Photovoltaic interconnection system and electric energy distribution method thereof

Abstract

The invention discloses a photovoltaic interconnection system and an electric energy distribution method thereof, the photovoltaic interconnection system comprises a grid-connected control device and a plurality of energy storage inversion devices, the energy storage inversion devices are in communication connection with the grid-connected control device, and the energy storage inversion devices are connected to a power grid through the grid-connected control device; the electric energy distribution method comprises the following steps: acquiring the generating capacity, standby power and load power consumption of each energy storage inversion device; according to the power generation amount, the standby power amount and the load power consumption, calculating the mismatched power amount of each energy storage inversion device; according to all the unmatched electric quantities, an active power function based on all the energy storage inversion devices is established; the minimum value of the active power function is solved, and the active power of each energy storage inversion device is obtained; and controlling the corresponding energy storage inversion equipment to perform active power according to the active power. According to the application, the distribution of the electric energy in the photovoltaic interconnection system can be optimal, so that the electric energy interaction between the photovoltaic interconnection system and the power grid is reduced, and the income of users of the photovoltaic interconnection system is improved.

Description

Technical Field

[0001] The present application relates to the field of photovoltaic energy storage technology, and in particular to a photovoltaic interconnection system and an electric energy distribution method thereof. Background Art

[0002] At present, photovoltaic energy storage inverter equipment has been widely used and promoted, and can be used as the second power supply equipment in residential buildings in addition to the power grid. When the power generation of photovoltaic energy storage inverter equipment cannot meet user needs, users can only purchase electricity from the power grid at a high price. When the power generation of photovoltaic energy storage inverter equipment is too much and exceeds the amount that can be stored, the excess power can only be discarded. This undoubtedly leads to unreasonable distribution of electricity, resulting in energy waste and reduced user benefits. Summary of the invention In view of this, the present application provides a photovoltaic interconnection system and a power distribution method thereof, so as to optimize the power distribution of each energy storage inverter device in the photovoltaic interconnection system, thereby reducing the power interaction between the photovoltaic interconnection system and the power grid, and improving the benefits of users of the photovoltaic interconnection system. The technical solution of the present application is as follows: The first aspect of the present application provides an electric energy distribution method for a photovoltaic interconnection system, wherein the photovoltaic interconnection system includes a grid-connected control device and a plurality of energy storage inverter devices, wherein the energy storage inverter device is communicatively connected to the grid-connected control device, and the energy storage inverter device is connected to the power grid through the grid-connected control device; the electric energy distribution method includes: obtaining the power generation, backup power and load power consumption of each of the energy storage inverter devices; calculating the mismatched power of each of the energy storage inverter devices based on the power generation, backup power and load power consumption; establishing an active power function based on all the energy storage inverter devices based on all the mismatched power; solving the minimum value of the active power function to obtain the active power of each of the energy storage inverter devices; and adjusting the active power of the energy storage inverter device corresponding to the active power control.

[0003] In one embodiment of the present application, the unmatched power of each of the energy storage inverter devices is calculated based on the power generation, the backup power and the load power consumption, including: establishing a photovoltaic mathematical model of the photovoltaic components of the energy storage inverter device, which is the power generation; establishing a battery mathematical model of the energy storage battery of the energy storage inverter device, which is the backup power; establishing a load mathematical model of the load of the energy storage inverter device, which is the load power consumption; and obtaining an active power model of the energy storage inverter device interacting with the outside world based on the photovoltaic mathematical model, the battery mathematical model and the load mathematical model, which is the unmatched power.

[0004] In one embodiment of the present application, the photovoltaic mathematical model of the photovoltaic component of the energy storage inverter device is established, including: obtaining the current light intensity, ambient temperature and output power of the photovoltaic component; and obtaining the photovoltaic mathematical model according to the light intensity, the ambient temperature, the output power and a preset comprehensive loss factor.

[0005] In one embodiment of the present application, establishing a battery mathematical model of the energy storage battery of the energy storage inverter device includes: obtaining the charge and discharge state, charge and discharge power, charge and discharge loss, placement loss, charge amount and charge amount range of the energy storage battery; obtaining the battery mathematical model according to the charge and discharge state, the charge and discharge power, the charge and discharge loss, the placement loss, the charge amount and the charge amount range.

