Energy storage converter and control method thereof

Abstract

The invention relates to the field of energy storage converters, and discloses an energy storage converter and a control method thereof.The control method is characterized in that the alternating current side of a converter main loop is connected with a power grid, and one end of the direct current side of the converter main loop is connected with the first end of a first switching circuit and the first end of a step-down circuit; the second end of the first switching circuit is connected with the second end of the step-down circuit; the third end of the step-down circuit is connected with the positive electrode of the energy storage battery, the fourth end of the step-down circuit is connected with the negative electrode of the energy storage battery, and the fifth end of the step-down circuit is connected with the other end of the direct current side of the converter main loop. When the energy storage battery is lack of electricity, a closed-loop control mode is adopted, the step-down circuit is closed, and the main loop of the converter is controlled to charge current of the energy storage battery by adjusting the duty ratio of a transistor in the step-down circuit, so that the energy storage converter is prevented from being damaged due to current backflow, and the safety and reliability are improved.

Description

Technical Field

[0001] The present invention relates to the field of energy storage converters, and in particular to an energy storage converter and a control method thereof. Background Art

[0002] At present, the DC side high voltage circuit of energy storage PCS (Power Conversion System, i.e. energy storage converter) is Figure 1 and Figure 2 As shown, K1 and K3 are main relays or contactors, K2 is a pre-charging relay or contactor, R is a pre-charging resistor, F is a fuse or circuit breaker, C is a DC side capacitor, and PCS is the main circuit of the converter. If the battery voltage is too low due to severe battery depletion, or the grid voltage is too high, that is, the battery voltage is less than 1.414 times the grid line voltage, if the grid connection is not disconnected, the current will flow back from the grid to the battery uncontrollably, and the converter will be damaged and fail due to overcurrent, which will harm the battery. At this time, an external charging device is usually used to charge the battery. The system can only be connected to the grid when the battery voltage reaches a certain value. Summary of the invention

[0003] In view of this, the present invention provides an energy storage converter and a control method thereof to solve the problem of power shortage of energy storage batteries.

[0004] In the first aspect, the present invention provides an energy storage converter, comprising: a converter main circuit, a first switch circuit, a step-down circuit, and an energy storage battery, wherein the AC side of the converter main circuit is connected to the power grid, one end of the DC side of the converter main circuit is connected to the first end of the first switch circuit and the first end of the step-down circuit; the second end of the first switch circuit is connected to the second end of the step-down circuit; the third end of the step-down circuit is connected to the positive electrode of the energy storage battery, the fourth end of the step-down circuit is connected to the negative electrode of the energy storage battery, and the fifth end of the step-down circuit is connected to the other end of the DC side of the converter main circuit. When the energy storage battery is depleted, a closed-loop control method is adopted to close the step-down circuit, and the duty cycle of the transistor inside the step-down circuit is adjusted to control the converter main circuit to be the charging current of the energy storage battery.

[0005] In the present invention, when the energy storage battery is low on power, a closed-loop control method is adopted to close the step-down circuit, and the charging current of the energy storage battery is controlled by adjusting the duty cycle of the transistor; compared with the prior art, when the battery is low on power or other reasons lead to severe undervoltage, the current backflow is prevented from damaging the PCS to improve safety and reliability, and the PCS can charge the battery autonomously without external charger, saving manpower and other costs, and improving operational efficiency. The hardware effectively protects the battery from reverse connection and improves product safety and reliability. In addition, the battery-side inductor can suppress the high-frequency ripple of the charging and discharging current, improve the power quality, and benefit the battery health.

[0006] In an optional embodiment, the step-down circuit further includes: a freewheeling diode, an energy storage inductor and a fuse, wherein the collector of the transistor is connected to the first end of the first switch circuit, the emitter of the transistor is connected to the first end of the energy storage inductor, the cathode of the freewheeling diode, and the second end of the first switch circuit; the second end of the energy storage inductor is connected to the first end of the fuse; the second end of the fuse is connected to the positive electrode of the energy storage battery; the anode of the freewheeling diode is connected to the negative electrode of the energy storage battery and the other end of the DC side of the converter main circuit.

[0007] In an optional implementation, the energy storage converter further includes: a pre-charging circuit, wherein the pre-charging circuit is connected in parallel with the first switching circuit.

[0008] In an optional embodiment, the pre-charging circuit includes: a controllable switch and a current limiting resistor, wherein the first end of the controllable switch is connected to the first end of the first switch circuit, the second end of the controllable switch is connected to the first end of the current limiting resistor; and the second end of the current limiting resistor is connected to the second end of the first switch circuit.

