AC side energy storage control method and system

Abstract

The invention relates to the technical field of photovoltaic control, in particular to an alternating current side energy storage control method and system. Comprising the following steps: acquiring the maximum output power of a photovoltaic power supply and the rated charging power of an energy storage device; presetting parameter control information, and carrying out analogue simulation on the photovoltaic power supply and the energy storage device according to the parameter control information; when analogue simulation is carried out on the photovoltaic power supply and the energy storage device, the load is increased within a preset time, and the increased load does not exceed 2000W; determining the stable working state of the photovoltaic power supply and the energy storage device according to the analogue simulation result, and controlling the photovoltaic power supply and the energy storage device according to the analogue simulation result of the stable working state of the photovoltaic power supply and the energy storage device. According to the invention, the working modes of the energy storage device and the photovoltaic power supply are coordinated based on adaptive PI droop control, so that the system can stably and autonomously switch and operate in multiple modes, and the stability of the system and the utilization rate of renewable energy sources are improved.

Description

Background Art

[0002] The energy storage system configured on the AC side of the power supply can also be called the energy storage system configured on the AC side. It uses a separate charge and discharge controller and inverter to charge or invert the battery. This solution is actually to add an energy storage device to the existing photovoltaic power generation system. It can be upgraded and installed in any current photovoltaic power station or even wind power station or other power station to form an in-station energy storage system. It can also be built into a completely independent energy storage power station according to the needs of the power grid. This model overcomes the problem that the DC side energy storage system cannot uniformly dispatch excess power. Its system charging or discharging is completely controlled by the intelligent control system or controlled by the power grid dispatch. It can not only concentrate the excess power in the entire station to charge the energy storage system quickly and effectively, but can even dispatch cheap low-valley excess power from the power grid outside the station, making the system operation more convenient and effective.

[0003] However, in the prior art, since the income of energy storage on the power generation side comes directly from the electricity market, the overall operation of the electricity market has a direct impact on energy storage. With a high proportion of photovoltaic grid-connected, it is easy to cause abnormal interaction with the power grid and cause small signal stability problems, resulting in instability in photovoltaic power generation, which is not conducive to the safe and stable operation of photovoltaic power stations. In addition, as the frequency of the power grid changes, the energy storage device is charged and discharged, which will cause different power flows of the energy storage device, and thus have different effects on the stability of photovoltaic power generation signals. Therefore, how to provide an AC side energy storage control method and system is a technical problem that technicians in this field urgently need to solve. Summary of the invention

[0004] The purpose of the present invention is to provide an AC side energy storage control method and system. The present invention realizes the coordination of the working modes of the energy storage device and the photovoltaic power supply based on adaptive PI droop control, so that the system can smoothly switch between multiple modes autonomously, overcome the uncertainty of renewable energy, and improve the stability of the system and the utilization rate of renewable energy.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] An AC side energy storage control method, applied to a photovoltaic AC power grid, comprises:

[0007] Obtain the maximum output power of the photovoltaic power source and the rated charging power of the energy storage device;

[0008] Preset parameter control information, and simulate the photovoltaic power source and the energy storage device according to the parameter control information; wherein,

[0009] The parameter control information includes that the SOC threshold is 75%, the frequency upper limit threshold is 50 Hz, and the frequency lower limit threshold is 49 Hz;

[0010] When simulating the photovoltaic power source and the energy storage device, the load is increased within a preset time, and the increased load does not exceed 2000W;

[0011] The stable working states of the photovoltaic power source and the energy storage device are determined according to the simulation results, and the photovoltaic power source and the energy storage device are controlled according to the simulation results of the stable working states of the photovoltaic power source and the energy storage device.

