Nonlinear control method applied to single-phase half-bridge LCLC resonant converters in aviation power supplies

Abstract

This invention relates to a nonlinear control method for a single-phase half-bridge LCLC resonant converter in aviation power supplies, belonging to the field of power electronic switching power supply control technology. The method includes: acquiring the output current and output voltage after rectification on the secondary side of the single-phase half-bridge LCLC resonant converter; establishing the original state-space equations and converting them into state-variable form; designing a sliding mode observer based on the state variables and sliding mode observer theory to output 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 finite-time backstepping control theory; performing an inverse transformation on the intermediate control law to obtain the actual control law of the converter; and using the actual control law as input to adjust the converter's output voltage through real-time frequency control. This invention solves the problem of stabilizing the DC output voltage when the converter encounters large-signal disturbances such as input voltage jumps, output voltage jumps, load switching, and circuit parameter perturbations.

Description

Technical Field

[0001] This invention belongs to the field of power electronic switching power supply control technology, and relates to a nonlinear control method for maintaining stable output voltage of a unidirectional half-bridge LCLC resonant converter under various large signal disturbances. Background Technology

[0002] With the development trends of multi-electric / all-electric aircraft, new energy power generation, and high-power integrated circuits, unidirectional half-bridge LCLC resonant converters have attracted widespread attention from the aerospace industry and academia due to their high transformation ratio, high efficiency, and high power density. The main advantages of unidirectional half-bridge LCLC resonant circuits include: 1) They can achieve soft-switching effects over a wide operating range, helping to solve the problem of increased switching losses caused by high voltage stress on switching devices, thus improving the power conversion efficiency of the converter; 2) Unidirectional half-bridge LCLC resonant converters have a wide voltage reduction capability, showing great potential for applications in aerospace power converters, microgrid distributed power converters, and energy storage converters.

[0003] Existing research on control strategies for unidirectional half-bridge LCLC converters has yielded numerous studies, primarily focusing on achieving wide-range voltage output and control under light-load conditions, but all loads are assumed to be purely resistive. However, in multi-electric aircraft applications, numerous constant-power loads (such as electric actuators and motor drivers) are connected to the DC bus of the power supply system. These strictly regulated constant-power loads exhibit negative impedance and nonlinear characteristics. Negative impedance reduces the output damping of the aircraft power supply system, causing instability in the control system; while nonlinearity causes a nonlinear relationship between the input and output of the unidirectional half-bridge LCLC converter, leading to the failure of the linear PI controller, which is most commonly used in practical engineering. Furthermore, when the unidirectional half-bridge LCLC converter experiences parameter perturbations and load switching, the resonant cavity gain changes. Existing PI control methods do not consider the adverse effects of load disturbances and parameter perturbations on the converter, resulting in poor performance in stabilizing the converter's output voltage.

[0004] Based on the above analysis, the problems and defects of the existing technology are as follows: the existing control strategies rarely consider the case 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 jumps, output voltage jumps, load switching, and circuit parameter perturbations. Summary of the Invention

[0005] The technical problem to be solved by this invention is:

[0006] To overcome the shortcomings of existing technologies, this invention provides a nonlinear control method for a single-phase half-bridge LCLC resonant converter in aviation power supplies. This method is used to stabilize the DC output voltage when the single-phase half-bridge LCLC resonant converter supplies power to a constant power load (such as a motor driver, an electric actuator, etc.) and encounters large signal disturbances such as input voltage jumps, output voltage jumps, load switching, and circuit parameter perturbations.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

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

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

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

[0011] S3: Design intermediate control laws based on the estimated values ​​of disturbance variables, reference values ​​of state variables, and finite-time backstepping control theory;

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

[0013] S5: The actual control law is used as input, and a switching signal with a changing frequency is obtained through a voltage-controlled oscillator as the drive signal for the converter's switching transistor. The output voltage of the converter is adjusted by real-time control of the frequency.

