Power conversion system and control method therefor

Abstract

The present application provides a power conversion system and a control method therefor. According to the control method, upon receipt of a zero-power operation instruction, an alternating-current grid connection switch on the alternating-current side of each power unit in a power conversion system is controlled to be kept closed, and the power units are controlled to respectively operate in a charging mode and a discharging mode, wherein the total charging power and the total discharging power of the power units satisfy a zero-power grid connection requirement. In this way, operation in a zero-power mode can be implemented, and all power units are enabled to generate waves, thereby avoiding problems such as burnout of an alternating-current capacitor that would easily occur due to wave blocking, avoiding the risk of system resonance, and enhancing system stability. Moreover, the zero-power mode of the power conversion system can be implemented without increasing any hardware cost, and the demand of power grid scheduling is satisfied.

Description

Energy storage converter and control method thereof

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on September 22, 2023, with application number 202311237145.9 and invention name “A Energy Storage Converter and Its Control Method”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of energy storage technology, and in particular to an energy storage converter and a control method thereof. Background Art

[0003] To meet the requirements of rapid grid dispatch, energy storage power stations usually require their converters to be in zero-power mode. In zero-power mode, the converter does not output power to the outside, but its AC grid-connected switch cannot be disconnected from the grid.

[0004] The current implementation method involves blocking the converter's PWM (Pulse Width Modulation) signal to keep its AC grid-connected switch closed. While this method can achieve zero converter output power across the entire station, due to the AC capacitors' connection to the grid, the influence of grid impedance and potential low-order harmonics can easily cause low-frequency resonance between the AC capacitors and the grid impedance, potentially damaging the AC capacitors.

[0005] Summary of the Invention

[0006] The present application provides an energy storage converter and a control method thereof to avoid problems such as burning of AC capacitors that may easily occur during wave blocking.

[0007] To achieve the above objectives, this application provides the following technical solutions:

[0008] In a first aspect, the present application provides a control method for an energy storage converter, wherein the energy storage converter comprises: at least two power units, wherein the DC side of each power unit is connected to a corresponding battery unit, and the AC side of each power unit is connected to a power grid via a corresponding AC grid-connected switch; the control method for the energy storage converter comprises:

[0009] Determine whether a zero-power operation instruction is received;

[0010] If the zero-power operation instruction is received, controlling each of the AC grid-connected switches to remain closed;

[0011] Each of the power units is controlled to operate in a charging mode and a discharging mode respectively, and the total charging power and the total discharging power of each of the power units meet the zero-power grid connection requirement.

[0012] Optionally, controlling each of the power units to operate in a charging mode and a discharging mode respectively includes:

[0013] controlling at least one of the power units to operate in a charging mode; and

[0014] The other power units are controlled to operate in a discharge mode.

[0015] Optionally, the zero-power grid-connected requirement is that the difference between the absolute values ​​of the total charging power and the total discharging power is less than or equal to the power threshold of the zero-power operation instruction.

[0016] Optionally, the zero-power grid-connected requirement is that the absolute value of the total charging power is equal to the absolute value of the total discharging power.

[0017] Optionally, after controlling each of the power units to operate in the charging mode and the discharging mode respectively, the method further includes:

[0018] Determine whether the state of charge (SOC) of the battery cell connected to the power unit operating in the charging mode is greater than or equal to a preset upper limit, and whether the SOC of the battery cell connected to the power unit operating in the discharging mode is less than or equal to a preset lower limit;

[0019] If the SOC of the battery cell connected to the power unit operating in the charging mode is greater than or equal to the preset upper limit, or the SOC of the battery cell connected to the power unit operating in the discharging mode is less than or equal to the preset lower limit, then the power units are controlled to switch the charging and discharging modes.

[0020] Optionally, controlling each of the power units to switch between charging and discharging modes includes:

[0021] controlling the power unit operating in the charging mode to operate in the discharging mode; and

[0022] The power unit operating in the discharge mode is controlled to operate in the charge mode.