[0006] In one embodiment of the present application, the load includes an electric vehicle and an electrical load, and the establishment of a load mathematical model of the load of the energy storage inverter device includes: obtaining the charge and discharge state, charge and discharge power, charge and discharge loss, placement loss, current charge, planned charge, and charge range of the electric vehicle; obtaining the electric vehicle mathematical model based on the charge and discharge state, the charge and discharge power, the charge and discharge loss, the placement loss, the current charge, the planned charge, and the charge range. Obtaining the electrical load mathematical model based on the preset load level, active load factor, and reactive load factor of the electrical load; obtaining the load mathematical model based on the electric vehicle mathematical model and the electrical load mathematical model.

[0007] In one embodiment of the present application, the photovoltaic interconnection system also includes a reactive compensation device, and the reactive compensation device is connected to the grid-connected control device. The electric energy distribution method also includes: in an off-grid state, establishing the active power function based on all the unmatched electrical quantities and the reactive power of the reactive compensation device.

[0008] The second aspect of the present application provides a photovoltaic interconnection system, including a grid-connected control device and multiple energy storage inverter devices, the energy storage inverter device is communicatively connected to the grid-connected control device, and the energy storage inverter device is connected to the power grid through the grid-connected control device; the energy storage inverter device is used to detect its power generation, backup power and load power consumption, and transmit them to the grid-connected control device; the grid-connected control device is used to obtain the power generation, backup power and load power consumption of each of the energy storage inverter devices, calculate the mismatched power of each of the energy storage inverter devices based on the power generation, backup power and load power consumption, establish an active power function based on all the energy storage inverter devices based on all the mismatched power, solve the minimum value of the active power function, obtain the active power of each of the energy storage inverter devices, and adjust the active power of the corresponding energy storage inverter device according to the active power control.

[0009] In one embodiment of the present application, the grid-connected control device is also used to: establish a photovoltaic mathematical model of the photovoltaic components of the energy storage inverter device, which is the power generation; establish a battery mathematical model of the energy storage battery of the energy storage inverter device, which is the backup power; establish a load mathematical model of the load of the energy storage inverter device, which is the load power consumption; and obtain an active power model of the energy storage inverter device interacting with the outside world based on the photovoltaic mathematical model, the battery mathematical model and the load mathematical model, which is the unmatched power.

[0010] In one embodiment of the present application, the energy storage inverter device is also used to obtain the current light intensity, ambient temperature and output power of the photovoltaic component, and transmit them to the grid-connected control device; the grid-connected control device is also used to obtain the photovoltaic mathematical model based on the light intensity, the ambient temperature, the output power and a preset comprehensive loss factor.

[0011] In one embodiment of the present application, the energy storage inverter device is also used to obtain the charging and discharging state, charging and discharging power, charging and discharging loss, placement loss, charge amount and charge amount range of the energy storage battery, and transmit them to the grid-connected control device; the grid-connected control device is also used to obtain the battery mathematical model based on the charging and discharging state, the charging and discharging power, the charging and discharging loss, the placement loss, the charge amount and the charge amount range.

[0012] The present application obtains the power generation, backup power and load power consumption of each energy storage inverter device in the photovoltaic interconnection system, and then obtains the mismatched power of each energy storage inverter device, and establishes an active power function based on all energy storage inverter devices based on all the mismatched power. Since the value of the power function is the electric energy required for the photovoltaic interconnection system and the power grid to interact after the electric energy interaction between the energy storage inverter devices in the photovoltaic interconnection system, after solving the active power of each energy storage inverter device corresponding to the minimum value of the power function, the grid-connected control device controls the corresponding energy storage inverter device to output active power according to the active power, which can optimize the distribution of electric energy in the photovoltaic interconnection system, thereby reducing the electric energy interaction between the photovoltaic interconnection system and the power grid and improving the benefits of users of the photovoltaic interconnection system. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic block diagram of a photovoltaic interconnection system provided in an embodiment of the present application.

[0014] Figure 2 It is a flow chart of a method for distributing electric energy in a photovoltaic interconnection system provided in an embodiment of the present application.

[0015] Figure 3 It is a flowchart of a method for calculating unmatched electricity provided in an embodiment of the present application.