[0014] A further technical solution of the present invention: the conversion of the original state-space equations into the state variable form required for the design of sliding mode observers and finite-time backstepping controllers specifically involves:

[0015]

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

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

[0018]

[0019] in, and These are the estimated values ​​of state variables x1 and x2. and It is the first derivative of the estimated state variable. and These are the estimated values ​​of the disturbances d1 and d2. and It is the first derivative of the estimated value of the disturbance variable, e x1 and e x2 It is the error of the state variable, e d1 and e x2 It 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 as follows:

[0021]

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

[0023] A further technical solution of the present invention: the calculation of the actual control law based on the intermediate control law specifically includes:

[0024]

[0025] Among them, f n =f s / f r It 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 resonant inductance to equivalent parallel inductance, Q is the quality factor, and L is the ratio of resonant inductance to equivalent parallel inductance. r and L m C represents the inductance values ​​of the resonant inductance and the magnetizing inductance, respectively. r and C m These are the capacitance values ​​of the resonant capacitor and the excitation capacitor, respectively, and n is the transformer turns ratio.

[0026] A nonlinear control system for a single-phase half-bridge LCLC resonant converter in aviation power supply is characterized by comprising 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 acquire the output current of the converter's secondary side after rectification;

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

[0029] The state variable calculation module calculates the real-time values ​​of the state variables based on the established state-space equations 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 changes of 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 reference value of the state variable based on the system model obtained from the state variable calculation module and the finite-time backstepping theory. and intermediate control law k;

[0033] The inverse transformation module is used to transform the control law in the finite-time backstepping control module and calculate the actual control law, i.e., the value of the converter switching frequency.

[0034] The voltage-controlled oscillator (VCO) obtains a converter drive signal with a variable frequency and fixed duty cycle based on the converter switching frequency value obtained by the inverse conversion module. By controlling the switching frequency in real time, the output voltage of the converter is adjusted.

[0035] An electronic device, characterized in that it comprises:

[0036] processor;

[0037] Memory used to store processor-executable instructions;

[0038] The processor is configured to execute the aforementioned nonlinear control method applied to a single-phase half-bridge LCLC resonant converter for aviation power supplies.

[0039] A computer-readable storage medium storing instructions, characterized in that, when executed by a processor, the instructions implement the aforementioned nonlinear control method applied to a single-phase half-bridge LCLC resonant converter for aviation power supplies.

[0040] The beneficial effects of this invention are as follows:

[0041] Existing single-phase half-bridge LCLC control methods are based on the single-phase half-bridge LCLC topology under resistive loads, and rarely consider the case where the load is a constant power load. This invention provides a nonlinear control method for single-phase half-bridge LCLC resonant converters in aviation power supplies. By establishing a finite-time backstepping controller with a sliding mode observer, the method can significantly improve the system's anti-interference capability and effectively suppress the adverse effects of large-signal disturbances such as input voltage jumps, output voltage jumps, load switching, and circuit parameter perturbations on the system. Attached Figure Description

[0042] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0043] Figure 1 This is a circuit 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 This is a control principle diagram of the 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 of the control method of the present invention when the input voltage changes.

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

[0047] Figure 5 This is a comparison chart of the output voltage control effects of the control method of this invention and the traditional PI control method under the same load variation.

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

[0049] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this 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, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0051] To enable those skilled in the art to better understand the present invention, the present invention will be described in detail below with reference to specific embodiments.

[0052] Example 1

[0053] This invention provides a nonlinear control method for a single-phase half-bridge LCLC resonant converter in aviation power supplies, comprising the following steps:

[0054] S01, obtain the output current and capacitor output voltage after rectification on the secondary side of the single-phase half-bridge LCLC resonant converter.

[0055] S02 uses the output current and output voltage values ​​obtained from the sampling in S01, and the known circuit element parameters to establish the state-space equations 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, a sliding mode observer is designed to obtain the output current observation value, saving the output current sensor in the system to reduce the size and weight of the airborne power supply and increase the power density.

[0057] S04. Based on the finite-time backstepping control theory, an intermediate control law is designed; the effect of control is optimized by combining the sliding mode observer with the finite-time backstepping control.

[0058] S05, the intermediate control law is inversely transformed to obtain the actual control quantity, that is, the value of the switching frequency of the single-phase half-bridge LCLC resonant converter. This value is used as the input, and the voltage-controlled oscillator is used to obtain the changing switching frequency as the driving signal of the converter switching transistor. The output voltage of the converter is adjusted by real-time control of the normalized frequency.

