Nonlinear control method applied to aviation power supply single-phase half-bridge LCLC resonant converter

Abstract

The invention relates to a nonlinear control method applied to a single-phase half-bridge LCLC resonant converter of an aviation power supply, and belongs to the technical field of power electronic switching power supply control. Comprising the following steps: acquiring output current and output voltage after secondary side rectification of a one-way half-bridge LCLC resonant converter, establishing an original state-space equation, and converting the original state-space equation into a state variable form; designing a sliding-mode observer based on the state variable and a sliding-mode observer theory, and outputting an estimated value of the disturbance variable; designing an intermediate control law based on the estimated value of the disturbance variable, the reference value of the state variable and a finite time backstepping control theory; performing inverse transformation on the intermediate control law to obtain an actual control law of the converter; the actual control law is used as input, and the output voltage of the converter is adjusted by controlling the frequency in real time. According to the invention, the DC output voltage is stabilized when the converter encounters large signal disturbances such as input voltage jump, output voltage jump, load switching, circuit parameter perturbation and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of power electronic switch power supply control, and relates to a nonlinear control method for a unidirectional half-bridge LCLC resonant converter to keep output voltage stable under various large signal disturbances. Background Art

[0002] With the development trend of more / all-electric aircraft, new energy power generation, and high-power integrated circuits, the unidirectional half-bridge LCLC resonant converter has attracted extensive attention in the aviation industry and academic fields due to its high transformation ratio, high efficiency, and high power density. The main advantages of the unidirectional half-bridge LCLC resonant circuit include: 1) It can achieve soft switching effect in a wide range of working range, which helps to solve the problem of increased switching loss caused by large voltage stress on switching devices and improve the efficiency of converter power conversion; 2) The unidirectional half-bridge LCLC resonant converter has a wide step-down capability and has great potential for application in aviation power converters, microgrid distributed power converters, energy storage converters, etc.

[0003] At present, there have been many studies on the control strategy of unidirectional half-bridge LCLC converters, mainly focusing on achieving wide-range voltage output and light-load working state control, but the loads are all assumed to be pure resistive loads by default. However, in the application scenario of more-electric aircraft, a large number of constant power loads (such as electric actuators, motor drivers, etc.) will be connected to the DC bus of the power supply system. These strictly regulated constant power loads have negative impedance and nonlinear characteristics. Among them, negative impedance will reduce the output damping of the aircraft power supply system, causing instability of the control system; and nonlinearity will cause the input and output of the unidirectional half-bridge LCLC converter to present a nonlinear relationship, causing the most common linear PI controller in actual engineering to fail. At the same time, when there are parameter perturbations and load switching in the unidirectional half-bridge LCLC converter, the resonant cavity gain of the unidirectional half-bridge LCLC will change, and the existing PI control method does not consider the adverse effects of load disturbances and parameter perturbations on the converter, so its performance in stabilizing the converter output voltage is poor.

[0004] Through the above analysis, the problems and defects of the existing technology are as follows: the existing control strategies rarely consider the situation where the load of the unidirectional half-bridge LCLC resonant converter is a constant power load, and there is little research on the stability of the unidirectional half-bridge LCLC resonant converter under large signal disturbances such as input voltage jump, output voltage jump, load switching, circuit parameter perturbation, etc. Summary of the invention

[0005] The technical problems to be solved by the present invention are:

[0006] In order to avoid the shortcomings of the prior art, the present invention provides a nonlinear control method for a single-phase half-bridge LCLC resonant converter applied to an aviation power supply, which is used to solve the problem of stabilizing the DC output voltage when the unidirectional half-bridge LCLC resonant converter encounters large signal disturbances such as input voltage jumps, output voltage jumps, load switching, circuit parameter perturbations, etc. when supplying energy to a constant power load (such as a motor driver, an electric actuator, etc.).

