Dual-band current control system and control method for dual-active full-bridge converter

Abstract

The invention relates to the technical field of power electronic conversion, in particular to a dual-band current control system and method for a dual-active full-bridge converter, and the system comprises a voltage controller, a dual-band current controller, and a combinational logic circuit. The voltage controller is used for obtaining an output target current according to the sampled actual output voltage and the output target voltage of the dual-active full-bridge converter; the dual-band current controller is used for obtaining a setting signal and a zero setting signal according to the output target current and the sampled actual inductive current of the dual-active full-bridge converter; and the combinational logic circuit is used for generating a conduction signal of each switch tube of the dual-active full-bridge converter according to the setting signal, the zero setting signal and the auxiliary signal, and further controlling the conduction of each switch tube of the dual-active full-bridge converter according to the conduction signal. According to the invention, the generation of transient and steady-state DC bias can be suppressed without an additional blocking capacitor, and the saturation of the transformer is effectively avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of power electronic conversion, and in particular to a dual-band current control system and a control method for a dual-active full-bridge converter. Background Art

[0002] DC / DC converters serve as the hub for energy collection and distribution in DC distribution networks, connecting high- and low-voltage DC buses of varying voltage levels. Distributed energy resources and DC loads are also connected to the grid through corresponding DC / DC converters. Dual Active Bridge (DAB) DC-DC converters, with their symmetrical structure, wide voltage conversion range, electrical isolation, and bidirectional energy flow, are well-suited for use in DC distribution networks. They also fully utilize the transformer's leakage inductance, facilitate soft switching, reduce switching losses, and achieve high efficiency. However, DAB DC / DC converters can suffer from inconsistent device characteristics in steady state or DC bias during dynamic switching, leading to adverse effects such as magnetic saturation and increased current stress, potentially damaging power equipment. Furthermore, DC bias can affect controllers in closed-loop systems, causing severe oscillations and deteriorating transient response.

[0003] To suppress DC bias, blocking capacitors are typically connected in series on both sides of the transformer. Larger capacitance values are generally required to mitigate the impact on the original circuit, but this increases the size and cost of the converter and introduces additional losses. Without blocking capacitors, the primary and secondary currents of the transformer are sampled and the drive signals on both sides are adjusted based on the average current value. This is clearly a slow control method that cannot eliminate transient shocks. Another approach is to use a predictive controller with peak current control. This approach predicts the phase of the DAB converter's bridge arm to obtain the required peak current reference value, effectively avoiding transformer saturation. However, predictive control is highly dependent on the accuracy of inductance measurement and calculation precision; otherwise, the predicted phase result will deviate significantly from the actual phase. Summary of the Invention

[0004] To address the problems in the prior art, the present invention provides a dual-band current control system and control method for a dual-active full-bridge converter. This effectively suppresses DC bias during dual-active full-bridge operation, ensuring excellent system reliability and facilitating safe system operation. The specific technical solution is as follows:

[0005] A dual-band current control system for a dual-active full-bridge converter, comprising a voltage controller, a dual-band current controller, and a combinational logic circuit;

[0006] The voltage controller is used to obtain an output target current according to the actual output voltage of the dual-active full-bridge converter obtained by sampling and the output target voltage;

[0007] The dual-band current controller is used to obtain a set signal and a zero signal according to the output target current and the actual inductor current of the dual active full-bridge converter obtained by sampling;

[0008] The combinational logic circuit is used to generate a conduction signal for each switch tube of the dual active full-bridge converter according to the set signal, the zero signal and the auxiliary signal, and then control the conduction of each switch tube of the dual active full-bridge converter according to the conduction signal.

[0009] Preferably, the voltage controller comprises a summer, a PI regulator, and a limiter connected in sequence;

[0010] The actual output voltage and the output target voltage of the dual active full-bridge converter are passed through a summer to obtain a voltage error, and the voltage error is passed through a PI regulator and a limiter in sequence to obtain an output target current.

