Control method and control module for power conversion system (PCS) used in photovoltaic power generation

Abstract

A control method and a control module for an energy storage module of a power conversion system used in photovoltaic power generation. The control method comprises the following steps: S1, in an energy storage module, providing N energy storage monitoring units corresponding to N energy storage units, and each energy storage monitoring unit monitoring a current value and a voltage value of the corresponding energy storage unit and sending the current value and the voltage value to a control module; and S2, the control module outputting a control signal on the basis of the current value and the voltage value of each energy storage unit, and controlling each energy storage unit to connect to or disconnect from a direct-current bus.

Description

A control method and control module for a PCS energy storage converter for photovoltaic power generation

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is based on the Chinese patent application with application number 202311798117.4 and application date of December 25, 2023, and claims the priority of the Chinese patent application. The entire content of the Chinese patent application is hereby introduced into this application as a reference. Technical Field

[0003] The present disclosure relates to the technical field of energy storage converters, and in particular to a control method and a control module of a PCS energy storage converter for photovoltaic power generation. Background Art

[0004] Power conversion systems (PCSs) are used in photovoltaic power generation systems to convert the DC power generated by the system into AC power, storing the energy in energy storage units or feeding it back into the grid. The inverter is the core component of the PCS, responsible for achieving DC-to-AC conversion. Traditional inverters use silicon-based power devices (such as transistors and IGBTs) to achieve power conversion. With technological advancements, new semiconductor devices (such as SiC and GaN) are increasingly being used in inverters. These devices offer higher switching speeds, lower on-resistance, and greater temperature tolerance, improving system efficiency and reliability.

[0005] In the actual design and production process, due to the instability of the photovoltaic power generation system, how to control the energy storage unit in the PCS is also a problem that needs to be solved urgently. Summary of the Invention

[0006] The present disclosure aims to solve one of the technical problems in the related art at least to a certain extent.

[0007] To achieve the above objectives, the present disclosure proposes a method for controlling a PCS energy storage converter energy storage module for photovoltaic power generation, comprising the following steps:

[0008] S1. N energy storage monitoring units are provided in the energy storage module corresponding to the N energy storage units. Each energy storage monitoring unit monitors the energy storage unit current value and energy storage unit voltage value of the corresponding energy storage unit and sends them to the control module;

[0009] S2. The control module outputs a control signal according to the energy storage unit current value and the energy storage unit voltage value of each energy storage unit to control the N energy storage units to be connected or disconnected from the DC bus.

[0010] The present disclosure provides energy storage monitoring units in an energy storage module that are equal in number and correspond one to one to the energy storage units, thereby achieving independent control of multiple energy storage units and improving the stability of the power generation system.

[0011] Optionally, in S2, the control module outputs a control signal according to the energy storage unit current value and the energy storage unit voltage value of each energy storage unit according to the following steps:

[0012] S201. According to the current load demand, obtain the number N1 of energy storage units in operation and the number N2 of backup energy storage units, where N1 + N2 = N.

[0013] S202: Obtain the required operating time H for each energy storage unit based on the number of energy storage units N1, the total energy storage capacity M, and the total capacity T of the energy storage units. wi ;

[0014] S203: Obtain the required working time H of each backup energy storage unit based on the total capacity T of the number of backup energy storage units N2 and the number of energy storage units N1. si ;

[0015] S204, based on the number of energy storage units N1 and their working time H wi , and the number of backup energy storage units N2 and their working time H si , output control signals to control the on and off of each energy storage unit.

[0016] Furthermore, in S202, the time H required for each energy storage unit to work can be calculated according to the following formula: wi :

[0017] Wherein, M represents the total energy storage capacity to be stored in the energy storage unit, N1 represents the number of energy storage units put into operation, and T represents the total capacity of the energy storage units put into operation.

[0018] Furthermore, the total capacity T of the energy storage units put into operation can be obtained by adding the available capacities of the various energy storage units put into operation. The available capacity of each energy storage unit can be determined based on the current value and the voltage value of the energy storage unit. The available capacity of the energy storage unit is the product of the current value and the voltage value of the energy storage unit. The total energy storage capacity M refers to the amount of electric energy required to be stored by the current PCS energy storage converter, which can be determined based on actual demand and load conditions.

[0019] Furthermore, the ratio of the total energy storage capacity to be stored to the number of put-in-place energy storage units is used to determine the load proportion that each put-in-place energy storage unit needs to bear.