[0023] Optionally, determining whether the state of charge (SOC) of the battery cells connected to the power unit operating in the charging mode is greater than or equal to a preset upper limit includes: determining whether a maximum SOC of the battery cells connected to the power unit operating in the charging mode is greater than or equal to the preset upper limit;

[0024] Determining whether the SOC of the battery unit connected to the power unit operating in the discharge mode is less than or equal to a preset lower limit includes: determining whether the smallest one of the SOCs of the battery units connected to the power unit operating in the discharge mode is less than or equal to the preset lower limit.

[0025] Optionally, after determining whether the state of charge (SOC) of the battery cell connected to the power unit operating in the charging mode is greater than or equal to a preset upper limit, and whether the SOC of the battery cell connected to the power unit operating in the discharging mode is less than or equal to a preset lower limit, the method further includes:

[0026] If the SOC of the battery cell connected to the power unit operating in the charging mode is less than the preset upper limit, and the SOC of the battery cell connected to the power unit operating in the discharging mode is greater than the preset lower limit, each power unit is controlled to maintain the current charging and discharging mode.

[0027] Optionally, after controlling the power units to switch the charge and discharge modes, the method further includes:

[0028] again determining whether the SOC of the battery cell connected to the power unit operating in the charging mode is greater than or equal to the preset upper limit, and whether the SOC of the battery cell connected to the power unit operating in the discharging mode is less than or equal to the preset lower limit;

[0029] If the SOC of the battery cell connected to the power unit operating in the charging mode is greater than or equal to the preset upper limit, or the SOC of the battery cell connected to the power unit operating in the discharging mode is less than or equal to the preset lower limit, then controlling each power unit to switch the charging and discharging mode again;

[0030] If the SOC of the battery cell connected to the power unit operating in the charging mode is less than the preset upper limit, and the SOC of the battery cell connected to the power unit operating in the discharging mode is greater than the preset lower limit, each power unit is controlled to maintain the current charging and discharging mode.

[0031] The second aspect of the present application provides an energy storage converter, comprising: a controller and at least two power units; wherein,

[0032] The DC side of each power unit is connected to a corresponding battery unit;

[0033] The AC side of each power unit is connected to the power grid through a corresponding AC grid-connected switch;

[0034] Each of the power units is controlled by the controller, and the controller is used to execute the control method of the energy storage converter as described in any one of the first aspects above.

[0035] Optionally, the power unit is a bidirectional DC / AC conversion circuit.

[0036] Optionally, the battery unit includes: a battery cluster, or at least two battery clusters connected in parallel.

[0037] The control method of the energy storage converter provided in the present application controls the AC grid-connected switch on the AC side of each power unit in the energy storage converter to remain closed after receiving a zero-power operation instruction, and controls each power unit to operate in charging mode and discharging mode respectively, and the total charging power and total discharging power of each power unit meet the zero-power grid-connected requirements; thereby, it can realize zero-power mode operation and generate waves for each power unit, avoiding the problem of AC capacitor burning caused by wave blocking. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings to be used in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0039] FIG1 is a schematic structural diagram of an energy storage converter provided in an embodiment of the present application;

[0040] FIG2 is a flow chart of a control method for an energy storage converter according to an embodiment of the present application;

[0041] FIG3 is another flow chart of a control method for an energy storage converter according to an embodiment of the present application;

[0042] FIG4 is another flow chart of a control method for an energy storage converter according to an embodiment of the present application;

[0043] FIG5 is a partial working logic diagram of the control method of the energy storage converter provided in an embodiment of the present application. DETAILED DESCRIPTION

[0044] 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 the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0045] In this application, the terms "comprises," "comprising," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not preclude the presence of additional identical elements in the process, method, article, or apparatus that includes the element.

[0046] The present application provides a control method for an energy storage converter to avoid problems such as burning of AC capacitors that may occur during wave blocking.