[0009] In an optional implementation, the energy storage converter further includes: a second switch circuit, wherein the anode of the freewheeling diode is connected to the other end of the DC side of the converter main circuit through the second switch circuit.

[0010] In a second aspect, the present invention provides a control method for an energy storage inverter. Based on the energy storage inverter of some implementation modes of the first aspect, the control method includes: disconnecting the first switch circuit and the pre-charging circuit to obtain the voltage of the energy storage battery; judging whether the voltage of the energy storage battery is lower than a preset voltage threshold, and when it is lower than the preset voltage threshold, adopting a closed-loop control method to close the step-down circuit, and controlling the charging current of the energy storage battery by adjusting the duty cycle of the transistor.

[0011] In an optional implementation, the process of controlling the charging current of the energy storage battery includes: establishing an average value model for the energy storage inductor to calculate the average voltage of the energy storage inductor; calculating the average current of the energy storage inductor based on the average voltage of the energy storage inductor; calculating the difference between the average current of the energy storage inductor and a reference current value to obtain a current difference; performing PI control on the current difference to obtain a voltage compensation value; compensating the energy storage battery voltage using the voltage compensation value; and using the ratio of the compensated energy storage battery voltage to the DC side voltage of the converter main circuit as the duty cycle of the transistor in the next cycle.

[0012] In an optional implementation, when the voltage of the energy storage battery is not lower than a preset voltage threshold, the first switch circuit is closed, and the pre-charging circuit and the step-down circuit are disconnected.

[0013] In an optional implementation, under normal operating conditions, before closing the first switch circuit, the pre-charging circuit is closed; after a preset time, the pre-charging circuit is opened.

[0014] In a third aspect, the present invention provides a control device for an energy storage inverter, comprising: an acquisition module, used to disconnect the first switch circuit and the pre-charging circuit to obtain the voltage of the energy storage battery; a charging module, used to determine whether the voltage of the energy storage battery is lower than a preset voltage threshold, and when it is lower than the preset voltage threshold, a closed-loop control method is adopted to close the step-down circuit, and the charging current of the energy storage battery is controlled by adjusting the duty cycle of the transistor.

[0015] In a fourth aspect, the present invention provides a computer device, comprising: a memory and a processor, the memory and the processor being communicatively connected to each other, the memory storing computer instructions, and the processor executing the control method of the energy storage inverter of the above-mentioned second aspect or any corresponding embodiment thereof by executing the computer instructions.

[0016] In a fifth aspect, the present invention provides a computer-readable storage medium having computer instructions stored thereon, the computer instructions being used to enable a computer to execute the control method for an energy storage converter according to the second aspect or any corresponding embodiment thereof. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 It is a topological structure diagram of an energy storage converter in the related art;

[0019] Figure 2 It is a topological structure diagram of an energy storage converter in the related art;

[0020] Figure 3 is a composition diagram of an energy storage converter according to an embodiment of the present invention;

[0021] Figure 4 is a composition diagram of another energy storage converter according to an embodiment of the present invention;

[0022] Figure 5 is a composition diagram of another energy storage converter according to an embodiment of the present invention;

[0023] Figure 6 is a composition diagram of another energy storage converter according to an embodiment of the present invention;

[0024] Figure 7 is a flow chart of a control method of an energy storage converter according to an embodiment of the present invention;

[0025] Figure 8 is a model diagram of an average value of an energy storage inductor according to an embodiment of the present invention;

[0026] Fig. 9 is a control block diagram of an energy storage converter according to an embodiment of the present invention;

[0027] Fig.10 Schematic diagram of the hardware structure of a computer device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0029] In this embodiment, an energy storage converter is provided, such as Figure 3 As shown, it includes: a converter main circuit, a first switch circuit, a step-down circuit, and an energy storage battery.

[0030] like Figure 3 As shown, the AC side of the converter main circuit is connected to the power grid, and one end of the DC side of the converter main circuit is connected to the first end of the first switch circuit and the first end of the step-down circuit.

[0031] Specifically, the converter main circuit is a three-phase converter, which can realize bidirectional flow, that is, it can constitute a discharge circuit or a charging circuit of the energy storage battery.

[0032] like Figure 3 As shown, the second end of the first switch circuit is connected to the second end of the step-down circuit.

