Predictive control method and module for LC filtering type dual-active bridge direct current converter system

Abstract

The invention discloses a predictive control method and module for an LC filter type dual-active bridge direct current converter system, and belongs to the field of power electronic control. The method comprises the steps of sampling an input voltage, an output voltage and a load current of an LC filter type dual-active bridge direct current converter system, and establishing a state space averaging model of the system; discretizing the state space averaging model to establish a system output voltage discretization prediction equation; constructing a benchmark prediction performance function based on output voltage reference tracking, and obtaining a phase shift control signal reference value through minimizing the prediction performance function; correcting an output voltage reference value by extracting a high-frequency resonance component of a system input voltage, and obtaining a damping phase shift control signal reference value; and generating a control pulse signal by using the damping phase shift control signal reference value, and acting on a switching tube of the system. According to the method, input voltage resonance damping and output voltage reference tracking prediction control of the LC filter type dual-active bridge direct current converter system is realized.

Description

Technical Field

[0001] The invention relates to a predictive control method and a module for an LC filter type dual active bridge DC converter system, and relates to the field of power electronic converter control. Background Art

[0002] As the penetration rate of distributed photovoltaic, wind power and other new energy sources continues to increase, the inherent strong volatility and intermittency of these energy sources have brought challenges to the operational stability of large power grids, and the local consumption of new energy has become an urgent problem to be solved. For this reason, equipping energy storage units is considered to be an effective solution, which helps to reduce peaks and fill valleys, and realize local consumption and balance of energy. As a key interface device of distributed new energy storage systems, dual active bridge DC converters have the advantages of high power density, soft switching characteristics, electrical isolation and fewer passive components. They can realize bidirectional energy flow and meet diverse energy management and distribution needs. However, in practical applications, dual active bridge DC converters are usually affected by complex electromagnetic environments and nonlinear loads. The fluctuation of the output signal may affect the input signal of the previous stage through coupling, thereby generating high-frequency harmonics and causing electromagnetic interference and other problems. For this reason, it is necessary to cascade LC filters at the front end of the dual active bridge DC converter to filter out high-frequency harmonics, improve the quality of the output signal waveform, and improve the electromagnetic compatibility of the system.

[0003] Although the dual active bridge DC converter is relatively stable when operating alone, due to the inherent resonant frequency of the LC filter, when the working conditions change, the voltage at the cascade of the LC filter and the dual active bridge DC converter may resonate, which in turn leads to output voltage instability. The control scheme of the traditional dual active bridge DC converter mainly adopts proportional-integral (PI) control. Although this mature control method is widely used, it has many parameters to be adjusted, and there is coupling between the adjustment parameters, which makes the adjustment difficult. At the same time, the system dynamic performance is also insufficient. These problems are particularly serious in the damping control of the LC filter type dual active bridge DC converter system. In contrast, the predictive control method has gradually attracted attention due to its intuitive concept, few parameters, and support for multi-objective optimization. However, the existing predictive control strategy for the LC filter type dual active bridge DC converter system requires multiple voltage sensors and current sensors, which is costly, and because it is necessary to add additional control targets to the performance function predicted by the model, the calculation complexity of the control signal reference value is high, which is not conducive to its application in engineering practice. Therefore, an improved predictive control strategy is urgently needed to solve the resonance problem of the LC filter type dual active bridge DC converter system. Summary of the invention

[0004] In view of the shortcomings of the prior art, a predictive control method and module for an LC filter dual active bridge DC converter system are provided. The method takes into account the change of the system input voltage, thereby correcting the output voltage reference value in the required phase shift control signal reference expression, and uses the coupling relationship between the output signal and the previous stage input signal to achieve the resonant damping of the input voltage. There is no need to add additional control targets to the performance function predicted by the model, so the calculation complexity of the control signal reference value will not be increased. At the same time, the method does not need to sample additional current signals, and only an additional voltage sensor is added for the resonant damping control of the input voltage, which is low in cost.