[0047] Referring to Figure 1, the energy storage converter includes: at least two power units (as shown in the figure, power unit 1 to power unit N); the DC side of each power unit is connected to a corresponding battery unit, which may include one or at least two battery clusters connected in parallel, and the battery cluster includes one or at least two battery packs connected in series; the AC side of each power unit is connected to the grid through a corresponding AC grid-connected switch (as shown in the figure, S1 to SN); N is an integer greater than 1.

[0048] Referring to FIG2 , the control method of the energy storage converter includes:

[0049] S101: Determine whether a zero-power operation instruction is received.

[0050] The zero-power operation instruction is a scheduling instruction sent by the host computer to the energy storage converter, which is used to control the energy storage converter to operate in zero-power mode, that is, no power is output to the outside, but each AC grid-connected switch is continuously disconnected from the grid.

[0051] If a zero-power operation instruction is received, S102 and S103 are executed. In actual applications, S102 and S103 can be executed simultaneously; or S102 can be executed first and then S103; it depends on the specific application environment and is within the scope of protection of this application.

[0052] S102. Control each AC grid-connected switch to remain closed.

[0053] If the AC grid-connected switches are in the disconnected state at the last moment, S102 specifically controls the AC grid-connected switches to be closed; if the AC grid-connected switches are in the closed state at the last moment, S102 specifically maintains corresponding control over the AC grid-connected switches to keep them in the closed state.

[0054] In actual applications, it is not ruled out that some AC grid-connected switches are in the disconnected state and some AC grid-connected switches are in the closed state. If a zero-power operation instruction is received at this time, S102 specifically controls the AC grid-connected switches in the disconnected state to be attracted, and controls the AC grid-connected switches in the closed state to remain in the closed state.

[0055] S103 , controlling each power unit to operate in a charging mode and a discharging mode respectively, and the total charging power and the total discharging power of each power unit meet the zero-power grid-connected requirement.

[0056] The process of controlling each power unit to operate in the charging mode and the discharging mode respectively can be specifically as follows: controlling at least one of the power units to operate in the charging mode; and controlling each of the other power units to operate in the discharging mode. For the energy storage converter shown in FIG. 1, this process is specifically to control N1 power units to operate in the discharging mode; and control N2 power units to operate in the charging mode; where N = N1 + N2, thereby ensuring that each power unit needs to perform wave control and will not be in the wave-blocking state.

[0057] Moreover, for the N1 power units operating in the discharging mode, the total discharging power output is denoted as P1; for the N2 power units operating in the charging mode, the total charging power received is denoted as P2; by adjusting the duty cycle of the wave generation of each power unit, P1 and P2 can be made to meet the zero-power grid connection requirement, ensuring that the grid connection will not be disconnected due to non-compliance with this zero-power grid connection requirement. In practical applications, this zero-power grid connection requirement can specifically be that the absolute value difference between the total charging power and the total discharging power is less than or equal to the power threshold of the zero-power operation instruction, that is, |P1| - |P2| < Pmin; Pmin is this power threshold, and its value can be determined according to the actual situation, such as a positive value slightly greater than zero; or, directly by adjusting the duty cycle of the wave generation of each power unit, |P1| = |P2| can be made to ensure that the power output at the grid port of the energy storage converter is zero.

[0058] Based on the above principle, the control method of the energy storage converter provided in this embodiment can not only achieve zero-power mode operation but also perform wave generation for each power unit, avoiding problems such as the burnout of AC capacitors easily caused by wave blocking, avoiding the risk of system resonance, and improving system stability. Moreover, without adding any hardware costs, the zero-power mode of the energy storage converter can be achieved to meet the requirements of grid dispatching.

[0059] It is worth noting that there is also an implementation method in the prior art, which is to control each power unit to discharge at an extremely low power and keep the AC grid connection switch closed; however, in practical applications, limited by the zero drift, temperature drift, and accuracy of the sensors, the control of the power unit often causes its output power to be too large. In the case of a large number of converters in a whole station, the total output power may be greater than the dispatching requirement and not meet the conditions for grid disconnection.