[0012] In some embodiments of the present application, before simulating the photovoltaic power source and the energy storage device according to the parameter control information, the method further includes:

[0013] The photovoltaic power source is subjected to droop control, and the working mode of the photovoltaic power source is determined, wherein the working mode of the photovoltaic power source includes a voltage control mode and a power control mode; wherein,

[0014] When the droop control is P / PD control, determining that the working mode of the photovoltaic power source is the voltage control mode;

[0015] When the droop control is PI / PID control, determining that the working mode of the photovoltaic power source is the power control mode;

[0016] When the working mode of the photovoltaic power source is a dual-mode control combining the voltage control mode and the power control mode, the frequency PI control of the photovoltaic power source is determined according to a preset formula, and the preset formula is:

[0017] w=w * -G p(s) (PP * )

[0018]

[0019] Wherein, mp is the proportional droop coefficient, mi is the integral droop coefficient, P is the power value of the power supply, P* is the power value of the rated operating point of the power supply, and MD is the logic signal of mode switching, which takes a value of 0 or 1.

[0020] In some embodiments of the present application, when the SOC in the parameter control information is less than a preset value or less than the frequency lower limit threshold, it is determined that the photovoltaic power source is in the voltage control mode, and the integral droop coefficient in the preset formula is determined to be 0 and the MD is 0;

[0021] When the SOC in the parameter control information is greater than a preset value or greater than the frequency upper limit threshold, controlling to stop charging the photovoltaic power source and enter the power control mode, and determining that the integral droop coefficient in the preset formula is 1 and MD is 1;

[0022] When the photovoltaic power source is in the power control mode and when the output power is greater than the upper frequency limit threshold, the photovoltaic power source is switched from the power control mode to the voltage control mode, and the integral droop coefficient in the preset formula is determined to be 0 and MD is 0;

[0023] When the photovoltaic power supply is in the voltage control mode and when the output power is greater than the power value of the rated operating point of the power supply, the photovoltaic power supply is switched from the voltage control mode to the power control mode, and the integral droop coefficient in the preset formula is determined to be 1 and MD is 1.

[0024] In some embodiments of the present application, when simulating the photovoltaic power source and the energy storage device, it also includes:

[0025] Acquire simulation quantities of the photovoltaic power source and the energy storage device, wherein the simulation quantities include the SOC of the battery, the battery output power, the photovoltaic panel output power, the load power and the grid frequency;

[0026] Determine the stable working state according to the simulation value; wherein,

[0027] When the SOC of the battery, the battery output power, the photovoltaic panel output power, the load power and the grid frequency reach a balance, the working mode of the photovoltaic power source is determined, and the working mode is determined as the stable working state.

[0028] In some embodiments of the present application, it also includes:

[0029] When the photovoltaic power source switches from the power control mode to the voltage control mode, or when the photovoltaic power source switches from the voltage control mode to the power control mode, the frequency is kept stable by a low-frequency filter.

[0030] In order to achieve the above object, the present invention also provides an AC side energy storage control system, which is applied to the AC side energy storage control method, and includes:

[0031] An acquisition unit, used to acquire the maximum output power of the photovoltaic power source and the rated charging power of the energy storage device;

[0032] The setting unit is used to pre-set parameter control information and simulate the photovoltaic power source and the energy storage device according to the parameter control information; wherein,

[0033] The parameter control information includes that the SOC threshold is 75%, the frequency upper limit threshold is 50 Hz, and the frequency lower limit threshold is 49 Hz;

[0034] A simulation unit, used to increase the load within a preset time when simulating the photovoltaic power source and the energy storage device, and the increased load does not exceed 2000W;

[0035] A control unit is used to determine the stable working state of the photovoltaic power source and the energy storage device according to the simulation results, and control the photovoltaic power source and the energy storage device according to the simulation results of the stable working state of the photovoltaic power source and the energy storage device.

[0036] In some embodiments of the present application, the setting unit is further used to perform droop control on the photovoltaic power source and determine the working mode of the photovoltaic power source, and the working mode of the photovoltaic power source includes a voltage control mode and a power control mode; wherein,

[0037] When the droop control is P / PD control, determining that the working mode of the photovoltaic power source is the voltage control mode;

[0038] When the droop control is PI / PID control, determining that the working mode of the photovoltaic power source is the power control mode;

[0039] When the working mode of the photovoltaic power source is a dual-mode control combining the voltage control mode and the power control mode, the frequency PI control of the photovoltaic power source is determined according to a preset formula, and the preset formula is:

[0040] w=w * -G p(s) (PP * )

[0041]

[0042] Wherein, mp is the proportional droop coefficient, mi is the integral droop coefficient, P is the power value of the power supply, P* is the power value of the rated operating point of the power supply, and MD is the logic signal of mode switching, which takes a value of 0 or 1.