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

[0006] Step 1: The system input voltage u of the LC filter type dual active bridge DC converter system cf , output voltage u o And the load current i o Sampling input and output state variables, using output voltage u o And the load current i o Establish the state space average model of LC filter dual active bridge DC converter system;

[0007] Step 2: discretize the state space average model of the LC filter type dual active bridge DC converter system by using the forward difference method to obtain a discrete model, and establish a discrete prediction equation for the output voltage of the LC filter type dual active bridge DC converter system based on the discrete model;

[0008] Step 3, designing a benchmark prediction performance function g based on output voltage reference tracking of the LC filter type dual active bridge DC converter system;

[0009] Step 4: Based on the function minimum solution principle: let the partial derivative of the benchmark prediction performance function g with respect to the phase shift control signal d be equal to 0, and calculate the phase shift control signal reference value d that can minimize the benchmark prediction performance function g. ref ;

[0010] Step 5: Use a high-pass filter to extract the high-frequency resonant component u of the input voltage of the LC filter type dual active bridge DC converter system cf，k , k represents the current sampling moment, using the output voltage reference value U given by the LC filter dual active bridge DC converter system o_ref Subtract the high-frequency resonant component of the high-pass filter to obtain the corrected output voltage reference value use Calculate the reference value d of the damping phase shift control signal with resonance suppression function ref_dam ;

[0011] Step 6: Use damping phase shift control signal reference value d ref_dam A phase-shift pulse signal is generated, and the generated phase-shift pulse signal acts on the switch tube of the dual active bridge DC converter to achieve resonance suppression of the input voltage of the LC filter type dual active bridge DC converter system and accurate predictive control of the output voltage.

[0012] Furthermore, the state space average model of the LC filter type dual active bridge DC converter system is expressed as follows:

[0013]

[0014] In the formula, u in is the power input voltage, u o is the system output voltage obtained by sampling, i o is the load current obtained by sampling, R is the system load resistance value, C is the system output capacitance value, n is the high-frequency isolation transformer ratio, L is the auxiliary phase shift inductance value, f sw is the switching frequency of the LC filter dual active bridge DC converter system, and d is the phase shift control signal for controlling the switch tube;

[0015] The LC filter dual active bridge DC converter system includes 8 switch tubes S 1～ S8, the phase shift control signal d for controlling the switch tube is defined as the absolute value of the difference between the rising edge trigger time of the turn-on signal of the switch tubes S1 and S5 in one switching cycle and the difference between ... sw Ratio of / 2:

[0016]

[0017] in, and Respectively represent the rising edge trigger time of the conduction signal of S1 and S5, T sw Represents the switching cycle of the LC filter type dual active bridge DC converter.

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

[0019]

[0020] In the formula, u o,k represents the system output voltage at the current sampling time k, i o,k represents the load current at the current sampling time k, u o,k+1 represents the predicted value of the system output voltage at sampling time k+1, T sis the sampling period of the state variable of the LC filter dual active bridge DC converter, and is the sampling frequency f s The reciprocal of , d is the phase shift control signal that controls the switch tube;

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

[0022]

[0023] Furthermore, the benchmark prediction performance function g of the output voltage reference tracking of the LC filter type dual active bridge 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] Where U o_ref It is the output voltage reference value of the LC filter dual active bridge DC converter system.