[0016] Figure 4 It is a flow chart of a method for establishing a photovoltaic mathematical model provided in an embodiment of the present application.

[0017] Figure 5 It is a flow chart of a method for establishing a battery mathematical model provided in an embodiment of the present application.

[0018] Figure 6 It is a flow chart of a method for establishing a load mathematical model provided in an embodiment of the present application.

[0019] Figure 7 It is a schematic block diagram of another photovoltaic interconnection system provided in an embodiment of the present application.

[0020] Figure 8 It is a flow chart of a method for distributing electric energy in a photovoltaic interconnection system provided in an embodiment of the present application.

[0021] Fig. 9 It is a flow chart of a control method for a photovoltaic interconnection system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0022] It should be noted that in the embodiments of the present application, "at least one" refers to one or more, and "more than one" refers to two or more than two. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. The terms "first", "second", "third", "fourth", etc. (if any) in the specification, claims and drawings of this application are used to distinguish similar objects, rather than to describe a specific order or sequence.

[0023] It should also be noted that the method disclosed in the embodiments of the present application or the method shown in the flowchart includes one or more steps for implementing the method. Without departing from the scope of the claims, the execution order of multiple steps can be interchangeable with each other, and some of the steps can also be deleted.

[0024] At present, photovoltaic energy storage inverter equipment has been widely used and promoted, and can be used as the second power supply equipment in residential buildings in addition to the power grid. When the power generation of photovoltaic energy storage inverter equipment cannot meet user needs, users can only purchase electricity from the power grid at a high price. When the power generation of photovoltaic energy storage inverter equipment is too much and exceeds the amount that can be stored, the excess power can only be discarded. This undoubtedly leads to unreasonable distribution of electricity, resulting in energy waste and reduced user benefits. The present application provides a photovoltaic interconnection system and an electric energy distribution method thereof, so as to optimize the electric energy distribution of each energy storage inverter device in the photovoltaic interconnection system, thereby reducing the electric energy interaction between the photovoltaic interconnection system and the power grid, and improving the benefits of users of the photovoltaic interconnection system.

[0025] Please refer to Figure 1 , Figure 1 A schematic block diagram of a photovoltaic interconnection system provided in an embodiment of the present application, wherein the photovoltaic interconnection system 100 includes a grid-connected control device 110 and a plurality of energy storage inverter devices 120 ( Figure 1 There are 3 examples).

[0026] The energy storage inverter device 120 is in communication connection with the grid control device 110, and the energy storage inverter device 120 is connected to the power grid 101 through the grid control device 110. For example, in a residential area consisting of multiple households, each household house may be provided with the above energy storage inverter device 120, which are interconnected through the grid control device 110 to form a photovoltaic interconnection system 100 in the residential area.

[0027] In the embodiment of the present application, the energy storage inverter device 120 includes a photovoltaic module, an energy storage battery and a power converter. The photovoltaic module includes a plurality of photovoltaic panels for converting light energy into DC power and transmitting it to the power converter. The power converter is used to convert the DC voltage of the photovoltaic module into AC voltage to supply power to the household, or convert the DC power into a charging voltage to charge the energy storage battery, or convert the DC voltage of the photovoltaic module and the discharge voltage of the energy storage battery into AC voltage to supply power to the household. Moreover, when connected to the power grid 101 through the grid control device 110, if the photovoltaic module and the energy storage battery cannot meet the load of the household power supply, the load required for voltage supplement is also obtained from the power grid 101. If the power provided by the photovoltaic module and the energy storage battery exceeds the load of the household power supply, the excess power can also be sold to the power grid 101.

[0028] In some embodiments, the grid-connected control device 110 includes a master controller, and the energy storage inverter device 120 includes a slave controller. The master controller can be communicatively connected to each slave controller, so that the grid-connected control device 110 can control multiple energy storage inverter devices 120 separately to control the power distribution within the photovoltaic interconnection system 100, and control the power interaction between the photovoltaic interconnection system 100 and the power grid 101.

[0029] Next, combine Figure 1 A method for distributing electric energy in a photovoltaic interconnection system provided in an embodiment of the present application is introduced. Figure 2 As shown, the specific steps include: Step S21: Obtain the power generation, backup power and load power consumption of each energy storage inverter device.

