Control method, device and system of bidirectional direct current conversion circuit and power supply system

Abstract

The invention provides a control method, a control device, a conversion system and a power supply system of a bidirectional direct current conversion circuit, and the method comprises the steps: controlling a switch unit in the bidirectional direct current conversion circuit to adjust an output voltage after voltage and current comparison, thereby achieving the logic control of the conversion circuit according to the size of a load, and improving the reliability of the conversion circuit. And high-precision and high-gain control is realized, and the robustness is high.

Description

Technical Field

[0001] The present application relates to the field of direct current (DC) power supply, and in particular to a control method, a control device, a conversion system and a power supply system for a bidirectional DC conversion circuit. Background Art

[0002] Compared with the traditional single power supply, parallel DC power supply has many advantages: for example, it can easily achieve high power and high efficiency, and can ensure high reliability, etc. However, in practical applications, multiple power modules (especially small power modules) directly connected in parallel to supply power to the load will bring many problems: for example, the current between modules is unbalanced, the total current ripple amplitude of the system output is too large, etc.

[0003] Due to the limitation of process level and the inevitability of error, there will always be differences in the parameters of each module in the actual parallel DC power supply system. This difference is inherent in the module itself and can only be minimized as much as possible but cannot be completely eliminated. In addition, the parameters of the components in the converter will be affected by external factors such as time and temperature, such as component aging and resistance value changes with temperature. The parameter changes caused by such external factors will inevitably not be exactly the same in different modules, which may cause the parameter differences between modules to further increase.

[0004] To address the above problems, no effective solution has been proposed yet. Summary of the invention

[0005] In view of this, the present application proposes a control method, a control device, a conversion system and a power supply system for a bidirectional DC conversion circuit, wherein, after comparing the voltage and the current, the switching unit in the bidirectional DC conversion circuit is controlled to adjust the output voltage, so that the conversion circuit can be logically controlled according to the load size, thereby achieving high-precision, high-gain control and strong robustness.

[0006] According to one aspect of the present application, a control method for a bidirectional DC conversion circuit is provided, comprising:

[0007] The bidirectional DC conversion circuit includes a first voltage interface, a second voltage interface, a first switch unit, a second switch unit and an inductor unit, wherein the first switch unit and the second switch unit are connected in series at both ends of the first voltage interface, the positive end of the second voltage interface is connected to between the first switch unit and the second switch unit through the inductor unit, the negative end of the second voltage interface is electrically connected to the negative end of the first voltage interface and one end of the first switch unit that is not connected to the inductor unit, one of the first voltage interface and the second voltage interface is connected to a power supply that provides an input voltage, and the other interface outputs a voltage to a load;

[0008] Characterized in that the method comprises:

[0009] Comparing the output voltage value of the conversion circuit with the expected voltage value;

[0010] Based on the comparison result of the voltage, output a first control signal for the first switch unit, and obtain a current reference value for the inductor unit;

[0011] comparing the current value of the inductor unit with the current reference value;

[0012] Based on the comparison result of the current, a second control signal for the second switching unit is output.

[0013] Optionally, the first switch unit includes a plurality of first switch devices connected in parallel, and the first control signal includes a control signal for each first switch device.

[0014] Optionally,

[0015] The inductor unit includes a plurality of inductors connected in parallel, and obtaining a current reference value for the inductor unit includes: obtaining a current reference value for each of the inductors;

[0016] Comparing the current value of the inductor unit with the current reference value includes: comparing the current value of each inductor device with the corresponding current reference value;

[0017] The second switch unit includes a plurality of second switch devices connected in parallel, and the second control signal includes a control signal for each second switch device.

[0018] Optionally,

[0019] Outputting a first control signal for the first switch unit based on the comparison result of the voltage includes:

[0020] Based on the comparison result of the voltage, obtaining a first control signal for the first switch unit through a proportional-integral regulator, and outputting the first control signal to the first switch unit;

[0021] Based on the comparison result of the current, outputting a second control signal for the second switch unit comprises:

[0022] Based on the comparison result of the current, a second control signal for the second switch unit is obtained through a proportional-integral regulator, and the second control signal is output to the second switch unit.

[0023] Optionally, the first control signal and the second control signal include a duty cycle required for controlling the switch unit.

[0024] Optionally,

[0025] When a voltage is input from the first voltage interface and a voltage is output from the second voltage interface, the control method controls the bidirectional DC conversion circuit to implement a voltage reduction function;

[0026] When a voltage is input from the second voltage interface and a voltage is output from the first voltage interface, the control method controls the bidirectional DC conversion circuit to realize a voltage boost function.

