Predictive Control Method and Module for LC Filtered Dual Active Bridge DC-DC Converter System

Abstract

This invention discloses a predictive control method and module for an LC-filtered dual active bridge DC-DC converter system, belonging to the field of power electronics control. The method involves sampling the input voltage, output voltage, and load current of the LC-filtered dual active bridge DC-DC converter system to establish a state-space average model. The state-space average model is discretized to establish a discretized prediction equation for the system output voltage. A benchmark prediction performance function based on output voltage reference tracking is constructed, and the phase-shift control signal reference value is obtained by minimizing the prediction performance function. The output voltage reference value is corrected by extracting the high-frequency resonant component of the system input voltage, and a damped phase-shift control signal reference value is obtained. A control pulse signal is generated using the damped phase-shift control signal reference value and applied to the system's switching transistors. This method achieves predictive control of the input voltage resonant damping and output voltage reference tracking of the LC-filtered dual active bridge DC-DC converter system.

Description

Technical Field

[0001] This invention relates to a predictive control method and module for an LC-filtered dual active bridge DC-DC converter system, and relates to the field of power electronic converter control. Background Technology

[0002] With the increasing penetration rate of distributed photovoltaic and wind power, the inherent volatility and intermittency of these energy sources pose challenges to the operational stability of large power grids, making local consumption of new energy a pressing issue. Therefore, equipping these grids with energy storage units is considered an effective solution, helping to smooth peak flows and achieve local energy consumption and balance. Dual active bridge DC-DC converters, as key interface devices in distributed new energy storage systems, possess advantages such as high power density, soft-switching characteristics, electrical isolation, and fewer passive components, enabling bidirectional energy flow and meeting diverse energy management and distribution needs. However, in practical applications, dual active bridge DC-DC converters are often affected by complex electromagnetic environments and nonlinear loads. Fluctuations in the output signal may couple to the input signal, generating high-frequency harmonics and causing electromagnetic interference. Therefore, it is necessary to cascade an LC filter at the front end of the dual active bridge DC-DC converter to filter out high-frequency harmonics, improve the quality of the output signal waveform, and enhance the system's electromagnetic compatibility.

[0003] Although dual active bridge DC-DC converters are relatively stable when operating independently, the inherent resonant frequency of the LC filter can cause voltage resonance at the cascade point of the LC filter and the dual active bridge DC-DC converter when operating conditions change, leading to output voltage instability. Traditional control schemes for dual active bridge DC-DC converters mainly employ proportional-integral (PI) control. While this mature control method is widely used, it involves numerous adjustable parameters, and the coupling between these parameters makes adjustment difficult. Furthermore, the system's dynamic performance is insufficient, and these problems are particularly severe in the damped control of LC-filtered dual active bridge DC-DC converter systems. In contrast, predictive control methods are gaining attention due to their intuitive concept, fewer parameters, and support for multi-objective optimization. However, existing predictive control strategies for LC-filtered dual active bridge DC-DC converter systems require multiple voltage and current sensors, resulting in high costs. Additionally, the need to add extra control objectives to the performance function of the model prediction leads to high computational complexity of the control signal reference values, hindering their application in engineering practice. Therefore, an improved predictive control strategy is urgently needed to address the resonance problem in LC-filtered dual active bridge DC-DC converter systems. Summary of the Invention

[0004] To address the shortcomings of existing technologies, a predictive control method and module for an LC-filtered dual active bridge DC-DC converter system is provided. This method considers the changes in the system input voltage, thereby correcting the output voltage reference value in the calculated phase-shift control signal reference expression. It utilizes the coupling relationship between the output signal and the preceding input signal to achieve resonant damping of the input voltage. It eliminates the need to add additional control objectives to the model's predictive performance function, thus avoiding increased computational complexity of the control signal reference value. Furthermore, this method does not require sampling additional current signals; only one voltage sensor is added for the resonant damping control of the input voltage, resulting in lower costs.

[0005] To achieve the above technical objectives, this invention discloses a predictive control method for an LC-filtered dual active bridge DC-DC converter system, comprising the following steps:

[0006] Step 1: Calculate the system input voltage u of the LC filter-type dual active bridge DC-DC converter system. cf Output voltage u o and load current i o Input and output state variables are sampled, and the output voltage u is used. o and load current i o Establish a state-space average model for an LC-filtered dual active bridge DC-DC converter system;

[0007] Step 2: Discretize the state-space average model of the LC filter type dual active bridge DC converter system using the forward difference method to obtain a discrete model. Based on this discrete model, establish the discretized prediction equation for the output voltage of the LC filter type dual active bridge DC converter system.

