A control method, device and converter for modular multi-level energy storage converter

Abstract

The present invention relates to the field of power transmission technology, and discloses a control method, device, and converter for a modular multi-level energy storage converter. In the present invention, a protection branch composed of a transistor and a resistor in series is newly connected in parallel to the battery pack of the power module on the basis of the topological structure of the original modular multi-level energy storage converter, and a control method and device for the converter are provided accordingly, wherein when the system is operating normally, a pulse width modulation instruction is sent to each power module, and at the same time, the transistor in the protection branch is controlled to remain in an off state, and whether the system has a fault in real time is detected. When a system fault is detected, the transistor in the protection branch is controlled to be turned on. Compared with the original solution, the power module of the new topological structure of the present invention has a stronger ability to cross system faults, avoids damage to power electronic equipment due to overcharging of system energy, and can minimize the frequent switching of power modules during faults, has good economic efficiency, and the control method and device are simple and convenient.

Description

Technical Field

[0001] The present invention relates to the field of power transmission technology, and in particular to a control method and device for a modular multi-level energy storage converter, and a converter. Background Art

[0002] Modular multilevel energy storage converters (MMC for short) are widely used in power systems to ensure the safe and stable operation of power systems.

[0003] The general topology of a modular multi-level energy storage converter consists of three phase units, each composed of multiple identical power modules connected in series. Each power module includes a battery pack, a bidirectional DC / DC converter, and a half-bridge module. The battery pack is connected in parallel with the half-bridge module via the bidirectional DC / DC converter. This structure allows for matching the lower voltage of the battery pack with the higher DC voltage of the half-bridge module, providing greater flexibility.

[0004] However, modular multi-level energy storage converters contain several power modules, each of which includes a battery pack, a bidirectional DC / DC converter, and a half-bridge sub-module. Due to the large number of components and the limited current-carrying capacity of each power electronic device, when a serious AC or DC fault occurs, the current will rise rapidly, which can easily cause the entire power module to fail and be forced to be disconnected, having a serious impact on the entire power system.

[0005] Currently, most fault handling measures for modular multi-level energy storage converters rely on switching redundant submodules to achieve fault ride-through. This solution requires redundant power modules, which is uneconomical in low- and medium-voltage applications with a small number of power modules and low voltages. Furthermore, due to the rapid increase in current during a fault, excessive current flows through the power modules. If the excess energy is not dissipated and consumed, it can easily damage the power modules. Summary of the Invention

[0006] The present invention provides a control method, device and converter for a modular multi-level energy storage converter, which solves the technical problem of how to economically protect the modular multi-level energy storage converter when the current rises rapidly due to a fault.

[0007] A first aspect of the present invention provides a modular multi-level energy storage converter, which includes three phase units, each phase unit is composed of multiple identical power modules connected in series, each power module includes a battery pack, a bidirectional DC / DC converter and a half-bridge sub-module, the battery pack is connected in parallel with the half-bridge sub-module through the bidirectional DC / DC converter, and the power module also includes a protection branch composed of a transistor and a resistor connected in series, and the protection branch is connected in parallel with the battery pack in the power module.

[0008] According to an implementation of the first aspect of the present invention, the resistance value of the resistor is set according to the following formula:

[0009]

[0010] In the formula, R represents the resistance value of the resistor, V Cmax is the maximum voltage allowed by the capacitor in the half-bridge submodule, V Bmin is the minimum voltage for normal operation of the battery pack, N is the number of power modules of the energy storage converter, P S0 is the DC side rated power of the system where the modular multilevel energy storage converter is located during normal operation, η is the percentage of power that the modular multilevel energy storage converter can still deliver during voltage drop, P G0 P is the AC side output power when the system where the modular multi-level energy storage converter is located is in normal operation. B0 is the energy storage battery power of the battery pack.

[0011] According to an achievable manner of the first aspect of the present invention, the transistor in the protection branch is an insulated gate bipolar transistor.