[0059] In specific embodiments, the current modeling methods for various LC series resonant converters often employ 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 exhibit nonlinear changes, while the latter establishes a high-order mathematical model, which is not conducive to controller design and system stability analysis. Therefore, it is necessary to transform the high-order mathematical model of the system into an equivalent low-order mathematical model, and rewrite the low-order model into the standard state-space form required for sliding mode observer design and finite-time backstepping controller design.

[0060] This method uses a reduced-order model derived from the 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 For output power, i s The output current after secondary rectification, v s The voltage is the equivalent value of the secondary side of the resonant cavity output voltage, C is the output capacitance, and L is the capacitance. s L is the equivalent output inductance after secondary-side rectification. s This can be equivalent to:

[0063]

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

[0065] Considering the deviation between the actual and rated values ​​of the equivalent output inductance and output capacitance on the secondary side of a single-phase half-bridge LCLC resonant converter due to circuit aging, this 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 C represents the actual inductance and actual capacitance values, and L represents the actual capacitance value. s0 And C0 rated inductance and capacitance values, η L =ΔLs / L s0 and η C =ΔC / C0 represents the perturbation of the inductance and capacitance values.

[0068] Transform the reduced-order model into the form required for designing sliding mode observers and finite-time backstepping controllers:

[0069]

[0070] Where x1 = v o x2 = i s / C0 is a state variable. The disturbance is mainly composed of uncertainties in load power, output voltage, and parameters.

[0071] Furthermore, designing a suitable sliding mode observer to acquire the output current value not only saves on the number of current sensors, thus increasing power density, but also provides observational data on disturbance information, which helps to provide a fast dynamic response to external disturbances. The sliding mode observer in this invention is designed as follows:

[0072]

[0073] in, and These are the estimated values ​​of state variables x1 and x2. and These are the estimated values ​​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, based on the finite-time backstepping control theory, a finite-time backstepping control law is designed.

[0075] First, define a new set of error functions for the state variables:

[0076]

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

[0078] Based on the Lyapunov error function, the reference values ​​of the state variables are obtained respectively. Let k be the intermediate control law.

[0079]

[0080] Differentiating with respect to V, we get

[0081]

[0082] According to the finite-time backstepping control theory, in order to make Converging to zero, the designed state variable reference value Let the intermediate control law k be:

[0083]

[0084] at this time, It can be represented 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, they can be... It converges to zero in a finite time, at which point we can obtain

[0087]

[0088] When satisfied At that time, z 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 quantity, switching frequency f, is obtained from the intermediate control law k. s Because the unidirectional half-bridge LCLC resonant converter uses a variable frequency control method, 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 relation is:

[0090]

[0091] Among them, f n =f s / f r It 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 resonant inductance to equivalent parallel inductance, and Q is the quality factor.

[0092] Substituting the intermediate control law k obtained from the control system into this equation, the normalized frequency f can be calculated. n The value is determined, and a voltage-controlled oscillator is used to generate a PWM signal as the control signal for the switching transistor.

[0093] Example 2

[0094] Corresponding to the finite-time backstepping control method based on a sliding mode observer for feeding a constant power load using a unidirectional half-bridge LCLC resonant converter provided in the above embodiments, this invention also provides a finite-time backstepping control system based on a sliding mode observer for feeding a constant power load using a unidirectional half-bridge LCLC resonant converter. 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 transformation module, and a voltage-controlled oscillator module.

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

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

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

[0098] The sliding mode observer module, designed based on the state-space model and the sliding mode observer design method, is used to calculate the changes in 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 reference value of the state variable based on the system model obtained from the state variable calculation module and the finite-time backstepping theory. and 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, i.e., the value of the converter switching frequency.

[0102] The voltage-controlled oscillator (VCO) obtains a converter drive signal with a variable frequency and fixed duty cycle based on the converter switching frequency value obtained by the inverse conversion module. By controlling the switching frequency in real time, the output voltage of the converter is adjusted.

