Sliding mode control method and system based on phase-shifted full-bridge converter

Abstract

The embodiment of the invention provides a sliding mode control method and system based on a phase-shifted full-bridge converter, and the method comprises the steps: building a state space model corresponding to the phase-shifted full-bridge converter based on a topological structure of the phase-shifted full-bridge converter; according to the state space model, processing a sliding mode surface of the state space model in a voltage outer ring of the phase-shifted full-bridge converter by adopting a super-spiral sliding mode control algorithm to obtain a current inner ring reference value; according to the current inner ring reference value, a PI algorithm is adopted in a current inner ring of the phase-shifted full-bridge converter to generate a target PWM wave, and the target PWM wave is used for controlling the phase-shifted full-bridge converter. The phase-shifted full-bridge converter can meet the requirements of high precision and fast dynamic response, and the control precision of the phase-shifted full-bridge converter is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of converter application, and in particular to a sliding mode control method and system based on a phase-shifted full-bridge converter. Background Art

[0002] In the classification of isolated converters, the phase-shifted full-bridge converter is an excellent topology and is widely used in DC / DC converter power supplies in high-voltage to low-voltage applications.

[0003] In the field of industrial control, PID control structure has been used in various control systems. Although PID control has a simple application structure and is widely used, conventional PID controllers are difficult to adapt to the requirements of high precision and fast dynamic response. It is impossible to obtain the best control effect. Summary of the invention

[0004] In view of this, an embodiment of the present invention provides a sliding mode control method and system based on a phase-shifted full-bridge converter, which can meet the requirements of high precision and fast dynamic response and improve the control accuracy of the phase-shifted full-bridge converter.

[0005] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0006] In a first aspect, an embodiment of the present invention provides a sliding mode control method based on a phase-shifted full-bridge converter, comprising:

[0007] Based on the topological structure of the phase-shifted full-bridge converter, a state space model corresponding to the phase-shifted full-bridge converter is constructed;

[0008] According to the state space model, a super spiral sliding mode control algorithm is used in the voltage outer loop of the phase-shifted full-bridge converter to process the sliding mode surface of the state space model to obtain a current inner loop reference value;

[0009] According to the current inner loop reference value, a PI algorithm is used in the current inner loop of the phase-shifted full-bridge converter to generate a target PWM wave, and the target PWM wave is used to control the phase-shifted full-bridge converter.

[0010] Optionally, according to the state space model, a super spiral sliding mode control algorithm is used in the voltage outer loop of the phase-shifted full-bridge converter to process the sliding mode surface of the state space model to obtain a current inner loop reference value, including:

[0011] A sliding surface is set according to a difference between an output voltage reference value and an output voltage measurement value of the phase-shifted full-bridge converter;

[0012] The sliding surface variables of the sliding surface are selected as the input values ​​of the super-helical sliding mode controller, so as to utilize the super-helical sliding mode controller to output the current inner loop reference value.

[0013] Optionally, a super-helical sliding mode controller is used to output a current inner loop reference value, including:

[0014] Determining a first parameter and a second parameter based on a control law of a super-helical sliding mode controller;

[0015] Select state variables;

[0016] Using Lyapunov function, based on state variables and in combination with real symmetric positive definite matrix, determining constraint relationships, wherein the constraint relationships include first constraint relationships and second constraint relationships between the first parameter and the second parameter and the non-negative parameter, respectively;

[0017] The current inner loop reference value is output based on the constraint relationship.

[0018] Optionally, the method of generating a target PWM wave by using a PI algorithm in the current inner loop of the phase-shifted full-bridge converter according to the current inner loop reference value, wherein the target PWM wave is used to control the phase-shifted full-bridge converter, and includes:

[0019] The PI algorithm is used to determine the duty cycle based on the transfer function;

[0020] Based on the preset rules, the phase shift angle is obtained by converting the duty cycle;

[0021] Based on the phase shift angle combined with the constant frequency PWM drive waveform, the target PWM wave is obtained.

[0022] Optionally, in the buck mode, the duty cycle has a value range of 0≤D≤1; and the preset rule is θ=(1-D)π.

[0023] In a second aspect, an embodiment of the present invention provides a sliding mode control system based on a phase-shifted full-bridge converter, comprising:

[0024] A calculation module, used for constructing a state space model corresponding to the phase-shifted full-bridge converter based on the topological structure of the phase-shifted full-bridge converter;

[0025] A super spiral sliding mode controller, for processing the sliding mode surface of the state space model using a super spiral sliding mode control algorithm in the voltage outer loop of the phase-shifted full-bridge converter according to the state space model to obtain a current inner loop reference value;

[0026] A PI controller is used to generate a target PWM wave using a PI algorithm in the current inner loop of the phase-shifted full-bridge converter according to the current inner loop reference value, and the target PWM wave is used to control the phase-shifted full-bridge converter.