[0011] Preferably, the output target current is calculated as follows:

[0012]

[0013] ε=V ref -V o ;

[0014] Among them, i ref is the output target current, K p is the proportional gain, K i is the integral gain, ε is the voltage error, V ref is the output target voltage, V o is the actual output voltage of the dual active full-bridge converter.

[0015] Preferably, the dual-band current controller includes a first comparator and a second comparator;

[0016] The first comparator is used to obtain a zero signal according to the output target current; the second comparator is used to obtain a set signal according to the output target current.

[0017] Preferably, the positive input terminal of the first comparator inputs the negative output target current, the negative input terminal of the first comparator inputs the sampled actual inductor current of the dual active full-bridge converter, and the output terminal of the first comparator outputs a zero signal;

[0018] The negative input terminal of the second comparator inputs the output target current, the positive input terminal of the second comparator inputs the sampled actual inductor current of the dual active full-bridge converter, and the output terminal of the second comparator outputs a set signal.

[0019] Preferably, the combinational logic circuit includes a NOT gate, a first OR gate, a second OR gate, a first AND gate, a second AND gate, and an RS trigger; the auxiliary signal includes an auxiliary ON signal, an auxiliary OFF signal, and a reference signal;

[0020] The two input terminals of the first OR gate are respectively input with a set signal and an auxiliary enable signal, the output terminal of the first OR gate is connected to one input terminal of the first AND gate, the other input terminal of the first AND gate is input with a reference signal, and the output terminal of the first AND gate is connected to the S terminal of the RS flip-flop;

[0021] The reference signal is input into the input terminal of the NOT gate, and the output terminal is connected to an input terminal of the second AND gate;

[0022] The two input terminals of the first OR gate are respectively input with a reset signal and an auxiliary shutdown signal, the output terminal of the first OR gate is connected to the other input terminal of the second AND gate, and the output terminal of the second AND gate is connected to the R terminal of the RS trigger;

[0023] The Q terminal of the RS trigger outputs a conduction signal S5, which is used to control the conduction of the switch tube S5 in the upper half of the first half bridge of the secondary side of the transformer of the dual active full-bridge converter;

[0024] The reference signal is directly used as the conduction signal S1 to control the conduction of the switch tube S1 in the upper half of the first half-bridge on the primary side of the transformer of the dual active full-bridge converter.

[0025] Preferably, the signal S input to the S terminal of the RS trigger is expressed as follows:

[0026] S=(Set+V b+ )·V D ;

[0027] Among them, Set is the set signal, V b+ is the auxiliary opening signal, V D is the reference signal.

[0028] Preferably, the signal R input to the R terminal of the RS trigger is expressed as follows:

[0029]

[0030] Among them, Reset is the zero reset signal, V b- To assist the shutdown signal, is the reference signal V D The signal after negation.

[0031] Preferably, the turn-on signal S4 of the switch tube S4 in the lower half of the second half-bridge on the primary side of the transformer of the dual-active full-bridge converter is the same as the turn-on signal S1; the turn-on signal S8 of the switch tube S8 in the lower half of the second half-bridge on the secondary side of the transformer of the dual-active full-bridge converter is the same as the turn-on signal S5; and the switches in the same bridge arm are complementary to each other.

[0032] A dual-band current control method for a dual-active full-bridge converter, using the system, comprises the following steps:

[0033] Step S1, collecting the actual output voltage of the dual active full-bridge converter and the actual inductor current of the dual active full-bridge converter;

[0034] Step S2, obtaining an output target current according to the sampled actual output voltage and the output target voltage of the dual-active full-bridge converter;

[0035] Step S3, obtaining a set signal and a zero signal according to the output target current and the actual inductor current of the dual active full-bridge converter;

[0036] Step S4: generating a conduction signal for each switch tube of the dual active full-bridge converter according to the set signal, the zero signal, and the auxiliary signal, and then controlling the conduction of each switch tube of the dual active full-bridge converter according to the conduction signal.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] The present invention strictly controls the changes of the inductor current at positive and negative positions with the same absolute value, ensures that the inductor current waveform is symmetrical about 0, suppresses the generation of transient and steady-state DC bias without the need for additional DC blocking capacitors, and effectively avoids transformer saturation. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly describes the drawings required for the specific embodiments or the description of the prior art. Similar elements or parts are generally identified by similar reference numerals throughout the drawings. Elements or parts in the drawings are not necessarily drawn to scale.

