Operation control method of micro-grid power supply system and micro-grid controller

Abstract

The invention provides an operation control method of a micro-grid power supply system and a micro-grid controller, and the method comprises the steps: determining whether the micro-grid power supply system operates in a grid-connected mode or an off-grid mode according to the collected voltage of the high-voltage side of a power grid system; if the photovoltaic power generation system operates in the grid-connected mode, determining an on-load mode according to the magnitude relationship between the generated power of the photovoltaic power generation system and the power required by the load, and realizing the power generation of the photovoltaic power generation system, the charging and discharging of the energy storage system and the power supply of the load in each on-load mode; if the photovoltaic power generation system operates in the off-grid mode, the time for starting the diesel generator system is determined according to the electric quantity of the energy storage battery system, and combined operation of the photovoltaic power generation system, the energy storage battery system and the diesel generator system is achieved. Configuration and use of three systems of the photovoltaic energy storage diesel generator in a micro-grid application scene are achieved, the utilization rate of a photovoltaic system can be increased, the service life of a battery can be protected, and photovoltaic power generation is more efficient.

Description

Technical Field

[0001] The present invention relates to the field of microgrid photovoltaic energy storage, and more specifically, to an operation control method of a microgrid power supply system and a microgrid controller. Background Art

[0002] A microgrid is a miniaturized power generation and distribution system that integrates multiple functions such as energy storage devices, distributed power sources, and converters. A photovoltaic energy storage system is a system that converts solar energy into electrical energy and stores it for subsequent use. It generally consists of a photovoltaic panel array (PV) and an energy storage device (battery). The main function of the battery is to store the electrical energy converted by PV and use it to supply power to the load when needed to improve the utilization rate of PV power generation.

[0003] At present, the power supply mode of most microgrid systems is: when the power grid is normal, the power generated by photovoltaics is used to supply power to the load, and the insufficient power is supplemented by the energy storage system. The charging and discharging of the battery depends entirely on the SOC state of the battery, and the charging and discharging of the energy storage system is not linked with the power generation of the photovoltaic system. In this way, when the battery SOC is low and the light intensity is insufficient, the power grid suddenly loses power, and the energy storage system is discharged off the grid, which will greatly affect the battery life.

[0004] In many microgrid application scenarios, the generated power cannot be sent to the grid, and the transformer cannot be overloaded. It is necessary to adjust the power generation power of the photovoltaic power generation device and the charging and discharging power of the energy storage device. Summary of the invention

[0005] The present invention aims at the technical problems existing in the prior art and provides an operation control method of a microgrid power supply system and a microgrid controller.

[0006] According to a first aspect of the present invention, there is provided an operation control method for a microgrid power supply system, wherein the microgrid power supply system comprises a power grid system, a photovoltaic power generation system, an energy storage battery system, a diesel generator system and a load, and the method comprises: Collecting the voltage on the high-voltage side of the power grid system, and determining whether the microgrid power supply system is operating in a grid-connected mode or an off-grid mode according to the voltage on the high-voltage side of the power grid system; If the microgrid power supply system operates in the grid-connected mode, the load mode is determined according to the relationship between the power generation power of the photovoltaic power generation system and the power required by the load; In each load mode, the photovoltaic power generation system generates electricity, the energy storage system charges and discharges, and the load is supplied with electricity; If the microgrid power supply system operates in off-grid mode, the time to enable the diesel generator system is determined according to the power level of the energy storage battery system, so as to realize the joint operation of the photovoltaic power generation system, the energy storage battery system and the diesel generator system.

[0007] According to a second aspect of the present invention, a microgrid controller is provided for controlling the operation of a microgrid power supply system, wherein the microgrid power supply system comprises a power grid system, a photovoltaic power generation system, an energy storage battery system, a diesel generator system and a microgrid controller, wherein the microgrid controller comprises: A first determination module is used to collect the voltage on the high-voltage side of the power grid system, and determine whether the microgrid power supply system is operating in a grid-connected mode or an off-grid mode according to the voltage on the high-voltage side of the power grid system; The second determination module is used to determine the load mode according to the relationship between the power generation power of the photovoltaic power generation system and the power required by the load if the microgrid power supply system operates in the grid-connected mode, and the load mode includes photovoltaic load, energy storage load and grid load; A control module is used to control the power generation of the photovoltaic power generation system, the charging and discharging of the energy storage system, and the power supply of the load in each load mode; and if the microgrid power supply system operates in an off-grid mode, determine the time to enable the diesel generator system according to the power level of the energy storage battery system, and control the joint operation of the photovoltaic power generation system, the energy storage battery system, and the diesel generator system.