[0027] According to another aspect of the present application, a control device for a bidirectional DC conversion circuit is provided, wherein:

[0028] The bidirectional DC conversion circuit includes a first voltage interface, a second voltage interface, a first switch unit, a second switch unit and an inductor unit, wherein the first switch unit and the second switch unit are connected in series at both ends of the first voltage interface, the positive end of the second voltage interface is connected to between the first switch unit and the second switch unit through the inductor unit, the negative end of the second voltage interface is electrically connected to the negative end of the first voltage interface and one end of the first switch unit that is not connected to the inductor unit, one of the first voltage interface and the second voltage interface is connected to a power supply that provides an input voltage, and the other interface outputs a voltage to a load;

[0029] Characterized in that the control device comprises:

[0030] A voltage comparison unit, used for comparing the output voltage value of the conversion circuit with an expected voltage value;

[0031] a first voltage regulating unit, configured to output a first control signal for the first switch unit based on the voltage comparison result, and obtain a current reference value for the inductor unit;

[0032] a current comparison unit, configured to compare the current value of the inductor unit with the current reference value;

[0033] The second voltage regulating unit is used to output a second control signal for the second switch unit based on the comparison result of the current.

[0034] According to another aspect of the present application, a control device for a bidirectional DC conversion circuit is provided, wherein:

[0035] The bidirectional DC conversion circuit comprises a first voltage interface, a second voltage interface, a first switch unit, a second switch unit and an inductor unit, wherein the first switch unit and the second switch unit are connected in series at both ends of the first voltage interface, the positive end of the second voltage interface is connected between the first switch unit and the second switch unit through the inductor unit, the negative end of the second voltage interface is electrically connected to the negative end of the first voltage interface and one end of the first switch unit that is not connected to the inductor unit, and either of the first voltage interface and the second voltage interface inputs a voltage, while the other interface outputs a voltage;

[0036] The control device comprises a memory and a processor, and is characterized in that:

[0037] The processor executes the method described above.

[0038] According to another aspect of the present application, a bidirectional DC conversion system is provided, characterized by comprising: the bidirectional DC conversion circuit and control device as described above.

[0039] According to another aspect of the present application, a bidirectional DC conversion power supply system is provided, characterized by comprising: the bidirectional DC conversion circuit, control device and power supply as described above.

[0040] According to the present application, a control method, a control device, a conversion system and a power supply system for a bidirectional DC conversion circuit are proposed. After comparing the voltage and current, the switch unit in the bidirectional DC conversion circuit is controlled to adjust the output voltage. The conversion circuit can be logically controlled according to the load size to achieve high-precision, high-gain control with strong robustness. Moreover, when there are multiple modules in parallel in the system, current equalization control can be achieved for each module, solving the problem of current imbalance between modules. Furthermore, when the number of modules in parallel in the system changes, the solution of the present application can also be automatically adjusted so that the system can reach the ripple clock staggered state again in the new parallel state.

[0041] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present application in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0043] Figure 1 A principle block diagram of an existing bidirectional Buck-Boost circuit is shown;

[0044] Figure 2 A schematic diagram showing an embodiment of an existing bidirectional Buck-Boost circuit topology;

[0045] Figure 3 A schematic diagram showing an embodiment of a bidirectional DC conversion power supply system of the present application is shown;

[0046] Figure 4 A schematic diagram showing an embodiment of a control device for a bidirectional DC conversion circuit of the present application is shown;

[0047] Figure 5 A schematic diagram showing an embodiment of a control method for a bidirectional DC conversion circuit of the present application;

[0048] Figure 6 A schematic diagram showing an embodiment of a closed-loop control block diagram of a bidirectional DC conversion circuit of the present application;

[0049] Figure 7 Shows Figure 6 A schematic diagram of an embodiment of a voltage and current waveform diagram of a bidirectional DC conversion circuit;

[0050] Figure 8a-8c A schematic diagram showing an embodiment of a simulation model of a control method for a bidirectional DC conversion circuit of the present application;

[0051] Fig. 9 The comparison result of the three interleaved inductor currents and the total current after parallel connection is shown;

[0052] Fig.10 A graph showing the result of three-staggered duty cycle control is shown;

[0053] Fig.11 The figure shows the result of the three-staggered duty cycle PWM waveform shown by the control method of the present application in actual situation using an oscilloscope. DETAILED DESCRIPTION

[0054] In order to make the purpose, technical solution and advantages of the present application clearer, the technical solution of the present application will be clearly and completely described below in combination with the specific embodiments of the present application and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present application.