[0008] Step 3: Design the benchmark prediction performance function g for output voltage reference tracking of the LC-filtered dual active bridge DC-DC converter system;

[0009] Step 4: Based on the principle of minimizing the function: Set the partial derivative of the reference prediction performance function g with respect to the phase shift control signal d to 0, and calculate the reference value d of the phase shift control signal that minimizes the reference prediction performance function g. ref ;

[0010] Step 5: Extract the high-frequency resonant component u of the input voltage of the LC-filtered dual active bridge DC-DC converter system using a high-pass filter. cf，k k represents the current sampling time, using the output voltage reference value U given by the LC filter type dual active bridge DC-DC converter system. o_ref The corrected output voltage reference value is obtained by subtracting the high-frequency resonant component of the high-pass filter. use Calculate the reference value d of the damped phase-shift control signal with resonance suppression function. ref_dam ;

[0011] Step 6: Use the damped phase shift control signal reference value d ref_dam A phase-shifting pulse signal is generated and applied to the switching transistors of the dual active bridge DC-DC converter to achieve resonance suppression of the input voltage and precise predictive control of the output voltage of the LC filter-type dual active bridge DC-DC converter system.

[0012] Furthermore, the state-space averaged model of the LC-filtered dual active bridge DC-DC converter system is expressed as follows:

[0013]

[0014] In the formula, u in The power supply input voltage, u o i is the system output voltage obtained through sampling. o The load current is obtained through sampling, R is the system load resistance, C is the system output capacitance, n is the turns ratio of the high-frequency isolation transformer, L is the auxiliary phase-shifting inductance, and f is the load current obtained through sampling. sw d is the switching frequency of the LC-filtered dual active bridge DC-DC converter system, and d is the phase shift control signal for controlling the switching transistors.

[0015] The LC-filtered dual active bridge DC-DC converter system contains 8 switching transistors S 1～ S8 defines the phase-shift control signal d for controlling the switching transistors as the absolute value of the difference between the rising edge trigger times of the turn-on signals of transistors S1 and S5 within one switching cycle and half a switching cycle T. sw The ratio of / 2:

[0016]

[0017] in, and T represents the rising edge trigger time of the conduction signals S1 and S5, respectively. sw This indicates the switching cycle of the LC-filtered dual active bridge DC-DC converter.

[0018] Furthermore, the method for discretizing the state-space average model of the LC-filtered dual active bridge DC-DC converter system using the forward difference method is as follows:

[0019]

[0020] In the formula, u o,k i represents the system output voltage at the current sampling time k. o,k U represents the load current at the current sampling time k. o,k+1 T represents the predicted value of the system output voltage at sampling time k+1. sThe sampling period for the state variables of the LC-filtered dual active bridge DC-DC converter is given by f, where f is the sampling frequency. s The reciprocal of , where d is the phase-shift control signal controlling the switching transistor;

[0021] Based on the above discrete model, the discretized prediction equation for the output voltage of the LC-filtered dual active bridge DC-DC converter system is established:

[0022]

[0023] Furthermore, the benchmark prediction performance function g for output voltage reference tracking of the LC-filtered dual active bridge DC-DC converter system is expressed as follows:

[0024] g=(U o_ref -u o,k+1 ) 2 +(u o,k+1 -u o,k ) 2

[0025] In the formula, U o_ref This is the reference value for the output voltage of an LC-filtered dual active bridge DC-DC converter system.

[0026] Furthermore, based on the principle of solving for the minimum value of a function, the reference value d of the phase-shift control signal that minimizes the baseline prediction performance function g is calculated. ref The process is as follows:

[0027] Let the partial derivative of the reference prediction performance function g with respect to the phase shift control signal d be equal to 0, and then use the formula: Obtain the phase-shift control signal reference value d that minimizes g. ref :

[0028] In the formula, variable M va The specific expression is as follows:

[0029]

[0030] Furthermore, the corrected output voltage reference value is calculated using the following formula.