[0008] The present invention provides an operation control method and a microgrid controller for a microgrid power supply system. The microgrid controller obtains photovoltaic power generation power, load power, and battery capacity of an energy storage system to achieve multi-energy complementarity in the microgrid, maximize photovoltaic power generation without light abandonment and light limitation, and greatly ensure energy utilization efficiency. In the off-grid operation mode, the combined operation of the photovoltaic power generation system, the energy storage battery system, and the diesel generator system ensures that the load can operate uninterruptedly in the microgrid. In the off-grid mode, the off-grid energy storage battery system and the flexible switching of the diesel generator system ensure the reliability of the power supply of the microgrid system. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 A main wiring diagram of a microgrid power supply system provided by the present invention; Figure 2 A flow chart of an operation control method of a microgrid power supply system provided by the present invention; Figure 3 This is a flow chart of photovoltaic load in the grid-connected mode in an embodiment of the present invention; Figure 4 This is a flow chart of energy storage grid load in grid-connected mode in an embodiment of the present invention; Figure 5 This is a flow chart of the photovoltaic-storage-diesel operation mode in the off-grid mode in an embodiment of the present invention; Figure 6 This is a flow chart of on-grid and off-grid switching in an embodiment of the present invention; Figure 7 A structural block diagram of a microgrid controller in a microgrid power supply system provided by the present invention. DETAILED DESCRIPTION

[0010] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, 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 described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. In addition, the technical features in the various embodiments or single embodiments provided by the present invention can be arbitrarily combined with each other to form a feasible technical solution. This combination is not subject to the constraints of the sequence of steps and / or the structural composition mode, but must be based on the ability of ordinary technicians in this field to achieve. When the combination of technical solutions is contradictory or cannot be achieved, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0011] See also Figure 1 , is a wiring diagram of a microgrid power supply system of the present invention, the microgrid power supply system includes a photovoltaic power generation system, an energy storage battery system, a diesel generator system, a microgrid controller and power loads.

[0012] Among them, the photovoltaic power generation system is connected to the AC bus through the inverter DC / AC, the energy storage battery system is connected to the AC bus through the PCS DA / AC, the diesel generator system as a backup power supply is connected to the AC bus through DC / AC, and the AC load is directly connected to the AC bus through the circuit breaker.

[0013] The microgrid controller communicates with the inverter of the photovoltaic power generation system to control the operating status and power generation of the inverter; communicates with the energy storage battery system PCS to control the operating mode and power distribution of the PCS, and communicates with the energy storage battery system BMS to know the operating status of the battery; and exchanges information with the diesel generator system to know the operating status of the diesel generator system.

[0014] Figure 2 A flow chart of an operation control method of a microgrid power supply system provided by the present invention, such as Figure 2 As shown, the method includes: Step 1: collect the high-voltage side voltage of the power grid system, and determine whether the microgrid power supply system is operating in a grid-connected mode or an off-grid mode according to the high-voltage side voltage of the power grid system.

[0015] In a possible implementation manner of the present invention, determining whether the microgrid power supply system operates in a grid-connected mode or an off-grid mode according to the high-voltage side voltage of the grid system includes: If the high-voltage side voltage of the power grid system exists, the microgrid power supply system operates in the grid-connected mode; If the high-voltage side voltage of the power grid system does not exist, the microgrid power supply system operates in an off-grid mode.

[0016] Specifically, the microgrid controller checks the voltage on the high-voltage side of the grid. If the collected voltage exists, it means that the mains is present and the microgrid power supply system operates in the grid-connected mode. If the voltage on the high-voltage side of the grid system does not exist, it means that the mains is off and the microgrid power supply system operates in the off-grid mode.

[0017] Step 2: If the microgrid power supply system operates in the grid-connected mode, the load mode is determined according to the relationship between the power generation power of the photovoltaic power generation system and the power required by the load. The load mode includes photovoltaic load, energy storage load and grid load.