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0008] A nonlinear control method for a single-phase half-bridge LCLC resonant converter for an aviation power supply, characterized by comprising:

[0009] S1: Obtain the output current and output voltage after secondary side rectification of the unidirectional half-bridge LCLC resonant converter, establish the original state space equation of the unidirectional half-bridge LCLC resonant converter with the known circuit element parameters, and convert the original state space equation into the state variable form required for the design of the sliding mode observer and the finite time backstepping controller;

[0010] S2: Design a sliding mode observer based on state variables and sliding mode observer theory to output an estimated value of the disturbance variable;

[0011] S3: Design the intermediate control law based on the estimated value of the disturbance variable, the reference value of the state variable and the finite time backstepping control theory;

[0012] S4: Perform inverse transformation on the intermediate control law to obtain the actual control law of the unidirectional half-bridge LCLC resonant converter;

[0013] S5: Taking the actual control law as input, a switching signal with a variable frequency is obtained through a voltage-controlled oscillator as a driving signal for the converter switch tube, and the output voltage of the converter is adjusted by real-time control of the frequency.

[0014] A further technical solution of the present invention is: the conversion of the original state space equation into the state variable form required for the design of the sliding mode observer and the finite time backstepping controller is specifically:

[0015]

[0016] Where x1 = v o , x2=i s / C0 is the state variable, is the disturbance, v0 is the output voltage of the converter, P o is the output power, i s is the output current after secondary side rectification, v s is the secondary equivalent value of the resonant cavity output voltage, L sis the equivalent output inductance after secondary side rectification, L s0 and C0 are the rated inductance and capacitance respectively, η L and η C are the perturbations of inductance and capacitance respectively.

[0017] A further technical solution of the present invention: the sliding mode observer is specifically:

[0018]

[0019] in, and are the estimated values ​​of the state variables x1 and x2, and is the first-order derivative of the state variable estimate, and are estimates of the disturbances d1 and d2, and is the first-order derivative of the estimated value of the disturbance variable, e x1 and e x2 is the state variable error, e d1 and e x2 is the disturbance error, K x1 >0,K x2 >0,K d1 >0,K d2 >0,0<λ1<1,0<λ2<1 are the observer gains.

[0020] A further technical solution of the present invention: the intermediate control law is specifically:

[0021]

[0022] in, is the reference value of the state variable x2, h 11 ,h 12 ,h 21 ,h 22 ,ρ1,ρ2 are the finite time backstepping controller gains, z x1 and z x2 is the state error.

[0023] A further technical solution of the present invention is as follows: the actual control law is calculated based on the intermediate control law, specifically:

[0024]

[0025] Among them, f n =f s / f r is the ratio of the switching frequency to the series resonant angular frequency, h=L r / (L m -1 / 4π 2 C m ) is the ratio of the resonant inductance to the equivalent parallel inductance, Q is the quality factor, L r and L m are the inductance values ​​of resonant inductance and excitation inductance respectively, C r and C m are the capacitances of the resonant capacitor and the excitation capacitor respectively, and n is the transformer ratio.

[0026] A nonlinear control system for a single-phase half-bridge LCLC resonant converter for an aviation power supply, characterized in that it includes a current sensor, a voltage sensor, a state variable calculation module, a sliding mode observer module, a reference value calculation module, a finite time backstepping controller, a control law transformation module and a voltage controlled oscillator module;

[0027] The current sensor is used to obtain the output current of the secondary side of the converter after rectification;

[0028] The voltage sensor is used to obtain the voltage of the converter output capacitor;

[0029] The state variable calculation module calculates the real-time value of the state variable based on the established state space equation of the unidirectional half-bridge LCLC resonant converter;

[0030] The sliding mode observer module is designed based on the state space equation and the design method of the sliding mode observer, and is used to calculate the change of the constant power load;

[0031] The reference value calculation module calculates the reference value of the state variable

[0032] The finite time backstepping controller calculates the state variable reference value based on the system model obtained by the state variable calculation module and the finite time backstepping theory. and the intermediate control law k;

[0033] The inverse transformation module is used to transform the control law in the finite time backstepping control module to calculate the actual control law, that is, the value of the converter switching frequency;

[0034] The voltage-controlled oscillator obtains a converter driving signal with a variable frequency and a fixed duty cycle based on the value of the converter switching frequency obtained by the inverse conversion module, and adjusts the output voltage of the converter by real-time control of the switching frequency.

[0035] An electronic device, comprising:

[0036] processor;

[0037] a memory for storing processor-executable instructions;

[0038] Wherein, the processor is configured to execute the above-mentioned nonlinear control method applied to the single-phase half-bridge LCLC resonant converter of the aviation power supply.