[0055] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0056] Figure 1 A principle block diagram of an existing bidirectional Buck-Boost (buck-boost) circuit is shown. The bidirectional Buck-Boost circuit is used to perform step-up and step-down conversion on a DC power supply. As shown in the figure, one of the first voltage interface 1 and the second voltage interface 2 is connected to a power supply that provides an input voltage, and the other interface outputs a voltage to a load. Through the bidirectional Buck-Boost circuit, the input voltage is stepped up or stepped down to obtain a stepped-up or stepped-down output voltage. The first switch unit 3 and the second switch unit 4 are connected in series at both ends of the first voltage interface 1, the positive terminal of the second voltage interface 2 is connected between the first switch unit 3 and the second switch unit 4 through the inductor unit 5, and the negative terminal of the second voltage interface 2 is electrically connected to the negative terminal of the first voltage interface 1 and one end of the first switch unit 3 that is not connected to the inductor unit.

[0057] As an implementation method, when a voltage is input by the first voltage interface 1 (for example, connected to a power supply) and a voltage is output by the second voltage interface 2, the bidirectional Buck-Boost circuit realizes a voltage reduction function; conversely, when a voltage is input by the second voltage interface 2 and a voltage is output by the first voltage interface 1, the bidirectional Buck-Boost circuit realizes a voltage increase function.

[0058] Optionally, the first switch unit 3 and the second switch unit 4 may respectively include a plurality of switch devices connected in parallel, for example, the first switch unit includes a plurality of first switch devices connected in parallel, and the second switch unit includes a plurality of second switch devices connected in parallel. Also optionally, the inductor unit 5 may include a plurality of inductors connected in parallel.

[0059] Figure 2 A schematic diagram of an embodiment of an existing bidirectional Buck-Boost circuit topology is shown.

[0060] Among them, L1, L2 and L3 are input inductors, and the currents flowing through the inductors are iL1, iL2 and iL3. S1, S2, S3, S4, S5 and S6 are switch tubes, D1, D2, D3, D4, D5 and D2 are output diodes, and C1 is the output filter capacitor. S1, S2, L1 form a branch, S3, S4, L2 form a branch, and S5, S6, L3 form a branch. When the left side Udc is the input end (input voltage), the topological circuit plays a step-down role, and the output voltage is Ubat; when the right side Ubat is the input voltage, the topological circuit plays a step-up role, and the output voltage is Udc. When it is used in the parallel DC power supply scenario, high power, high efficiency, and high reliability control can be achieved in both step-up and step-down situations.

[0061] However, in the control method of the bidirectional Buck-Boost circuit of the existing DC power supply system, the same or fixed control strategy is often used for each switch unit or switch tube, without considering the changes or differences of each branch, resulting in current imbalance between each branch module and too large total current ripple amplitude of the power supply system output. This application focuses on solving this problem.

[0062] Figure 3 A schematic diagram of an embodiment of a bidirectional DC conversion power supply system of the present application is shown.

[0063] As shown in the figure, the bidirectional DC conversion power supply system 10 at least includes a power supply 11, a bidirectional DC conversion circuit 12 and a control device 13. The control device 13 controls the bidirectional DC conversion circuit 12 to step up or step down the power supply 11 that provides the input voltage, so as to obtain the voltage required by the load. Through the control device 13, the present application can perform logical control according to the size of the system load, solves the problem that the output ripple amplitude of the traditional parallel DC power supply system is too large, and enhances the robustness of the system. As an implementation method, the bidirectional DC conversion circuit and the control device can form a bidirectional DC conversion system.

[0064] Figure 4 A schematic diagram of an embodiment of a control device for a bidirectional DC conversion circuit of the present application is shown. Figure 5 A schematic diagram showing an embodiment of a control method for a bidirectional DC conversion circuit of the present application is shown. Figure 4 The control device can be implemented by hardware, or by software based on hardware. Figure 4 The control device performs Figure 5 The control method realizes the step-up and step-down of the power supply by controlling the bidirectional DC conversion circuit. Figure 4As shown, the control device 13 includes a voltage comparison unit 131, a current comparison unit 132, a first voltage adjustment unit 133, and a second voltage adjustment unit 134. The control device 13 performs Figure 5 Steps S1-S4.