[0103] The control methods of this system include:

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

[0105] Step 2: For the established unidirectional half-bridge LCLC resonant converter model, while considering circuit parameter perturbations, establish the state-space form required to transform the original state-space equations into the state-space form required for sliding mode observer design and finite-time backstepping controller design.

[0106] Step 3: Design a sliding mode observer for the state-space equations obtained in Step 2; calculate reference values ​​of the state variables based on the estimates of the sliding mode observer for finite-time backstepping control; design intermediate control laws according to finite-time backstepping control theory.

[0107] Step 4: The intermediate control law obtained in step 3 is inversely transformed to obtain the actual control law of the unidirectional half-bridge LCLC resonant converter. This law is used as input, and the voltage-controlled oscillator is used to obtain a switching signal with a changing frequency as the driving signal for the converter's switching transistors. The output voltage of the converter is adjusted by real-time frequency control.

[0108] Step 1:

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

[0110]

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

[0112]

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

[0114] Considering the deviation between the actual and rated values ​​of the output voltage and output capacitance of a single-phase half-bridge LCLC resonant converter due to circuit aging, this invention takes into account the perturbation of the inductance and capacitance values, and expresses the actual inductance and capacitance values ​​as follows:

[0115]

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

[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 a state variable The disturbance is mainly composed of uncertainties in load power, output voltage, and parameters.

[0121] Step 3:

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

[0123]

[0124] in, and These are the estimated values ​​of state variables x1 and x2. and These are the estimated values ​​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, based on finite-time backstepping control theory, a finite-time backstepping control law is designed. First, a new set of state variable error functions is defined:

[0126]

[0127] Among them, z x1 and z x2 For state error, and This serves as a reference value for the state variable. Because the state variable... For the output voltage v o Therefore, its reference value is the desired output voltage.

[0128] Based on the Lyapunov error function, the reference values ​​are obtained respectively. And intermediate control quantity k.

[0129]

[0130] Differentiating with respect to V, we get

[0131]

[0132] According to the finite-time backstepping control theory, in order to make V converge to zero, the designed reference value is... Let the intermediate control law k be:

[0133]

[0134] at this time, It can be represented 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, they can be... It converges to zero in a finite time, at which point we can obtain

[0137]

[0138] When satisfied At that time, z 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 quantity, switching frequency f, is obtained from the intermediate control law k. s Because the unidirectional half-bridge LCLC resonant converter uses a variable frequency control method, 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 relation is:

[0141]

[0142] Among them, f n =f s / f r It 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 resonant inductance to equivalent parallel inductance, and Q is the quality factor.

[0143] Substituting the intermediate control law k obtained from the control system into this equation, the normalized frequency f can be calculated. n The value is determined, and a voltage-controlled oscillator is used to generate a PWM signal as the control signal for the switching transistor.

[0144] The following is a detailed description of the effects of this application, using simulation results.

[0145] Simulation conditions

[0146] This invention is a simulation performed using MATLAB / Simulink software on a CPU consisting of an Intel(R) Core(TM) Ultra 7 155H 1.40GHz processor, 32GB of RAM, and a Windows 10 operating system.

[0147] The nonlinear control method proposed in this invention, applied to a single-phase half-bridge LCLC resonant converter for aviation power supplies, was simulated and verified in Matlab / Simulink to confirm its effectiveness. All simulations were performed under the condition that the single-phase half-bridge LCLC resonant converter was feeding a pure constant power load.

[0148] First, verify the existence of the input voltage V. in Cases of mutation. For example... Figure 3 As shown, when step changes are applied to the input voltage at t = 0.2s (from 270V to 240V) and t = 0.3s (from 240V to 300V), the proposed controller still stabilizes the output voltage at its reference value.

[0149] Then the output voltage reference value V0 was verified. ref Cases of mutation. For example... Figure 4 As shown, step changes were added to the output voltage reference value at t = 0.2s (from 48V to 36V) and t = 0.3s (from 36V to 24V), respectively. After experiencing small fluctuations, the output voltage quickly tracked the reference voltage again.

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

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

[0152] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the scope of the technology disclosed in the present invention, and such modifications or substitutions should all be covered within the scope of protection of the present invention.