[0030] In an embodiment of the present application, the energy storage inverter device can monitor its own power generation, backup power and load power consumption in real time, and transmit the real-time power generation, backup power and load power consumption to the grid-connected control device, so that the grid-connected control device can obtain the power generation, backup power and load power consumption of each energy storage inverter device in the photovoltaic interconnection system.

[0031] Among them, the energy storage inverter device includes a photovoltaic module, an energy storage battery and a power conversion device. A first electricity meter can be set at the output end of the photovoltaic module for real-time collection of the above-mentioned power generation. A second electricity meter can be set at the port of the energy storage battery for real-time collection of the above-mentioned backup power. And a third electricity meter is set at the output end of the power conversion device for collecting the above-mentioned load power consumption. After obtaining the power generation, backup power and load power consumption, the slave controller of the energy storage inverter device transmits the power generation, backup power and load power consumption to the main controller of the grid-connected control device.

[0032] In some embodiments, the grid-connected control device may also store scale data of the photovoltaic components of each energy storage inverter device and scale data of the energy storage battery. The power generation of the energy storage inverter device can be predicted based on the scale data of the photovoltaic components combined with real-time weather data, and today's load power consumption can be predicted based on the load power consumption of the previous day.

[0033] Step S22: Calculate the mismatched power of each energy storage inverter device according to the power generation, backup power and load power consumption.

[0034] In the embodiment of the present application, after receiving the power generation, backup power and load power consumption transmitted by each energy storage inverter device, the main controller of the grid-connected control device can calculate the unmatched power of each energy storage inverter device. The unmatched power includes the excess power or lack of power when the energy storage inverter device supplies power to the load. After calculating the unmatched power of each energy storage inverter device, the grid-connected control device can control each energy storage inverter device to perform power interaction based on the unmatched power, thereby reducing the power interaction between the photovoltaic interconnection system and the power grid.

[0035] Step S23: According to all the mismatched electric quantities, an active power function based on all the energy storage inverter devices is established.

[0036] In the embodiment of the present application, after calculating the mismatched power of each energy storage inverter device, the main controller of the grid-connected control device will establish an active power function based on all energy storage inverter devices according to the mismatched power.

[0037] Step S24: solving the minimum value of the active power function to obtain the active power of each energy storage inverter device.

[0038] It can be understood that the value of the power function is the electric energy required for the photovoltaic interconnection system to interact with the power grid after the various energy storage inverter devices in the photovoltaic interconnection system interact with each other. Therefore, when the power function reaches the minimum value, the active power of each energy storage inverter device solved can optimize the distribution of electric energy in the photovoltaic interconnection system.

[0039] Step S25: Control the corresponding energy storage inverter device to adjust the active power according to the active power.

[0040] In the embodiment of the present application, the power generation, backup power and load power consumption of each energy storage inverter device in the photovoltaic interconnection system are obtained, and then the mismatched power of each energy storage inverter device is obtained. Based on all the mismatched power, an active power function based on all the energy storage inverter devices is established. Since the value of the power function is the electric energy required to be interacted between the photovoltaic interconnection system and the power grid after the electric energy interaction between each energy storage inverter device in the photovoltaic interconnection system, after solving the active power of each energy storage inverter device corresponding to the minimum value of the power function, the grid-connected control device adjusts the active power of the corresponding energy storage inverter device according to the active power control, so that the distribution of electric energy in the photovoltaic interconnection system can be optimized, thereby reducing the electric energy interaction between the photovoltaic interconnection system and the power grid, and improving the benefits of users of the photovoltaic interconnection system.

[0041] It can be understood that the process of adjusting the active power of the energy storage inverter device corresponding to the active power control includes adjusting the active power output of the energy storage inverter device and adjusting the input active power of the energy storage inverter device. For example, for energy storage inverter devices whose power generation and backup power are greater than the load power, their output active power can be adjusted to sell electricity to other users within the system. For energy storage inverter devices whose power generation and backup power are less than the load power, their input active power can be adjusted to buy electricity from other users within the system.

[0042] In some embodiments, Figure 3 As shown, the above step S22 may further include the following steps: Step S31: Establishing a photovoltaic mathematical model of the photovoltaic components of the energy storage inverter device, which is the power generation.

[0043] Step S32: Establish a battery mathematical model of the energy storage battery of the energy storage inverter device for backup power.