[0020] Furthermore, in the step S203, the time H required for each backup energy storage unit to work can be calculated according to the following formula:si :

[0021] Wherein, N2 represents the number of backup energy storage units, and I represents the operating current of the backup energy storage unit.

[0022] Further, wherein, M-N1×H wi It is the capacity available for backup energy storage units after deducting the workload allocated to each working energy storage unit from the total capacity of all energy storage units. The remaining capacity is then allocated according to the number of backup energy storage units.

[0023] Furthermore, in S204, the energy storage unit current value and the energy storage unit voltage value are used to determine the available capacity of the energy storage unit.

[0024] The present disclosure also provides a PCS energy storage converter for photovoltaic power generation, comprising an inverter, an energy storage module, a DC / DC converter, and a control module;

[0025] One end of the DC / DC converter is connected to the photovoltaic power generation unit for converting the direct current output by the photovoltaic power generation unit, and the other end of the DC / DC converter is connected to the inverter via a DC bus for outputting the converted direct current to the inverter;

[0026] One end of the inverter is connected to a DC / DC converter for performing DC / AC conversion on the direct current, and the other end of the inverter is connected to a power grid for outputting the converted alternating current to the power grid;

[0027] The energy storage module includes N energy storage units, each of which is controllably connected to the DC bus and is used to connect or disconnect with the DC bus according to a control signal output by the control module.

[0028] Furthermore, the energy storage module further includes N energy storage monitoring units, each of which monitors the energy storage unit current value and energy storage unit voltage value of the corresponding energy storage unit and sends them to the control module;

[0029] The control module includes a working node corresponding to the connected energy storage module. The working node is configured to receive the energy storage unit current value and energy storage unit voltage value of each energy storage unit to output a control signal, and control the N energy storage units to be connected or disconnected from the DC bus according to the signal.

[0030] Additional aspects and advantages of the present disclosure will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The above and / or additional aspects and advantages of the present disclosure will become apparent and readily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0032] FIG1 is a schematic structural diagram of a PCS energy storage converter for photovoltaic power generation provided by one embodiment of the present disclosure;

[0033] FIG2 is a schematic structural diagram of an inverter in a PCS energy storage converter for photovoltaic power generation provided by one embodiment of the present disclosure;

[0034] FIG3 is a schematic structural diagram of an inverter in a PCS energy storage converter for photovoltaic power generation provided by one embodiment of the present disclosure;

[0035] FIG4 is a schematic structural diagram of an extrusion mechanism of an inverter in a PCS energy storage converter for photovoltaic power generation provided by one embodiment of the present disclosure;

[0036] FIG5 is a schematic structural diagram of a shielding mechanism of an inverter in a PCS energy storage converter for photovoltaic power generation provided by an embodiment of the present disclosure;

[0037] FIG6 is a schematic cross-sectional view of an inverter in a PCS energy storage converter for photovoltaic power generation according to an embodiment of the present disclosure;

[0038] FIG7 is a flow chart of control steps of a method for controlling an energy storage module of a PCS energy storage converter for photovoltaic power generation provided by one embodiment of the present disclosure;

[0039] FIG8 is a schematic diagram showing the detailed steps of step S2 of a method for controlling an energy storage module of a PCS energy storage converter for photovoltaic power generation provided by an embodiment of the present disclosure.

[0040] Explanation of the accompanying symbols: 1. Shell; 2. Mounting top cover; 3. Heat dissipation port; 4. Sponge body; 5. Partition; 6. Heat dissipation fan; 7. Drain outlet; 8. Extrusion mechanism; 81. Screw rod; 82. Extrusion plate; 83. Guide rod; 9. Shielding mechanism; 91. Mounting cover; 92. Rotating shaft; 93. Shielding cloth; 94. Driven bevel gear; 95. Driving bevel gear; 10. Support leg. DETAILED DESCRIPTION

[0041] The following describes in detail embodiments of the present disclosure, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present disclosure, and should not be construed as limiting the present disclosure.

[0042] The present application provides a PCS energy storage converter for photovoltaic power generation, which is described in detail below with reference to FIG. 1 to FIG. 6 .