[0033] like Figure 3 As shown, the third end of the step-down circuit is connected to the positive electrode of the energy storage battery, the fourth end of the step-down circuit is connected to the negative electrode of the energy storage battery, and the fifth end of the step-down circuit is connected to the other end of the DC side of the converter main circuit.

[0034] Specifically, the energy storage current device mainly involves the following situations:

[0035] (1) When the energy storage battery discharges to the grid, the first switch circuit is closed, the step-down circuit is disconnected, and the main circuit of the converter converts direct current into alternating current.

[0036] (2) When the energy storage battery is depleted, the first switch circuit is disconnected and the step-down circuit is closed, and the main circuit of the converter converts AC power into DC power to charge the energy storage battery.

[0037] During the charging process of the energy storage battery, the charging current is adjusted by controlling the duty cycle of the power switching device inside the buck circuit.

[0038] In some optional embodiments, such as Figure 4 As shown, the step-down circuit includes: a transistor Q, a freewheeling diode D, an energy storage inductor L and a fuse F, wherein the collector of the transistor Q is connected to the first end (i.e., K1) of the first switch circuit, and the emitter of the transistor Q is connected to the first end of the energy storage inductor L, the cathode of the freewheeling diode D, and the second end of the first switch circuit; the second end of the energy storage inductor L is connected to the first end of the fuse F; the second end of the fuse F is connected to the positive electrode of the energy storage battery; the anode of the freewheeling diode D is connected to the negative electrode of the energy storage battery and the other end of the DC side of the converter main circuit (i.e., PCS).

[0039] Specifically, Figure 4 The transistor Q in the middle is IGBT, and the charging current is controlled by controlling the duty cycle of the IGBT.

[0040] In traditional solutions, the battery positive and negative poles are reversed and protected by software. The battery voltage is detected before the device is operated. If the battery voltage sampling value is negative, a fault is reported. Figure 1 However, if the battery voltage sampling function is abnormal, or K1 and K2 are adhered, the battery reverse connection fault cannot be effectively protected, and the three-phase main circuit of the converter will be short-circuited and damaged.

[0041] In view of the above situation, Figure 4 , Figure 6 Since the diode D is added, if K1 and K2 are adhered and the battery voltage sampling function cannot identify the reverse connection, or in more serious cases, the control board fails and the control software fails, if the battery is reversed, since the path from the battery to the PCS three-phase power module is longer and the impedance is greater, the short-circuit current will preferentially flow through the freewheeling diode D, and then the fuse F will blow to effectively protect the main circuit of the converter.

[0042] In some optional embodiments, such as Figure 5 As shown, the energy storage converter further includes: a pre-charging circuit, wherein the pre-charging circuit is connected in parallel with the first switching circuit.

[0043] Specifically, under normal operating conditions, before closing the first switch circuit, the pre-charging circuit is closed first, and the energy storage battery is charged through the pre-charging circuit to prevent excessive current.

[0044] In some optional embodiments, such as Figure 4As shown, the pre-charging circuit includes: a controllable switch K2 and a current limiting resistor R, wherein the first end of the controllable switch is connected to the first end of the first switch circuit (i.e., K1), the second end of the controllable switch is connected to the first end of the current limiting resistor; and the second end of the current limiting resistor is connected to the second end of the first switch circuit.

[0045] In some optional embodiments, the energy storage converter further includes: a second switch circuit, wherein the anode of the freewheeling diode D is connected to the other end of the DC side of the converter main circuit through the second switch circuit.

[0046] Alternatively, if Figure 6 As shown, the second switch circuit is K3. When a fault occurs, the connection between the negative electrode of the energy storage battery and the main circuit of the converter is disconnected by disconnecting K3.

[0047] Figure 4 , Figure 6 The types of medium Q switch devices include but are not limited to IGBT, silicon carbide, gallium nitride and other devices, and K1 and K2 include but are not limited to relays, contactors and the like.

[0048] In this embodiment, a control method for an energy storage converter is provided, based on the energy storage converter of some implementation methods of the above embodiments, such as Figure 7 As shown, the control method includes:

[0049] Step S1: disconnect the first switch circuit and the pre-charging circuit to obtain the energy storage battery voltage.

[0050] Step S2: Determine whether the energy storage battery voltage is lower than a preset voltage threshold. When it is lower than the preset voltage threshold, a closed-loop control method is adopted to close the buck circuit and control the charging current of the energy storage battery by adjusting the duty cycle of transistor Q.