[0027] Optionally, the super spiral sliding mode controller is used to process the sliding mode surface of the state space model using a super spiral sliding mode control algorithm in the voltage outer loop of the phase-shifted full-bridge converter according to the state space model to obtain a current inner loop reference value, including:

[0028] A sliding surface is set according to a difference between an output voltage reference value and an output voltage measurement value of the phase-shifted full-bridge converter;

[0029] Based on the sliding surface variable of the sliding surface, the current inner loop reference value is output.

[0030] Optionally, the super-helical sliding mode controller outputs a current inner loop reference value, including:

[0031] Determining a first parameter and a second parameter based on a control law of a super-helical sliding mode controller;

[0032] Select state variables;

[0033] Using Lyapunov function, based on state variables and in combination with real symmetric positive definite matrix, determining constraint relationships, wherein the constraint relationships include first constraint relationships and second constraint relationships between the first parameter and the second parameter and the non-negative parameter, respectively;

[0034] The current inner loop reference value is output based on the constraint relationship.

[0035] Optionally, the PI controller is used to generate a target PWM wave using a PI algorithm in the current inner loop of the phase-shifted full-bridge converter according to the current inner loop reference value, and the target PWM wave is used to control the phase-shifted full-bridge converter, including:

[0036] The PI algorithm is used to determine the duty cycle based on the transfer function;

[0037] Based on the preset rules, the phase shift angle is obtained by converting the duty cycle;

[0038] Based on the phase shift angle combined with the constant frequency PWM drive waveform, the target PWM wave is obtained.

[0039] Optionally, in the buck mode, the duty cycle has a value range of 0≤D≤1; and the preset rule is θ=(1-D)π.

[0040] The embodiment of the present invention provides a sliding mode control method based on a phase-shifted full-bridge converter, comprising: constructing a state space model corresponding to the phase-shifted full-bridge converter based on the topological structure of the phase-shifted full-bridge converter; according to the state space model, using a super spiral sliding mode control algorithm in the voltage outer loop of the phase-shifted full-bridge converter to process the sliding mode surface of the state space model to obtain a current inner loop reference value; according to the current inner loop reference value, using a PI algorithm in the current inner loop of the phase-shifted full-bridge converter to generate a target PWM wave, and the target PWM wave is used to control the phase-shifted full-bridge converter. The embodiment of the present invention discloses that using the PI algorithm in the current inner loop can effectively improve the steady-state error and enhance the anti-interference ability of the system, while using the super spiral sliding mode control algorithm in the voltage outer loop provides fast dynamic response and superior robustness. The combination of the two can improve the stability and anti-interference ability of the system while ensuring the fast response of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0042] Figure 1 A schematic diagram of the steps of a sliding mode control method for a phase-shifted full-bridge converter provided in an embodiment of the present invention.

[0043] Figure 2 A schematic diagram of the principle of the sliding mode control process of the phase-shifted full-bridge converter provided in an embodiment of the present invention.

[0044] Figure 3 Schematic diagram of the topological structure of the phase-shifted full-bridge converter in an embodiment of the present invention.

[0045] Figure 4 A schematic diagram of the switching timing for driving different switch tubes provided in an embodiment of the present invention.

[0046] Figure 5 A block diagram of a sliding mode control system of a phase-shifted full-bridge converter provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0047] Traditional control generally adopts single voltage closed-loop control, dual voltage and current closed-loop control and multiple closed-loop control, etc., but single closed-loop control has many obvious defects, cannot adjust to external changes, has poor stability, and has poor output waveform quality. The dual closed-loop voltage and current PI control has obvious improvements, enhances the adaptability to the load and suppresses the disturbance of the loop, and can avoid overcurrent in the system, playing a certain protective role, but the above-mentioned overcurrent phenomenon still exists. In order to overcome the above problems, the inventor has found that for the phase-shifted full-bridge converter, the current inner loop mainly plays a role in improving the performance of part of the system, and the overall performance of the system still depends on the voltage outer loop. Therefore, the inventor changed the control logic in the outer loop to super-helical sliding mode control. Super-helical sliding mode control has stronger robustness and resistance to load mutation than PI control, and can effectively improve the accuracy of the control converter.