[0012] A second aspect of the present invention provides a control method for a modular multi-level energy storage converter as described in any one of the above implementations, the control method comprising:

[0013] When the system in which the modular multi-level energy storage converter is located is operating normally, a pulse width modulation instruction is sent to each power module of the modular multi-level energy storage converter, and at the same time, the transistor in the protection branch is controlled to remain in an off state;

[0014] Real-time detection is performed to determine whether the system has failed. If so, the transistor in the protection branch is controlled to be turned on.

[0015] According to an achievable manner of the second aspect of the present invention, detecting whether a failure occurs in the system includes:

[0016] Obtaining real-time detection values ​​of operating parameters of the system, wherein the operating parameters include system DC voltage, bridge arm DC current, DC side power, AC power measurement, and energy storage battery power;

[0017] Calculating the bridge arm DC current using the real-time detection value to obtain a bridge arm DC current calculation value;

[0018] The real-time detection value of the bridge arm DC current is compared with the calculated value of the bridge arm DC current. If the real-time detection value of the bridge arm DC current is greater than or equal to the calculated value of the bridge arm DC current, it is determined that a fault occurs in the system.

[0019] According to an achievable manner of the second aspect of the present invention, the calculating the bridge arm DC current by using the real-time detection value includes:

[0020] Calculate the bridge arm DC current according to the following formula:

[0021]

[0022] Where i dc_arm Represents the calculated value of the bridge arm DC current, P R (t) represents the average power that the resistor needs to bear at time t, P S0 (t) represents the DC side power detected at time t, P G0 (t) represents the AC side output power detected at time t, P B0 (t) represents the energy storage battery power detected at time t, V dc (t) represents the system DC voltage detected at time t.

[0023] A third aspect of the present invention provides a control device for a modular multi-level energy storage converter as described in any one of the above implementations, the control device comprising:

[0024] A first control module is configured to send a pulse width modulation instruction to each power module of the modular multi-level energy storage converter when the system in which the modular multi-level energy storage converter is located is operating normally, and at the same time control the transistors in the protection branch to remain in an off state;

[0025] A fault detection module, used for detecting in real time whether a fault occurs in the system;

[0026] The second control module is configured to control the transistors in the protection branch to conduct when a fault is detected in the system.

[0027] According to an achievable manner of the second aspect of the present invention, the fault detection module includes:

[0028] A data acquisition unit, configured to acquire real-time detection values ​​of operating parameters of the system, wherein the operating parameters include system DC voltage, bridge arm DC current, DC side power, AC power measurement, and energy storage battery power;

[0029] a calculation unit, configured to calculate the bridge arm DC current using the real-time detection value to obtain a bridge arm DC current calculation value;

[0030] The fault judgment unit is used to compare the real-time detection value of the bridge arm DC current with the calculated value of the bridge arm DC current, and if the real-time detection value of the bridge arm DC current is greater than or equal to the calculated value of the bridge arm DC current, it is determined that a fault has occurred in the system.

[0031] According to an achievable manner of the second aspect of the present invention, the computing unit is specifically configured to:

[0032] Calculate the bridge arm DC current according to the following formula:

[0033]

[0034] Where i dc_arm Represents the calculated value of the bridge arm DC current, P R (t) represents the average power that the resistor needs to bear at time t, P S0 (t) represents the DC side power detected at time t, P G0 (t) represents the AC side output power detected at time t, P B0 (t) represents the energy storage battery power detected at time t, V dc (t) represents the system DC voltage detected at time t.

[0035] A third aspect of the present invention provides an automatic scheduling device for a smart card test platform, comprising:

[0036] A memory for storing instructions; wherein the instructions are used to implement the control method of the modular multi-level energy storage converter as described in any one of the above implementation methods;

[0037] A processor is configured to execute instructions in the memory.

[0038] A fourth aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the control method of the modular multi-level energy storage converter as described in any of the above implementation methods is implemented.