[0044] Step S33: Establish a load mathematical model of the load of the energy storage inverter device, which is the load power consumption.

[0045] Step S34: According to the photovoltaic mathematical model, the battery mathematical model and the load mathematical model, the active power model of the energy storage inverter device interacting with the outside is obtained, which is the unmatched power.

[0046] In some embodiments, Figure 4 As shown, the above step S31 may further include the following steps: Step S41: obtaining the current light intensity, ambient temperature and output power of the photovoltaic module.

[0047] Step S42: Obtaining a photovoltaic mathematical model according to light intensity, ambient temperature, output power and a preset comprehensive loss factor.

[0048] It can be understood that the power generation of photovoltaic modules is directly related to the light intensity and ambient temperature. The output power per unit time is affected by the light intensity and ambient temperature. The formula of the photovoltaic mathematical model can be obtained as follows: In formula (1.1) is the actual output power per unit time of a photovoltaic panel. is the maximum power output of the photovoltaic module under standard conditions. and are the actual solar radiation intensity and the solar radiation intensity under standard conditions, respectively. is the temperature coefficient of the photovoltaic panel, and are the temperatures of the photovoltaic module and the environment respectively. Formula (1.2) is the actual output power per unit time of the photovoltaic module composed of N photovoltaic panels. In formula (1.3) It is the upper limit of the output power of household photovoltaic panels, that is, considering the influence of factors such as light, environment and aging, the actual power output of the photovoltaic panel should be less than the standard output power.

[0049] In the embodiment of the present application, the energy storage inverter device may also be provided with a light intensity detection unit and a temperature detection unit to detect the light intensity and temperature of the photovoltaic module in real time, and transmit the light intensity and temperature to the grid-connected control device. The grid-connected control device inputs the light intensity, temperature and output power of the energy storage inverter device into the above-mentioned photovoltaic mathematical model to obtain the actual output power per unit time of the photovoltaic module, which is the above-mentioned power generation.

[0050] In some embodiments, Figure 5 As shown, the above step S32 may further include the following steps: Step S51: Obtain the charge and discharge state, charge and discharge power, charge and discharge loss, storage loss, charge amount and charge amount range of the energy storage battery.

[0051] Step S52: Obtain a battery mathematical model according to the charge and discharge state, charge and discharge power, charge and discharge loss, storage loss, charge amount and charge amount range.

[0052] It can be understood that the capacity of the energy storage battery is in ampere-hours, and the charging and discharging power per unit time is related to the remaining power. The formula of the battery mathematical model can be obtained as follows: In the formula, and Represent the power of the energy storage battery at the tth and t-1th time respectively, is the state variable of the energy storage battery. When the energy storage battery does not participate in the interaction of electric energy, ,on the contrary . , It is the charging and discharging state variable of the energy storage battery. When the energy storage battery is in the charging state , on the contrary, when discharging . is the actual energy change duration per unit hour, , Respectively The battery charge and discharge power within a time period. are the upper and lower bounds of the charging power constraint, are the upper and lower bounds of the discharge power constraint, for The charge and discharge loss during the period, It is the storage loss of the energy storage battery when it is not working.

[0053] In the embodiment of the present application, the charge and discharge power and charge and discharge depth of the energy storage battery may also be limited due to the capacity and battery life of the energy storage battery. Then: The charging depth is: The depth of discharge is: In the formula, is the charge of the energy storage battery, It is the maximum capacity of the energy storage battery. It is the upper and lower limits of the amount of charge that the energy storage battery is allowed to store, that is, the above-mentioned charge range.

[0054] In some embodiments, the loads include electric vehicles and electrical loads. Figure 6 As shown, the above step S33 may further include the following steps: Step S61: Obtain the charging and discharging state, charging and discharging power, charging and discharging loss, storage loss, current charge amount, planned charge amount and charge amount range of the electric vehicle.

[0055] Step S62: Obtaining a mathematical model of the electric vehicle according to the charge and discharge state, charge and discharge power, charge and discharge loss, storage loss, current charge amount, planned charge amount and charge amount range.