[0040] Figure 1 It is a dual active full-bridge basic topology.

[0041] Figure 2 The present invention discloses a dual-band current control strategy for a dual active full-bridge.

[0042] Figure 3 The auxiliary signal and combinational logic circuit disclosed in the present invention.

[0043] Figure 4This is the simplified working waveform of the dual active full-bridge DC.

[0044] Figure 5 Schematic diagram of dual active full-bridge dual-band current control.

[0045] Figure 6 This is the steady-state operating waveform of the dual active full-bridge.

[0046] Figure 7 This is the transient working waveform of the dual active full bridge. Figure 8 This is a flow chart of the control method of the present invention. DETAILED DESCRIPTION

[0047] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0048] It will be understood that when used in this specification and the appended claims, the terms “comprises” and “comprising” indicate the presence of described features, integers, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0049] It should also be understood that the terms used in the present specification are only for the purpose of describing particular embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0050] It should be further understood that the term "and / or" used in the present description and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0051] Example 1:

[0052] This embodiment provides a dual-band current control system for a dual-active full-bridge converter. Figure 1As shown, the dual-active full-bridge converter includes two full bridges, each of which includes two half bridges. The first half bridge of the full bridge on the primary side of transformer T includes switches S1 and S2; the second half bridge of the full bridge on the primary side of transformer T includes switches S3 and S4. The first half bridge of the full bridge on the secondary side of transformer T includes switches S5 and S6; the second half bridge of the full bridge on the primary side of transformer T includes switches S7 and S8.

[0053] like Figure 2 As shown, the dual-band current control system for the dual-active full-bridge converter provided in this embodiment includes a voltage controller, a dual-band current controller, and a combinational logic circuit; the voltage controller is used to obtain an output target current based on the actual output voltage of the dual-active full-bridge converter obtained by sampling and the output target voltage; the dual-band current controller is used to obtain a set signal and a zero signal based on the output target current and the actual inductor current of the dual-active full-bridge converter obtained by sampling; the combinational logic circuit is used to generate a conduction signal for each switch tube of the dual-active full-bridge converter based on the set signal, the zero signal, and the auxiliary signal, and then control the conduction of each switch tube of the dual-active full-bridge converter based on the conduction signal. Wherein, the auxiliary signal includes an auxiliary turn-on signal, an auxiliary turn-off signal, and a reference signal, as shown in FIG. Figure 3 (a) shows that the reference signal is a fixed 50% duty cycle switching signal.

[0054] As a preferred embodiment, the voltage controller includes a summer, a PI regulator, and a limiter connected in sequence. The actual output voltage of the dual-active full-bridge converter and the output target voltage are passed through the summer to obtain a voltage error. The voltage error is then passed through the PI regulator and the limiter to obtain the output target current. The output target current is calculated as follows:

[0055]

[0056] ε=V ref -V o ;

[0057] Among them, i ref is the output target current, K p is the proportional gain, K i is the integral gain, ε is the voltage error, V ref is the output target voltage, V o is the actual output voltage of the dual active full-bridge converter, and t is the current moment.

[0058] As a preferred embodiment, the dual-band current controller includes a first comparator and a second comparator; the first comparator is used to obtain a zero signal according to the output target current; the second comparator is used to obtain a set signal according to the output target current.

[0059] Specifically, the positive input terminal of the first comparator inputs the negative output target current, the negative input terminal of the first comparator inputs the sampled actual inductor current of the dual active full-bridge converter, and the output terminal of the first comparator outputs a zero signal;

[0060] The negative input terminal of the second comparator inputs the output target current, the positive input terminal of the second comparator inputs the sampled actual inductor current of the dual active full-bridge converter, and the output terminal of the second comparator outputs a set signal.