[0018] In a possible implementation manner of the present invention, if the microgrid power supply system operates in a grid-connected mode, the load mode is determined according to the relationship between the power generation power of the photovoltaic power generation system and the power required by the load, including: When the microgrid power supply system operates in the grid-connected mode, the power generation power P (light) of the photovoltaic power generation system and the power required by the load P (negative) are obtained through the microgrid controller; If P(light)>P(negative), the microgrid power supply system operates in photovoltaic load mode; If P(light)<P(negative), the microgrid power supply system operates in the energy storage load mode and the grid load mode.

[0019] Specifically, the microgrid power supply system can operate in the grid-connected mode, which can be divided into: photovoltaic load, energy storage load, and grid load. In the grid-connected mode, the photovoltaic power generation system and the energy storage battery system achieve multi-energy complementarity. If the city power is disconnected, the microgrid power supply system is converted to off-grid operation mode to supply power to the load line. The photovoltaic power generation system, energy storage battery system, and diesel generator system are configured with each other to achieve power supply balance.

[0020] Step 3, realizing power generation of the photovoltaic power generation system, charging and discharging of the energy storage system, and power supply of the load in each load mode.

[0021] It is understandable that the control strategies for each load mode in the grid-connected mode will be described in detail below.

[0022] See Figure 3 , which is the operation control flowchart of the photovoltaic load mode in the grid-connected mode, realizing the combined operation of the photovoltaic power generation system and the energy storage battery system. See Figure 3 , and the main steps include: S101. The microgrid controller checks the voltage on the high-voltage side of the grid. If the collected voltage exists, it indicates that the system has mains power, and the energy storage system operates in the grid-connected mode.

[0023] S102. The microgrid controller obtains the power generation power P(light) of the photovoltaic power generation system and the power required by the load P(negative) through communication. When P(light) > P(negative), the microgrid power supply system operates in the photovoltaic load mode.

[0024] S103. Further judge the power storage situation of the energy storage battery system, and judge the relationship between SOC(t) and SOC(H), where SOC(H) is the power when the energy storage battery system is full.

[0025] S104. If SOC(t) < SOC(H).

[0026] S105. Then while the photovoltaic power generation system supplies power to the load, the extra power generated can charge the energy storage battery system; the energy storage battery system charges at a power of P(storage) = P(light) - P(negative). S106. If SOC(t) >= SOC(H), it means that the power of the energy storage battery system is full, and the microgrid controller needs to suppress the photovoltaic power generation so that the power generation power P(light) of the photovoltaic power generation system = P(negative).

[0027] In the grid-connected mode, when the microgrid controller detects that the power generation of the photovoltaic power generation system is insufficient, that is, P(light) < P(negative), the microgrid power supply system operates in the energy storage load and grid load modes. The specific control process can be seen in Figure 4 , and mainly includes the following steps: S201. The microgrid controller checks the voltage on the high-voltage side of the grid. If the collected voltage exists, it indicates that the system has mains power, and the energy storage system operates in the grid-connected mode.

[0028] S202. The microgrid controller determines that the power generation power P(light) of the photovoltaic power generation system < P(negative). For better economy, the judgment of the time period needs to be added for energy storage discharge to determine whether the energy storage battery system supplies power to the load or the grid system supplies power to the load, and the microgrid controller makes an economic control.

[0029] S203. Judge whether the current time period electricity price is greater than or equal to the parity price.

[0030] S204. If the electricity price is not at the parity level, further determine the power level of the energy storage battery system, i.e., whether SOC(t) is greater than SOC(L). S205. If SOC(t) > SOC(L), the microgrid controller controls the energy storage battery system to supply power to the load. The microgrid controller calculates the output of the energy storage battery system as: P(storage) = P(load) - P(solar), and issues the execution to the energy storage PCS for output.

[0031] S206. If the energy storage battery system has no power, i.e., SOC(t) < SOC(L), the energy storage battery system remains stationary, and the power grid system supplies power to the load.

[0032] S207. If the electricity price is at the valley price level, further determine whether the energy storage battery system is fully charged.

[0033] S208. If the energy storage battery is not fully charged, i.e., SOC(t) < SOC(H), in addition to supplying power to the load, the power grid system also charges the energy storage battery system. The power supplied by the power grid system to the energy storage battery system is: P(grid) = P(load) - P(solar) + P(storage).

[0034] Step 4. If the microgrid power supply system operates in the off-grid mode, determine the activation time of the diesel generator system according to the power level of the energy storage battery system, so as to realize the combined operation of the photovoltaic power generation system, the energy storage battery system, and the diesel generator system.

