycle are calculated using the second set of equations to obtain the first voltage estimate of the current control cycle, the second voltage estimate of the current control cycle, and the external disturbance of the current control cycle. The second set of equations is as follows: , in, For the first The first voltage estimate for each control cycle. For the first The first voltage estimate for each control cycle. To control the total number of cycles, For the first The second voltage estimate for each control cycle The gain coefficient of the first observer. This is the gain coefficient of the second observer. This represents the gain coefficient of the third observer. For the first Output voltage per control cycle For the first The second voltage estimate for each control cycle These are the parameters of the first model. For the second model parameters, For the first External disturbances in each control cycle For control quantity gain coefficient, For the first The switching frequency control signal for each control cycle For the first External disturbances for each control cycle.

[0050] Optionally, another embodiment of the present invention provides an LLC resonant converter control system, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the LLC resonant converter control method as described above. This system can be a computer or similar system.

[0051] Optionally, another embodiment of the present invention provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the LLC resonant converter control method as described above.

[0052] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0053] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working process of the above-described apparatus and unit can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0054] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative. For instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed.

[0055] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of the embodiments of the present invention, depending on actual needs.

[0056] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0057] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0058] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A control method for an LLC resonant converter, characterized in that, Includes the following steps: An LLC resonant circuit is constructed using an LLC resonant converter, and the LLC resonant circuit is fitted to obtain a set of model parameters. Import the controller closed-loop bandwidth angular frequency, obtain the first voltage estimate, the second voltage estimate, the external disturbance, the output voltage, and the switching frequency control signal of the previous control cycle, and update the estimated values ​​of the model parameter group, the controller closed-loop bandwidth angular frequency, the first voltage estimate, the second voltage estimate, the external disturbance, the output voltage, and the switching frequency control signal of the previous control cycle to obtain the first voltage estimate, the second voltage estimate, and the external disturbance of the current control cycle. Import the reference voltage, and perform sliding surface analysis on the reference voltage, the first voltage estimate of the current control cycle, and the second voltage estimate of the current control cycle to obtain the sliding surface of the current control cycle; The switching frequency control signal of the current control cycle is analyzed based on the sliding surface of the current control cycle and the external disturbance of the current control cycle to obtain the switching frequency control signal of the current control cycle, and the LLC resonant converter is controlled according to the switching frequency control signal of the current control cycle.

2. The LLC resonant converter control method according to claim 1, characterized in that, The process of fitting the LLC resonant circuit to obtain the model parameter set includes: The LLC resonant circuit is fitted using the extended description function algorithm to obtain the first model parameters and the second model parameters. A set of model parameters is then obtained using the first model parameters and the second model parameters.

3. The LLC resonant converter control method according to claim 2, characterized in that, The process of updating the estimated values ​​of the model parameter set, the controller closed-loop bandwidth angular frequency, the first voltage estimate of the previous control cycle, the second voltage estimate of the previous control cycle, the external disturbance of the previous control cycle, the output voltage of the previous control cycle, and the switching frequency control signal of the previous control cycle to obtain the first voltage estimate of the current control cycle, the second voltage estimate of the current control cycle, and the external disturbance of the current control cycle includes: The first set of equations is used to calculate the first model parameters, the second model parameters, and the closed-loop bandwidth angular frequency of the controller to obtain the first observer gain coefficient, the second observer gain coefficient, and the third observer gain coefficient. The first set of equations is as follows: ， in, , in, The gain coefficient of the first observer. This is the gain coefficient of the second observer. This represents the gain coefficient of the third observer. The characteristic angular frequency of the observer, For the first model parameters, For the second model parameters, The closed-loop bandwidth angular frequency of the controller; The first observer gain coefficient, the second observer gain coefficient, the third observer gain coefficient, the first model parameter, the second model parameter, the first voltage estimate of the previous control cycle, the second voltage estimate of the previous control cycle, the external disturbance of the previous control cycle, the output voltage of the previous control cycle, and the switching frequency control signal of the previous control cycle are calculated using the second set of equations to obtain the first voltage estimate of the current control cycle, the second voltage estimate of the current control cycle, and the external disturbance of the current control cycle. The second set of equations is as follows: ， in, For the first The first voltage estimate for each control cycle. For the first The first voltage estimate for each control cycle. To control the total number of cycles, For the first The second voltage estimate for each control cycle The gain coefficient of the first observer. This is the gain coefficient of the second observer. This represents the gain coefficient of the third observer. For the first Output voltage per control cycle For the first The second voltage estimate for each control cycle For the first model parameters, For the second model parameters, For the first External disturbances in each control cycle For control quantity gain coefficient, For the first The switching frequency control signal for each control cycle For the first External disturbances for each control cycle.