[0043] A PCS energy storage converter for photovoltaic power generation, comprising an inverter, an energy storage module, a DC / DC converter, and a control module;

[0044] Among them, the inverter includes an inverter housing 1, and a mounting top cover 2 is provided directly above the housing 1 and is separated from the housing 1. The housing 1 is a box-type structure, and a accommodating cavity for accommodating electronic components is provided in the housing 1. Water absorption cavities are provided at both ends of the accommodating cavity. The water absorption cavity and the accommodating cavity are separated by a partition 5. A water absorption and drainage mechanism is provided in the water absorption cavity. A first exhaust channel for discharging water vapor in the accommodating cavity is correspondingly provided on the partition 5, and an exhaust part is provided in the first exhaust channel. A heat dissipation port 3 for discharging air out of the water absorption cavity is provided on a side wall of the housing 1 corresponding to the first exhaust channel, and a plurality of drainage ports 7 are provided on the bottom wall of the water absorption cavity directly opposite to the flexible water absorbent part.

[0045] The present invention changes the internal structure of the inverter, discharges the water vapor and higher temperature air in the accommodating cavity for accommodating electronic components into the water absorption cavity through the exhaust part, absorbs the water vapor through the water absorption and drainage mechanism, and then controls the water absorption and drainage mechanism to discharge the absorbed water vapor out of the water absorption cavity along the heat dissipation port 3, thereby completing the extraction of water vapor inside the inverter.

[0046] In some embodiments, the exhaust component is configured as a heat dissipation fan 6, and it should be noted that the two heat dissipation fans 6 are arranged in two partitions 5 corresponding to the first exhaust channel, one group is an air inlet fan and the other group is an air outlet fan, and the air inlet fan and the air outlet fan are arranged directly opposite each other to facilitate air flow and improve heat dissipation efficiency.

[0047] In some embodiments, the water absorption and drainage mechanism includes a flexible absorbent member that can absorb moisture from the air discharged through the exhaust member and discharge the absorbed moisture when needed. The flexible absorbent member is configured to restore its original shape. In one embodiment, the flexible absorbent member is configured as a water-absorbing sponge. The water absorption and drainage mechanism also includes an extrusion structure disposed on one side of the flexible absorbent member. The extrusion mechanism 8 includes a drive portion disposed on the bottom wall of the water absorption chamber and a screw 81 disposed perpendicular to the bottom wall of the water absorption chamber. A squeezing plate 82 is disposed on the side of the flexible absorbent member facing away from the bottom wall of the water absorption chamber, and the squeezing plate 82 is threadedly connected to the screw.

[0048] The exhaust member extracts the higher temperature and water vapor-containing air from the accommodating chamber. After the air enters the water absorption chamber, it first contacts the flexible water absorbent member, which absorbs the water vapor in the air. Under the action of the exhaust member, the air, after absorbing all the water vapor, is discharged from the water absorption chamber along the heat dissipation port 3. When the flexible water absorbent member absorbs a large amount of water vapor and needs to be discharged, the drive unit of the squeezing mechanism 8 is controlled to operate, and the squeezing plate 82 is driven downward by the screw 81. At this time, the volume of the flexible water absorbent is compressed by the squeezing plate 82 and the bottom wall of the water absorption chamber. The water contained in the flexible water absorbent is squeezed into the water absorption chamber, and the water forms water droplets or water streams and is discharged along the drain port 7 on the bottom wall of the water absorption chamber.

[0049] In some embodiments, the drive unit is driven by a motor. The drive unit can be electrically connected to a control module, and a control program and hardware for controlling the operation of the drive motor can be added to the control module to achieve timed water vapor discharge from the flexible water absorbent member.

[0050] In some embodiments, a guide rod 83 is provided between the extrusion plate 82 and the drive unit. The guide rod 83 is arranged parallel to the lead screw, passes through the extrusion plate 82, and the extrusion plate 82 is slidably connected to the guide rod 83. The shape of the extrusion plate 82 is the same as the horizontal cross-section of the water absorption chamber, but the area of ​​the extrusion plate 82 is smaller than the area of ​​the horizontal cross-section of the water absorption chamber. Therefore, the extrusion plate 82 can move freely up and down within the water absorption chamber. However, due to the gap between the boundary of the extrusion plate 82 and the inner wall of the water absorption chamber, there is room for the extrusion plate 82 to rotate a certain angle following the lead screw 81 during its movement. Therefore, the guide rod 83 is provided. Under the action of the guide rod 83, it can guide and limit the extrusion plate 82, thereby ensuring the stability of the extrusion plate 82 as it descends.

[0051] In some embodiments, auxiliary fixing members are provided at the tops of the screw rod 81 and the guide rod 83 to assist in securing the water suction and drainage mechanism. The auxiliary fixing members are configured as rectangular plates, and a stepped groove is provided at the opening of the water suction chamber for the auxiliary fixing members to be placed in. When the water suction and drainage mechanism is placed in the water suction chamber, the auxiliary fixing members fit into the corresponding stepped grooves, which facilitates positioning and auxiliary securing of the water suction and drainage mechanism.