[0061] As a preferred embodiment, Figure 3 As shown in (b), the combinational logic circuit includes a NOT gate, a first OR gate, a second OR gate, a first AND gate, a second AND gate, and an RS flip-flop. The first OR gate has two inputs that receive a set signal and an auxiliary turn-on signal, respectively. The output of the first OR gate is connected to one input of the first AND gate, the other input of the first AND gate receives a reference signal, and the output of the first AND gate is connected to the S terminal of the RS flip-flop. The NOT gate has an input that receives a reference signal, and its output is connected to one input of the second AND gate. The first OR gate has two inputs that receive a zero signal and an auxiliary turn-off signal, respectively. The output of the first OR gate is connected to the other input of the second AND gate, and the output of the second AND gate is connected to the R terminal of the RS flip-flop. The Q terminal of the RS flip-flop outputs a conduction signal S5, which is used to control the conduction of the switch S5 in the upper half of the first half-bridge on the secondary side of the transformer of the dual-active full-bridge converter. When S=1 and R=0, Q=1; when S=0 and R=1, Q=0; and when S=R=0, Q remains unchanged.

[0062] The reference signal directly serves as the turn-on signal S1, controlling the conduction of the switch S1 in the upper half of the first half-bridge on the primary side of the dual-active full-bridge converter. The turn-on signal S4 for the switch S4 in the lower half of the second half-bridge on the primary side of the dual-active full-bridge converter is the same as the turn-on signal S1. The turn-on signal S8 for the lower half of the second half-bridge on the secondary side of the dual-active full-bridge converter is the same as the turn-on signal S5. The switches in the same bridge arm are complementary. That is, the turn-on signal S2 for the switch S2 in the lower half of the first half-bridge on the primary side of the dual-active full-bridge converter's transformer T is complementary to the turn-on signal S1, and the turn-on signal S3 for the switch S3 in the upper half of the second half-bridge on the primary side of the dual-active full-bridge converter's transformer T is complementary to the turn-on signal S4.

[0063] The turn-on signal S6 of the switch tube S6 in the lower half of the first half-bridge on the secondary side of the transformer T of the dual-active full-bridge converter is complementary to the turn-on signal S5, and the turn-on signal S7 of the switch tube S7 in the upper half of the second half-bridge on the secondary side of the transformer T of the dual-active full-bridge converter is complementary to the turn-on signal S8.

[0064] Among them, the signal S input to the S terminal of the RS trigger is expressed as follows:

[0065] S=(Set+V b+ )·V D ;

[0066] Among them, Set is the set signal, V b+ is the auxiliary opening signal, V D is the reference signal.

[0067] The signal R input to the R terminal of the RS trigger is expressed as follows:

[0068]

[0069] Among them, Reset is the zero reset signal, V b- To assist the shutdown signal, is the reference signal V D The signal after negation.

[0070] To illustrate the DC bias suppression principle of the present invention, Figure 4 The working waveform of the dual active full-bridge converter is shown, where V in is the input voltage, V o is the output voltage, n is the transformation ratio of transformer T, T s is the switching period of the dual active full-bridge converter, and the voltage conversion ratio k = nV o / V in .

[0071] When the voltage conversion ratio k<1, DAB works in Buck mode; when k>1, DAB works in Boost mode. ab is the midpoint voltage of the primary arm of the dual active full bridge, v cd is the midpoint voltage of the secondary bridge arm of the dual active full bridge, i L is the inductor current.

[0072] When DAB works in Boost mode, i T is the peak value of the inductor current. When the inductor current i L When the peak or valley value is reached, v cd However, when DAB operates in Buck mode, i T It is not the peak value, but this time point still determines v cd The voltage switching time is short, so the control is also effective. This control is called band current control. The “band current” is i P , let i P =i T .