[0043] In some embodiments of the present application, it also includes:

[0044] The setting unit is further configured to determine that the photovoltaic power source is in the voltage control mode when the SOC in the parameter control information is less than a preset value or less than the frequency lower limit threshold, and determine that the integral droop coefficient in the preset formula is 0 and the MD is 0;

[0045] The setting unit is further configured to control the photovoltaic power source to stop charging and enter the power control mode when the SOC in the parameter control information is greater than a preset value or greater than the upper frequency limit threshold, and determine that the integral droop coefficient in the preset formula is 1 and the MD is 1;

[0046] The setting unit is further used for switching the photovoltaic power supply from the power control mode to the voltage control mode when the photovoltaic power supply is in the power control mode and when the output power is greater than the upper frequency limit threshold, and determining that the integral droop coefficient in the preset formula is 0 and MD is 0;

[0047] The setting unit is also used to switch the photovoltaic power supply from the voltage control mode to the power control mode when the photovoltaic power supply is in the voltage control mode and when the output power is greater than the power value of the rated operating point of the power supply, and determine that the integral droop coefficient in the preset formula is 1 and MD is 1.

[0048] In some embodiments of the present application, the simulation unit is further used to obtain simulation quantities of the photovoltaic power source and the energy storage device, wherein the simulation quantities include the SOC of the battery, the battery output power, the photovoltaic panel output power, the load power and the grid frequency;

[0049] The control unit is also used to determine the stable working state according to the simulation value; wherein,

[0050] When the SOC of the battery, the battery output power, the photovoltaic panel output power, the load power and the grid frequency reach a balance, the working mode of the photovoltaic power source is determined, and the working mode is determined as the stable working state.

[0051] In some embodiments of the present application, it also includes:

[0052] A low-frequency filter is arranged in the setting unit, and the low-frequency filter is used to keep the frequency stable when the photovoltaic power source switches from the power control mode to the voltage control mode, or when the photovoltaic power source switches from the voltage control mode to the power control mode.

[0053] The present invention provides an AC side energy storage control method and system, which have the following beneficial effects compared with the prior art:

[0054] The present invention controls the AC side energy storage based on "soft" adaptive PI droop control taking into account the battery charge state, which can effectively coordinate the working modes of the energy storage battery and the photovoltaic voltage, so that the system can smoothly perform multi-mode autonomous switching operation without causing instability of the overall system. In view of the different power flows when the energy storage unit releases and absorbs energy, a stable control strategy for autonomous switching with the energy storage power flow is proposed to improve the signal stability of the photovoltaic power station containing energy storage. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 is a flow chart of an AC side energy storage control method in an embodiment of the present invention;

[0056] Figure 2 It is a functional block diagram of the AC side energy storage control system in an embodiment of the present invention. DETAILED DESCRIPTION

[0057] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0058] In the description of the present application, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0059] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0060] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be a communication between the inner sides of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0061] See also Figure 1As shown, the disclosed embodiment of the present invention provides an AC side energy storage control method, which is applied to a photovoltaic AC power grid, including:

[0062] Obtain the maximum output power of the photovoltaic power source and the rated charging power of the energy storage device;

[0063] Preset parameter control information, and simulate the photovoltaic power source and energy storage device according to the parameter control information; wherein,

[0064] The parameter control information includes a SOC threshold of 75%, a frequency upper limit threshold of 50 Hz, and a frequency lower limit threshold of 49 Hz;

[0065] When simulating the photovoltaic power source and energy storage device, the load is increased within the preset time, and the increased load does not exceed 2000W;

[0066] The stable working state of the photovoltaic power source and the energy storage device is determined according to the simulation results, and the photovoltaic power source and the energy storage device are controlled according to the simulation results of the stable working state of the photovoltaic power source and the energy storage device.