[0052] In some embodiments, a synchronous shielding mechanism 9 is provided in the water absorption chamber, and the synchronous shielding mechanism 9 includes a mounting cover 91 arranged above the partition 5, and a rotating shaft 92 is provided in the mounting cover 91 to rotate parallel to the vertical direction of the screw rod 81, and a driven bevel gear 94 is provided on the rotating shaft 92 toward the side of the screw rod 81, and an active bevel gear 95 meshing with the driven bevel gear 94 is provided at the end of the screw rod 81 away from the driving part, and a shielding cloth 93 for shielding the first exhaust channel is provided on the rotating shaft 92, and the free end of the shielding cloth 93 is fixedly connected to the top of the flexible water-absorbing member.

[0053] Under the setting of the shielding mechanism 9, it is installed on the side of the partition 5 through the mounting cover 91, and is connected to the top of the sponge 4 through the shielding cloth 93 on the surface of the rotating shaft 92, so that when the sponge 4 is compressed, the shielding cloth 93 can be synchronously lowered, thereby blocking the first exhaust channel of the partition 5, preventing the water vapor outside the accommodating chamber from entering the interior of the shell 1 through the first exhaust channel of the partition 5, which may easily cause electrical hazards. Referring to Figure 5, one end of the rotating shaft 92 passes through the mounting cover 91 and extends to be fixedly connected with a driven bevel gear 94, and the surface of the driven bevel gear 94 is meshedly connected with the driving bevel gear 95, and the driving bevel gear 95 is fixedly connected to the surface of the screw 81. The driven bevel gear 94 is meshed with the driving bevel gear 95, so that it can synchronously drive the driving bevel gear 95 to rotate during the rotation of the screw 81, and the driving bevel gear 95 drives the rotating shaft 92 fixed to the driven bevel gear 94 to rotate, so that the rotation work can be carried out synchronously.

[0054] In some embodiments, to ensure that the various components of the inverter do not interfere with each other during installation, the installation cover 91 is set at a height not exceeding the height of the water absorption chamber opening. In other words, the installation cover 91 is completely inside the water absorption chamber and is fixedly mounted on the partition 5.

[0055] In some embodiments, referring to FIG6 , the inner bottom wall of the water absorption chamber is provided with a plurality of drainage holes, located directly below the flexible water-absorbing member. Furthermore, the bottom wall of the housing 1 is provided with hollowed-out legs, each hollowed-out leg having a drainage channel. The hollowed-out drainage channel within the leg faces a drainage port 7, and the number of drainage ports 7 is the same as the number of legs. The provision of a plurality of drainage holes facilitates the discharge of moisture from the compressed flexible water-absorbing member, preventing it from remaining within the housing 1 and potentially causing a secondary electrical hazard. A support leg 10 is fixedly connected to the bottom of the housing 1. The support leg 10 is located directly below the drainage hole. Water flowing out of the drainage hole flows away along the hollowed-out channel within the support leg 10. The provision of the support leg 10 allows it to support and install the housing 1. The hollowed-out support leg 10 reduces the overall weight while ensuring water flow.

[0056] In some embodiments, the front of the heat dissipation vent 3 is provided with a dust screen to protect the flexible water-absorbing member. The technical solution provided by the disclosed embodiments, with the dust screen, can effectively filter impurities contained in the air during air circulation, preventing impurities from entering the flexible water-absorbing member and affecting its use.

[0057] Considering the instability of photovoltaic power generation systems, controlling the energy storage units in the PCS is also an urgent issue to be addressed. This disclosure also provides a method for controlling the energy storage modules of a PCS energy storage converter for photovoltaic power generation, which is described in detail below with reference to Figures 7 and 8.

[0058] A method for controlling a PCS energy storage converter energy storage module for photovoltaic power generation comprises the following steps:

[0059] S1. N energy storage monitoring units are provided in the energy storage module corresponding to the N energy storage units. Each energy storage monitoring unit monitors the energy storage unit current value and energy storage unit voltage value of the corresponding energy storage unit and sends them to the control module;

[0060] S2. The control module outputs a control signal according to the energy storage unit current value and the energy storage unit voltage value of each energy storage unit to control the N energy storage units to be connected or disconnected with the DC bus.