[0039] A computer-readable storage medium having instructions stored thereon, characterized in that when the instructions are executed by a processor, the nonlinear control method for a single-phase half-bridge LCLC resonant converter applied to an aviation power supply is implemented.

[0040] The beneficial effects of the present invention are:

[0041] The existing unidirectional half-bridge LCLC control method is based on the unidirectional half-bridge LCLC topology under resistive load, and seldom pays attention to the case where the load is a constant power load. The present invention provides a nonlinear control method for a single-phase half-bridge LCLC resonant converter for aviation power supply, and establishes a finite time backstepping controller of a sliding mode observer, which can significantly improve the anti-interference ability of the system and effectively suppress the adverse effects of large signal disturbances such as input voltage jump, output voltage jump, load switching, circuit parameter perturbation, etc. on the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like components throughout the drawings.

[0043] Figure 1 It is a circuit structure diagram of a unidirectional half-bridge LCLC resonant converter feeding a constant power load according to an embodiment of the present invention.

[0044] Figure 2 It is a control principle diagram of a finite time backstepping control method based on a sliding mode controller according to an embodiment of the present invention.

[0045] Figure 3 This is a diagram showing the output voltage control effect when the input voltage changes according to the control method of the present invention.

[0046] Figure 4 It is a diagram showing the output voltage control effect when the voltage output reference value changes according to the control method of the present invention.

[0047] Figure 5 It is a comparison chart of the output voltage control effect of the control method of the present invention and the traditional PI control method under the same load change.

[0048] Figure 6 This is a diagram showing the output voltage control effect when the circuit parameters are perturbed by the control method of the present invention. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0050] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchangeable where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0051] In order to enable those skilled in the art to better understand the present invention, the present invention is described in detail below in conjunction with specific embodiments.

[0052] Example 1

[0053] The present invention provides a nonlinear control method for a single-phase half-bridge LCLC resonant converter for an aviation power supply, and the steps are as follows:

[0054] S01, obtaining the output current after secondary side rectification of the unidirectional half-bridge LCLC resonant converter and the output voltage of the capacitor.

[0055] S02, using the output current and output voltage values ​​sampled in S01 and the known circuit element parameters to establish the state space equation of the unidirectional half-bridge LCLC resonant converter required for the sliding mode observer design and the finite time backstepping controller design.

[0056] S03, based on the obtained state space equation, design a sliding mode observer to obtain the output current observation value, save the output current sensor in the system to reduce the volume and weight of the onboard power supply and improve the power density;

[0057] S04, based on the finite-time backstepping control theory, design the intermediate control law; combine the sliding mode observer with the finite-time backstepping control to optimize the control effect.

[0058] S05, inversely transform the intermediate control law to obtain the actual control quantity, that is, the value of the switching frequency of the unidirectional half-bridge LCLC resonant converter, which is used as input, and then the changing switching frequency is obtained through the voltage-controlled oscillator as the driving signal of the converter switch tube, and the output voltage of the converter is adjusted by real-time control of the normalized frequency.

[0059] In a specific embodiment, the current modeling methods of various LC series resonant converters often use the average period method or the extended description method. The former is no longer applicable because the voltage and current in the resonant cavity of the resonant converter show a nonlinear change relationship, and the converter model established by the latter is a high-order mathematical model, which is not conducive to controller design and system stability analysis. Therefore, it is necessary to convert the system high-order mathematical model into an equivalent low-order mathematical model, and rewrite the low-order model into the state space standard form required for the sliding mode observer design and the finite time backstepping controller design.

[0060] This method uses a reduced-order model derived from a full-order model and transforms the reduced-order model into the form required for sliding mode observer design and finite-time backstepping controller design:

[0061]

[0062] Where v0 is the output voltage of the converter, P o is the output power, i s is the output current after secondary side rectification, v s is the secondary equivalent value of the resonant cavity output voltage, C is the output capacitance, L s is the equivalent output inductance after secondary side rectification, L s Can be equivalent to:

[0063]

[0064] Among them, L r and L m are the inductance values ​​of resonant inductance and excitation inductance respectively, C m is the capacitance of the excitation capacitor.