[0056] It can be understood that electric vehicles, as bidirectional energy storage units, consume electricity from power converters or power grids under normal circumstances, and are an important part of energy storage inverter equipment. As the capacity of electric vehicle batteries continues to increase, they can participate in the storage or output of electricity in energy storage inverter equipment like energy storage batteries. Therefore, its charging and discharging model is similar to that of energy storage batteries, and its electric vehicle mathematical model can be: It can be understood that, unlike energy storage batteries, when electric vehicles are used as discharge units to supply power to loads through power converters, their discharge capacity will change dynamically with the travel plan. If the planned charge capacity of the trip is , then the discharge depth becomes: Step S63: Obtaining an electrical load mathematical model based on a preset load level, active load factor, and reactive load factor of the electrical load.

[0057] In the embodiment of the present application, the preset load level may include necessary load, important load and general load, that is, for electrical loads, they are divided into necessary load, important load and general load according to their importance to life. , important load and general load . Then the mathematical model of electrical load includes: In the formula , is the active load factor, satisfying , the proportion of load types in different situations can be distinguished. For example, a user's load in daily life is , in emergencies such as extreme weather and power grid failures , similarly, , is the reactive load factor, satisfying .

[0058] In the embodiment of the present application, since the power load is limited, when the photovoltaic interconnection system works in the off-grid mode, and the power of the energy storage battery cannot meet the load demand, there is no need to reduce the load. Therefore, the above-mentioned active load and reactive load must be limited by upper limits: Step S64: Obtain a load mathematical model according to the electric vehicle mathematical model and the electrical load mathematical model.

[0059] It can be understood that the above-mentioned grid-connected control device can control the electric energy interaction between each energy storage inverter device and between each energy storage inverter device and the power grid, so the electric energy flow of the grid-connected control device is balanced within a unit time. According to the short-term (1.1) to (1.27), for the unmatched power of one of the energy storage inverter devices, that is, the active power model formula is: In the formula, is the active power of the ith energy storage inverter device interacting with the outside world. By default, the output power to the grid-connected control device is positive. For the photovoltaic interconnection system, the energy interaction between it and the grid is also balanced, so it satisfies: In the formula, is the working mode state variable of the photovoltaic interconnection system, Indicates that it is working in the grid-connected state, otherwise It means that the photovoltaic interconnection system is working in an off-grid state. Since photovoltaic power abandonment and load shedding are mutually exclusive in the off-grid state, a 0-1 variable is used. To constrain.

[0060] In some embodiments, the photovoltaic interconnection system can operate in a droop control mode or a V / f control mode, or in a hybrid mode to carry as much load as possible while ensuring voltage and frequency stability. In the droop control mode, the power converter's regulation of voltage and frequency can be summarized as follows: The droop coefficient is: In the formula, For the The maximum power that the power converter of the energy storage inverter device is allowed to output when the frequency decreases; The output power of the power converter of the i-th energy storage inverter device operating at the rated frequency; is the rated frequency of the power grid; The minimum frequency allowed when the power converter of the i-th energy storage inverter device outputs maximum power; The reactive power output when the power converter of the i-th energy storage inverter device reaches the maximum allowable voltage drop value; is the output voltage amplitude when the reactive power output of the power converter of the i-th energy storage inverter device is 0; is the minimum voltage amplitude allowed.

[0061] It can be understood that since the output power of the power converter is limited, in order to maximize the load-carrying capacity of the power converter output, it can be stipulated that the actual power output of the power converter is all used for active power output, and the reactive power is provided by the reactive power compensation device to ensure the stability of the node voltage and the reactive load requirements of the user, then there are: Among them, formula (1.40) includes reactive power support in both grid-connected mode and off-grid mode, but the reactive power provided is limited, and there will be: Taking into account the cost of electricity purchase in the grid-connected mode and minimizing the occurrence of power abandonment or load shedding in the off-grid mode, the minimum value of the above active power function can be solved as follows: In some embodiments, you can ,pass After the constraints are met, the solver is used to solve the problem, thereby obtaining the active power of each energy storage inverter device.

[0062] Among them, Z is the decision variable related to the objective function and constraints, A and B are the coefficient matrices of variable Z in the equality constraints, and C is the coefficient matrix of variable Z in the inequality constraints. , Please refer to Figure 7 , Figure 7 A schematic block diagram of another photovoltaic interconnection system provided in an embodiment of the present application, wherein the photovoltaic interconnection system 700 includes a grid-connected control device 710, a plurality of energy storage inverter devices 720 and a reactive power compensation device 730.