[0067] In a specific embodiment of the present application, before simulating the photovoltaic power source and the energy storage device according to the parameter control information, the method further includes:

[0068] The photovoltaic power source is subjected to droop control and the working mode of the photovoltaic power source is determined. The working mode of the photovoltaic power source includes a voltage control mode and a power control mode; wherein,

[0069] When the droop control is P / PD control, the working mode of the photovoltaic power source is determined to be the voltage control mode;

[0070] When the droop control is PI / PID control, the working mode of the photovoltaic power source is determined to be the power control mode;

[0071] When the working mode of the photovoltaic power source is a combination of voltage control mode and power control mode, the frequency PI control of the photovoltaic power source is determined according to a preset formula, and the preset formula is:

[0072] w=w * -G p(s) (PP * )

[0073]

[0074] Wherein, mp is the proportional droop coefficient, mi is the integral droop coefficient, P is the power value of the power supply, P* is the power value of the rated operating point of the power supply, and MD is the logic signal of mode switching, which takes a value of 0 or 1.

[0075] In a specific embodiment of the present application, when the SOC in the parameter control information is less than a preset value or less than a frequency lower limit threshold, it is determined that the photovoltaic power source is in a voltage control mode, and the integral droop coefficient in the preset formula is determined to be 0 and the MD is 0;

[0076] When the SOC in the parameter control information is greater than a preset value or greater than the upper frequency threshold, the control stops charging the photovoltaic power source and enters the power control mode, and determines that the integral droop coefficient in the preset formula is 1 and the MD is 1;

[0077] When the photovoltaic power source is in a power control mode and when the output power is greater than the upper frequency limit threshold, the photovoltaic power source is switched from the power control mode to the voltage control mode, and the integral droop coefficient in the preset formula is determined to be 0 and the MD is 0;

[0078] When the photovoltaic power supply is in voltage control mode and when the output power is greater than the power value of the rated operating point of the power supply, the photovoltaic power supply is switched from voltage control mode to power control mode, and the integral droop coefficient in the preset formula is determined to be 1 and MD is 1.

[0079] In a specific embodiment of the present application, when simulating a photovoltaic power source and an energy storage device, it also includes:

[0080] Acquire the simulation quantities of photovoltaic power source and energy storage device, including battery SOC, battery output power, photovoltaic panel output power, load power and grid frequency;

[0081] Determine the stable working state according to the simulation value; among them,

[0082] When the battery SOC, battery output power, photovoltaic panel output power, load power and grid frequency reach a balance, the working mode of the photovoltaic power source is determined, and the working mode is determined as a stable working state.

[0083] In a specific embodiment of the present application, it also includes:

[0084] When the photovoltaic power source switches from the power control mode to the voltage control mode, or when the photovoltaic power source switches from the voltage control mode to the power control mode, the frequency is kept stable through the low-frequency filter.

[0085] Based on the same technical concept, see Figure 2 As shown, the present invention also provides an AC side energy storage control system accordingly, which is applied to the AC side energy storage control method, including:

[0086] An acquisition unit, used to acquire the maximum output power of the photovoltaic power source and the rated charging power of the energy storage device;

[0087] The setting unit is used to pre-set parameter control information and simulate the photovoltaic power source and energy storage device according to the parameter control information; wherein,

[0088] The parameter control information includes a SOC threshold of 75%, a frequency upper limit threshold of 50 Hz, and a frequency lower limit threshold of 49 Hz;

[0089] The simulation unit is used to increase the load within a preset time when simulating the photovoltaic power source and the energy storage device, and the increased load does not exceed 2000W;

[0090] The control unit is used to determine the stable working state of the photovoltaic power source and the energy storage device according to the simulation results, and control the photovoltaic power source and the energy storage device according to the simulation results of the stable working state of the photovoltaic power source and the energy storage device.