[0039] It can be seen from the above technical solutions that the present invention has the following advantages:

[0040] The present invention, based on the topology of the original modular multi-level energy storage converter, newly connects a protection branch consisting of a transistor and a resistor in series in parallel to the battery pack of the power module, and correspondingly provides a control method and device for the converter. When the system is operating normally, a pulse width modulation instruction is sent to each power module, and at the same time, the transistor in the protection branch is controlled to remain in an off state, so as to detect in real time whether the system has a fault. When the system fault is detected, the transistor in the protection branch is controlled to be turned on. Compared with the original solution, the new converter topology of the present invention has a power module with a stronger ability to ride through system faults, avoiding damage to power electronic equipment due to overcharging of system energy, and can minimize the frequent switching of power modules during faults. It has good economic efficiency, and the control method and device are simple and convenient, effectively solving the technical problem of how to economically protect the modular multi-level energy storage converter when the current rises rapidly due to a fault. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] 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 required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0042] Figure 1 A schematic diagram of the topology of an existing modular multi-level energy storage converter;

[0043] Figure 2 A schematic diagram of the topological structure of a modular multi-level energy storage converter provided in an optional embodiment of the present invention;

[0044] Figure 3 A flowchart of a control method for a modular multi-level energy storage converter provided in an optional embodiment of the present invention;

[0045] Figure 4 A logic diagram of a control method for a modular multi-level energy storage converter provided in an optional embodiment of the present invention;

[0046] Figure 5 A structural connection block diagram of a control device for a modular multi-level energy storage converter provided in an optional embodiment of the present invention.

[0047] Reference numerals:

[0048] 1-First control module; 2-Fault detection module; 3-Second control module. DETAILED DESCRIPTION

[0049] Embodiments of the present invention provide a control method, device, and converter for a modular multi-level energy storage converter, which are used to solve the technical problem of how to economically protect the modular multi-level energy storage converter when a current rises rapidly due to a fault.

[0050] In order to make the purpose, features, and advantages of the present invention more obvious and easy to understand, the technical solutions 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 embodiments described below 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 work are within the scope of protection of the present invention.

[0051] The present invention provides a modular multi-level energy storage converter.

[0052] The topology of existing modular multi-level energy storage converters is as follows: Figure 1 The modular multi-level energy storage converter includes three phase units: phase unit A, phase unit B, and phase unit C. Each phase unit is composed of multiple identical power modules connected in series. Each power module includes a battery pack, a bidirectional DC / DC converter, and a half-bridge submodule. The battery pack is connected in parallel with the half-bridge submodule via the bidirectional DC / DC converter. Figure 1 In the figure, Lo represents inductance.

[0053] This structure allows for greater flexibility by matching the lower voltage of the battery pack with the higher DC voltage of the half-bridge submodule. However, a modular multilevel energy storage converter consists of several power modules, each of which contains a battery pack, a bidirectional DC / DC converter, and a half-bridge submodule. Due to the large number of components and the limited current flow capacity of each power electronic device, the current can rise rapidly in the event of a severe AC or DC fault, easily leading to the failure of the entire power module and forced disconnection, severely impacting the entire energy storage system.

[0054] Figure 2 A schematic diagram of the topological structure of a modular multi-level energy storage converter provided by an embodiment of the present invention is shown.

[0055] The embodiment of the present invention Figure 1 Based on the topology of the modular multi-level energy storage converter shown, the topology of the power module is improved. Specifically, a protection branch consisting of a transistor and a resistor connected in series is added, and the protection branch is connected in parallel with the battery pack in the power module.

[0056] like Figure 2In the topology shown, the DC / DC converter of the original power module includes two insulated gate bipolar transistors T1 and T2, the half-bridge sub-module of the original power module includes two insulated gate bipolar transistors T3 and T4, and a protection branch is connected in parallel with the battery pack of the DC / DC converter. The protection branch includes an insulated gate bipolar transistor T0 and a resistor R.

[0057] Since a transistor and a resistor are newly added, the resistance value of the resistor needs to be designed to provide a resistor with a suitable resistance value and improve the performance of the protection branch.

[0058] Assume that the rated power of the DC side is P when the system is operating normally S0 , the AC side output power is P G0 , the power of the energy storage battery is P B0 , then there exists:

[0059] P S0 +P B0 =P G0 .

[0060] When a system failure occurs, the DC side power cannot generally change quickly and remains P S0 , the AC side power will be reduced to ηP G0 , so that P S0 Much larger than P G0 , η is the percentage of power that can still be delivered during the voltage drop.