[0026] Furthermore, based on the function minimum solution principle, the phase shift control signal reference value d that can minimize the benchmark prediction performance function g is calculated. ref The process is as follows:

[0027] Let the partial derivative of the benchmark prediction performance function g with respect to the phase shift control signal d be equal to 0, through the formula: Get the phase shift control signal reference value d that can minimize g ref :

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

[0029]

[0030] Further, the corrected output voltage reference value is calculated using the following formula:

[0031]

[0032] Where s represents the Laplace operator, H (s) Represents a high-pass filter, which is specifically expressed as:

[0033]

[0034] Where 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 The corresponding damping phase shift control signal reference value d is obtained in the calculation formula ref_dam ,

[0036]

[0037] In this way, the resonance damping of the system input voltage is ensured based on the output voltage reference tracking control. In the formula, the variable M va_dam The specific expression is as follows:

[0038]

[0039] Furthermore, the damping phase shift control signal reference value d ref_dam The generated phase-shift pulse signal acts on the switch tube of the dual active bridge DC converter. Specifically, in each sampling period, a pulse signal with a duty cycle of 50% is applied to the eight switch tubes S1 to S8 of the H bridge on both sides. The pulse signals of the switch tubes S1 and S2 of the first bridge arm of the converter front-stage H bridge are complementary, and the pulse signals of the switch tubes S3 and S4 of the second bridge arm are complementary; wherein the pulse signals of the switch tubes S1 and S4 or the switch tubes S2 and S3 are consistent; the pulse signals of the switch tubes S5 and S6 of the first bridge arm of the converter rear-stage H bridge are complementary, and the pulse signals of the switch tubes S7 and S8 of the second bridge arm are complementary, and the pulse signals of the switch tubes S5 and S7 or the switch tubes S6 and S8 are consistent; the pulse signal applied to the switch tube S5 of the converter rear-stage H bridge lags behind the pulse signal applied to the switch tube 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 filter type dual active bridge DC converter system comprises: an input and output state variable sampling unit, a state space average model, a discretization prediction unit, a reference model prediction performance function unit, a damping phase shift control signal reference value unit, and a shift pulse generating unit, which are connected in sequence, wherein the input and output state variable sampling unit is also connected to a high-pass filter, and the output end of the high-pass filter is connected to the phase shift control signal reference signal unit;

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

[0043] The state space average model uses the acquired state variable information of the LC filter type dual active bridge DC converter system to construct the corresponding state space average mathematical model;

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

[0045] A benchmark model prediction performance function unit, used to construct a benchmark prediction performance function based on output voltage reference tracking;

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

[0047] A phase shift control signal reference signal unit combines the corrected output voltage reference value and the benchmark prediction performance function to obtain a phase shift control signal reference value by minimizing the benchmark prediction performance function;

[0048] The damping phase shift control signal reference value unit extracts the high-frequency resonance component of the input voltage of the LC filter type dual active bridge DC converter system to correct the output voltage reference value, thereby obtaining the damping phase shift control signal reference value;

[0049] The phase shift pulse generating unit generates a control pulse signal using a damped phase shift control signal reference value and acts on the switch tube of the system.

[0050] A computer device comprises a processor and a memory, wherein the processor is electrically connected to the memory, the memory is used to store instructions and data, and the processor is used to execute a predictive control method for an LC filter type dual active bridge DC converter system.

[0051] Compared with the prior art, the present invention has the following beneficial effects:

[0052] 1. This method corrects the output voltage reference value in the reference expression of the required phase-shift control signal by considering the change of the system input voltage, and uses the coupling effect of the output signal on the previous input signal to achieve the resonance damping of the input voltage. There is no need to add additional control objectives to the performance function predicted by the model, so it does not increase the calculation complexity of the control signal.

[0053] 2. This method samples the system input voltage, output voltage and load current. Compared with the existing resonant suppression predictive control scheme for this topology, it does not need to sample the power supply input current, thus reducing the use of current sensors and achieving significant cost reduction.

[0054] 3. This method only introduces one parameter, the high-pass filter coefficient α, and the adjustment is simple. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1It is a schematic diagram of the topological structure and control method of the LC filter type dual active bridge DC converter system of the present invention;

[0056] Figure 2 A schematic diagram of signal response obtained by the LC filter type dual active bridge DC converter system of the present invention;

[0057] Figure 3 Schematic diagram of the output voltage waveform of the LC filter type dual active bridge DC converter system after damping in an embodiment of the present invention. DETAILED DESCRIPTION

[0058] The embodiments of the present invention are further described below in conjunction with the accompanying drawings.