[0065] Considering that there is a deviation between the actual value and the rated value of the equivalent output inductance and output capacitance of the secondary side of the unidirectional half-bridge LCLC resonant converter due to circuit aging, the present invention takes into account the perturbation of the inductance and capacitance values, and expresses the actual inductance and capacitance values ​​as follows:

[0066]

[0067] Among them, L s and C are the actual inductance and capacitance values, L s0 and C0 rated inductance and capacitance, η L =ΔLs / L s0 and η C =ΔC / C0 represents the perturbation of inductance and capacitance.

[0068] Convert the reduced-order model into the form required for sliding mode observer and finite-time backstepping controller design:

[0069]

[0070] where x1 = v o , x2=i s / C0 is the state variable, is the disturbance quantity, which is mainly composed of load power, output voltage and parameter uncertainties.

[0071] Furthermore, a suitable sliding mode observer is designed to obtain the output current value. On the one hand, the number of current sensors can be saved to improve the power density. On the other hand, the observation value of the disturbance information can help provide a fast dynamic response to external disturbances. The design of the sliding mode observer in the present invention is as follows:

[0072]

[0073] in, and are the estimated values ​​of the state variables x1 and x2, and are the estimates of the disturbances d1 and d2, K x1 >0,K x2 >0,K d1 >0,K d2 >0,0<λ1<1,0<λ2<1 are the observer gains.

[0074] Furthermore, according to the finite-time backstepping control theory, a finite-time backstepping control law is designed.

[0075] First, a new set of state variable error functions are defined:

[0076]

[0077] Among them, z x1 and z x2 is the state error, and is the reference value of the state variable. Since the state variable x1 is the output voltage v o , so its reference value is the desired output voltage Right now

[0078] According to the Lyapunov error function, the reference values ​​of the state variables are obtained respectively is the intermediate control law k.

[0079]

[0080] Taking the derivative of V we get

[0081]

[0082] According to the finite time backstepping control theory, in order to make Converges to zero, the designed state variable reference value The and intermediate control laws k are:

[0083]

[0084] at this time, It can be expressed as

[0085]

[0086] When the finite-time backstepping controller gain h 11 ,h 12 ,h 21 ,h 22 When ρ1 and ρ2 take appropriate values, It converges to zero in a finite time, and we can get

[0087]

[0088] When satisfied When x2 The static error can converge to 0, and the intermediate control law k can be adjusted to make the converter output voltage equal to the reference voltage value.

[0089] Furthermore, the actual control variable switching frequency f is obtained from the intermediate control law k s Since the unidirectional half-bridge LCLC resonant converter uses variable frequency control, the actual control signal is the normalized frequency f n The intermediate control law k and the actual control law f can be obtained n The relationship is:

[0090]

[0091] Among them, f n =f s / f r is the ratio of the switching frequency to the series resonant angular frequency, h=L r / (L m -1 / 4π 2 C m) is the ratio of the resonant inductance to the equivalent parallel inductance, and Q is the quality factor.

[0092] Substituting the intermediate control law k obtained by the control system into this equation, the normalized frequency f can be calculated n value, and use a voltage-controlled oscillator to generate a PWM signal as the control signal of the switch tube.

[0093] Example 2

[0094] Corresponding to the finite time backstepping control method based on sliding mode observer for a unidirectional half-bridge LCLC resonant converter feeding a constant power load provided in the above embodiment, a specific embodiment of the present invention further provides a finite time backstepping control system based on sliding mode observer for a unidirectional half-bridge LCLC resonant converter feeding a constant power load. The control system includes: a current sensor, a voltage sensor, a state variable calculation module, a reference value calculation module, a sliding mode observer module, a finite time backstepping controller, a control law conversion module and a voltage controlled oscillator module.

[0095] The current sensor is used to obtain the output current of the secondary side of the converter after rectification;

[0096] The voltage sensor is used to obtain the voltage of the converter output capacitor;

[0097] The state variable calculation module calculates the real-time value of the state variable based on the established state space model of the unidirectional half-bridge LCLC resonant converter;

[0098] The sliding mode observer module is designed based on the state space model and the design method of the sliding mode observer, and is used to calculate the change of the constant power load;

[0099] The reference value calculation module calculates the reference value of the state variable

[0100] The finite time backstepping controller calculates the state variable reference value based on the system model obtained by the state variable calculation module and the finite time backstepping theory. and the intermediate control law k;

[0101] The inverse transformation module is used to transform the control law in the finite time backstepping control module and calculate the actual control law, that is, the value of the converter switching frequency.