[0051] Specifically, the electrical diagram of the energy storage converter is as follows: Figure 3 As shown in FIG. , a power device switch, a freewheeling diode D, and an energy storage inductor L are added to the traditional solution. When the voltage of the energy storage battery is too low, the battery current can be prevented from being reversely charged from the power grid, the battery can be charged with a controllable current, and hardware protection for battery reverse connection can be achieved.

[0052] Optionally, the process of controlling the charging current of the energy storage battery includes:

[0053] (1) Establishing an average value model for the energy storage inductor L and calculating the average voltage of the energy storage inductor L;

[0054] (2) Based on the average voltage of the energy storage inductor L, the average current of the energy storage inductor L is calculated;

[0055] (3) Calculate the difference between the average current of the energy storage inductor L and the reference current value to obtain the current difference;

[0056] (4) Perform PI control on the current difference to obtain a voltage compensation value;

[0057] (5) Compensating the voltage of the energy storage battery using the voltage compensation value;

[0058] (6) The ratio of the compensated energy storage battery voltage to the DC side voltage of the converter main circuit is used as the duty cycle of the transistor Q in the next cycle.

[0059] Specifically, refer to Figure 4 , Figure 6 When the battery voltage is too low, K1, K2, and Q are disconnected for a long time, and when PCS is connected to the grid, the voltage V across the capacitor C is dc Greater than the battery voltage V bat If K1 is closed, the charging current will over-current and damage the PCS. If only K2 is closed, the current limiting resistor will be damaged if it has to withstand a large current for too long. The above problems can be solved by controlling Q. At this time, K1 and K2 are both disconnected, and the inductor current is controlled in continuous mode.

[0060] When Q is turned on, the energy storage inductor current increases, part of the energy is used to charge the energy storage battery, and part of the energy is stored in the energy storage inductor L. According to the characteristics of the energy storage inductor L and ignoring the internal resistance of the energy storage inductor L:

[0061]

[0062] Among them, V L is the energy storage inductor voltage; V dc is the voltage across capacitor C; V bat is the voltage of the energy storage battery; L is the inductance value of the energy storage inductor L; T on is the single opening time of Q; i L is the energy storage inductor current.

[0063] When the energy storage inductor current increases to a certain value, Q is disconnected. At this time, the energy storage inductor current decreases and continues to charge the energy storage battery through the freewheeling diode D:

[0064]

[0065] Among them, T off is the single off time of Q.

[0066] In steady state, during a Q on and off cycle, the increase and decrease of the energy storage inductor current are equal:

[0067] Δi L + =-Δi L -(3)

[0068] According to formula (1) to formula (3), we can get:

[0069]

[0070] Where d is the Q on duty cycle.

[0071] Since the duty cycle is always less than 1, it can be concluded from formula (4) that Vbat is less than Vdc, which satisfies the working condition that the actual DC bus voltage is greater than the energy storage battery voltage. The voltage difference between the bus voltage and the energy storage battery voltage can be achieved through a reasonable duty cycle, that is, the step-down conversion function from the DC bus to the energy storage battery is realized.

[0072] The average value model of the energy storage inductor L is as follows: Figure 8 As shown:

[0073]

[0074] in, is the average voltage of the energy storage inductor; is the average current of the energy storage inductor; r is the internal resistance of the energy storage inductor L.

[0075] According to formula (5) and Figure 4 , which can realize the control of the energy storage inductor current. The average current of the energy storage inductor current is the battery charging current. Current command value Given by BMS, it is guaranteed to be within the safe charging current range of the battery. The proportional-integral controller is used to control the inductor current. The charging current can be changed according to the instruction. The control principle diagram is as follows Fig. 9 shown.

[0076] In some optional implementations, the control method of the energy storage converter further includes: when the voltage of the energy storage battery is not lower than a preset voltage threshold, closing the first switch circuit and disconnecting the pre-charging circuit and the step-down circuit.

[0077] In some optional implementations, the control method of the energy storage converter further includes: under normal operating conditions, before closing the first switch circuit, closing the pre-charging circuit; and after a preset time, opening the pre-charging circuit.

[0078] Specifically, under normal operating conditions, the control method of the high-voltage circuit on the PCS DC side is the same as before, that is, Figure 4 , Figure 6 Q in the middle remains in the disconnected state. When PCS starts working, K2 is closed first and K1 is disconnected. The battery charges the capacitor C through the pre-charging resistor R. After the capacitor C is fully charged, K1 is closed and then K2 is disconnected. PCS starts to respond to the power command and output power. When the energy storage battery voltage is too low, PCS can charge the energy storage battery through Q first.