[0059] like Figure 1 As shown, the present invention discloses an LC filter type dual active bridge DC converter system corresponding to the predictive control method of the LC filter type dual active bridge DC converter system. The overall topological structure of the LC filter type dual active bridge DC converter system is composed of a DC input power supply voltage u from left to right. in , LC filter, dual active bridge DC converter and load with voltage stabilizing capacitor are cascaded. The LC filter part includes filter inductor L f , equivalent filter impedance R f And filter capacitor C f The dual active bridge DC converter part 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 (IGBT) S1~S4 and their anti-parallel diodes, and the right H bridge consists of four IGBTs S5~S8 and their anti-parallel diodes; the high-frequency isolation transformer ratio is n:1. o Indicates the system output voltage, i o represents the load current, which is sampled by the sampling module and used to establish the state space average model of the LC filter type dual active bridge DC converter system. cf Represents the system input voltage, which is sampled by the sampling module and processed by the high-pass filter to correct the output voltage reference value U o_ref .

[0060] A predictive control module for an LC filter type dual active bridge DC converter system comprises: an input and output state variable sampling unit, a state space average model, a discretization prediction unit, a reference model prediction performance function unit, a damping phase shift control signal reference value unit, and a shift pulse generating unit, which are connected in sequence, wherein the input and output state variable sampling unit is also connected to a high-pass filter, and the output end of the high-pass filter is connected to the phase shift control signal reference signal unit;

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

[0062] The state space average model uses the acquired state variable information of the LC filter type dual active bridge DC converter system to construct the corresponding state space average mathematical model;

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

[0064] A benchmark model prediction performance function unit, used to construct a benchmark prediction performance function based on output voltage reference tracking;

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

[0066] A phase shift control signal reference signal unit combines the corrected output voltage reference value and the benchmark prediction performance function to obtain a phase shift control signal reference value by minimizing the benchmark prediction performance function;

[0067] The damping phase shift control signal reference value unit extracts the high-frequency resonance component of the input voltage of the LC filter type dual active bridge DC converter system to correct the output voltage reference value, thereby obtaining the damping phase shift control signal reference value;

[0068] The phase shift pulse generating unit generates a control pulse signal using a damped phase shift control signal reference value and acts on the switch tube of the system.

[0069] A predictive control method for an LC filter type dual active bridge DC converter system comprises the following steps:

[0070] Step 1: Establish the state space average model of the LC filter type dual active bridge DC converter system, which is as follows:

[0071]

[0072] In the formula, u in is the power input voltage, u o is the system output voltage obtained by sampling, i o is the load current obtained by sampling, R is the load resistance value, C is the system output capacitance value, n is the high-frequency isolation transformer ratio, L is the auxiliary phase shift inductance value, f sis the sampling frequency of the state variable of the LC filter dual active bridge DC converter system, d is the phase shift control signal for controlling the switch tube, which is specifically defined as the ratio of the absolute value of the difference between the rising edge trigger time of the turn-on signals of the switch tubes S1 and S5 in one switching cycle to half a switching cycle:

[0073]

[0074] Among them, t S1_up and t S5_up They respectively represent the rising edge triggering time of the conduction signal of S1 and S5.

[0075] In the formula, i 1αβ 、v cαβ 、i 2αβ They represent the inverter side current, LCL capacitor voltage, and grid side current of the three-phase AC grid of the LCL filter type three-phase grid-connected inverter system under the α-β axis, respectively. iαβ represents the inverter voltage under the α-β axis, v gαβ represents the α-β axis grid voltage; L1 and R1 represent the filter inductance and parasitic resistance output by the LCL filter type three-phase grid-connected inverter system; L2 and R2 are the grid-side filter inductance and parasitic resistance; and C is the filter capacitor.