[0048] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0049] The present application provides a sliding mode control method based on a phase-shifted full-bridge converter, such as Figure 1 As shown, including:

[0050] Step S11, based on the topological structure of the phase-shifted full-bridge converter, constructing a state space model corresponding to the phase-shifted full-bridge converter;

[0051] Step S12: According to the state space model, a super spiral sliding mode control algorithm is used in the voltage outer loop of the phase-shifted full-bridge converter to process the sliding mode surface of the state space model to obtain a current inner loop reference value;

[0052] Step S13: according to the current inner loop reference value, a PI algorithm is used in the current inner loop of the phase-shifted full-bridge converter to generate a target PWM wave, wherein the target PWM wave is used to control the phase-shifted full-bridge converter.

[0053] The embodiment of the present invention discloses that the use of the PI algorithm in the current inner loop can effectively improve the steady-state error and enhance the anti-interference ability of the system, while the use of the super-twisting sliding mode control algorithm (Super-Twisting Siliding Mode) in the voltage outer loop provides fast dynamic response and superior robustness. The combination of the two can improve the stability and anti-interference ability of the system while ensuring the fast response of the system.

[0054] Specifically, the topology of the phase-shifted full-bridge converter in this application is as follows: Figure 2 As shown, V in is the DC high voltage side input voltage value, V o is the DC low voltage output voltage, i L is the current flowing through the output filter inductor L. In buck mode, the higher input DC voltage V in After the converter outputs a DC low voltage V o The primary duty cycle is defined as D.

[0055] Continue to combine Figure 2 As shown, there are 6 switch tubes, namely Q1-Q6. Among these switch tubes, the bridge arm formed by the connection of switch tubes Q1 and Q3 is the leading arm, the bridge arm formed by the connection of switch tubes Q2 and Q4 is the lagging arm, and the two switch tubes on the same bridge arm are complementary. For example, the PWM drive of switch tubes Q1 and Q3 is complementary, the PWM drive of Q2 and Q4 is complementary, and the drive PWM signal frequency of switch tubes Q1, Q2, Q3, and Q4 is the same and remains unchanged.

[0056] When the leading bridge arm Q1 is turned on, Q6 is turned on, and the lagging bridge arm Q4 is turned off and Q6 is turned off at the same time; when the leading bridge arm Q3 is turned on, Q5 is turned on, and the lagging bridge arm Q2 is turned off and Q5 is turned off at the same time. That is, the ratio of the time when the leading arm Q1 and the lagging arm Q4 are simultaneously turned on to half a PWM pulse period. The leading arm Q3 and the lagging arm Q2 have the same duty cycle. By changing the duty cycle by changing the phase shift angle θ, the output voltage value can be adjusted. The switching timing diagram of different switch tubes to achieve drive is shown in the figure below. Figure 3 shown.

[0057] The topology of the phase-shifted full-bridge converter in the present application has two working states, namely, boost mode and buck mode. In boost mode, the phase-shifted full-bridge converter is usually used to convert a low-voltage DC power supply into a high-voltage DC power supply; in buck mode, the phase-shifted full-bridge converter is used to convert a high-voltage DC power supply into a low-voltage DC power supply. The embodiment of the present invention is described with the topology of the phase-shifted full-bridge converter in buck mode. In other optional embodiments, the topology of the phase-shifted full-bridge converter can also be in boost mode, which is not limited here.

[0058] In the specific implementation, it is necessary to first establish a state space average equation model in the buck mode based on the topology of the phase-shifted full-bridge converter. Figure 3 In the topology of the phase-shifted full-bridge converter shown in FIG. 1 , the current of the filter inductor L is denoted as i L , the output capacitor parameter is recorded as C o , the load resistance is recorded as R, and the load resistance current is recorded as i o , the high-voltage side DC input voltage is recorded as V in, the voltage of the load resistor R at the low voltage output end is recorded as V o , the effective duty cycle of the secondary side is recorded as D eff , the duty cycle of the primary side is recorded as u, the resonant inductor L r , the transformer primary and secondary ratio is K, the driving PWM frequency is F, first analyze the phase shift angle θ between Q1 and Q4, Q3 and Q2 of the phase-shifted full-bridge DC / DC converter to achieve the buck characteristics, the state space average equation model is as follows:

[0059]

[0060] in:

[0061] After the state space model is obtained, the sliding mode surface of the state space model can be processed using a super spiral sliding mode controller to obtain a current inner loop reference value, which is used to be input into the current inner loop as a current reference value.