[0063] The energy storage inverter device 720 is communicatively connected with the grid-connected control device 710 , the energy storage inverter device 720 is connected to the power grid 701 through the grid-connected control device 710 , and the reactive power compensation device 730 is connected to the grid-connected control device 710 .

[0064] It can be understood that in the embodiment of the present application, the reactive power of the photovoltaic interconnection system 700 is provided by the power grid 701 in the grid-connected state, and the reactive power of the photovoltaic interconnection system 700 is provided by the reactive compensation device 730 in the off-grid state.

[0065] Next, combine Figure 7 A method for distributing electric energy in a photovoltaic interconnection system provided in an embodiment of the present application is introduced. Figure 8 As shown, the specific steps include: Step S81: Obtain the power generation, backup power and load power consumption of each energy storage inverter device.

[0066] Step S82: Calculate the mismatched power of each energy storage inverter device based on the power generation, backup power and load power consumption.

[0067] Step S83: In the grid-connected state, an active power function based on all energy storage inverter devices connected to the grid is established according to all unmatched power quantities.

[0068] Step S84: in the off-grid state, an active power function is established according to all the unmatched power and the reactive power of the reactive compensation device.

[0069] Step S85: solving the minimum value of the active power function to obtain the active power of each energy storage inverter device.

[0070] Step S86: Control the corresponding energy storage inverter device according to the active power to adjust the active power.

[0071] Next, combine Figure 7 A flow chart of a control method for a photovoltaic interconnection system provided in an embodiment of the present application is introduced, please refer to Fig. 9 , specifically including the following steps: Step S91: The grid-connected control device determines the number of energy storage inverter devices participating in the photovoltaic interconnection.

[0072] Step S92: The grid-connected control device establishes communication with each energy storage inverter device.

[0073] Step S93: the grid-connected control device determines whether the photovoltaic interconnection system is connected to the grid.

[0074] Step S941: If connected to the power grid, the grid-connected control device obtains the active power of each energy storage inverter device according to the power distribution method of any of the above embodiments.

[0075] Step S942: If not connected to the grid, the grid-connected control device coordinates each energy storage inverter device to output according to the initial voltage and initial frequency.

[0076] Step S943: the grid-connected control device controls the reactive power compensation device to output reactive power.

[0077] Step S944: the grid-connected control device obtains the active power of each energy storage inverter device according to the electric energy distribution method of any of the above embodiments.

[0078] In an embodiment of the present application, the grid-connected control device controls the reactive power compensation device to output reactive power to the photovoltaic interconnection system to reduce the reactive power output of each energy storage inverter device, and then obtains the active power of each energy storage inverter device according to the above-mentioned power distribution method.

[0079] Step S95: the grid-connected control device transmits the information of each active power to the corresponding energy storage inverter device.

[0080] Step S96: Each energy storage inverter device is adjusted according to the received active power.

[0081] It can be understood that the beneficial effects of the control method of the embodiment of the present application can refer to the beneficial effects of the power distribution method in the aforementioned embodiment, and will not be repeated here.

[0082] An embodiment of the present application further provides a computer storage medium, which stores a computer program. When the computer program is executed by a processor, the processor executes the above-mentioned current control method.

[0083] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer storage medium or transmitted through the computer storage medium. The computer instructions may be transmitted from a website site, computer, server or data center to another website site, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer storage medium may be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integrated. The available medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a digital versatile disc (DVD)), or a semiconductor medium (eg, a solid state disk (SSD)).

[0084] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program, and the program can be stored in a computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above-mentioned methods. The aforementioned storage medium includes: ROM, RAM, magnetic disk or optical disk and other media that can store program codes. In the absence of conflict, the technical features in this embodiment and the implementation scheme can be combined arbitrarily.

[0085] The embodiments described above are merely preferred embodiments of the present application and are not intended to limit the scope of the present application. Without departing from the design spirit of the present application, various modifications and improvements made to the technical solutions of the present application by ordinary technicians in this field should fall within the scope of protection determined by the claims of the present application.