[0073] The voltage controller regulates the output voltage to stabilize it, and the output of the voltage controller serves as a reference value for the dual-band current controller. Figure 5 The schematic diagram of dual-band current control is shown. At time T1, the inductor current reaches the positive band i P When v cd The output voltage switches to a positive value (ie S5 and S8 are turned on); at time T2, when the inductor current reaches the negative frequency band -i P When v cd Switch to negative value (i.e. S6 and S7 are turned on), when the current is between the two frequency bands, keep v cd The current state of V in the combinational logic circuit remains unchanged. D It is a fixed 50% duty cycle switching signal with adjustable switching frequency, and also serves as the driving signal for S1; V b+ and V b- This determines the system's maximum phase shift, serving as the system boundary and ensuring that the shift ratio of conduction signal S5 relative to conduction signal S1 is within the range of (0, 0.5). The drive signal for switch S5 is generated by an RS flip-flop. The remaining switching signals can be naturally generated based on conduction signals S1 and S5. Specifically, conduction signals S1 and S4 share the same conduction signal, while conduction signals S5 and S8 share the same conduction signal. Furthermore, the switches in the same bridge arm are complementary.

[0074] The PSIM simulation platform is used to verify the proposed solution of the present invention. The simulation results are as follows: Figure 6 and Figure 7 As shown. Where the input voltage V in is 10V, the output voltage V o The voltage is 15V, the transformer ratio n is 1, the inductor value L is 6.67uH, and the switching frequency f is 20kHz. As an example, a DC resistor is connected to the output side as a load.

[0075] from Figure 6 It can be seen that after adding dual-band current control, the output voltage is stable at 15V in steady state, and the inductor current remains free of DC current bias, which illustrates the steady-state characteristics of dual-band current control.

[0076] from Figure 7 It can be seen that after adding dual-band current control, the inductor current always remains free of DC current bias when the load switches from 2.56Ω to 2Ω. The controller can respond quickly to keep the output voltage stable, and the inductor current quickly reaches a new equilibrium state.

[0077] The above simulation results show the stability and speed of the dual-band current control strategy in the dual active full bridge.

[0078] Example 2:

[0079] like Figure 8 As shown, this embodiment provides a dual-band current control method for a dual-active full-bridge converter, and the system is applied, including the following steps:

[0080] Step S1: collect the actual output voltage V of the dual active full-bridge converter o and the actual inductor current i of the dual active full-bridge converter L ;

[0081] In step S2, the voltage controller obtains an output target current according to the sampled actual output voltage of the dual-active full-bridge converter and the output target voltage.

[0082] The actual output voltage V of the dual active full-bridge converter o and the output target voltage V ref After passing through the voltage controller's summator, the voltage error ε is obtained. The voltage error ε is passed through the PI regulator and the limiter in turn to obtain the output target current i ref The output target current is calculated as follows:

[0083]

[0084] ε=V ref -V o ;

[0085] Among them, K p is the proportional gain, K i is the integral gain.

[0086] Step S3, the dual-band current controller outputs the target current i ref and the actual inductor current i of the dual active full-bridge converter L A set signal Set and a reset signal Reset are obtained. The dual-band current controller includes a first comparator and a second comparator.

[0087] The output target current -i after the positive input terminal of the first comparator is negatively inputted ref The negative input terminal of the first comparator inputs the actual inductor current i of the dual active full-bridge converter obtained by sampling. L , the output end of the first comparator outputs a zero reset signal Reset;

[0088] The negative input terminal of the second comparator inputs the output target current i ref The actual inductor current i of the dual active full-bridge converter obtained by sampling is input into the positive input terminal of the second comparator. L , the output end of the second comparator outputs a set signal Set.

[0089] Step S4, generating a turn-on signal for each switch tube of the dual-active full-bridge converter according to the set signal Set, the reset signal Reset, and the auxiliary signal, and then controlling the turn-on of each switch tube of the dual-active full-bridge converter according to the turn-on signal. The auxiliary signal includes an auxiliary turn-off signal V b- , auxiliary opening signal V b+ , reference signal V D .

[0090] The two input terminals of the first OR gate are respectively input with the set signal Set and the auxiliary opening signal V b+ The output of the first OR gate is connected to one input of the first AND gate, and the other input of the first AND gate is input with a reference signal V D , the output of the first AND gate is connected to the S terminal of the RS flip-flop. The signal S input to the S terminal of the RS flip-flop is expressed as follows:

[0091] S=(Set+V b+ )·V D .