[0065] The voltage comparison unit 131 executes step S1 to compare the output voltage value of the bidirectional DC conversion circuit with the expected voltage value.

[0066] In this step, the expected voltage is the voltage required by the load. The output voltage value of the bidirectional DC conversion circuit can be obtained through a voltage feedback unit or a voltage acquisition unit (not shown in the drawings) and fed back to the control device of the bidirectional DC conversion circuit, and then compared with the expected voltage through a voltage comparison unit (not shown in the drawings).

[0067] The first voltage regulating unit 133 executes step S2, outputs a first control signal for the first switch unit of the bidirectional DC conversion circuit based on the voltage comparison result, and obtains a current reference value of the inductor unit of the bidirectional DC conversion circuit.

[0068] In this step, based on the voltage comparison result of step S1, according to the difference between the currently collected or fed-back output voltage and the expected voltage, a first control signal for the first switch unit of the bidirectional DC conversion circuit is calculated, and the output voltage value of the conversion circuit is adjusted by controlling the opening and closing of the first switch unit, so that the output voltage value approaches the expected voltage value. In addition, in this step, it is also necessary to calculate the current reference value of the inductor unit of the bidirectional DC conversion circuit, and its purpose is also to control the conversion circuit based on the current reference value so that the output voltage value approaches the expected voltage value.

[0069] As an example, a proportional integral regulator (PI regulator) may be used in this step. The PI regulator obtains a first control signal of the first switch unit through an internal algorithm according to a voltage comparison result, and outputs the first control signal to the first switch unit.

[0070] PI regulator is a linear controller that uses a linear combination of the proportion and integral of the deviation to form a control quantity based on the control deviation between the given value and the actual output value. Through the PI regulator, it can be achieved with a relatively simple algorithm, but the control is precise, the adjustment is timely, the adaptability is strong, and the residual error can be effectively eliminated.

[0071] The current comparison unit 132 executes step S3 to compare the current value of the inductor unit with the current reference value;

[0072] In this step, the current value of the inductor unit in the bidirectional DC conversion circuit can be obtained through a current feedback unit or a current acquisition unit (not shown in the accompanying drawings) and fed back to the control device of the bidirectional DC conversion circuit, and then compared with the current reference value obtained in step S2 through a current comparison unit (not shown in the accompanying drawings).

[0073] The second voltage regulating unit 134 executes step S4 to output a second control signal for the second switch unit of the bidirectional DC conversion circuit based on the comparison result of the current.

[0074] In this step, based on the current comparison result of step S3, according to the difference between the current value at the inductor currently collected or fed back and the current reference value, a second control signal for the second switch unit of the bidirectional DC conversion circuit is calculated, and the output voltage value of the conversion circuit is adjusted by controlling the opening and closing of the second switch unit so that the output voltage value approaches the expected voltage value.

[0075] As an example, a proportional integral regulator (PI regulator) may be used in this step. The PI regulator obtains the second control signal of the second switch unit through an internal algorithm according to the current comparison result, and outputs the second control signal to the second switch unit.

[0076] Preferably, when the first switch unit includes a plurality of first switch devices connected in parallel, the first control signal includes a control signal for each first switch device. When the inductor unit includes a plurality of inductors connected in parallel, a current reference value for each of the inductors is obtained, and the current value of each of the inductors is compared with the corresponding current reference value. When the second switch unit includes a plurality of second switch devices connected in parallel, the second control signal includes a control signal for each second switch device. Based on this, when the conversion circuit includes a plurality of parallel modules, the control method / control device of the present application can perform logic control on the plurality of parallel modules separately according to the system load size, thereby realizing high-precision, high-gain current sharing control, and the current sharing loops are independent of each other and have strong robustness.

[0077] As an implementation manner, the first control signal and the second control signal include a duty cycle required for controlling the switch unit. Based on the duty cycle, the switch unit can be controlled by PWM (pulse width modulation).

[0078] Taking the output of three-phase AC power as an example, a three-phase PFC (power factor correction) circuit (control circuit) is provided, and the three phases are phase A, phase B and phase C. There is a current sensor on each phase, and the detected currents are Ia, Ib and Ic respectively. The control unit (for example, using PI control) calculates the average value Iavg of the three-phase current:

[0079] Iavg=3Ia+Ib+Ic

[0080] Then, calculate the current error for each phase:

[0081] ea=Ia-Iavg

[0082] eb=Ib-Iavg

[0083] ec=Ic-Iavg

[0084] The control unit generates corresponding compensation signals based on these errors and adjusts the PWM signal of each phase so that Ia, Ib and Ic gradually approach Iavg to achieve current sharing.