Claims

1. A nonlinear control method for a single-phase half-bridge LCLC resonant converter in aviation power supplies, characterized in that, include: S1: Obtain the output current and output voltage after rectification on the secondary side of the unidirectional half-bridge LCLC resonant converter, and establish the original state space equation of the unidirectional half-bridge LCLC resonant converter with the known circuit component parameters. Then, convert the original state space equation into the state variable form required for the design of the sliding mode observer and finite-time backstepping controller. The process of converting the original state-space equations into the state variable form required for the design of sliding mode observers and finite-time backstepping controllers is as follows: in, , For state variables, , For the disturbance quantity, The output voltage of the converter. For output power, The output current is the result of rectification on the secondary side. This is the equivalent value of the secondary side output voltage of the resonant cavity. The equivalent output inductance after secondary-side rectification. and Rated inductance and capacitance values and These are the perturbations of the inductance and capacitance values, respectively. For intermediate control quantities; S2: Design a sliding mode observer based on state variables and sliding mode observer theory to output the estimated value of the disturbance variable; S3: Design an intermediate control law based on the estimated values ​​of the disturbance variables, the reference values ​​of the state variables, and finite-time backstepping control theory; the intermediate control law is specifically as follows: in, State variables Reference value, , , , , , For the finite-time backstepping controller gain, and For state error, and It is a disturbance and The estimated value; S4: Perform an inverse transformation on the intermediate control law to obtain the actual control law of the unidirectional half-bridge LCLC resonant converter; S5: The actual control law is used as input, and a switching signal with a changing frequency is obtained through a voltage-controlled oscillator as the drive signal for the converter's switching transistor. The output voltage of the converter is adjusted by real-time control of the frequency.

2. The nonlinear control method for a single-phase half-bridge LCLC resonant converter in aviation power supply according to claim 1, characterized in that, The sliding mode observer is specifically: in, and It is a state variable and The estimated value, and It is the first derivative of the estimated state variable. and It is the first derivative of the estimated value of the disturbance variable. and It is a state variable error. and It is a disturbance error. , , , , , It is the observer gain.

3. The nonlinear control method for a single-phase half-bridge LCLC resonant converter in aviation power supply according to claim 2, characterized in that, The calculation of the actual control law based on the intermediate control law is specifically as follows: in, It is the ratio of the switching frequency to the series resonant angular frequency. , It is the ratio of resonant inductance to equivalent parallel inductance. Q It is the quality factor. and These are the inductance values ​​of the resonant inductor and the magnetizing inductor, respectively. and These are the capacitance values ​​of the resonant capacitor and the magnetizing capacitor, respectively. n This refers to the transformer turns ratio.

4. A nonlinear control system for a single-phase half-bridge LCLC resonant converter in aviation power supplies, 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 acquire the output current of the converter's secondary side after rectification; The voltage sensor is used to acquire the voltage of the converter output capacitor; The state variable calculation module calculates the real-time values ​​of the state variables based on the established state-space equations 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 changes of constant power load. The reference value calculation module calculates the reference value of the state variable. ; The finite-time backstepping controller calculates the reference value of the state variable based on the system model obtained from the state variable calculation module and the finite-time backstepping theory. and intermediate control law ; The control law transformation module is used to transform the control law in the finite-time backstepping control module and calculate the actual control law, i.e., the value of the converter switching frequency. The voltage-controlled oscillator (VCO) obtains a converter drive signal with a variable frequency and fixed duty cycle based on the converter switching frequency value obtained by the inverse conversion module. By controlling the switching frequency in real time, the output voltage of the converter is adjusted.

5. An electronic device, characterized in that, include: processor; Memory used to store processor-executable instructions; The processor is configured to execute the nonlinear control method for a single-phase half-bridge LCLC resonant converter for aviation power supply as described in any one of claims 1 to 3.

6. A computer-readable storage medium storing instructions thereon, characterized in that, When the instruction is executed by the processor, it implements the nonlinear control method for a single-phase half-bridge LCLC resonant converter of an aviation power supply as described in any one of claims 1 to 3.

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