[0102] The voltage-controlled oscillator obtains a converter driving signal with a variable frequency and a fixed duty cycle based on the value of the converter switching frequency obtained by the inverse conversion module, and adjusts the output voltage of the converter by real-time control of the switching frequency.

[0103] The control method of this system includes:

[0104] Step 1, using the sampled current and voltage values ​​and known circuit component parameters to establish the original state space equation of the unidirectional half-bridge LCLC resonant converter.

[0105] Step 2, for the established unidirectional half-bridge LCLC resonant converter model, while considering the circuit parameter perturbation, establish a state space form required for converting the original state space equation into the sliding mode observer design and the finite time backstepping controller design;

[0106] Step 3, design a sliding mode observer for the state space equation obtained in step 2; calculate the reference value of the state quantity based on the estimated quantity of the sliding mode observer for finite time backstepping control; design an intermediate control law based on the finite time backstepping control theory.

[0107] Step 4, the intermediate control law obtained in step 3 is transformed inversely to obtain the actual control law of the unidirectional half-bridge LCLC resonant converter, which is used as input, and then a switching signal with a variable frequency is obtained through a voltage-controlled oscillator as the driving signal of the converter switch tube, and the output voltage of the converter is adjusted by real-time control of the frequency.

[0108] Step 1:

[0109] In a specific embodiment, the method uses a reduced-order model derived from a full-order model, and converts the reduced-order model into the form required for the design of a sliding mode observer and a finite-time backstepping controller:

[0110]

[0111] Where v0 is the output voltage of the converter, P o is the output power, i s is the output current after secondary side rectification, v s is the secondary equivalent value of the resonant cavity output voltage, C is the output capacitance, L s is the equivalent output inductance after secondary side rectification, L s Can be equivalent to:

[0112]

[0113] Among them, L r and L m are the inductance values ​​of resonant inductance and excitation inductance respectively, C m is the capacitance of the excitation capacitor.

[0114] Considering that there is a deviation between the actual value and the rated value of the output electric value and the output capacitance of the unidirectional half-bridge LCLC resonant converter due to circuit aging, the present invention takes into account the perturbation of the inductance value and the capacitance value, and expresses the actual inductance value and the capacitance value as follows:

[0115]

[0116] Among them, L s and C are the actual inductance and capacitance values, L s0 and C0 rated inductance and capacitance, η L =ΔL s / L s0 and η C =ΔC / C0 represents the perturbation of inductance and capacitance.

[0117] Step 2:

[0118] The sliding mode observer and finite time backstepping controller are designed based on the following form:

[0119]

[0120] where x1 = v o , x2=i s / C0 is the state variable is the disturbance quantity, which is mainly composed of load power, output voltage and parameter uncertainties.

[0121] Step 3:

[0122] In order to eliminate the impact of load power changes on the output voltage, disturbance information needs to be obtained. Designing a suitable sliding mode observer not only helps to provide a fast dynamic response to external disturbances, but also reduces the number of output current sensors. The design of the sliding mode observer is as follows:

[0123]

[0124] in, and are the estimated values ​​of the state variables x1 and x2, and are the estimates of the disturbances d1 and d2, K x1 >0,K x2 >0,K d1 >0,K d2 >0,0<λ1<1,0<λ2<1 are the observer gains.

[0125] Furthermore, according to the finite time backstepping control theory, a finite time backstepping control law is designed. First, a set of new state variable error functions are defined:

[0126]

[0127] Among them, z x1 and z x2 is the state error, and is the reference value of the state variable. is the output voltage v o , so its reference value is the desired output voltage

[0128] According to the Lyapunov error function, the reference values ​​are obtained respectively and the intermediate control quantity k.