[0062] Specifically, step S12, according to the state space model, using a super spiral sliding mode control algorithm in the voltage outer loop of the phase-shifted full-bridge converter to process the sliding mode surface of the state space model to obtain a current inner loop reference value, includes:

[0063] Step S121, setting a sliding surface according to the difference between the output voltage reference value and the output voltage measurement value of the phase-shifted full-bridge converter.

[0064] In an optional implementation, the sliding surface is designed based on the difference e between the output voltage reference value Vref and the output voltage measurement value Vo of the phase-shifted full-bridge converter, and the output voltage measurement value Vo is the voltage value of the capacitor Co.

[0065] e=V ref -V o Formula 2

[0066] Step S122: Select a sliding surface variable of the sliding surface as an input value of the super-helical sliding mode controller, so as to utilize the super-helical sliding mode controller to output a current inner loop reference value.

[0067] In an optional implementation, the sliding surface variable S of the sliding surface may be the sliding surface e, that is:

[0068] S=e=V ref -V o Formula 3

[0069] By taking the derivative of formula 3, we can get the derivative of S, which is recorded as Substitute formula 1 into the equation to get formula 4:

[0070]

[0071] In an optional embodiment, a super-helical sliding mode controller is used to output a current inner loop reference value, including:

[0072] Step S21, determining a first parameter and a second parameter based on a control law of a super-helical sliding mode controller;

[0073] The control law of the super-helical sliding mode controller is shown in Formula 5. Under the control of the control law, the control system is guaranteed to reach the sliding mode surface within a finite time.

[0074]

[0075] Among them, sgn(S) is the sign function, S is the sliding surface variable, The inductor current i is the output of the voltage outer loop. L Reference value. Control parameters k>0, λ>0. Where: k and λ are gain coefficients.

[0076] Based on Formula 5 and Formula 4, we can get:

[0077]

[0078] Where, e = V o / RC o

[0079] Simplifying formula 6, we get:

[0080]

[0081] Where: α = λ / C o , β=k / C o , α can be used as the first parameter in this application; β can be used as the second parameter in this application.

[0082] Step S22, selecting a state variable ξ;

[0083]

[0084] Step S23, using the Lyapunov function, based on the state variables, combined with a real symmetric positive definite matrix, to determine a constraint relationship, wherein the constraint relationship includes a first constraint relationship and a second constraint relationship between the first parameter and the second parameter and the non-negative parameter δ respectively;

[0085] Step S24: outputting a current inner loop reference value based on the constraint relationship.

[0086] The constructed Lyapunov function is shown in formula 9:

[0087] V=ξ T Πξ Formula 9

[0088] Π is a real symmetric positive definite matrix, and the function V>0, then take

[0089]

[0090] By taking the derivative of formula 9, we can get:

[0091]

[0092] in

[0093] When δ>0 is selected to satisfy When , based on formula 11, we can get formula 12:

[0094]

[0095] in,

[0096]

[0097] In order to realize the control of the phase-shifted full-bridge converter, it is usually necessary to meet the stability condition of the Lyapunov function V<0, that is, the above symmetric matrix Q is a positive definite matrix. It should be noted that when the order principal minors of each order in the symmetric matrix Q are greater than 0, when the controller parameters meet the following conditions, the matrix Q can be guaranteed to be positive definite.

[0098]

[0099] Based on the above, a constraint relationship can be obtained, which includes a first constraint relationship and a second constraint relationship. The first constraint relationship is a constraint relationship between a first parameter α and a non-negative parameter δ, and the second constraint relationship is a constraint relationship between a second parameter β and a non-negative parameter δ. Based on the above constraint relationship, a current inner loop reference value is obtained. The current inner loop reference value enables the voltage loop control system to realize sliding mode motion and converge asymptotically to the state origin.

[0100]

[0101] After obtaining the current inner loop reference value, a PI algorithm is used in the current inner loop to generate a target PWM wave, and the target PWM wave is used to control the phase-shifted full-bridge converter.

[0102] The specific steps of using the PI algorithm to generate the target PWM wave include:

[0103] Step S131, using the PI algorithm to determine the duty cycle based on the transfer function;

[0104] Step S132: Based on a preset rule, obtain a phase shift angle by converting the duty cycle;

[0105] Step S133: Obtain a target PWM wave based on the phase shift angle and the constant-frequency PWM driving waveform.