[0076] Step 2: Use the forward difference method to discretize the state space average model of the LC filter dual active bridge DC converter system:

[0077]

[0078] In the formula, u o,k Indicates the system output voltage at the current sampling moment, i o,k Indicates the load current at the current sampling moment, u o,k+1 represents the predicted value of the system output voltage at the next sampling moment, T s is the sampling period of the state variable of the LC filter dual active bridge DC converter, and 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 the LC filter type dual active bridge DC converter system can be established:

[0080]

[0081] Step 3: Design a benchmark prediction performance function g based on the output voltage reference tracking of the LC filter dual active bridge DC converter system:

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

[0083] Where U o_ref It is the system output voltage reference value.

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

[0085]

[0086] In the formula, the 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 convert the high-frequency resonant component from the output voltage reference value U o_ref Subtract the above value to get the corrected output voltage reference value

[0089]

[0090] Where s represents the Laplace operator, H (s) Represents a high-pass filter, which is specifically expressed as:

[0091]

[0092] Where α represents the high-pass filter coefficient.

[0093] Furthermore, the corrected output voltage reference value Substitute into the reference value d of the original phase shift control signal ref , the corresponding damping phase shift control signal reference value d can be obtained ref_dam , thereby achieving the resonance damping of the system input voltage based on the output voltage reference tracking control, d ref_dam The specific form is as follows:

[0094]

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

[0096]

[0097] Step 6: Use damping phase shift control signal reference value d ref_damGenerate a phase-shift pulse signal and act on the switch tube of the dual active bridge DC converter. Specifically, in each sampling period, a pulse signal with a duty cycle of 50% is applied to the eight switch tubes S1 to S8 of the H bridge on both sides, wherein the pulse signals of the first bridge arm S1 and S2 of the front-stage H bridge of the converter are complementary, the pulse signals of the second bridge arm S3 and S4 are complementary, and the pulse signals of S1 (S2) and S4 (S3) are consistent; the pulse signals of the first bridge arm S5 and S6 of the rear-stage H bridge of the converter are complementary, the pulse signals of the second bridge arm S7 and S8 are complementary, and the pulse signals of S5 (S6) and S8 (S7) are consistent; the pulse signal applied to the switch tube S5 of the rear-stage H bridge of the converter should lag behind the pulse signal applied to the switch tube S1 of the front-stage H bridge by a phase shift time T d , the time is calculated as follows:

[0098]

[0099] In order to verify the predictive control method of an LC filter type dual active bridge DC converter system provided by the present invention, the method provided by the present invention is applied to an LC filter type dual active bridge DC converter system, and the system parameters are given in Table 1.

[0100] Table 1

[0101]

[0102] Figure 2 The signal response obtained by using the proposed method to control the LC filter type dual active bridge DC converter system, specifically, the upper figure is the system input voltage signal response, and the lower figure is the system output voltage signal response. At the simulation time of 0.2s, the α high-pass filter coefficient is adjusted from 0 to 0.9, and the damping module begins to work. It can be seen that after 0.2s, the oscillation state of the input voltage is quickly suppressed, and stabilizes to the reference value within 0.05s, and the damping response speed is fast; the output voltage fluctuation also disappears, achieving the control goal of the system output voltage reference tracking. It can be proved that the predictive control method of the LC filter type dual active bridge DC converter system proposed in the present invention is real and effective. The method can realize the system input voltage resonance damping and output voltage reference tracking for the LC filter type dual active bridge DC converter system, and has good dynamic performance.

[0103] Figure 3 This is the amplified waveform of the system output voltage 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, and there is no steady-state error, which proves that this method has a strong output voltage reference tracking capability while achieving resonance damping.