[0031]

[0032] In the formula, s represents the Laplace operator, and H (s) This represents a high-pass filter, specifically:

[0033]

[0034] In the formula, α represents the high-pass filter coefficient;

[0035] The corrected output voltage reference value Substitute into the phase shift control signal reference value d ref From the calculation formula, the corresponding damping phase shift control signal reference value d is obtained. ref_dam ,

[0036]

[0037] This achieves resonant damping of the system input voltage while maintaining output voltage reference tracking control, where the variable M... va_dam The specific expression is as follows:

[0038]

[0039] Furthermore, the damped phase-shift control signal reference value d is used. ref_dam The generated phase-shifted pulse signals are applied to the switching transistors of the dual active bridge DC-DC converter. Specifically, within each sampling period, pulse signals with a duty cycle of 50% are applied to the eight switching transistors S1 to S8 of the two H-bridges. The pulse signals of switching transistors S1 and S2 in the first arm of the front-stage H-bridge are complementary, and the pulse signals of switching transistors S3 and S4 in the second arm are complementary; wherein the pulse signals of switching transistors S1 and S4 or S2 and S3 are consistent. The pulse signals of switching transistors S5 and S6 in the first arm of the rear-stage H-bridge are complementary, and the pulse signals of switching transistors S7 and S8 in the second arm are complementary; the pulse signals of switching transistors S5 and S7 or S6 and S8 are consistent. The pulse signal applied to the switching transistor S5 of the rear-stage H-bridge lags behind the pulse signal applied to the switching transistor S1 of the front-stage H-bridge by a phase shift time T. d Phase shift time T d The calculation method is as follows:

[0040]

[0041] A predictive control module for an LC-filtered dual active bridge DC-DC converter system includes, in sequence: an input / output state variable sampling unit, a state-space averaging model, a discretized prediction unit, a reference model prediction performance function unit, a damped phase-shift control signal reference value unit, and a phase-shift pulse generation unit. The input / output state variable sampling unit is also connected to a high-pass filter, and the output of the high-pass filter is connected to the phase-shift control signal reference signal unit.

[0042] Input / output state variable sampling unit, used to acquire input voltage, output voltage and load current information of LC filter type dual active bridge DC converter system;

[0043] The state-space average model is constructed by using the state variable information of the obtained LC filter type dual active bridge DC converter system to build the corresponding state-space average mathematical model.

[0044] The discretization prediction unit is used to discretize the mathematical model of the acquired LC filter type dual active bridge DC converter system to obtain the discretized prediction equation.

[0045] The benchmark model prediction performance function unit is used to construct the benchmark prediction performance function based on output voltage reference tracking.

[0046] A high-pass filter is used to extract the high-frequency resonant component of the input voltage of an LC-filtered dual active bridge DC-DC converter system and to correct the output voltage reference value.

[0047] The phase-shift control signal reference signal unit combines the corrected output voltage reference value and the reference prediction performance function to obtain the phase-shift control signal reference value by minimizing the reference prediction performance function.

[0048] The damping phase-shift control signal reference value unit obtains the damping phase-shift control signal reference value by extracting the high-frequency resonant component of the input voltage of the LC filter type dual active bridge DC converter system and correcting the output voltage reference value.

[0049] The phase shift pulse generation unit uses the damped phase shift control signal reference value to generate a control pulse signal, which is then applied to the switching transistors of the system.

[0050] A computer device includes a processor and a memory, the processor being electrically connected to the memory, the memory being used to store instructions and data, and the processor being used to execute a predictive control method for an LC-filtered dual active bridge DC-DC converter system.

[0051] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0052] 1. This method corrects the output voltage reference value in the phase-shifting control signal reference expression by considering the change of the system input voltage. It utilizes the coupling effect of the output signal on the previous stage input signal to achieve the resonant damping of the input voltage. There is no need to add an additional control target to the performance function predicted by the model, so it does not increase the computational complexity of the control signal.

[0053] 2. This method samples the system input voltage, output voltage, and load current. Compared with existing resonant suppression predictive control schemes for this topology, it does not require sampling the power supply input current, reducing the use of current sensors and significantly lowering the cost.