[0106] Determine the transfer function G based on the constraint relationship from the current inner loop duty cycle to the inductor current id (s):

[0107]

[0108] in,

[0109] The transfer function of the PI controller is shown in Equation 17:

[0110]

[0111] The output of the current inner loop PI controller is the primary side duty cycle D of the phase-shifted full-bridge circuit, and the duty cycle range is 0≤D≤1. Then the phase shift angle θ can be obtained through preset rules.

[0112] θ=(1-D)πFormula 18

[0113] The value range of θ is: 0≤θ≤π

[0114] According to the phase shift angle θ in formula 18, combined with the constant-frequency PWM drive waveform, a target PWM wave is generated, and the target PWM wave is used to control the on and off of the switch tube corresponding to the phase-shifted full-bridge converter to achieve a stable voltage output.

[0115] The embodiment of the present invention discloses that the use of the PI algorithm in the inner current loop can effectively improve the steady-state error and enhance the anti-interference ability of the system, while the use of the super-helical sliding mode control algorithm in the outer voltage loop provides fast dynamic response and superior robustness. The combination of the two can improve the stability and anti-interference ability of the system while ensuring the fast response of the system.

[0116] As an optional implementation of the disclosed content of the embodiment of the present invention, the embodiment of the present invention also provides a sliding mode control system based on a phase-shifted full-bridge converter, such as Figure 5 As shown, Figure 5 A schematic diagram of a sliding mode control system based on a phase-shifted full-bridge converter is provided for one embodiment of the present invention. The sliding mode control system based on a phase-shifted full-bridge converter includes:

[0117] A calculation module 51, configured to construct a state space model corresponding to the phase-shifted full-bridge converter based on the topological structure of the phase-shifted full-bridge converter;

[0118] A super spiral sliding mode controller 52, configured to process the sliding mode surface of the state space model using a super spiral sliding mode control algorithm in the voltage outer loop of the phase-shifted full-bridge converter according to the state space model to obtain a current inner loop reference value;

[0119] The PI controller 53 is used to generate a target PWM wave using a PI algorithm in the current inner loop of the phase-shifted full-bridge converter according to the current inner loop reference value, and the target PWM wave is used to control the phase-shifted full-bridge converter.

[0120] In an optional manner in an embodiment of the present invention, the super spiral sliding mode controller is used to process the sliding mode surface of the state space model using a super spiral sliding mode control algorithm in the voltage outer loop of the phase-shifted full-bridge converter according to the state space model to obtain a current inner loop reference value, including:

[0121] A sliding surface is set according to a difference between an output voltage reference value and an output voltage measurement value of the phase-shifted full-bridge converter;

[0122] Based on the sliding surface variable of the sliding surface, the current inner loop reference value is output.

[0123] In an optional manner in the embodiment of the present invention, the super spiral sliding mode controller outputs a current inner loop reference value, including:

[0124] Determining a first parameter and a second parameter based on a control law of a super-helical sliding mode controller;

[0125] Select state variables;

[0126] Using Lyapunov function, based on state variables and in combination with real symmetric positive definite matrix, determining constraint relationships, wherein the constraint relationships include first constraint relationships and second constraint relationships between the first parameter and the second parameter and the non-negative parameter, respectively;

[0127] The current inner loop reference value is output based on the constraint relationship.

[0128] In an optional manner in an embodiment of the present invention, the PI controller is used to generate a target PWM wave using a PI algorithm in the current inner loop of the phase-shifted full-bridge converter according to the current inner loop reference value, and the target PWM wave is used to control the phase-shifted full-bridge converter, including:

[0129] The PI algorithm is used to determine the duty cycle based on the transfer function;

[0130] Based on the preset rules, the phase shift angle is obtained by converting the duty cycle;

[0131] Based on the phase shift angle combined with the constant frequency PWM drive waveform, the target PWM wave is obtained.

[0132] In an optional manner in the embodiment of the present invention, in the buck mode, the duty cycle has a value range of: 0≤D≤1; and the preset rule is θ=(1-D)π.

[0133] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0134] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A sliding mode control method based on a phase-shifted full-bridge converter, characterized in that: include: Based on the topological structure of the phase-shifted full-bridge converter, a state space model corresponding to the phase-shifted full-bridge converter is constructed; According to the state space model, a super spiral sliding mode control algorithm is used in the voltage outer loop of the phase-shifted full-bridge converter to process the sliding mode surface of the state space model to obtain a current inner loop reference value; According to the current inner loop reference value, a PI algorithm is used in the current inner loop of the phase-shifted full-bridge converter to generate a target PWM wave, and the target PWM wave is used to control the phase-shifted full-bridge converter.