[0085] Figure 6 A schematic diagram showing an embodiment of a closed-loop control method for a bidirectional DC conversion circuit of the present application is shown.

[0086] As shown in the figure, V dc_ref is the expected output DC voltage, V dc_bk The actual output DC voltage fed back by the system is compared and PI adjusted to obtain the current reference value I required by the current loop. ref ,I ref / 2 and I ref / 3. The actual feedback values ​​of the three inductor currents are I bk ,I 2bk and I 3bk After comparison, PI control can be performed to obtain the control switch S 1_boost , S 1_buck , S 2_boost , S 2_buck , S 3_boost , and S 3_buck The required duty cycle is used to control the PWM wave generation. Boost means it is used for increasing the voltage, and buck means it is used for decreasing the voltage.

[0087] The current sharing process of the three-phase PFC circuit is a closed-loop control process, involving multiple links such as current detection, signal processing, control algorithm, error compensation, drive circuit and real-time feedback. Through the coordinated work of these links, the balance of the three-phase current can be ensured and the efficiency and reliability of the system can be improved.

[0088] Figure 7 Shows Figure 6 A schematic diagram of an embodiment of a voltage and current waveform diagram of a bidirectional DC conversion circuit. Figure 7 It can be seen that, through the control method / control device of the present application, the control of multiple parallel modules in the conversion circuit is independent of each other, and high-gain current sharing of each module is achieved.

[0089] Figure 8a-8c A schematic diagram of an embodiment of a simulation model of a control method for a bidirectional DC conversion circuit of the present application is shown. For example, Simulink simulation is used. The simulation uses p1, p2 and p3 to control the switching frequency of the g-stage of the first switch tubes 31, 32, 33, k1, k2 and k3 to control the switching frequency of the g-stage of the second switch tubes 41, 42, 43, and p1, p2, p3, k1, k2 and k3 are calculated by, for example, PI control. Current meters 51, 52, 53 are used to measure the inductor currents of inductors L1, L2 and L3, respectively, and voltage meters 61 and 62 are used to measure the voltages on both sides of voltage Uout and Uout1, respectively. When the input voltage is Uout1, the topological circuit acts as a boost, and the output voltage is Uout. When the input voltage is Uout, the topological circuit acts as a step-down, and the output voltage is Uout1. Wherein Figure 8b This is the control part interface diagram. Figure 8c It is a schematic diagram of the internal logic of the control part.

[0090] Fig. 9 and Fig.10 Shown based on Figure 8a-8c Result diagram of the simulation model after simulation. Fig. 9 The comparison result diagram of the three-interleaved inductor current and the total current after parallel connection is shown. It can be seen that after the parallel DC power supply system (bidirectional DC conversion power supply system) is logically controlled by the control method proposed in this application, the parameter differences of each parallel module in the parallel DC power supply system can be reduced, and the current ripple amplitude can be greatly reduced. Fig.10 The three-staggered duty cycle control result diagram is shown, and it can be seen that the control method described in the present application can achieve high-precision, high-gain current sharing control of the current loop, and each current sharing loop is independent of each other and has strong robustness.

[0091] Fig.11 The three-staggered duty cycle PWM waveform result diagram shown by the oscilloscope in the actual situation of the control method of the present application can verify that the present application can perform logical control on the parallel modules in the parallel DC power supply system and realize high-precision, high-gain current sharing control. The experimental results show that the scheme of the present application is highly robust, and can automatically adjust when the number of modules participating in the parallel connection in the system changes, so that the system can re-reach the ripple clock staggered state in the new parallel state, and has an automatic staggering function.

[0092] Since the processing and functions implemented by the method of this embodiment basically correspond to the embodiments, principles and examples of the aforementioned system, for the details not fully described in this embodiment, please refer to the relevant descriptions in the aforementioned embodiments, and no further elaboration will be made here.