[0061] In S2, the control module outputs a control signal according to the energy storage unit current value and the energy storage unit voltage value of each energy storage unit, which can be based on the following steps:

[0062] S201. According to the current load demand, obtain the number N1 of energy storage units in operation and the number N2 of backup energy storage units, where N1 + N2 = N.

[0063] S202: Obtain the required operating time H for each energy storage unit based on the number of energy storage units N1, the total energy storage capacity M, and the total capacity T of the energy storage units. wi ;

[0064] S203: Obtain the required working time H of each backup energy storage unit based on the total capacity T of the number of backup energy storage units N2 and the number of energy storage units N1. si ;

[0065] S204, based on the number of energy storage units N1 and their working time H wi , and the number of backup energy storage units N2 and their working time H si , output control signals to control the on and off of each energy storage unit.

[0066] In S202, the time H required for each energy storage unit to work can be calculated according to the following formula: wi :

[0067] Wherein, M represents the total energy storage capacity to be stored in the energy storage unit, N1 represents the number of energy storage units put into operation, and T represents the total capacity of the energy storage units put into operation.

[0068] The total capacity T of the energy storage units put into operation can be obtained by adding the available capacity of each energy storage unit put into operation. The available capacity of each energy storage unit can be determined based on the current value and voltage value of the energy storage unit. The available capacity of the energy storage unit is the product of the current value and voltage value of the energy storage unit. The total energy storage capacity M refers to the amount of electric energy required to be stored by the current PCS energy storage converter, which can be determined based on actual demand and load conditions.

[0069] In the above formula, the ratio of the total energy storage capacity to be stored to the number of energy storage units in operation can be used to determine the load proportion that each energy storage unit needs to bear. This calculation takes into account the workload proportion that each energy storage unit needs to bear when the total capacity T is fixed, the total energy storage capacity M to be stored, and the number of energy storage units are known. This ensures that each energy storage unit has sufficient operating time while preventing some energy storage units from overworking.

[0070] In S203, the time H required for each backup energy storage unit to work can be calculated according to the following formula: si :

[0071] Wherein, N2 represents the number of backup energy storage units, and I represents the operating current of the backup energy storage unit.

[0072] In the above formula, M-N1×H wi It represents the remaining capacity available for backup energy storage units after deducting the workload allocated to each working energy storage unit from the total capacity of all energy storage units. The remaining capacity is then distributed according to the number of backup energy storage units.

[0073] In S204 , the energy storage unit current value and the energy storage unit voltage value are used to determine the available capacity of the energy storage unit.

[0074] The present application also provides a PCS energy storage converter energy storage module for photovoltaic power generation, which is used to implement the above energy storage module control method, including an inverter, an energy storage module, a DC / DC converter, and a control module;

[0075] One end of the DC / DC converter is connected to the photovoltaic power generation unit to convert the DC power output by the photovoltaic power generation unit. The other end of the DC / DC converter is connected to the inverter via a DC bus to output the converted DC power to the inverter. The DC / DC converter can use a common DC / DC converter topology, such as a full-bridge converter or a half-bridge converter.

[0076] One end of the inverter is connected to the DC / DC converter for converting DC power to AC power, and the other end of the inverter is connected to the grid for outputting the converted AC power to the grid.

[0077] The energy storage module includes N energy storage units, each of which is controllably connected to the DC bus and is used to connect or disconnect with the DC bus according to a control signal output by the control module.

[0078] The energy storage module further includes N energy storage monitoring units, each of which monitors the energy storage unit current value and energy storage unit voltage value of the corresponding energy storage unit and sends them to the control module. Each energy storage unit in the energy storage module is also provided with a corresponding DC / DC converter for converting the voltage output by the energy storage module or the voltage input to the energy storage module.

[0079] The control module is communicatively connected to the energy storage module, the inverter, and the DC / DC converter, and includes a working node corresponding to the communication connection with the energy storage module. The working node is configured to receive the energy storage unit current value and the energy storage unit voltage value of each energy storage unit to output a control signal, and control the N energy storage units to connect or disconnect with the DC bus according to the signal to achieve control of the energy storage module.

[0080] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification and features of different embodiments or examples, unless they are mutually inconsistent.

[0081] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. Throughout the present disclosure, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0082] Although the embodiments of the present disclosure have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and alterations may be made to the embodiments without departing from the principles and spirit of the present disclosure, the scope of which is defined by the claims and their equivalents.