[0060] The control method of the energy storage converter provided in this embodiment controls some power units to charge while controlling some power units to discharge, and then through the adjustment of the two powers, it can ensure charge-discharge matching and make the power output at the grid port of the energy storage converter meet the requirements.

[0061] On the basis of the previous embodiment, this embodiment provides some more preferred examples for the control method of the energy storage converter. For example, referring to FIG3 , after S103 , the method further includes:

[0062] S201. Determine whether the SOC (State of Charge) of the battery cell connected to the power unit operating in the charging mode is greater than or equal to a preset upper limit, and whether the SOC of the battery cell connected to the power unit operating in the discharging mode is less than or equal to a preset lower limit.

[0063] S201 determines whether the SOC exceeds a limit. In practical applications, the determination of whether the state of charge (SOC) of the battery cells connected to the power unit operating in the charging mode is greater than or equal to a preset upper limit may be performed by determining whether the maximum SOC among the battery cells connected to the power unit operating in the charging mode is greater than or equal to the preset upper limit. Similarly, the determination of whether the SOC of the battery cells connected to the power unit operating in the discharging mode is less than or equal to a preset lower limit may be performed by determining whether the minimum SOC among the battery cells connected to the power unit operating in the discharging mode is less than or equal to the preset lower limit.

[0064] Alternatively, the SOC of the battery cells connected to the power units in the same mode can be averaged, and then the average value can be compared with the preset upper limit or the preset lower limit to make a judgment; it depends on the specific application environment and is not limited here.

[0065] If the SOC of the battery cell connected to the power unit operating in the charging mode is greater than or equal to the preset upper limit, or the SOC of the battery cell connected to the power unit operating in the discharging mode is less than or equal to the preset lower limit, S202 is executed.

[0066] S202 , controlling each power unit to switch the charge and discharge mode.

[0067] S202 specifically includes: controlling the power units operating in the charging mode to operate in the discharging mode; and controlling the power units operating in the discharging mode to operate in the charging mode. For the structure shown in FIG1 , this step is to control the N1 power units to switch to the charging mode and control the N2 power units to switch to the discharging mode.

[0068] If the SOC of the battery cell connected to the power unit operating in the charging mode is less than the preset upper limit, and the SOC of the battery cell connected to the power unit operating in the discharging mode is greater than the preset lower limit, each power unit is controlled to maintain the current charging and discharging mode, that is, the process returns to S103 to control the mode of each power unit. For the structure shown in Figure 1, this step controls the N1 power unit to maintain the discharging mode and controls the N2 power unit to maintain the charging mode.

[0069] In addition, referring to FIG4 , after S202 , controlling each power unit to switch the charge and discharge mode, the process further includes:

[0070] S203 , again determining whether the SOC of the battery cell connected to the power unit operating in the charging mode is greater than or equal to a preset upper limit, and whether the SOC of the battery cell connected to the power unit operating in the discharging mode is less than or equal to a preset lower limit.

[0071] S203 again determines whether the SOC exceeds the limit. At this time, if the SOC of the battery cell connected to the power unit operating in the charging mode is greater than or equal to the preset upper limit, or if the SOC of the battery cell connected to the power unit operating in the discharging mode is less than or equal to the preset lower limit, the power units are again controlled to switch the charging and discharging modes, that is, return to the mode control of each power unit in S103. For the structure shown in Figure 1, this step controls the N1 power unit to operate in the discharging mode again and controls the N2 power unit to operate in the charging mode again.

[0072] If the SOC of the battery cell connected to the power unit operating in the charging mode is less than a preset upper limit, and the SOC of the battery cell connected to the power unit operating in the discharging mode is greater than a preset lower limit, each power unit is controlled to maintain the current charging and discharging mode, that is, the process returns to S202 to control the mode of each power unit. For the structure shown in Figure 1, this step controls the N1 power unit to maintain the charging mode and controls the N2 power unit to maintain the discharging mode.