[0054] 3. This method only introduces one parameter, the high-pass filter coefficient α, which is simple to tune. Attached Figure Description

[0055] Figure 1This is a schematic diagram of the topology and control method of the LC-filtered dual active bridge DC-DC converter system of the present invention;

[0056] Figure 2 This is a schematic diagram of the signal response obtained by the LC-filtered dual active bridge DC-DC converter system of the present invention;

[0057] Figure 3 This is a schematic diagram of the output voltage waveform of the LC filter type dual active bridge DC-DC converter system after damping in an embodiment of the present invention. Detailed Implementation

[0058] The embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0059] like Figure 1 As shown, this invention discloses a predictive control method for an LC-filtered dual active bridge DC-DC converter system, corresponding to an LC-filtered dual active bridge DC-DC converter system. The overall topology of the LC-filtered dual active bridge DC-DC converter system, from left to right, consists of the DC input power supply voltage u... in It consists of an LC filter, a dual active bridge DC-DC converter, and a load with a voltage regulator capacitor cascaded together. The LC filter section includes a filter inductor L... f Equivalent filter impedance R f and filter capacitor C f The dual active bridge DC-DC converter section includes two H-bridges connected by a high-frequency isolation transformer, an auxiliary phase-shifting inductor L, and a high-frequency isolation transformer T. The left H-bridge consists of four insulated-gate bipolar transistors (IGBTs) S1-S4 and their anti-parallel diodes, while the right H-bridge consists of four IGBTs S5-S8 and their anti-parallel diodes. The high-frequency isolation transformer has a turns ratio of n:1. o Indicates the system output voltage, i o This represents the load current, which is sampled by the sampling module and used to establish the state-space average model of the LC-filtered dual active bridge DC-DC converter system. cf This represents the system input voltage, which is sampled by the sampling module and processed by a high-pass filter to correct the output voltage reference value U. o_ref .

[0060] A predictive control module for an LC-filtered dual active bridge DC-DC converter system includes, in sequence: an input / output state variable sampling unit, a state-space averaging model, a discretized prediction unit, a reference model prediction performance function unit, a damped phase-shift control signal reference value unit, and a phase-shift pulse generation unit. The input / output state variable sampling unit is also connected to a high-pass filter, and the output of the high-pass filter is connected to the phase-shift control signal reference signal unit.

[0061] Input / output state variable sampling unit, used to acquire input voltage, output voltage and load current information of LC filter type dual active bridge DC converter system;

[0062] The state-space average model is constructed by using the state variable information of the obtained LC filter type dual active bridge DC converter system to build the corresponding state-space average mathematical model.

[0063] The discretization prediction unit is used to discretize the mathematical model of the acquired LC filter type dual active bridge DC converter system to obtain the discretized prediction equation.

[0064] The benchmark model prediction performance function unit is used to construct the benchmark prediction performance function based on output voltage reference tracking.

[0065] A high-pass filter is used to extract the high-frequency resonant component of the input voltage of an LC-filtered dual active bridge DC-DC converter system and to correct the output voltage reference value.

[0066] The phase-shift control signal reference signal unit combines the corrected output voltage reference value and the reference prediction performance function to obtain the phase-shift control signal reference value by minimizing the reference prediction performance function.

[0067] The damping phase-shift control signal reference value unit obtains the damping phase-shift control signal reference value by extracting the high-frequency resonant component of the input voltage of the LC filter type dual active bridge DC converter system and correcting the output voltage reference value.

[0068] The phase shift pulse generation unit uses the damped phase shift control signal reference value to generate a control pulse signal, which is then applied to the switching transistors of the system.

[0069] A predictive control method for an LC-filtered dual active bridge DC-DC converter system includes the following steps:

[0070] Step 1: Establish the state-space average model of the LC-filtered dual active bridge DC-DC converter system, specifically as follows:

[0071]

[0072] In the formula, u in The power supply input voltage, u o i is the system output voltage obtained through sampling. o The load current is obtained through sampling, R is the load resistance, C is the system output capacitance, n is the turns ratio of the high-frequency isolation transformer, L is the auxiliary phase-shifting inductance, and f is the load current obtained through sampling. sHere, is the sampling frequency of the state variables in the LC-filtered dual active bridge DC-DC converter system, and d is the phase-shift control signal controlling the switching transistors, specifically defined as the ratio of the absolute value of the difference between the rising edge trigger times of the conduction signals of switching transistors S1 and S5 within one switching cycle to half a switching cycle:

[0073]

[0074] Among them, t S1_up and t S5_up These represent the rising edge trigger times of the conduction signals S1 and S5, respectively.