[0061] The power of the energy storage battery is still P B0 Assuming that the number of power modules in the energy storage converter is N, the average power that the resistor needs to bear is:

[0062]

[0063] Where, P R Indicates the average power that the resistor needs to bear.

[0064] Furthermore, the resistance value of the resistor can be set to:

[0065]

[0066] In the formula, R represents the resistance value of the resistor, V Cmax is the maximum voltage allowed by the capacitor in the half-bridge submodule, V Bmin This is the minimum voltage for normal operation of the battery pack.

[0067] Based on the above analysis, the resistance value of the resistor is set according to the following formula:

[0068]

[0069] In the formula, R represents the resistance value of the resistor, VCmax is the maximum voltage allowed by the capacitor in the half-bridge submodule, V Bmin is the minimum voltage for normal operation of the battery pack, N is the number of power modules of the energy storage converter, P S0 is the DC side rated power of the system where the modular multilevel energy storage converter is located during normal operation, η is the percentage of power that the modular multilevel energy storage converter can still deliver during voltage drop, P G0 P is the AC side output power when the system where the modular multi-level energy storage converter is located is in normal operation. B0 is the energy storage battery power of the battery pack.

[0070] The type of transistor in the protection branch can be set according to actual conditions, as long as it can provide a conduction or isolation function for the protection branch. As a preferred embodiment, the transistor is an insulated gate bipolar transistor.

[0071] The present invention also provides a control method for a modular multi-level energy storage converter, which is used to control the improved modular multi-level energy storage converter described in the above embodiment.

[0072] See also Figure 3 , Figure 3 A flow chart of a control method for a modular multi-level energy storage converter provided by an embodiment of the present invention is shown.

[0073] An embodiment of the present invention provides a control method for a modular multi-level energy storage converter, comprising steps S1-S2.

[0074] Step S1: When the system where the modular multi-level energy storage converter is located is operating normally, a pulse width modulation instruction is sent to each power module of the modular multi-level energy storage converter, and at the same time, the transistors in the protection branch are controlled to remain in an off state.

[0075] for Figure 2 In the topology shown, during normal system operation, each power module executes the pulse-width modulation instructions, causing IGBTs T1, T2, T3, and T4 to use normal pulse-width modulation and perform normal switching. IGBT T0 remains off, and the series branch formed by IGBT T0 and resistor R is in an open circuit state.

[0076] Step S2: detecting in real time whether the system has a fault, and if so, controlling the transistors in the protection branch to be turned on.

[0077] for Figure 2 In the topology shown, when it is determined that a system fault occurs, a conduction signal is applied to the insulated gate bipolar transistor T0, and a protection branch composed of the insulated gate bipolar transistor T0 and the resistor R is put into operation.

[0078] Applying an on or off signal to the transistor in the protection branch requires a judgment basis. In one achievable manner, detecting whether a fault occurs in the system includes:

[0079] Obtaining real-time detection values ​​of operating parameters of the system, wherein the operating parameters include system DC voltage, bridge arm DC current, DC side power, AC power measurement, and energy storage battery power;

[0080] Calculating the bridge arm DC current using the real-time detection value to obtain a bridge arm DC current calculation value;

[0081] The real-time detection value of the bridge arm DC current is compared with the calculated value of the bridge arm DC current. If the real-time detection value of the bridge arm DC current is greater than or equal to the calculated value of the bridge arm DC current, it is determined that a fault occurs in the system.

[0082] The present invention calculates the current bridge arm DC current based on the real-time detection value of the system's operating parameters, and then determines that a system fault has occurred when the real-time detection value of the bridge arm DC current is greater than or equal to the calculated bridge arm DC current value. This enables the protection branch to respond promptly based on the real-time detection result of the system, improves the real-time performance of system current control, and can effectively ensure the safe and stable operation of the power system.

[0083] In one achievable manner, the calculating the bridge arm DC current using the real-time detection value includes:

[0084] Calculate the bridge arm DC current according to the following formula:

[0085]

[0086] Where i dc_arm Represents the calculated value of the bridge arm DC current, P R (t) represents the average power that the resistor needs to bear at time t, P S0 (t) represents the DC side power detected at time t, P G0 (t) represents the AC side output power detected at time t, P B0 (t) represents the energy storage battery power detected at time t, V dc (t) represents the system DC voltage detected at time t.