[0079] In this embodiment, a control device for an energy storage converter is also provided, which is used to implement the above-mentioned embodiments and preferred implementation modes, and the descriptions that have been made will not be repeated. As used below, the term "module" can implement a combination of software and / or hardware for a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, the implementation of hardware, or a combination of software and hardware, is also possible and conceivable.

[0080] In this embodiment, a control device for an energy storage converter is provided, comprising:

[0081] An acquisition module, used to disconnect the first switch circuit and the pre-charging circuit to obtain the voltage of the energy storage battery;

[0082] The charging module is used to determine whether the voltage of the energy storage battery is lower than a preset voltage threshold. When it is lower than the preset voltage threshold, a closed-loop control method is adopted to close the step-down circuit and control the charging current of the energy storage battery by adjusting the duty cycle of the transistor Q.

[0083] The control device of the energy storage converter in this embodiment is presented in the form of a functional unit, where the unit refers to an ASIC circuit, a processor and a memory that executes one or more software or fixed programs, and / or other devices that can provide the above functions.

[0084] The further functional description of each of the above modules and units is the same as that of the above corresponding embodiments and will not be repeated here.

[0085] An embodiment of the present invention further provides a computer device having the control device of the energy storage converter.

[0086] See also Fig.10 , Fig.10 is a schematic diagram of the structure of a computer device provided by an optional embodiment of the present invention, such as Fig.10 As shown, the computer device includes: one or more processors 10, a memory 20, and interfaces for connecting various components, including high-speed interfaces and low-speed interfaces. Various components are connected to each other using different buses for communication, and can be installed on a common mainboard or installed in other ways as needed. The processor can process the instructions executed in the computer device, including instructions stored in or on the memory to display the graphical information of the GUI on an external input / output device (such as, a display device coupled to the interface). In some optional embodiments, if necessary, multiple processors and / or multiple buses can be used together with multiple memories and multiple memories. Similarly, multiple computer devices can be connected, and each device provides some necessary operations (for example, as a server array, a group of blade servers, or a multi-processor system). Fig.10 A processor 10 is taken as an example.

[0087] The processor 10 may be a central processing unit, a network processor or a combination thereof. The processor 10 may further include a hardware chip. The hardware chip may be a dedicated integrated circuit, a programmable logic device or a combination thereof. The programmable logic device may be a complex programmable logic device, a field programmable gate array, a general purpose array logic or any combination thereof.

[0088] The memory 20 stores instructions executable by at least one processor 10, so that at least one processor 10 executes the method shown in the above embodiment.

[0089] The memory 20 may include a program storage area and a data storage area, wherein the program storage area may store an operating system, an application required for at least one function; the data storage area may store data created by the use of a computer device based on the presentation of a small program landing page, etc. In addition, the memory 20 may include a high-speed random access memory, and may also include a non-transient memory, such as at least one disk storage device, a flash memory device, or other non-transient solid-state storage device. In some optional embodiments, the memory 20 may optionally include a memory remotely arranged relative to the processor 10, and these remote memories may be connected to the computer device via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0090] The memory 20 may include a volatile memory, such as a random access memory; the memory may also include a non-volatile memory, such as a flash memory, a hard disk or a solid state drive; the memory 20 may also include a combination of the above types of memory.

[0091] The computer device further comprises a communication interface 30 for the computer device to communicate with other devices or a communication network.

[0092] The embodiment of the present invention also provides a computer-readable storage medium. The method according to the embodiment of the present invention can be implemented in hardware, firmware, or can be implemented as a computer code that can be recorded in a storage medium, or can be implemented as a computer code that is originally stored in a remote storage medium or a non-temporary machine-readable storage medium and will be stored in a local storage medium through a network download, so that the method described herein can be stored in such software processing on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. Among them, the storage medium can be a magnetic disk, an optical disk, a read-only storage memory, a random access memory, a flash memory, a hard disk or a solid-state hard disk, etc.; further, the storage medium can also include a combination of the above types of memories. It can be understood that a computer, a processor, a microprocessor controller, or programmable hardware includes a storage component that can store or receive software or computer code. When the software or computer code is accessed and executed by a computer, a processor, or hardware, the method shown in the above embodiment is implemented.