[0092] The reference signal V is input to the input terminal of the NOT gate. D , the output end is connected to one input end of the second AND gate; the two input ends of the first OR gate are respectively input with the reset signal Reset and the auxiliary shutdown signal V b- , the output of the first OR gate is connected to the other input of the second AND gate, and the output of the second AND gate is connected to the R terminal of the RS flip-flop. The signal R input to the R terminal of the RS flip-flop is expressed as follows:

[0093]

[0094] in is the reference signal V D The signal after negation.

[0095] The Q terminal of the RS trigger outputs a conduction signal S5, which is used to control the conduction of the switch tube S5 in the upper half of the first half bridge of the secondary side of the dual active full-bridge converter; the reference signal V DIt directly serves as the conduction signal S1, controlling the conduction of the switch S1 in the upper half of the first half-bridge on the primary side of the dual-active full-bridge converter. The conduction signal S4 for the switch S4 in the lower half of the second half-bridge on the primary side of the dual-active full-bridge converter is the same as the conduction signal S1; the conduction signal S8 for the lower half of the second half-bridge on the secondary side of the dual-active full-bridge converter is the same as the conduction signal S5. The switches in the same bridge arm are complementary. That is, the conduction signal S2 for the switch S2 in the lower half of the first half-bridge on the primary side of the dual-active full-bridge converter is complementary to the conduction signal S1, and the conduction signal S3 for the switch S3 in the upper half of the second half-bridge on the primary side of the dual-active full-bridge converter is complementary to the conduction signal S4.

[0096] The turn-on signal S6 of the switch tube S6 in the lower half of the first half-bridge on the secondary side of the transformer T of the dual-active full-bridge converter is complementary to the turn-on signal S5, and the turn-on signal S7 of the switch tube S7 in the upper half of the second half-bridge on the secondary side of the transformer T of the dual-active full-bridge converter is complementary to the turn-on signal S8.

[0097] Those skilled in the art will appreciate that the modules of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition of each example has been generally described in terms of function in the above description. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0098] In the embodiments provided by the present invention, it should be understood that the division of modules is merely a logical function division, and there may be other division methods in actual implementation, for example, multiple modules can be combined into one module, one module can be split into multiple modules, or some features can be ignored, etc.

[0099] In addition, the functional modules in various embodiments of the present invention may be integrated into a single processing module, or each module may exist physically separately, or two or more modules may be integrated into a single module. The aforementioned integrated modules may be implemented in the form of hardware or software functional modules.

[0100] If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server or network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, read-only memory (ROM, Read-0nly Memory), random access memory (RAM, Random Access Memory), mobile hard disk, magnetic disk or optical disk, etc., various media that can store program code.

[0101] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and description of the present invention.

Claims

1. A dual-band current control system for a dual active full-bridge converter, characterized in that: It includes voltage controller, dual-band current controller, and combinational logic circuit; The voltage controller is used to obtain an output target current according to the actual output voltage of the dual-active full-bridge converter obtained by sampling and the output target voltage; The dual-band current controller is used to obtain a set signal and a zero signal according to the output target current and the actual inductor current of the dual active full-bridge converter obtained by sampling; The combinational logic circuit is used to generate a conduction signal for each switch tube of the dual active full-bridge converter according to the set signal, the zero signal and the auxiliary signal, and then control the conduction of each switch tube of the dual active full-bridge converter according to the conduction signal.

2. A dual-band current control system for a dual active full-bridge converter according to claim 1, characterized in that: The voltage controller includes a summer, a PI regulator, and a limiter connected in sequence; the actual output voltage and the output target voltage of the dual-active full-bridge converter are passed through the summer to obtain a voltage error, and the voltage error is passed through the PI regulator and the limiter in sequence to obtain the output target current.