[0087] The embodiment of the present invention provides a specific method for calculating the real-time value of the bridge arm DC current.

[0088] It should be noted that if the real-time detection value of the bridge arm DC current is less than the calculated value of the bridge arm DC current, it indicates that the system has not failed, and the process returns to the step of obtaining the real-time detection value of the operating parameters of the system. Figure 4 If the calculated value of the bridge arm DC current is still less than the detected value and this condition persists, and if the duration is greater than the designed value, the fault is considered unrecoverable and the system is shut down.

[0089] The present invention also provides a control device for the modular multi-level energy storage converter as described in any one of the above embodiments.

[0090] Figure 5 A structural connection block diagram of a control device for a modular multi-level energy storage converter provided by an embodiment of the present invention is shown.

[0091] like Figure 5 As shown, the control device includes:

[0092] A first control module 1 is configured to send a pulse width modulation instruction to each power module of the modular multi-level energy storage converter when the system in which the modular multi-level energy storage converter is located is operating normally, and at the same time control the transistors in the protection branch to remain in an off state;

[0093] Fault detection module 2, used for detecting whether the system has a fault in real time;

[0094] The second control module 3 is configured to control the transistors in the protection branch to conduct when a fault is detected in the system.

[0095] In one possible implementation, the fault detection module 2 includes:

[0096] A data acquisition unit, configured to acquire real-time detection values ​​of operating parameters of the system, wherein the operating parameters include system DC voltage, bridge arm DC current, DC side power, AC power measurement, and energy storage battery power;

[0097] a calculation unit, configured to calculate the bridge arm DC current using the real-time detection value to obtain a bridge arm DC current calculation value;

[0098] The fault judgment unit is used to compare the real-time detection value of the bridge arm DC current with the calculated value of the bridge arm DC current, and if the real-time detection value of the bridge arm DC current is greater than or equal to the calculated value of the bridge arm DC current, it is determined that a fault has occurred in the system.

[0099] In one possible implementation, the computing unit is specifically configured to:

[0100] Calculate the bridge arm DC current according to the following formula:

[0101]

[0102] Where i dc_arm Represents the calculated value of the bridge arm DC current, P R(t) represents the average power that the resistor needs to bear at time t, P S0 (t) represents the DC side power detected at time t, P G0 (t) represents the AC side output power detected at time t, P B0 (t) represents the energy storage battery power detected at time t, V dc (t) represents the system DC voltage detected at time t.

[0103] The present invention also provides an automatic scheduling device for a smart card test platform, comprising:

[0104] A memory for storing instructions; wherein the instructions are used to implement the control method of the modular multi-level energy storage converter as described in any one of the above embodiments;

[0105] A processor is configured to execute instructions in the memory.

[0106] The present invention also provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the control method of the modular multi-level energy storage converter as described in any one of the above embodiments is implemented.

[0107] Those skilled in the art can clearly understand that, for the convenience and conciseness of description, the specific working processes of the devices and modules described above can refer to the corresponding processes in the aforementioned method embodiments, and the specific beneficial effects of the devices and modules described above can refer to the corresponding beneficial effects in the aforementioned method embodiments, which will not be repeated here.

[0108] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the module division is merely a logical function division. In actual implementation, other division methods may be used, such as combining or integrating multiple modules or components into another system, or ignoring or not implementing certain features.

[0109] The modules described as separate components may or may not be physically separate, and the components shown as modules may or may not be physical modules, that is, they may be located in one place or distributed across multiple network modules. Some or all of the modules may be selected to achieve the purpose of the present embodiment according to actual needs.

[0110] In addition, the functional modules in various embodiments of the present invention may be integrated into a single processing module, or each module may exist physically separately, or two or more modules may be integrated into a single module. The aforementioned integrated modules may be implemented in the form of hardware or software functional modules.