[0035] It can be understood that if the main power supply is disconnected, the microgrid power supply system operates in the off-grid mode. In the off-grid mode, the microgrid controller controls the photovoltaic power generation system, the energy storage battery system, and the diesel generator system to supply power to the entire microgrid. Refer to Figure 5 , and the specific steps are as follows: S301. When the main power supply is suddenly disconnected and the microgrid controller cannot detect the high-voltage side switch of the transformer, the microgrid power supply system operates in the off-grid mode.

[0036] S302. The microgrid controller issues a DO signal to disconnect the S1 circuit breaker on the low-voltage side of the transformer; S303. The microgrid controller determines whether the power level SOC(t) of the energy storage battery system is less than SOC(L) to further control whether to activate the diesel generator system.

[0037] S304. If the energy storage battery system has sufficient power, i.e., SOC(t) > SOC(H), the microgrid controller controls the energy storage battery system to operate in the off-grid mode. The energy storage battery system operates in the VF mode, and the photovoltaic power generation system operates in the PQ mode.

[0038] S305, if the photovoltaic power generation system generates enough electricity, that is, P (light)>P (negative), the excess electricity is used to charge the energy storage battery system, P (storage) = P (light)-P (negative), and the energy storage battery system is charged to SOC (t) = SOC (H), that is, it is fully charged. At this time, the microgrid controller suppresses the photovoltaic power generation system from generating electricity, so that P (light) = P (negative).

[0039] S306, if the photovoltaic power generation system does not generate enough power, that is, P (light) < P (negative), the energy storage battery system starts to discharge, and the photovoltaic power generation system and the energy storage battery system jointly supply power to the load; the microgrid controller calculates the output of the energy storage battery system P (storage) = P (negative) - P (light).

[0040] S307, the microgrid controller determines that the capacity of the energy storage battery system is insufficient, that is, SOC (t) < SOC (L). At this time, the microgrid controller controls the diesel generator system to start, allows the diesel generator system to establish a VF source, and controls the energy storage battery system to switch to the grid-connected mode.

[0041] S308, the microgrid controller controls the charging of the energy storage battery system, and the diesel generator system and the photovoltaic power generation system supply power to the load, wherein P (diesel) + P (light) = P (storage) + P (load).

[0042] S309. If the energy storage battery system is fully charged, the microgrid controller controls the diesel generator system to exit operation, and re-controls the energy storage battery system to switch to off-grid operation. The off-grid overload cycle is repeated to ensure the stability of power supply.

[0043] When the mains electricity comes, the microgrid controller needs to control the microgrid power supply system to switch to grid-connected mode. Figure 6 , the specific steps are as follows: S401, the voltage on the high-voltage side of the power grid system collected by the microgrid controller does not exist, and the microgrid power supply system operates in off-grid mode.

[0044] S402: The microgrid controller detects that the mains power is restored.

[0045] S403, the microgrid controller controls the energy storage battery system to shut down.

[0046] S404, the microgrid controller controls the closing of the transformer low-voltage side switch S1 to connect the grid to the entire power supply system.

[0047] S405, the microgrid controller controls the energy storage battery system to switch to the grid-connected mode, and turns on the energy storage battery system, and the entire microgrid power supply system operates in the grid-connected mode again.

[0048] See also Figure 7 , a microgrid controller provided by the present invention is used to control the operation of a microgrid power supply system, and the microgrid controller includes: The first determination module 701 is used to collect the high-voltage side voltage of the power grid system, and determine whether the microgrid power supply system is operating in a grid-connected mode or an off-grid mode according to the high-voltage side voltage of the power grid system; The second determination module 702 is used to determine the load mode according to the relationship between the power generation power of the photovoltaic power generation system and the power required by the load if the microgrid power supply system operates in the grid-connected mode, and the load mode includes photovoltaic load, energy storage load and grid load; The control module 703 is used to control the power generation of the photovoltaic power generation system, the charging and discharging of the energy storage system, and the power supply of the load in each load mode; and if the microgrid power supply system operates in an off-grid mode, determine the time to enable the diesel generator system according to the power level of the energy storage battery system, and control the joint operation of the photovoltaic power generation system, the energy storage battery system, and the diesel generator system.

[0049] It can be understood that the operation control process of the microgrid controller controlling the microgrid power supply system can refer to the technical features of the operation control method of the above-mentioned microgrid power supply system, which will not be repeated here.