[0129]

[0130] Taking the derivative of V we get

[0131]

[0132] According to the finite time backstepping control theory, in order to make V converge to zero, the reference value designed is The and intermediate control laws k are:

[0133]

[0134] at this time, It can be expressed as

[0135]

[0136] When the finite-time backstepping controller gain h 11 ,h 12 ,h 21 ,h 22 When ρ1 and ρ2 take appropriate values, It converges to zero in a finite time, and we can get

[0137]

[0138] When satisfied When x2 The static error can converge to 0, and the intermediate control law k can be controlled to make the converter output voltage equal to the reference voltage value.

[0139] Step 4:

[0140] The actual control variable switching frequency f is obtained from the intermediate control law k s Since the unidirectional half-bridge LCLC resonant converter uses variable frequency control, the actual control signal is the normalized frequency f n The intermediate control law k and the actual control law f can be obtained n The relationship is:

[0141]

[0142] Among them, f n =f s / f r is the ratio of the switching frequency to the series resonant angular frequency, h=L r / (L m -1 / 4π 2 C m ) is the ratio of the resonant inductance to the equivalent parallel inductance, and Q is the quality factor.

[0143] Substituting the intermediate control law k obtained by the control system into this equation, the normalized frequency f can be calculated n value, and use a voltage-controlled oscillator to generate a PWM signal as the control signal of the switch tube.

[0144] The effects of this application are described in detail below in conjunction with simulation.

[0145] Simulation conditions

[0146] The present invention is a simulation performed by using MATLAB / Simulink software on a central processing unit of Intel(R) Core(TM) Ultra 7 155H 1.40GHz, a memory of 32G, and a WINDOWS10 operating system.

[0147] In Matlab / Simulink, the nonlinear control method proposed in the present invention for the single-phase half-bridge LCLC resonant converter applied to aviation power supply is simulated and verified to confirm its effectiveness. All simulations are performed under the condition that the unidirectional half-bridge LCLC resonant converter feeds a pure constant power load.

[0148] First verify that there is an input voltage V in Mutation situation. Figure 3 As shown, a step change is added to the input voltage at t=0.2s (from 270V to 240V) and t=0.3s (from 240V to 300V), respectively, and the proposed controller still stabilizes the output voltage at its reference value.

[0149] Then the output voltage reference value V0 is verified ref Mutation situation. Figure 4 As shown in the figure, the step changes are added to the output voltage reference value at t = 0.2s (from 48V to 36V) and t = 0.3s (from 36V to 24V). After experiencing a small fluctuation, the output voltage quickly tracks the reference voltage.

[0150] The proposed control method is then compared with the traditional PI controller. Figure 5The output response of the unidirectional half-bridge LCLC resonant converter controlled by the method of the present invention and the conventional PI under the same constant power load power change is shown. It can be seen that at 0.4s, when the power of the constant power load rises to 500W, the unidirectional half-bridge LCLC converter controlled by the conventional PI loses output stability, and the controller designed by the method maintains the output stability of the unidirectional half-bridge LCLC converter. And compared with PI control, when the controller of the present invention is used, the system output has a faster response speed.

[0151] Finally, the perturbation of the circuit rated parameters is verified. Figure 6 As shown, the secondary side equivalent inductance of the unidirectional half-bridge LCLC resonant converter is set to 1.2L s0 , the output capacitor is set to 0.8C0, keeping the same Figure 5 The same constant power load power changes. It can be seen that when there is a circuit parameter perturbation in the unidirectional half-bridge LCLC resonant converter, the controller of the present invention ensures that the system maintains a similar dynamic response speed.

[0152] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should be included in the protection scope of the present invention.

Claims

1. A nonlinear control method for a single-phase half-bridge LCLC resonant converter for an aviation power supply, characterized in that: include: S1: Obtain the output current and output voltage after secondary side rectification of the unidirectional half-bridge LCLC resonant converter, establish the original state space equation of the unidirectional half-bridge LCLC resonant converter with the known circuit element parameters, and convert the original state space equation into the state variable form required for the design of the sliding mode observer and the finite time backstepping controller; S2: Design a sliding mode observer based on state variables and sliding mode observer theory to output an estimated value of the disturbance variable; S3: Design the intermediate control law based on the estimated value of the disturbance variable, the reference value of the state variable and the finite time backstepping control theory; S4: Perform inverse transformation on the intermediate control law to obtain the actual control law of the unidirectional half-bridge LCLC resonant converter; S5: Taking the actual control law as input, a switching signal with a variable frequency is obtained through a voltage-controlled oscillator as a driving signal for the converter switch tube, and the output voltage of the converter is adjusted by real-time control of the frequency.