[0111] If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0112] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments can still be modified, or some of the technical features thereof can be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A control method for a modular multi-level energy storage converter, characterized in that: The control method is applied to a modular multi-level energy storage converter, which includes three phase units, each phase unit consisting of multiple identical power modules connected in series, each power module including a battery pack, a bidirectional DC / DC converter, and a half-bridge sub-module, the battery pack being connected in parallel with the half-bridge sub-module via the bidirectional DC / DC converter. The power module further includes a protection branch consisting of a transistor and a resistor connected in series, the protection branch being connected in parallel with the battery pack in the power module. The control method includes: When the system in which the modular multi-level energy storage converter is located is operating normally, a pulse width modulation instruction is sent to each power module of the modular multi-level energy storage converter, and at the same time, the transistor in the protection branch is controlled to remain in an off state; Real-time detection is performed to determine whether the system has failed. If so, the transistor in the protection branch is controlled to be turned on.

2. The control method of the modular multi-level energy storage converter according to claim 1, characterized in that: The resistance value of the resistor is set according to the following formula: ； Where, Indicates the resistance value of the resistor, is the maximum voltage allowed by the capacitor in the half-bridge submodule, The minimum voltage for normal operation of the battery pack. is the number of power modules of the energy storage converter, is the DC side rated power of the system where the modular multi-level energy storage converter is located during normal operation, is the percentage of power that the modular multilevel energy storage converter can still deliver during voltage sag, The AC side of the modular multi-level energy storage converter delivers power during normal operation of the system. is the energy storage battery power of the battery pack.

3. The control method of the modular multi-level energy storage converter according to claim 2, characterized in that: The transistor in the protection branch is an insulated gate bipolar transistor.

4. The control method of the modular multi-level energy storage converter according to claim 1, characterized in that: The detecting whether the system fails comprises: Obtaining real-time detection values ​​of operating parameters of the system, wherein the operating parameters include system DC voltage, bridge arm DC current, DC side power, AC power measurement, and energy storage battery power; Calculating the bridge arm DC current using the real-time detection value to obtain a bridge arm DC current calculation value; The real-time detection value of the bridge arm DC current is compared with the calculated value of the bridge arm DC current. If the real-time detection value of the bridge arm DC current is greater than or equal to the calculated value of the bridge arm DC current, it is determined that a fault occurs in the system.

5. A control device for a modular multi-level energy storage converter, characterized in that: The control device is applied to a modular multi-level energy storage converter, which includes three phase units, each phase unit is composed of multiple identical power modules connected in series, each power module includes a battery pack, a bidirectional DC / DC converter and a half-bridge sub-module, and the battery pack is connected in parallel with the half-bridge sub-module through the bidirectional DC / DC converter. It is characterized in that the power module also includes a protection branch composed of a transistor and a resistor connected in series, and the protection branch is connected in parallel with the battery pack in the power module. The control device includes: A first control module is configured to send a pulse width modulation instruction to each power module of the modular multi-level energy storage converter when the system in which the modular multi-level energy storage converter is located is operating normally, and at the same time control the transistors in the protection branch to remain in an off state; A fault detection module, used for detecting in real time whether a fault occurs in the system; The second control module is configured to control the transistors in the protection branch to conduct when a fault is detected in the system.

6. The control device for the modular multi-level energy storage converter according to claim 5, characterized in that: The fault detection module includes: A data acquisition unit, configured to acquire real-time detection values ​​of operating parameters of the system, wherein the operating parameters include system DC voltage, bridge arm DC current, DC side power, AC power measurement, and energy storage battery power; a calculation unit, configured to calculate the bridge arm DC current using the real-time detection value to obtain a bridge arm DC current calculation value; The fault judgment unit is used to compare the real-time detection value of the bridge arm DC current with the calculated value of the bridge arm DC current, and if the real-time detection value of the bridge arm DC current is greater than or equal to the calculated value of the bridge arm DC current, it is determined that a fault has occurred in the system.

7. A control device for a modular multi-level energy storage converter, characterized in that: include: A memory for storing instructions; wherein the instructions are used to implement the control method of the modular multi-level energy storage converter according to claim 1; A processor is configured to execute instructions in the memory.

8. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the control method of the modular multi-level energy storage converter according to claim 1 is implemented.

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