[0091] In a specific embodiment of the present application, the setting unit is also used to perform droop control on the photovoltaic power supply and determine the working mode of the photovoltaic power supply, and the working mode of the photovoltaic power supply includes a voltage control mode and a power control mode; wherein,

[0092] When the droop control is P / PD control, the working mode of the photovoltaic power source is determined to be the voltage control mode;

[0093] When the droop control is PI / PID control, the working mode of the photovoltaic power source is determined to be the power control mode;

[0094] When the working mode of the photovoltaic power source is a combination of voltage control mode and power control mode, the frequency PI control of the photovoltaic power source is determined according to a preset formula, and the preset formula is:

[0095] w=w * -G p(s) (PP * )

[0096]

[0097] Wherein, mp is the proportional droop coefficient, mi is the integral droop coefficient, P is the power value of the power supply, P* is the power value of the rated operating point of the power supply, and MD is the logic signal of mode switching, which takes a value of 0 or 1.

[0098] In a specific embodiment of the present application, it also includes:

[0099] The setting unit is also used to determine that the photovoltaic power source is in a voltage control mode when the SOC in the parameter control information is less than a preset value or less than a frequency lower limit threshold, and determine that the integral droop coefficient in the preset formula is 0 and the MD is 0;

[0100] The setting unit is also used for controlling to stop charging the photovoltaic power source and enter a power control mode when the SOC in the parameter control information is greater than a preset value or greater than a frequency upper limit threshold, and determining that the integral droop coefficient in the preset formula is 1 and the MD is 1;

[0101] The setting unit is further used for switching the photovoltaic power supply from the power control mode to the voltage control mode when the photovoltaic power supply is in the power control mode and when the output power is greater than the upper frequency limit threshold, and determining that the integral droop coefficient in the preset formula is 0 and MD is 0;

[0102] The setting unit is also used to switch the photovoltaic power supply from the voltage control mode to the power control mode when the photovoltaic power supply is in the voltage control mode and when the output power is greater than the power value of the rated operating point of the power supply, and determine that the integral droop coefficient in the preset formula is 1 and MD is 1.

[0103] In a specific embodiment of the present application, the simulation unit is also used to obtain simulation quantities of the photovoltaic power source and the energy storage device, and the simulation quantities include the SOC of the battery, the battery output power, the photovoltaic panel output power, the load power and the grid frequency;

[0104] The control unit is also used to determine the stable working state according to the simulation value; wherein,

[0105] When the battery SOC, battery output power, photovoltaic panel output power, load power and grid frequency reach a balance, the working mode of the photovoltaic power source is determined, and the working mode is determined as a stable working state.

[0106] In a specific embodiment of the present application, it also includes:

[0107] A low-frequency filter is provided in the setting unit, and the low-frequency filter is used to keep the frequency stable when the photovoltaic power source switches from the power control mode to the voltage control mode, or when the photovoltaic power source switches from the voltage control mode to the power control mode.

[0108] In summary, the present invention controls the AC side energy storage based on the "soft" adaptive PI droop control taking into account the battery charge state, which can effectively coordinate the working mode of the energy storage battery and the photovoltaic voltage, so that the system can smoothly perform multi-mode autonomous switching operation without causing the instability of the overall system. In view of the different power flows when the energy storage unit releases and absorbs energy, a stable control strategy that switches autonomously with the energy storage power flow is proposed to improve the signal stability of the photovoltaic power station containing energy storage. The present invention has the advantages of low cost, high reliability and good stability.

[0109] The above is only an example of implementation of the present invention, but it cannot be used to limit the scope of the present invention. Any structural changes made according to the present invention should be regarded as falling within the protection scope of the present invention and subject to restrictions as long as they do not lose the essence of the present invention.

[0110] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process and related instructions of the system described above can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here.

[0111] It should be noted that the system provided in the above embodiment is only illustrated by the division of the above functional modules. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the modules or steps in the embodiments of the present invention can be decomposed or combined. For example, the modules in the above embodiments can be combined into one module, or further divided into multiple sub-modules to complete all or part of the functions described above. The names of the modules and steps involved in the embodiments of the present invention are only for distinguishing the modules or steps, and are not regarded as improper limitations of the present invention.