[0075] In the formula, i 1αβ v cαβ i 2αβ These represent the inverter-side current, LCL capacitor voltage, and grid-side current of the three-phase AC grid in an LCL-filtered three-phase grid-connected inverter system under the α-β axes, respectively. iαβ This represents the inverter voltage along the α-β axis, v. gαβ L1 and R1 represent the grid voltage along the α-β axis; L2 and R2 represent the filter inductance and parasitic resistance of the LCL-filtered three-phase grid-connected inverter system output; C represents the filter capacitor on the grid side.

[0076] Step 2: Discretize the state-space average model of the LC-filtered dual active bridge DC-DC converter system using the forward difference method:

[0077]

[0078] In the formula, u o,k i represents the system output voltage at the current sampling moment. o,k U represents the load current at the current sampling moment. o,k+1 T represents the predicted value of the system output voltage at the next sampling time. s The sampling period for the state variables of the LC-filtered dual active bridge DC-DC converter is the sampling frequency f. s The reciprocal of.

[0079] Furthermore, based on the above discrete model, a discretized prediction equation for the output voltage of an LC-filtered dual active bridge DC-DC converter system can be established:

[0080]

[0081] Step 3: Design a benchmark prediction performance function g for output voltage reference tracking of an LC-filtered dual active bridge DC-DC converter system:

[0082] g=(U o_ref -u o,k+1 ) 2 +(uo,k+1 -u o,k ) 2

[0083] In the formula, U o_ref This is the reference value for the system output voltage.

[0084] Step 4: Based on the principle of solving for the minimum value of a function, that is: by setting the partial derivative of the reference prediction performance function g with respect to the phase shift control signal d equal to 0, the reference value of the phase shift control signal d that minimizes g can be obtained. ref :

[0085]

[0086] In the formula, variable M va The specific expression is as follows:

[0087]

[0088] Step 5: Use a high-pass filter to extract the high-frequency resonant component of the system input voltage, and then extract this high-frequency resonant component from the output voltage reference value U. o_ref The corrected output voltage reference value is obtained by subtracting from the above.

[0089]

[0090] In the formula, s represents the Laplace operator, and H (s) This represents a high-pass filter, specifically:

[0091]

[0092] In the formula, α represents the high-pass filter coefficient.

[0093] Furthermore, the corrected output voltage reference value Substitute the reference value d into the original phase-shift control signal. ref The corresponding damping phase shift control signal reference value d can be obtained. ref_dam This achieves resonant damping of the system input voltage while maintaining output voltage reference tracking control. ref_dam The specific format is as follows:

[0094]

[0095] In the formula, variable M va_dam The specific expression is as follows:

[0096]

[0097] Step 6: Use the damped phase shift control signal reference value d ref_damA phase-shifted pulse signal is generated and applied to the switching transistors of the dual active bridge DC-DC converter. Specifically, within each sampling period, pulse signals with a duty cycle of 50% are applied to the eight switching transistors S1 to S8 of the two H-bridges. The pulse signals of the first arms S1 and S2 of the front-stage H-bridge are complementary, and the pulse signals of the second arms S3 and S4 are complementary; the pulse signals of S1 (S2) and S4 (S3) are consistent. Similarly, the pulse signals of the first arms S5 and S6 of the rear-stage H-bridge are complementary, and the pulse signals of the second arms S7 and S8 are complementary; the pulse signals of S5 (S6) and S8 (S7) are consistent. The pulse signal applied to the switching transistor S5 of the rear-stage H-bridge lags behind the pulse signal applied to the switching transistor S1 of the front-stage H-bridge by a phase shift time T. d The calculation method for this time is as follows:

[0098]

[0099] To verify the predictive control method for an LC-filtered dual active bridge DC-DC converter system provided by this invention, the method was applied to an LC-filtered dual active bridge DC-DC converter system, and the system parameters are given in Table 1.

[0100] Table 1

[0101]

[0102] Figure 2 To illustrate the signal response obtained by controlling the LC-filtered dual active bridge DC-DC converter system using the proposed method, specifically, the upper figure shows the system input voltage signal response, and the lower figure shows the system output voltage signal response. At the simulation time of 0.2s, the coefficient of the α high-pass filter is adjusted from 0 to 0.9, and the damping module begins to function. It can be seen that after 0.2s, the oscillation of the input voltage is rapidly suppressed, stabilizing to the reference value within 0.05s, demonstrating a fast damping response. The output voltage fluctuation also disappears, achieving the control objective of system output voltage reference tracking. This proves that the predictive control method for the LC-filtered dual active bridge DC-DC converter system proposed in this invention is truly effective. This method can achieve system input voltage resonant damping and output voltage reference tracking for the LC-filtered dual active bridge DC-DC converter system, and exhibits good dynamic performance.