Claims

1. A predictive control method for an LC filter type dual active bridge DC converter system, characterized in that: The steps include: Step 1: The system input voltage u of the LC filter type dual active bridge DC converter system cf , output voltage u o And the load current i o Sampling input and output state variables, using output voltage u o And the load current i o Establish the state space average model of LC filter dual active bridge DC converter system; Step 2: discretize the state space average model of the LC filter type dual active bridge DC converter system by using the forward difference method to obtain a discrete model, and establish a discrete prediction equation for the output voltage of the LC filter type dual active bridge DC converter system based on the discrete model; Step 3, designing a benchmark prediction performance function g based on output voltage reference tracking of the LC filter type dual active bridge DC converter system; Step 4: Based on the function minimum solution principle: let the partial derivative of the benchmark prediction performance function g with respect to the phase shift control signal d be equal to 0, and calculate the phase shift control signal reference value d that can minimize the benchmark prediction performance function g. ref ; Step 5: Use a high-pass filter to extract the high-frequency resonant component u of the input voltage of the LC filter type dual active bridge DC converter system cf，k , k represents the current sampling moment, using the output voltage reference value U given by the LC filter dual active bridge DC converter system o_ref Subtract the high-frequency resonant component of the high-pass filter to obtain the corrected output voltage reference value use Calculate the reference value d of the damping phase shift control signal with resonance suppression function ref_dam ; Step 6: Use damping phase shift control signal reference value d ref_dam A phase-shift pulse signal is generated, and the generated phase-shift pulse signal acts on the switch tube of the dual active bridge DC converter to achieve resonance suppression of the input voltage of the LC filter type dual active bridge DC converter system and accurate predictive control of the output voltage.

2. The predictive control method for a LC filter type dual active bridge DC converter system according to claim 1, characterized in that: The state space average model of the LC filter dual active bridge DC converter system is expressed as follows: In the formula, u in is the power input voltage, u o is the system output voltage obtained by sampling, i o is the load current obtained by sampling, R is the system load resistance value, C is the system output capacitance value, n is the high-frequency isolation transformer ratio, L is the auxiliary phase shift inductance value, f sw is the switching frequency of the LC filter type dual active bridge DC converter system, and d is the phase shift control signal for controlling the switch tube; The LC filter type dual active bridge DC converter system includes 8 switch tubes S 1～ S8, the phase shift control signal d for controlling the switch tube is defined as the absolute value of the difference between the rising edge trigger time of the turn-on signal of the switch tubes S1 and S5 in one switching cycle and the difference between ... sw / 2 ratio: in, and Respectively represent the rising edge trigger time of the conduction signal of S1 and S5, T sw Represents the switching cycle of the LC filter type dual active bridge DC converter.

3. The predictive control method for a LC filter type dual active bridge DC converter system according to claim 2, characterized in that: The method of discretizing the state space average model of the LC filter type dual active bridge DC converter system using the forward difference method is as follows: In the formula, u o,k represents the system output voltage at the current sampling time k, i o,k represents the load current at the current sampling time k, u o,k+1 represents the predicted value of the system output voltage at sampling time k+1, T s is the sampling period of the state variable of the LC filter dual active bridge DC converter, and is the sampling frequency f s The reciprocal of , d is the phase shift control signal that controls the switch tube; Based on the above discrete model, the discretization prediction equation of the output voltage of the LC filter dual active bridge DC converter system is established:

4. The predictive control method for a LC filter type dual active bridge DC converter system according to claim 3, characterized in that: The benchmark prediction performance function g of the output voltage reference tracking of the LC-filtered dual active bridge DC converter system is expressed as follows: g=(U o_ref -in o,k+1 ) 2 +(in o,k+1 -in o,k ) 2 Where U o_ref It is the output voltage reference value of the LC filter dual active bridge DC converter system.