[0093] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. An energy storage converter, characterized in that: include: The converter main circuit, the first switch circuit, the step-down circuit, and the energy storage battery, wherein: The AC side of the converter main circuit is connected to the power grid, and one end of the DC side of the converter main circuit is connected to the first end of the first switch circuit and the first end of the step-down circuit; The second end of the first switch circuit is connected to the second end of the step-down circuit; The third end of the step-down circuit is connected to the positive electrode of the energy storage battery, the fourth end of the step-down circuit is connected to the negative electrode of the energy storage battery, and the fifth end of the step-down circuit is connected to the other end of the DC side of the main circuit of the converter; When the energy storage battery is low on power, a closed-loop control method is adopted to close the buck circuit, and by adjusting the duty cycle of the transistor inside the buck circuit, the main circuit of the converter is controlled to provide the charging current for the energy storage battery.

2. The energy storage converter according to claim 1, characterized in that: The step-down circuit also includes: a freewheeling diode, an energy storage inductor and a fuse, wherein: The collector of the transistor is connected to the first end of the first switch circuit, and the emitter of the transistor is connected to the first end of the energy storage inductor, the cathode of the freewheeling diode, and the second end of the first switch circuit; The second end of the energy storage inductor is connected to the first end of the fuse; The second end of the fuse is connected to the positive electrode of the energy storage battery; The anode of the freewheeling diode is connected to the negative electrode of the energy storage battery and the other end of the DC side of the converter main circuit.

3. The energy storage converter according to claim 2, characterized in that: Also includes: Precharge circuit, where The pre-charging circuit is connected in parallel with the first switching circuit.

4. The energy storage converter according to claim 3, characterized in that: The pre-charging circuit comprises: a controllable switch and a current limiting resistor, wherein: The first end of the controllable switch is connected to the first end of the first switch circuit, and the second end of the controllable switch is connected to the first end of the current limiting resistor; The second end of the current limiting resistor is connected to the second end of the first switch circuit.

5. The energy storage converter according to claim 3, characterized in that: Also includes: The second switching circuit, wherein The anode of the freewheeling diode is connected to the other end of the DC side of the converter main loop through the second switch circuit.

6. A control method for an energy storage converter, characterized in that: Based on the energy storage converter according to any one of claims 3 to 5, the control method comprises: Disconnect the first switch circuit and the pre-charging circuit to obtain the voltage of the energy storage battery; It is determined whether the voltage of the energy storage battery is lower than the preset voltage threshold. When it is lower than the preset voltage threshold, a closed-loop control method is adopted to close the buck circuit and control the charging current of the energy storage battery by adjusting the duty cycle of the transistor.

7. The control method of the energy storage converter according to claim 6, characterized in that: The process of controlling the charging current of the energy storage battery includes: Establish an average value model for the energy storage inductor and calculate the average voltage of the energy storage inductor; Calculating an average current of the energy storage inductor based on an average voltage of the energy storage inductor; Calculating the difference between the average current of the energy storage inductor and the reference current value to obtain the current difference; Performing PI control on the current difference to obtain a voltage compensation value; Compensating the voltage of the energy storage battery using the voltage compensation value; The ratio of the compensated energy storage battery voltage to the DC side voltage of the converter main circuit is used as the duty cycle of the transistor in the next cycle.

8. The control method of the energy storage converter according to claim 6, characterized in that: Also includes: When the voltage of the energy storage battery is not lower than the preset voltage threshold, the first switch circuit is closed, and the pre-charging circuit and the step-down circuit are disconnected.

9. The control method of the energy storage converter according to claim 6, characterized in that: Also includes: Under normal operating conditions, before closing the first switch circuit, the pre-charge circuit is closed; After a preset time, the pre-charging circuit is disconnected.

10. A control device for an energy storage converter, characterized in that: include: An acquisition module, used to disconnect the first switch circuit and the pre-charging circuit to obtain the voltage of the energy storage battery; The charging module is used to determine whether the voltage of the energy storage battery is lower than a preset voltage threshold. When it is lower than the preset voltage threshold, a closed-loop control method is adopted to close the step-down circuit and control the charging current of the energy storage battery by adjusting the duty cycle of the transistor.

11. A computer device, characterized in that: include: A memory and a processor, wherein the memory and the processor are communicatively connected to each other, the memory stores computer instructions, and the processor executes the control method of the energy storage converter according to any one of claims 6 to 9 by executing the computer instructions.

12. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a computer to execute the control method of the energy storage converter according to any one of claims 6 to 9.

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