[0103] Figure 3 The output voltage waveform is amplified after damping. It can be seen that in steady state, the fluctuation amplitude of the output voltage is less than 0.1% of its reference value amplitude, and there is no steady-state error. This proves that while achieving resonant damping, the method still has a strong output voltage reference tracking capability.

Claims

1. A predictive control method for an LC-filtered dual active bridge DC-DC converter system, characterized in that, Includes the following steps: Step 1: Calculate the system input voltage u of the LC filter-type dual active bridge DC-DC converter system. cf Output voltage u o and load current i o Input and output state variables are sampled, and the output voltage u is used. o and load current i o Establish a state-space average model for an LC-filtered dual active bridge DC-DC converter system; The state-space average model of the LC-filtered dual active bridge DC-DC converter system is as follows: ， In the formula, u in U is the power supply input voltage. o i is the system output voltage obtained through sampling. o The load current is obtained through sampling, R is the system load resistance, C is the system output capacitance, n is the turns ratio of the high-frequency isolation transformer, L is the auxiliary phase-shifting inductance, and f is the load current obtained through sampling. sw d is the switching frequency of the LC-filtered dual active bridge DC-DC converter system, and d is the phase shift control signal for controlling the switching transistors. Step 2: Discretize the state-space average model of the LC filter type dual active bridge DC converter system using the forward difference method to obtain a discrete model. Based on this discrete model, establish the discretized prediction equation for the output voltage of the LC filter type dual active bridge DC converter system. Step 3: Design the benchmark prediction performance function g for output voltage reference tracking of the LC-filtered dual active bridge DC-DC converter system; Step 4: Based on the principle of minimizing the function: Set the partial derivative of the reference prediction performance function g with respect to the phase shift control signal d to 0, and calculate the reference value d of the phase shift control signal that minimizes the reference prediction performance function g. ref ; The reference prediction performance function g for output voltage reference tracking of a system based on an LC-filtered dual active bridge DC-DC converter is expressed as follows: ， In the formula, U o_ref This is the reference value for the output voltage of an LC-filtered dual active bridge DC-DC converter system. Step 5: Extract the high-frequency resonant component u of the input voltage of the LC-filtered dual active bridge DC-DC converter system using a high-pass filter. cf，k k represents the current sampling time, using the output voltage reference value U given by the LC filter type dual active bridge DC-DC converter system. o_ref The corrected output voltage reference value is obtained by subtracting the high-frequency resonant component of the high-pass filter. ,use Calculate the reference value d of the damped phase-shift control signal with resonance suppression function. ref_dam ; Step 6: Use the damped phase shift control signal reference value d ref_dam A phase-shifting pulse signal is generated and applied to the switching transistors of the dual active bridge DC-DC converter to achieve resonance suppression of the input voltage and precise predictive control of the output voltage of the LC filter-type dual active bridge DC-DC converter system.

2. The predictive control method for an LC-filtered dual active bridge DC-DC converter system according to claim 1, characterized in that, The LC-filtered dual active bridge DC-DC converter system contains 8 switching transistors S 1~ S8 defines the phase-shift control signal d for controlling the switching transistors as the absolute value of the difference between the rising edge trigger times of the turn-on signals of transistors S1 and S5 within one switching cycle and half a switching cycle T. sw The ratio of / 2: ， in, and T represents the rising edge trigger time of the conduction signals S1 and S5, respectively. sw This indicates the switching cycle of the LC-filtered dual active bridge DC-DC converter.