[0050] A microgrid power supply system and operation control method provided by an embodiment of the present invention have the following beneficial effects: (1) The photovoltaic power generation power and load power, as well as the battery capacity of the energy storage system, are obtained through the microgrid controller, realizing the multi-energy complementarity of the microgrid power supply system in the grid-connected mode and the off-grid mode, making the maximum use of photovoltaic power without abandonment and limitation of light, thus greatly ensuring the energy utilization efficiency.

[0051] (2) In the off-grid operation mode, the photovoltaic power generation system, energy storage battery system and diesel generator system are jointly operated to ensure that the load can operate uninterruptedly in the microgrid. In the off-grid mode, the off-grid operation of the energy storage battery system and the flexible switching of the diesel generator system ensure the reliability of the power supply of the microgrid system.

[0052] It should be noted that in the above embodiments, the description of each embodiment has its own emphasis, and for parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0053] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0054] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for controlling the operation of a microgrid power supply system, characterized in that: The microgrid power supply system includes a power grid system, a photovoltaic power generation system, an energy storage battery system, a diesel generator system and a load, and the method includes: Collecting the voltage on the high-voltage side of the power grid system, and determining whether the microgrid power supply system is operating in a grid-connected mode or an off-grid mode according to the voltage on the high-voltage side of the power grid system; If the microgrid power supply system operates in the grid-connected mode, the load mode is determined according to the relationship between the power generation power of the photovoltaic power generation system and the power required by the load; In each load mode, the photovoltaic power generation system generates electricity, the energy storage system charges and discharges, and the load is supplied with electricity; If the microgrid power supply system operates in off-grid mode, the time to enable the diesel generator system is determined according to the power level of the energy storage battery system, so as to realize the joint operation of the photovoltaic power generation system, the energy storage battery system and the diesel generator system.

2. The operation control method of the microgrid power supply system according to claim 1, characterized in that: The step of determining whether the microgrid power supply system operates in a grid-connected mode or an off-grid mode according to the high-voltage side voltage of the grid system includes: If the high-voltage side voltage of the power grid system exists, the microgrid power supply system operates in the grid-connected mode; If the high-voltage side voltage of the power grid system does not exist, the microgrid power supply system operates in an off-grid mode.

3. The operation control method of the microgrid power supply system according to claim 1, characterized in that: The load modes include photovoltaic load, energy storage load and grid load. If the microgrid power supply system operates in the grid-connected mode, the load mode is determined according to the relationship between the power generation power of the photovoltaic power generation system and the power required by the load, including: When the microgrid power supply system operates in the grid-connected mode, the power generation power P (light) of the photovoltaic power generation system and the power required by the load P (negative) are obtained; If P(light)>P(negative), the microgrid power supply system operates in photovoltaic load mode; If P(light)<P(negative), the microgrid power supply system operates in the energy storage load mode and the grid load mode.

4. The operation control method of the microgrid power supply system according to claim 3, characterized in that: The method of realizing power generation of the photovoltaic power generation system, charging and discharging of the energy storage system, and power supply of the load in each load mode includes: When the microgrid power supply system operates in the photovoltaic load mode, the power SOC(t) and SOC(H) of the energy storage battery system are determined, wherein SOC(H) is the power of the energy storage battery system when it is fully charged; If SOC(t)<SOC(H), the photovoltaic power generation system supplies power to the load and charges the energy storage battery system, and the charging power of the energy storage battery system is: P(storage)=P(light)-P(negative); If SOC(t)=SOC(H), the energy storage battery system is fully charged, and the microgrid controller inhibits the photovoltaic power generation system from generating electricity, so that the power generation power P(light)=P(negative) of the photovoltaic power generation system.

5. The operation control method of the microgrid power supply system according to claim 3, characterized in that: The method of realizing power generation of the photovoltaic power generation system, charging and discharging of the energy storage system, and power supply of the load in each load mode includes: When the microgrid power supply system operates in the energy storage load mode and the grid load mode, determining whether the electricity price in the current period is greater than or equal to the parity price; If the electricity price in the current period is greater than or equal to the parity price, determine the size of the power SOC(t) and SOC(L) of the energy storage battery system, and determine whether the energy storage battery system supplies power to the load or the power grid system supplies power to the load, wherein SOC(L) represents the minimum power required by the energy storage battery system; If the electricity price in the current period is lower than the parity price, the power grid system will supply power to the load.