5. The predictive control method for a LC filter type dual active bridge DC converter system according to claim 1, characterized in that: Based on the function minimum solution principle, the phase shift control signal reference value d that can minimize the benchmark prediction performance function g is calculated. ref The process is as follows: Let the partial derivative of the benchmark prediction performance function g with respect to the phase shift control signal d be equal to 0, through the formula: Get the phase shift control signal reference value d that can minimize g ref : In the formula, the variable M va The specific expression is as follows:

6. The predictive control method for a LC filter type dual active bridge DC converter system according to claim 1, characterized in that: The corrected output voltage reference value is calculated using the following formula: Where s represents the Laplace operator, H (s) Represents a high-pass filter, which is specifically expressed as: Where α represents the high-pass filter coefficient; The corrected output voltage reference value Substitute into the phase shift control signal reference value d ref The corresponding damping phase shift control signal reference value d is obtained in the calculation formula ref_dam , In this way, the resonance damping of the system input voltage is ensured based on the output voltage reference tracking control. In the formula, the variable M va_dam The specific expression is as follows:

7. The predictive control method for a LC filter type dual active bridge DC converter system according to claim 1, characterized in that: Using damping phase shift control signal reference value d ref_dam The generated phase-shift pulse signal acts on the switch tube of the dual active bridge DC converter. Specifically, in each sampling period, a pulse signal with a duty cycle of 50% is applied to the eight switch tubes S1 to S8 of the H bridge on both sides. The pulse signals of the switch tubes S1 and S2 of the first bridge arm of the converter front-stage H bridge are complementary, and the pulse signals of the switch tubes S3 and S4 of the second bridge arm are complementary; wherein the pulse signals of the switch tubes S1 and S4 or the switch tubes S2 and S3 are consistent; the pulse signals of the switch tubes S5 and S6 of the first bridge arm of the converter rear-stage H bridge are complementary, and the pulse signals of the switch tubes S7 and S8 of the second bridge arm are complementary, and the pulse signals of the switch tubes S5 and S7 or the switch tubes S6 and S8 are consistent; the pulse signal applied to the switch tube S5 of the converter rear-stage H bridge lags behind the pulse signal applied to the switch tube 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:

8. A predictive control module for a LC filter type dual active bridge DC converter system, characterized in that: It includes the following sequentially connected units: an input-output state variable sampling unit, a state space average model, a discretization prediction unit, a benchmark model prediction performance function unit, a damped phase shift control signal reference value unit, and a shift pulse generation unit, wherein the input-output state variable sampling unit is also connected to a high-pass filter, and the output end of the high-pass filter is connected to the phase shift control signal reference signal unit; An input and output state variable sampling unit is used to obtain input voltage, output voltage and load current information of the LC filter type dual active bridge DC converter system; The state space average model uses the acquired state variable information of the LC filter type dual active bridge DC converter system to construct the corresponding state space average mathematical model; A discretization prediction unit is used to discretize the acquired mathematical model of the LC filter type dual active bridge DC converter system to obtain a discretization prediction equation; A benchmark model prediction performance function unit, used to construct a benchmark prediction performance function based on output voltage reference tracking; A high-pass filter is used to extract the high-frequency resonance component of the input voltage of the LC filter type dual active bridge DC converter system and to correct the output voltage reference value; A phase shift control signal reference signal unit combines the corrected output voltage reference value and the benchmark prediction performance function to obtain a phase shift control signal reference value by minimizing the benchmark prediction performance function; The damping phase shift control signal reference value unit extracts the high-frequency resonance component of the input voltage of the LC filter type dual active bridge DC converter system to correct the output voltage reference value, thereby obtaining the damping phase shift control signal reference value; The phase shift pulse generating unit generates a control pulse signal using a damped phase shift control signal reference value and acts on the switch tube of the system.

9. A computer device, characterized in that: It comprises a processor and a memory, wherein the processor is electrically connected to the memory, the memory is used to store instructions and data, and the processor is used to execute the LC filter type dual active bridge DC converter system predictive control method described in any one of claims 1-7.

Images