Claims

1. A method for controlling a PCS energy storage converter energy storage module for photovoltaic power generation, comprising the following steps: S1. N energy storage monitoring units are provided in the energy storage module corresponding to the N energy storage units. Each energy storage monitoring unit monitors the energy storage unit current value and energy storage unit voltage value of the corresponding energy storage unit and sends them to the control module; S2. The control module outputs a control signal according to the energy storage unit current value and the energy storage unit voltage value of each energy storage unit to control the N energy storage units to be connected or disconnected from the DC bus.

2. A PCS energy storage converter energy storage module control method for photovoltaic power generation according to claim 1, wherein: In S2, the control module outputs a control signal according to the energy storage unit current value and the energy storage unit voltage value of each energy storage unit, which can be based on the following steps: S201, according to the current load demand, obtain the number of energy storage units N1 and the number of backup energy storage units N2, N1+N2=N; S202: Obtain the time H required for each energy storage unit to work according to the number of energy storage units put into operation N1, the total energy storage capacity M, and the total capacity T of the energy storage units put into operation. wi ; S203, according to the number of backup energy storage units N2 and the total capacity T of the number of energy storage units N1, the time H required for each backup energy storage unit to work is obtained. si ; S204, based on the number of energy storage units N1 and their working time H wi , and the number of backup energy storage units N2 and their working time H si , output control signals to control the on and off of each energy storage unit.

3. A PCS energy storage converter energy storage module control method for photovoltaic power generation as claimed in claim 2, wherein: In S202, the time H required for each energy storage unit to work can be calculated according to the following formula: wi : Among them, M represents the total energy storage capacity to be stored in the energy storage unit, N1 represents the number of energy storage units put into use, and T represents the total capacity of the energy storage units put into use.

4. A PCS energy storage converter energy storage module control method for photovoltaic power generation as claimed in claim 3, wherein: The total capacity T of the energy storage units put into operation can be obtained by adding the available capacities of the various energy storage units put into operation. The available capacity of each energy storage unit can be determined based on the current value and the voltage value of the energy storage unit. The available capacity of the energy storage unit is the product of the current value and the voltage value of the energy storage unit. The total energy storage capacity M refers to the amount of electrical energy required to be stored by the current PCS energy storage inverter, which can be determined based on actual demand and load conditions.

5. A PCS energy storage converter energy storage module control method for photovoltaic power generation as claimed in claim 3, wherein: The ratio of the total energy storage capacity to be stored to the number of energy storage units put into operation is used to determine the load proportion that each energy storage unit needs to bear.

6. A PCS energy storage converter energy storage module control method for photovoltaic power generation according to claim 2, wherein: In S203, the time H required for each backup energy storage unit to work can be calculated according to the following formula: si : Wherein, N2 represents the number of backup energy storage units, and I represents the operating current of the backup energy storage unit.

7. A method for controlling a PCS energy storage converter energy storage module for photovoltaic power generation according to claim 6, wherein: in, M-N1×H wi It is the capacity of all energy storage units that remains available for backup energy storage units after deducting the workload allocated to each working energy storage unit from the total capacity of all energy storage units. The remaining capacity is then allocated according to the number of backup energy storage units.

8. A PCS energy storage converter energy storage module control method for photovoltaic power generation according to claim 2, wherein: In S204, the energy storage unit current value and the energy storage unit voltage value are used to determine the available capacity of the energy storage unit.

9. A PCS energy storage converter for photovoltaic power generation, comprising an inverter, an energy storage module, a DC / DC converter, and a control module; One end of the DC / DC converter is connected to the photovoltaic power generation unit to convert the direct current output by the photovoltaic power generation unit, and the other end of the DC / DC converter is connected to the inverter through a direct current bus to output the converted direct current to the inverter; One end of the inverter is connected to a DC / DC converter for performing DC / AC conversion on the direct current, and the other end of the inverter is connected to a power grid for outputting the converted alternating current to the power grid; The energy storage module includes N energy storage units, each of which is controllably connected to the DC bus and is used to connect or disconnect with the DC bus according to a control signal output by the control module.

10. A PCS energy storage converter for photovoltaic power generation as claimed in claim 9, wherein: The energy storage module further includes N energy storage monitoring units, each of which monitors the energy storage unit current value and energy storage unit voltage value of the corresponding energy storage unit and sends them to the control module; The control module includes a working node corresponding to the connected energy storage module, which is configured to receive the energy storage unit current value and the energy storage unit voltage value of each energy storage unit to output a control signal, and control the N energy storage units to connect or disconnect with the DC bus according to the signal.

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