6. The operation control method of the microgrid power supply system according to claim 5, characterized in that: If the electricity price in the current period is greater than or equal to the parity price, determining the size of the power SOC(t) and SOC(L) of the energy storage battery system, and determining whether the energy storage battery system supplies power to the load or the power grid system supplies power to the load, includes: When the power SOC(t) of the energy storage battery system is greater than SOC(L), the energy storage battery system is controlled to supply power to the load, and the discharge power of the energy storage battery system is: P(storage)=P(negative)-P(light); When the power SOC(t) of the energy storage battery system is less than SOC(L), the energy storage battery system is stationary, and the power grid system supplies power to the load.

7. The operation control method of the microgrid power supply system according to claim 5, characterized in that: If the electricity price in the current period is less than the parity price, the power grid system supplies power to the load, including: When the power SOC(t) of the energy storage battery system is less than SOC(H), the power grid system charges the energy storage battery system while supplying power to the load, wherein the charging power of the power grid system is: P(electricity)=P(negative)-P(light)+P(storage); When the power SOC(t) of the energy storage battery system = SOC(H), the power grid system only supplies power to the load.

8. The operation control method of the microgrid power supply system according to claim 1, characterized in that: If the microgrid power supply system operates in an off-grid mode, the time to enable the diesel generator system is determined according to the power amount of the energy storage battery system, so as to realize the joint operation of the photovoltaic power generation system, the energy storage battery system and the diesel generator system, including: If the power SOC(t) of the energy storage battery system is greater than SOC(L), SOC(L) represents the minimum power required by the energy storage battery system, the diesel generator system is controlled not to start and the energy storage battery system is controlled to switch to off-grid operation, and the photovoltaic power generation system and the energy storage battery system are jointly operated to supply power to the load; if the power SOC(t) of the energy storage battery system is less than SOC(L), the diesel generator is controlled to start and the energy storage battery system is controlled to switch to the grid-connected mode; Controlling the charging of the energy storage battery system, and using the diesel generator system and the photovoltaic power generation system to supply power to the load, wherein P (diesel) + P (light) = P (storage) + P (negative); If the power SOC(t) of the energy storage battery system = SOC(H), the diesel generator system is controlled to exit operation, and the energy storage battery system is controlled again to switch to off-grid operation.

9. The operation control method of the microgrid power supply system according to claim 8, characterized in that: The method of controlling the diesel generator system not to start and controlling the energy storage battery system to switch to off-grid operation, wherein the photovoltaic power generation system and the energy storage battery system jointly operate to supply power to the load, includes: If the power generation power P(light) of the photovoltaic power generation system is greater than P(negative), the photovoltaic power generation system supplies power to the load, and the excess power is used to charge the energy storage battery system. The charging power P(storage) of the energy storage battery system is equal to P(light)-P(negative). When the energy storage battery system is charged to SOC(t)=SOC(H), the microgrid controller inhibits the photovoltaic power generation system from generating power, so that the power generation power P(light) of the photovoltaic power generation system is equal to P(negative). If the power generation power P(light) of the photovoltaic power generation system is less than P(negative), the energy storage battery system starts to discharge, and the photovoltaic power generation system and the energy storage battery system jointly supply power to the load, wherein the microgrid controller calculates the energy storage output P(storage)=P(negative)-P(light).

10. A microgrid controller for controlling the operation of a microgrid power supply system, characterized in that: The microgrid power supply system includes a power grid system, a photovoltaic power generation system, an energy storage battery system, a diesel generator system and a microgrid controller, and the microgrid controller includes: A first determination module is used to collect the voltage on the high-voltage side of the power grid system, and determine whether the microgrid power supply system is operating in a grid-connected mode or an off-grid mode according to the voltage on the high-voltage side of the power grid system; The second determination module is used to determine the load mode according to the relationship between the power generation power of the photovoltaic power generation system and the power required by the load if the microgrid power supply system operates in the grid-connected mode, and the load mode includes photovoltaic load, energy storage load and grid load; A control module is used to control the power generation of the photovoltaic power generation system, the charging and discharging of the energy storage system, and the power supply of the load in each load mode; and if the microgrid power supply system operates in an off-grid mode, determine the time to enable the diesel generator system according to the power level of the energy storage battery system, and control the joint operation of the photovoltaic power generation system, the energy storage battery system, and the diesel generator system.

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