4. The LLC resonant converter control method according to claim 1, characterized in that, The process of performing sliding surface analysis on the reference voltage, the first voltage estimate of the current control cycle, and the second voltage estimate of the current control cycle to obtain the sliding surface of the current control cycle includes: The sliding surface of the current control cycle is obtained by calculating the reference voltage, the first voltage estimate of the current control cycle, and the second voltage estimate of the current control cycle using the first formula. The first formula is: ， in, For the first Sliding surface for each control cycle For reference voltage, For the first The second voltage estimate for each control cycle This is the sliding surface weighting coefficient. For the first The first voltage estimate for each control cycle.

5. The LLC resonant converter control method according to claim 1, characterized in that, The process of analyzing the sliding surface of the current control cycle and the external disturbances of the current control cycle to obtain the switching frequency control signal of the current control cycle includes: The nonlinear feedback control value for the current control cycle is obtained by calculating the sliding surface of the current control cycle using a third-party program. The third-party program is: ， in, For the first The nonlinear feedback control value for each control cycle. and All are nonlinear switching gain coefficients. For the first Sliding surface for each control cycle For symbolic functions, For the first The continuous integral control value for each control cycle; The switching frequency control signal for the current control cycle is obtained by calculating the nonlinear feedback control value and the external disturbance of the current control cycle using the second equation. The second equation is: ， in, For the first The switching frequency control signal for each control cycle For control quantity gain coefficient, For the first The nonlinear feedback control value for each control cycle. For the first External disturbances for each control cycle.

6. A control device for an LLC resonant converter, characterized in that, include: The fitting module is used to construct an LLC resonant circuit through an LLC resonant converter, fit the LLC resonant circuit, and obtain a set of model parameters. The estimation update module is used to import the controller closed-loop bandwidth angular frequency, obtain the first voltage estimate, the second voltage estimate, the external disturbance, the output voltage, and the switching frequency control signal of the previous control cycle, and update the model parameter group, the controller closed-loop bandwidth angular frequency, the first voltage estimate, the second voltage estimate, the external disturbance, the output voltage, and the switching frequency control signal of the previous control cycle to obtain the first voltage estimate, the second voltage estimate, and the external disturbance of the current control cycle. The sliding surface analysis module is used to import a reference voltage, perform sliding surface analysis on the reference voltage, the first voltage estimate of the current control cycle, and the second voltage estimate of the current control cycle, and obtain the sliding surface of the current control cycle. The control module is used to analyze the sliding surface of the current control cycle and the external disturbance of the current control cycle to obtain the switching frequency control signal of the current control cycle, and to control the LLC resonant converter according to the switching frequency control signal of the current control cycle.

7. The LLC resonant converter control device according to claim 6, characterized in that, The fitting module includes the following process for fitting the LLC resonant circuit to obtain the model parameter set: The LLC resonant circuit is fitted using the extended description function algorithm to obtain the first model parameters and the second model parameters. A set of model parameters is then obtained using the first model parameters and the second model parameters.

8. The LLC resonant converter control device according to claim 6, characterized in that, The estimation update module updates the model parameter set, the controller closed-loop bandwidth angular frequency, the first voltage estimate of the previous control cycle, the second voltage estimate of the previous control cycle, the external disturbance of the previous control cycle, the output voltage of the previous control cycle, and the switching frequency control signal of the previous control cycle to obtain the first voltage estimate of the current control cycle, the second voltage estimate of the current control cycle, and the external disturbance of the current control cycle. The process includes: The first set of equations is used to calculate the first model parameters, the second model parameters, and the closed-loop bandwidth angular frequency of the controller to obtain the first observer gain coefficient, the second observer gain coefficient, and the third observer gain coefficient. The first set of equations is as follows: ， in, , in, The gain coefficient of the first observer. This is the gain coefficient of the second observer. This represents the gain coefficient of the third observer. The characteristic angular frequency of the observer, For the first model parameters, For the second model parameters, The closed-loop bandwidth angular frequency of the controller; The first observer gain coefficient, the second observer gain coefficient, the third observer gain coefficient, the first model parameter, the second model parameter, the first voltage estimate of the previous control cycle, the second voltage estimate of the previous control cycle, the external disturbance of the previous control cycle, the output voltage of the previous control cycle, and the switching frequency control signal of the previous control cycle are calculated using the second set of equations to obtain the first voltage estimate of the current control cycle, the second voltage estimate of the current control cycle, and the external disturbance of the current control cycle. The second set of equations is as follows: ， in, For the first The first voltage estimate for each control cycle. For the first The first voltage estimate for each control cycle. To control the total number of cycles, For the first The second voltage estimate for each control cycle The gain coefficient of the first observer. This is the gain coefficient of the second observer. This represents the gain coefficient of the third observer. For the first Output voltage per control cycle For the first The second voltage estimate for each control cycle For the first model parameters, For the second model parameters, For the first External disturbances in each control cycle For control quantity gain coefficient, For the first The switching frequency control signal for each control cycle For the first External disturbances for each control cycle.

9. A control device for an LLC resonant converter, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the LLC resonant converter control method as described in any one of claims 1 to 5.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the LLC resonant converter control method as described in any one of claims 1 to 5.

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