2. According to claim 1, a nonlinear control method for a single-phase half-bridge LCLC resonant converter for an aviation power supply is characterized in that: The original state space equation is converted into the state variable form required for the design of the sliding mode observer and the finite time backstepping controller, specifically: Where x1 = v o , x2=i s / C0 is the state variable, is the disturbance, v0 is the output voltage of the converter, P o is the output power, i s is the output current after secondary side rectification, v s is the secondary equivalent value of the resonant cavity output voltage, L s is the equivalent output inductance after secondary side rectification, L s0 and C0 are the rated inductance and capacitance respectively, η L and η C are the perturbations of inductance and capacitance respectively.

3. According to claim 2, a nonlinear control method for a single-phase half-bridge LCLC resonant converter for an aviation power supply is characterized in that: The sliding mode observer is specifically: in, and are the estimated values ​​of the state variables x1 and x2, and is the first-order derivative of the state variable estimate, and are estimates of the disturbances d1 and d2, and is the first-order derivative of the estimated value of the disturbance variable, e x1 and e x2 is the state variable error, e d1 and e x2 is the disturbance error, K x1 >0,K x2 >0,K d1 >0,K d2 >0,0<λ1<1,0<λ2<1 are the observer gains.

4. According to claim 3, a nonlinear control method for a single-phase half-bridge LCLC resonant converter for an aviation power supply is characterized in that: The intermediate control law is specifically: in, is the reference value of the state variable x2, h 11 ,h 12 ,h 21 ,h 22 ,ρ1,ρ2 are the finite time backstepping controller gains, z x1 and z x2 is the state error.

5. According to claim 4, a nonlinear control method for a single-phase half-bridge LCLC resonant converter for an aviation power supply is characterized in that: The actual control law is calculated based on the intermediate control law, specifically: Among them, f n =f s / f r is the ratio of the switching frequency to the series resonant angular frequency, h=L r / (L m -1 / 4π 2 C m ) is the ratio of the resonant inductance to the equivalent parallel inductance, Q is the quality factor, L r and L m are the inductance values ​​of resonant inductance and excitation inductance respectively, C r and C m are the capacitances of the resonant capacitor and the excitation capacitor respectively, and n is the transformer ratio.

6. A nonlinear control system for a single-phase half-bridge LCLC resonant converter for aviation power supply, characterized in that: It includes a current sensor, a voltage sensor, a state variable calculation module, a sliding mode observer module, a reference value calculation module, a finite time backstepping controller, a control law transformation module and a voltage controlled oscillator module; The current sensor is used to obtain the output current of the secondary side of the converter after rectification; The voltage sensor is used to obtain the voltage of the converter output capacitor; The state variable calculation module calculates the real-time value of the state variable based on the established state space equation of the unidirectional half-bridge LCLC resonant converter; The sliding mode observer module is designed based on the state space equation and the design method of the sliding mode observer, and is used to calculate the change of the constant power load; The reference value calculation module calculates the reference value of the state variable The finite time backstepping controller calculates the state variable reference value based on the system model obtained by the state variable calculation module and the finite time backstepping theory. and intermediate control law k; The inverse transformation module is used to transform the control law in the finite time backstepping control module to calculate the actual control law, that is, the value of the converter switching frequency; The voltage-controlled oscillator obtains a converter driving signal with a variable frequency and a fixed duty cycle based on the value of the converter switching frequency obtained by the inverse conversion module, and adjusts the output voltage of the converter by real-time control of the switching frequency.

7. An electronic device, characterized in that: include: processor; a memory for storing processor-executable instructions; Wherein, the processor is configured to execute the nonlinear control method applied to the single-phase half-bridge LCLC resonant converter of the aviation power supply as described in any one of claims 1 to 5.

8. A computer-readable storage medium having instructions stored thereon, characterized in that: When the instructions are executed by the processor, the nonlinear control method for a single-phase half-bridge LCLC resonant converter for an aviation power supply as described in any one of claims 1 to 5 is implemented.

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