3. The predictive control method for an LC-filtered dual active bridge DC-DC converter system according to claim 2, characterized in that, The method for discretizing the state-space average model of an LC-filtered dual active bridge DC-DC converter system using the forward difference method is as follows: ， In the formula, u o,k i represents the system output voltage at the current sampling time k. o,k U represents the load current at the current sampling time k. o,k+1 T represents the predicted value of the system output voltage at sampling time k+1. s The sampling period for the state variables of the LC-filtered dual active bridge DC-DC converter is given by f, where f is the sampling frequency. s The reciprocal of , where d is the phase-shift control signal controlling the switching transistor; Based on the above discrete model, the discretized prediction equation for the output voltage of the LC-filtered dual active bridge DC-DC converter system is established: 。 4. The predictive control method for an LC-filtered dual active bridge DC-DC converter system according to claim 1, characterized in that, Based on the principle of solving for the minimum value of a function, the phase-shift control signal reference value d that minimizes the baseline prediction performance function g is calculated. ref The process is as follows: Let the partial derivative of the reference prediction performance function g with respect to the phase shift control signal d be equal to 0, and then use the formula: The phase-shift control signal reference value d that minimizes g is obtained. ref : In the formula, variable M va The specific expression is as follows: 。 5. The predictive control method for an LC-filtered dual active bridge DC-DC converter system according to claim 1, characterized in that, The corrected output voltage reference value is calculated using the following formula. : ， In the formula, s represents the Laplace operator, and H (s) This represents a high-pass filter, specifically: ， In the formula, α represents the high-pass filter coefficient; The corrected output voltage reference value Substitute into the phase shift control signal reference value d ref From the calculation formula, the corresponding damping phase shift control signal reference value d is obtained. ref_dam , ， This achieves resonant damping of the system input voltage while maintaining output voltage reference tracking control, where the variable M... va_dam The specific expression is as follows: 。 6. The predictive control method for an LC-filtered dual active bridge DC-DC converter system according to claim 1, characterized in that, Using the damped phase-shift control signal reference value d ref_dam The generated phase-shifted pulse signals are applied to the switching transistors of the dual active bridge DC-DC converter. Specifically, within each sampling period, pulse signals with a duty cycle of 50% are applied to the eight switching transistors S1~S8 of both H-bridges. The pulse signals of switching transistors S1 and S2 in the first arm of the front-stage H-bridge are complementary, and the pulse signals of switching transistors S3 and S4 in the second arm are complementary; wherein the pulse signals of switching transistors S1 and S4 or S2 and S3 are consistent. The pulse signals of switching transistors S5 and S6 in the first arm of the rear-stage H-bridge are complementary, and the pulse signals of switching transistors S7 and S8 in the second arm are complementary; the pulse signals of switching transistors S5 and S7 or S6 and S8 are consistent. The pulse signal applied to the switching transistor S5 of the rear-stage H-bridge lags behind the pulse signal applied to the switching transistor S1 of the front-stage H-bridge by a phase shift time T. d Phase shift time T d The calculation method is as follows: 。 7. A control module for a predictive control method of an LC-filtered dual active bridge DC-DC converter system as described in any one of claims 1-6, characterized in that, The system includes the following components connected in sequence: an input / output state variable sampling unit, a state-space averaging model, a discretization prediction unit, a baseline model prediction performance function unit, a damped phase-shift control signal reference value unit, and a phase-shift pulse generation unit. The input / output state variable sampling unit is also connected to a high-pass filter, and the output of the high-pass filter is connected to the phase-shift control signal reference signal unit. Input / output state variable sampling unit, used to acquire input voltage, output voltage and load current information of LC filter type dual active bridge DC converter system; The state-space average model is constructed by using the state variable information of the obtained LC filter type dual active bridge DC converter system to build the corresponding state-space average mathematical model. The discretization prediction unit is used to discretize the mathematical model of the acquired LC filter type dual active bridge DC converter system to obtain the discretization prediction equation. The benchmark model prediction performance function unit is used to construct the benchmark prediction performance function based on output voltage reference tracking. A high-pass filter is used to extract the high-frequency resonant component of the input voltage of an LC-filtered dual active bridge DC-DC converter system and to correct the output voltage reference value. The phase-shift control signal reference signal unit combines the corrected output voltage reference value and the reference prediction performance function to obtain the phase-shift control signal reference value by minimizing the reference prediction performance function. The damping phase-shift control signal reference value unit obtains the damping phase-shift control signal reference value by extracting the high-frequency resonant component of the input voltage of the LC filter type dual active bridge DC converter system and correcting the output voltage reference value. The phase shift pulse generation unit uses the damped phase shift control signal reference value to generate a control pulse signal, which is then applied to the switching transistors of the system.

8. A computer device, characterized in that, It includes a processor and a memory, the processor being electrically connected to the memory, the memory being used to store instructions and data, and the processor being used to execute the predictive control method for the LC-filtered dual active bridge DC-DC converter system according to any one of claims 1-6.

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