[0112] Those skilled in the art should be able to appreciate that the modules and method steps of each example described in conjunction with the embodiments disclosed herein can be implemented by electronic hardware, computer software, or a combination of the two, and the programs corresponding to the software modules and method steps can be placed in random access memory (RAM), memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disks, removable disks, CD-ROMs, or any other form of storage medium known in the technical field. In order to clearly illustrate the interchangeability of electronic hardware and software, the composition and steps of each example have been generally described in the above description according to the function. Whether these functions are performed in electronic hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0113] The term "comprise" or any other similar term is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus / device that includes a list of elements includes not only those elements but also other elements not expressly listed, or also includes elements inherent to such process, method, article, or apparatus / device.

[0114] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

[0115] The above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention.

Claims

1. An AC side energy storage control method, applied to a photovoltaic AC power grid, characterized in that: include: Obtain the maximum output power of the photovoltaic power source and the rated charging power of the energy storage device; Parameter control information is preset, and the photovoltaic power source and the energy storage device are simulated according to the parameter control information; wherein, The parameter control information includes that the SOC threshold is 75%, the frequency upper limit threshold is 50 Hz, and the frequency lower limit threshold is 49 Hz; When simulating the photovoltaic power source and the energy storage device, the load is increased within a preset time, and the increased load does not exceed 2000W; The stable working states of the photovoltaic power source and the energy storage device are determined according to the simulation results, and the photovoltaic power source and the energy storage device are controlled according to the simulation results of the stable working states of the photovoltaic power source and the energy storage device.

2. The AC side energy storage control method according to claim 1, characterized in that: Before simulating the photovoltaic power source and the energy storage device according to the parameter control information, the method further includes: The photovoltaic power source is subjected to droop control, and the working mode of the photovoltaic power source is determined, wherein the working mode of the photovoltaic power source includes a voltage control mode and a power control mode; wherein, When the droop control is P / PD control, determining that the working mode of the photovoltaic power source is the voltage control mode; When the droop control is PI / PID control, determining that the working mode of the photovoltaic power source is the power control mode; When the working mode of the photovoltaic power source is a dual-mode control combining the voltage control mode and the power control mode, the frequency PI control of the photovoltaic power source is determined according to a preset formula, and the preset formula is: w=w * -G p(s) (P-P * ) Wherein, mp is the proportional droop coefficient, mi is the integral droop coefficient, P is the power value of the power supply, P* is the power value of the rated operating point of the power supply, and MD is the logic signal of mode switching, which takes a value of 0 or 1.

3. The AC side energy storage control method according to claim 2, characterized in that: Also includes: When the SOC in the parameter control information is less than a preset value or less than the frequency lower limit threshold, determining that the photovoltaic power source is in the voltage control mode, and determining that the integral droop coefficient in the preset formula is 0 and the MD is 0; When the SOC in the parameter control information is greater than a preset value or greater than the frequency upper limit threshold, controlling to stop charging the photovoltaic power source and enter the power control mode, and determining that the integral droop coefficient in the preset formula is 1 and MD is 1; When the photovoltaic power source is in the power control mode and when the output power is greater than the upper frequency limit threshold, the photovoltaic power source is switched from the power control mode to the voltage control mode, and the integral droop coefficient in the preset formula is determined to be 0 and MD is 0; When the photovoltaic power supply is in the voltage control mode and when the output power is greater than the power value of the rated operating point of the power supply, the photovoltaic power supply is switched from the voltage control mode to the power control mode, and the integral droop coefficient in the preset formula is determined to be 1 and MD is 1.

4. The AC side energy storage control method according to claim 3, characterized in that: When simulating the photovoltaic power source and the energy storage device, it also includes: Acquire simulation quantities of the photovoltaic power source and the energy storage device, wherein the simulation quantities include the SOC of the battery, the battery output power, the photovoltaic panel output power, the load power and the grid frequency; Determine the stable working state according to the simulation value; wherein, When the SOC of the battery, the battery output power, the photovoltaic panel output power, the load power and the grid frequency reach a balance, the working mode of the photovoltaic power source is determined, and the working mode is determined as the stable working state.