2. The sliding mode control method based on the phase-shifted full-bridge converter according to claim 1 is characterized in that: According to the state space model, a super spiral sliding mode control algorithm is used in the voltage outer loop of the phase-shifted full-bridge converter to process the sliding mode surface of the state space model to obtain a current inner loop reference value, including: A sliding surface is set according to a difference between an output voltage reference value and an output voltage measurement value of the phase-shifted full-bridge converter; The sliding surface variables of the sliding surface are selected as the input values ​​of the super-helical sliding mode controller, so as to utilize the super-helical sliding mode controller to output the current inner loop reference value.

3. The sliding mode control method based on the phase-shifted full-bridge converter according to claim 2 is characterized in that: The super-helical sliding mode controller is used to output the current inner loop reference value, including: Determining a first parameter and a second parameter based on a control law of a super-helical sliding mode controller; Select state variables; Using Lyapunov function, based on state variables and in combination with real symmetric positive definite matrix, determining constraint relationships, wherein the constraint relationships include first constraint relationships and second constraint relationships between the first parameter and the second parameter and the non-negative parameter, respectively; The current inner loop reference value is output based on the constraint relationship.

4. The sliding mode control method based on the phase-shifted full-bridge converter according to any one of claims 1 to 3, characterized in that: The method of generating a target PWM wave by using a PI algorithm in the current inner loop of the phase-shifted full-bridge converter according to the current inner loop reference value, wherein the target PWM wave is used to control the phase-shifted full-bridge converter, comprises: The PI algorithm is used to determine the duty cycle based on the transfer function; Based on the preset rules, the phase shift angle is obtained by converting the duty cycle; Based on the phase shift angle combined with the constant frequency PWM drive waveform, the target PWM wave is obtained.

5. The sliding mode control method based on the phase-shifted full-bridge converter according to claim 4 is characterized in that: In the buck mode, the duty cycle has a value range of 0≤D≤1; and the preset rule is θ=(1-D)π.

6. A sliding mode control system based on a phase-shifted full-bridge converter, characterized in that: include: A calculation module, used for constructing a state space model corresponding to the phase-shifted full-bridge converter based on the topological structure of the phase-shifted full-bridge converter; A super spiral sliding mode controller is used to process the sliding mode surface of the state space model using a super spiral sliding mode control algorithm in the voltage outer loop of the phase-shifted full-bridge converter according to the state space model to obtain a current inner loop reference value; A PI controller is used to generate a target PWM wave using a PI algorithm in the current inner loop of the phase-shifted full-bridge converter according to the current inner loop reference value, and the target PWM wave is used to control the phase-shifted full-bridge converter.

7. The sliding mode control system based on the phase-shifted full-bridge converter according to claim 6 is characterized in that: The super spiral sliding mode controller is used to process the sliding mode surface of the state space model using a super spiral sliding mode control algorithm in the voltage outer loop of the phase-shifted full-bridge converter according to the state space model to obtain a current inner loop reference value, including: A sliding surface is set according to a difference between an output voltage reference value and an output voltage measurement value of the phase-shifted full-bridge converter; Based on the sliding surface variable of the sliding surface, the current inner loop reference value is output.

8. The sliding mode control system based on the phase-shifted full-bridge converter according to claim 7 is characterized in that: The super-helical sliding mode controller outputs a current inner loop reference value, including: Determining a first parameter and a second parameter based on a control law of a super-helical sliding mode controller; Select state variables; Using Lyapunov function, based on state variables and in combination with real symmetric positive definite matrix, determining constraint relationships, wherein the constraint relationships include first constraint relationships and second constraint relationships between the first parameter and the second parameter and the non-negative parameter, respectively; The current inner loop reference value is output based on the constraint relationship.

9. The sliding mode control system based on the phase-shifted full-bridge converter according to any one of claims 6 to 8, characterized in that: The PI controller is used to generate a target PWM wave using a PI algorithm in the current inner loop of the phase-shifted full-bridge converter according to the current inner loop reference value, and the target PWM wave is used to control the phase-shifted full-bridge converter, including: The PI algorithm is used to determine the duty cycle based on the transfer function; Based on the preset rules, the phase shift angle is obtained by converting the duty cycle; Based on the phase shift angle combined with the constant frequency PWM drive waveform, the target PWM wave is obtained.

10. The sliding mode control system based on the phase-shifted full-bridge converter according to claim 9, characterized in that: In the buck mode, the duty cycle has a value range of 0≤D≤1; and the preset rule is θ=(1-D)π.

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