[0073] The following is a complete exemplary description of the control method using the structure shown in Figure 1 as an example:

[0074] When the power station dispatcher issues a zero-power operation command, N1 power units are controlled to operate in discharge mode, with a total discharge power of P1. The minimum or average SOC value of each battery unit is recorded as SOC1, SOC3≤SOC1, and SOC3 is the preset lower limit; and the other N2 power units are controlled to operate in charging mode, with a total charging power of P2. The maximum or average SOC value of each battery unit is recorded as SOC2, SOC2≤SOC4, and SOC4 is the preset upper limit.

[0075] As the discharge time increases, SOC1 will gradually decrease. When SOC1 reaches the preset lower limit SOC3, it means that the power of the N1 power units is low and it is not suitable to continue discharging. Similarly, as the charging time increases, SOC2 will gradually increase. When SOC2 reaches the preset upper limit SOC4, it means that the power of the N2 power units is high and it is not suitable to continue charging. Therefore, when SOC1 reaches the preset lower limit SOC3 or SOC2 reaches the preset upper limit SOC4, the N1 power units are controlled to operate in charging mode, and the N2 power units are controlled to operate in discharge mode; then the corresponding SOCs are continuously monitored and compared, and this is repeated. The working logic can be seen in Figure 5. When N=N1+N2 and P1=P2, the grid port output power of the energy storage converter can be made zero in real time.

[0076] Another embodiment of the present application further provides an energy storage converter, as shown in FIG1 , comprising: a controller (not shown) and at least two power units (power unit 1 to power unit N as shown in the figure), where N is an integer greater than 1; wherein:

[0077] The DC side of each power unit is connected to a corresponding battery unit; the battery unit includes: a battery cluster, or at least two battery clusters connected in parallel; the battery cluster includes a battery pack, or at least two battery packs connected in series.

[0078] The AC side of each power unit is connected to the grid through a corresponding AC grid-connected switch (S1 to SN as shown in the figure).

[0079] Each power unit can specifically be a bidirectional DC / AC conversion circuit and can adopt any topology in the prior art. There is no limitation here and it depends on the application environment and is within the protection scope of this application.

[0080] Each power unit is controlled by the controller, which is used to execute the control method of the energy storage converter as described in any of the above embodiments. The specific process and principle of the control method can be found in the above embodiments and will not be described here in detail.

[0081] The energy storage converter provided in this embodiment can realize the zero power mode of the energy storage converter by executing the above control method without increasing any hardware cost, meet the needs of grid scheduling, avoid the risk of system resonance, and improve system stability.

[0082] The same or similar parts between the various embodiments in this specification can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system or system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment. The system and system embodiments described above are merely schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. Ordinary technicians in this field can understand and implement it without making any creative efforts.

[0083] Professionals may further appreciate that the units and algorithm steps of each example 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 above description has generally described the components and steps of each example according to their functions. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present invention.

[0084] With respect to the above description of the disclosed embodiments, the features described in the various embodiments in this specification may be interchanged or combined to enable those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein, but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A control method for an energy storage converter, characterized in that: The energy storage converter comprises: at least two power units, the DC side of each power unit is connected to a corresponding battery unit, and the AC side of each power unit is connected to a power grid through a corresponding AC grid-connected switch; the control method of the energy storage converter comprises: Determine whether a zero-power operation instruction is received; If the zero-power operation instruction is received, controlling each of the AC grid-connected switches to remain closed; Each of the power units is controlled to operate in a charging mode and a discharging mode respectively, and the total charging power and the total discharging power of each of the power units meet the zero-power grid-connected requirement.

2. The control method of the energy storage converter according to claim 1, characterized in that: Controlling each of the power units to operate in a charging mode and a discharging mode respectively, comprising: controlling at least one of the power units to operate in a charging mode; and, The other power units are controlled to operate in a discharge mode.