5. The AC side energy storage control method according to claim 3, characterized in that: Also includes: When the photovoltaic power source switches from the power control mode to the voltage control mode, or when the photovoltaic power source switches from the voltage control mode to the power control mode, the frequency is kept stable by a low-frequency filter.

6. An AC side energy storage control system, applied to the AC side energy storage control method according to any one of claims 1 to 5, characterized in that: include: An acquisition unit, used to acquire the maximum output power of the photovoltaic power source and the rated charging power of the energy storage device; The setting unit is used to pre-set parameter control information and simulate the photovoltaic power source and the energy storage device according to the parameter control information; wherein, The parameter control information includes that the SOC threshold is 75%, the frequency upper limit threshold is 50 Hz, and the frequency lower limit threshold is 49 Hz; A simulation unit, used to increase the load within a preset time when simulating the photovoltaic power source and the energy storage device, and the increased load does not exceed 2000W; A control unit is used to determine the stable working state of the photovoltaic power source and the energy storage device according to the simulation results, and control the photovoltaic power source and the energy storage device according to the simulation results of the stable working state of the photovoltaic power source and the energy storage device.

7. An AC side energy storage control system according to claim 6, characterized in that: The setting unit is also used to perform droop control on the photovoltaic power source and determine the working mode of the photovoltaic power source, and the working mode of the photovoltaic power source includes a voltage control mode and a power control mode; wherein, When the droop control is P / PD control, determining that the working mode of the photovoltaic power source is the voltage control mode; When the droop control is PI / PID control, determining that the working mode of the photovoltaic power source is the power control mode; When the working mode of the photovoltaic power source is a dual-mode control combining the voltage control mode and the power control mode, the frequency PI control of the photovoltaic power source is determined according to a preset formula, and the preset formula is: w=w * -G p(s) (P-P * ) Wherein, mp is the proportional droop coefficient, mi is the integral droop coefficient, P is the power value of the power supply, P* is the power value of the rated operating point of the power supply, and MD is the logic signal of mode switching, which takes a value of 0 or 1.

8. An AC side energy storage control system according to claim 7, characterized in that: Also includes: The setting unit is further configured to determine that the photovoltaic power source is in the voltage control mode when the SOC in the parameter control information is less than a preset value or less than the frequency lower limit threshold, and determine that the integral droop coefficient in the preset formula is 0 and the MD is 0; The setting unit is further configured to control the photovoltaic power source to stop charging and enter the power control mode when the SOC in the parameter control information is greater than a preset value or greater than the upper frequency limit threshold, and determine that the integral droop coefficient in the preset formula is 1 and the MD is 1; The setting unit is further used for switching the photovoltaic power supply from the power control mode to the voltage control mode when the photovoltaic power supply is in the power control mode and when the output power is greater than the upper frequency limit threshold, and determining that the integral droop coefficient in the preset formula is 0 and MD is 0; The setting unit is also used to switch the photovoltaic power supply from the voltage control mode to the power control mode when the photovoltaic power supply is in the voltage control mode and when the output power is greater than the power value of the rated operating point of the power supply, and determine that the integral droop coefficient in the preset formula is 1 and MD is 1.

9. An AC side energy storage control system according to claim 8, characterized in that: The simulation unit is also used to obtain simulation quantities of the photovoltaic power source and the energy storage device, wherein the simulation quantities include the SOC of the battery, the battery output power, the photovoltaic panel output power, the load power and the grid frequency; The control unit is also used to determine the stable working state according to the simulation value; wherein, When the SOC of the battery, the battery output power, the photovoltaic panel output power, the load power and the grid frequency reach a balance, the working mode of the photovoltaic power source is determined, and the working mode is determined as the stable working state.

10. An AC side energy storage control system according to claim 5, characterized in that: Also includes: A low-frequency filter is arranged in the setting unit, and the low-frequency filter is used to keep the frequency stable when the photovoltaic power source switches from the power control mode to the voltage control mode, or when the photovoltaic power source switches from the voltage control mode to the power control mode.

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