[0093] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0094] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0095] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

[0096] It should be noted that the embodiments and features of the embodiments of the present invention can be combined with each other without conflict. Any simple modification, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A control method for a bidirectional DC conversion circuit, wherein: The bidirectional DC conversion circuit includes a first voltage interface, a second voltage interface, a first switch unit, a second switch unit and an inductor unit, wherein the first switch unit and the second switch unit are connected in series at both ends of the first voltage interface, the positive end of the second voltage interface is connected to between the first switch unit and the second switch unit through the inductor unit, the negative end of the second voltage interface is electrically connected to the negative end of the first voltage interface and one end of the first switch unit that is not connected to the inductor unit, one of the first voltage interface and the second voltage interface is connected to a power supply that provides an input voltage, and the other interface outputs a voltage to a load; Characterized in that the method comprises: Comparing the output voltage value of the conversion circuit with the expected voltage value; Based on the comparison result of the voltage, output a first control signal for the first switch unit, and obtain a current reference value for the inductor unit; comparing the current value of the inductor unit with the current reference value; Based on the comparison result of the current, a second control signal for the second switching unit is output.

2. The method according to claim 1, characterized in that: The first switch unit includes a plurality of first switch devices connected in parallel, and the first control signal includes a control signal for each first switch device.

3. The method according to claim 1 or 2, characterized in that: The inductor unit includes a plurality of inductors connected in parallel, and obtaining a current reference value for the inductor unit includes: obtaining a current reference value for each of the inductors; Comparing the current value of the inductor unit with the current reference value includes: comparing the current value of each inductor device with the corresponding current reference value; The second switch unit includes a plurality of second switch devices connected in parallel, and the second control signal includes a control signal for each second switch device.

4. The method according to any one of claims 1 to 3, characterized in that: Outputting a first control signal for the first switch unit based on the comparison result of the voltage includes: Based on the comparison result of the voltage, obtaining a first control signal for the first switch unit through a proportional-integral regulator, and outputting the first control signal to the first switch unit; Based on the comparison result of the current, outputting a second control signal for the second switch unit comprises: Based on the comparison result of the current, a second control signal for the second switch unit is obtained through a proportional-integral regulator, and the second control signal is output to the second switch unit.

5. The method according to claim 1, characterized in that: The first control signal and the second control signal include a duty cycle required for controlling the switch unit.

6. The method according to claim 1, characterized in that: When a voltage is input from the first voltage interface and a voltage is output from the second voltage interface, the control method controls the bidirectional DC conversion circuit to implement a voltage reduction function; When a voltage is input from the second voltage interface and a voltage is output from the first voltage interface, the control method controls the bidirectional DC conversion circuit to realize a voltage boost function.

7. A control device for a bidirectional DC conversion circuit, wherein: The bidirectional DC conversion circuit includes a first voltage interface, a second voltage interface, a first switch unit, a second switch unit and an inductor unit, wherein the first switch unit and the second switch unit are connected in series at both ends of the first voltage interface, the positive end of the second voltage interface is connected to between the first switch unit and the second switch unit through the inductor unit, the negative end of the second voltage interface is electrically connected to the negative end of the first voltage interface and one end of the first switch unit that is not connected to the inductor unit, one of the first voltage interface and the second voltage interface is connected to a power supply that provides an input voltage, and the other interface outputs a voltage to a load; Characterized in that the control device comprises: A voltage comparison unit, used for comparing the output voltage value of the conversion circuit with an expected voltage value; a first voltage regulating unit, configured to output a first control signal for the first switch unit based on the voltage comparison result, and obtain a current reference value for the inductor unit; a current comparison unit, configured to compare the current value of the inductor unit with the current reference value; The second voltage regulating unit is used to output a second control signal for the second switch unit based on the comparison result of the current.

8. A control device for a bidirectional DC conversion circuit, wherein: The bidirectional DC conversion circuit comprises a first voltage interface, a second voltage interface, a first switch unit, a second switch unit and an inductor unit, wherein the first switch unit and the second switch unit are connected in series at both ends of the first voltage interface, the positive end of the second voltage interface is connected between the first switch unit and the second switch unit through the inductor unit, the negative end of the second voltage interface is electrically connected to the negative end of the first voltage interface and one end of the first switch unit that is not connected to the inductor unit, and either of the first voltage interface and the second voltage interface inputs a voltage, while the other interface outputs a voltage; The control device comprises a memory and a processor, and is characterized in that: The processor executes the method according to any one of claims 1 to 6.

9. A bidirectional DC conversion system, characterized in that include: A bidirectional DC conversion circuit and control device as described in claim 7 or 8.

10. A bidirectional DC conversion power supply system, characterized in that include: A bidirectional DC conversion circuit, control device and power supply as described in claim 7 or 8.

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