3. The control method of the energy storage converter according to claim 1, characterized in that: The zero-power grid-connected requirement is that the difference between the absolute values ​​of the total charging power and the total discharging power is less than or equal to the power threshold of the zero-power operation instruction.

4. The control method of the energy storage converter according to claim 1, characterized in that: The zero-power grid-connected requirement is that the absolute value of the total charging power is equal to the absolute value of the total discharging power.

5. The control method of the energy storage converter according to any one of claims 1 to 4, characterized in that: After controlling each of the power units to operate in the charging mode and the discharging mode respectively, the method further includes: Determine whether the state of charge (SOC) of the battery unit connected to the power unit operating in the charging mode is greater than or equal to a preset upper limit, and whether the SOC of the battery unit connected to the power unit operating in the discharging mode is less than or equal to a preset lower limit; If the SOC of the battery cell connected to the power unit operating in the charging mode is greater than or equal to the preset upper limit, or the SOC of the battery cell connected to the power unit operating in the discharging mode is less than or equal to the preset lower limit, then the power units are controlled to switch the charging and discharging modes.

6. The control method of the energy storage converter according to claim 5, characterized in that: Controlling each of the power units to switch charging and discharging modes includes: controlling the power unit operating in the charging mode to operate in the discharging mode; and, The power unit operating in the discharge mode is controlled to operate in the charge mode.

7. The control method of the energy storage converter according to claim 5, characterized in that: Determining whether the state of charge SOC of the battery unit connected to the power unit operating in the charging mode is greater than or equal to a preset upper limit, comprising: determining whether the largest one of the SOCs of the battery units connected to the power unit operating in the charging mode is greater than or equal to the preset upper limit; Determining whether the SOC of the battery unit connected to the power unit operating in the discharge mode is less than or equal to a preset lower limit includes: determining whether the smallest one of the SOCs of the battery units connected to the power unit operating in the discharge mode is less than or equal to the preset lower limit.

8. The control method of the energy storage converter according to claim 5, characterized in that: After determining whether the state of charge SOC of the battery unit connected to the power unit operating in the charging mode is greater than or equal to a preset upper limit, and whether the SOC of the battery unit connected to the power unit operating in the discharging mode is less than or equal to a preset lower limit, the method further includes: If the SOC of the battery cell connected to the power unit operating in the charging mode is less than the preset upper limit, and the SOC of the battery cell connected to the power unit operating in the discharging mode is greater than the preset lower limit, each power unit is controlled to maintain the current charging and discharging mode.

9. The control method of the energy storage converter according to claim 5, characterized in that: After controlling each of the power units to switch the charging and discharging modes, the method further includes: Determine again whether the SOC of the battery unit connected to the power unit operating in the charging mode is greater than or equal to the preset upper limit, and whether the SOC of the battery unit connected to the power unit operating in the discharging mode is less than or equal to the preset lower limit; If the SOC of the battery unit connected to the power unit operating in the charging mode is greater than or equal to the preset upper limit, or the SOC of the battery unit connected to the power unit operating in the discharging mode is less than or equal to the preset lower limit, then each power unit is controlled to switch the charging and discharging mode again; If the SOC of the battery cell connected to the power unit operating in the charging mode is less than the preset upper limit, and the SOC of the battery cell connected to the power unit operating in the discharging mode is greater than the preset lower limit, each power unit is controlled to maintain the current charging and discharging mode.

10. An energy storage converter, characterized in that: include: A controller and at least two power units; wherein, The DC side of each power unit is connected to a corresponding battery unit respectively; The AC side of each power unit is connected to the power grid through a corresponding AC grid-connected switch; Each of the power units is controlled by the controller respectively, and the controller is used to execute the control method of the energy storage converter according to any one of claims 1 to 9.

11. The energy storage converter according to claim 10, characterized in that: The power unit is a bidirectional DC / AC conversion circuit.

12. The energy storage converter according to claim 10, characterized in that: The battery unit includes: a battery cluster, or at least two battery clusters connected in parallel.

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