3. The dual-band current control system for a dual active full-bridge converter according to claim 2, characterized in that: The output target current is calculated as follows: ε=V ref -V o ; Among them, i ref is the output target current, K p is the proportional gain, K i is the integral gain, ε is the voltage error, V ref is the output target voltage, V o is the actual output voltage of the dual active full-bridge converter.

4. The dual-band current control system for a dual active full-bridge converter according to claim 1, characterized in that: The dual-band current controller includes a first comparator and a second comparator; the first comparator is used to obtain a zero signal according to the output target current; the second comparator is used to obtain a set signal according to the output target current.

5. The dual-band current control system for a dual active full-bridge converter according to claim 4, characterized in that: The positive input terminal of the first comparator inputs the negative output target current, the negative input terminal of the first comparator inputs the sampled actual inductor current of the dual active full-bridge converter, and the output terminal of the first comparator outputs a zero signal; The negative input terminal of the second comparator inputs the output target current, the positive input terminal of the second comparator inputs the sampled actual inductor current of the dual active full-bridge converter, and the output terminal of the second comparator outputs a set signal.

6. The dual-band current control system for a dual active full-bridge converter according to claim 1, characterized in that: The combinational logic circuit includes a NOT gate, a first OR gate, a second OR gate, a first AND gate, a second AND gate, and an RS trigger; the auxiliary signal includes an auxiliary ON signal, an auxiliary OFF signal, and a reference signal; The two input terminals of the first OR gate are respectively input with a set signal and an auxiliary enable signal, the output terminal of the first OR gate is connected to one input terminal of the first AND gate, the other input terminal of the first AND gate is input with a reference signal, and the output terminal of the first AND gate is connected to the S terminal of the RS flip-flop; The reference signal is input into the input terminal of the NOT gate, and the output terminal is connected to an input terminal of the second AND gate; The two input terminals of the first OR gate are respectively input with a reset signal and an auxiliary shutdown signal, the output terminal of the first OR gate is connected to the other input terminal of the second AND gate, and the output terminal of the second AND gate is connected to the R terminal of the RS trigger; The Q terminal of the RS trigger outputs a conduction signal S5, which is used to control the conduction of the switch tube S5 in the upper half of the first half bridge of the secondary side of the transformer of the dual active full-bridge converter; The reference signal is directly used as the conduction signal S1 to control the conduction of the switch tube S1 in the upper half of the first half-bridge on the primary side of the transformer of the dual active full-bridge converter.

7. The dual-band current control system for a dual active full-bridge converter according to claim 6, characterized in that: The signal S input to the S terminal of the RS trigger is expressed as follows: S=(Set+V b+ )·V D ; Among them, Set is the set signal, V b+ is the auxiliary opening signal, V D is the reference signal.

8. The dual-band current control system for a dual active full-bridge converter according to claim 6, characterized in that: The signal R input to the R terminal of the RS trigger is expressed as follows: Among them, Reset is the zero reset signal, V b- To assist the shutdown signal, is the reference signal V D The signal after negation.

9. The dual-band current control system for a dual active full-bridge converter according to claim 6, characterized in that: The turn-on signal S4 of the switch tube S4 in the lower half of the second half-bridge on the primary side of the dual-active full-bridge converter is the same as the turn-on signal S1; the turn-on signal S8 of the lower half of the second half-bridge on the secondary side of the dual-active full-bridge converter is the same as the turn-on signal S5; the switches in the same bridge arm are turned on in a complementary manner.

10. A dual-band current control method for a dual active full-bridge converter, characterized in that: The system according to any one of claims 1 to 9 comprises the following steps: Step S1, collecting the actual output voltage of the dual active full-bridge converter and the actual inductor current of the dual active full-bridge converter; Step S2, obtaining an output target current according to the sampled actual output voltage and the output target voltage of the dual-active full-bridge converter; Step S3, obtaining a set signal and a zero signal according to the output target current and the actual inductor current of the dual active full-bridge converter; Step S4: generating a conduction signal for each switch tube of the dual active full-bridge converter according to the set signal, the zero signal, and the auxiliary signal, and then controlling the conduction of each switch tube of the dual active full-bridge converter according to the conduction signal.

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