Claims

1. A method for distributing electric energy in a photovoltaic interconnection system, characterized in that: The photovoltaic interconnection system includes a grid-connected control device and a plurality of energy storage inverter devices, wherein the energy storage inverter device is communicatively connected to the grid-connected control device, and the energy storage inverter device is used to be connected to the power grid through the grid-connected control device; The electric energy distribution method comprises: Obtaining the power generation, backup power and load power consumption of each of the energy storage inverter devices; Calculate the mismatched power of each of the energy storage inverter devices according to the power generation, the backup power and the load power consumption; According to all the unmatched electric quantities, an active power function based on all the energy storage inverter devices is established; Solving the minimum value of the active power function to obtain the active power of each of the energy storage inverter devices; Active power is adjusted according to the energy storage inverter device corresponding to the active power control.

2. The electric energy distribution method according to claim 1, characterized in that: The calculating the mismatched power of each energy storage inverter device according to the power generation, the backup power and the load power consumption includes: Establishing a photovoltaic mathematical model of the photovoltaic components of the energy storage inverter device for the power generation; Establishing a battery mathematical model of the energy storage battery of the energy storage inverter device to provide the backup power; Establishing a load mathematical model of the load of the energy storage inverter device, which is the load power consumption; According to the photovoltaic mathematical model, the battery mathematical model and the load mathematical model, an active power model of the energy storage inverter device interacting with the outside is obtained, which is the unmatched power.

3. The electric energy distribution method according to claim 2, characterized in that: The photovoltaic mathematical model of the photovoltaic components of the energy storage inverter device is established, including: Obtaining the current light intensity, ambient temperature and output power of the photovoltaic module; The photovoltaic mathematical model is obtained according to the light intensity, the ambient temperature, the output power and a preset comprehensive loss factor.

4. The electric energy distribution method according to claim 2, characterized in that: The step of establishing a battery mathematical model of the energy storage battery of the energy storage inverter device comprises: Obtaining the charge and discharge state, charge and discharge power, charge and discharge loss, storage loss, charge amount and charge amount range of the energy storage battery; The battery mathematical model is obtained according to the charge and discharge state, the charge and discharge power, the charge and discharge loss, the storage loss, the charge amount and the charge amount range.

5. The electric energy distribution method according to claim 2, characterized in that: The load includes electric vehicles and electrical appliance loads, and the load mathematical model of the load of the energy storage inverter device is established, including: Obtaining the charging and discharging state, charging and discharging power, charging and discharging loss, storage loss, current charge amount, planned charge amount and charge amount range of the electric vehicle; Obtaining a mathematical model of an electric vehicle according to the charging and discharging state, the charging and discharging power, the charging and discharging loss, the placement loss, the current charge amount, the planned charge amount, and the charge amount range; Based on the preset load level, active load factor and reactive load factor of the electrical load, a mathematical model of the electrical load is obtained; The load mathematical model is obtained according to the electric vehicle mathematical model and the electrical load mathematical model.

6. The electric energy distribution method according to claim 1, characterized in that: The photovoltaic interconnection system further includes a reactive power compensation device, wherein the reactive power compensation device is connected to the grid connection control device, and the electric energy distribution method further includes: In an off-grid state, the active power function is established according to all the unmatched electric quantities and the reactive power of the reactive compensation device.

7. A photovoltaic interconnection system, characterized in that: It includes a grid-connected control device and a plurality of energy storage inverter devices, wherein the energy storage inverter device is communicatively connected to the grid-connected control device, and the energy storage inverter device is connected to the power grid through the grid-connected control device; The energy storage inverter device is used to detect its power generation, backup power and load power consumption, and transmit them to the grid connection control device; The grid-connected control device is used to obtain the power generation, backup power and load power consumption of each of the energy storage inverter devices, calculate the mismatched power of each of the energy storage inverter devices based on the power generation, backup power and load power consumption, establish an active power function based on all of the energy storage inverter devices based on all of the mismatched power, solve the minimum value of the active power function, obtain the active power of each of the energy storage inverter devices, and adjust the active power of the corresponding energy storage inverter device according to the active power control.

8. The photovoltaic interconnection system according to claim 7, characterized in that: The grid-connected control device is also used for: Establishing a photovoltaic mathematical model of the photovoltaic components of the energy storage inverter device for the power generation; Establishing a battery mathematical model of the energy storage battery of the energy storage inverter device to provide the backup power; Establishing a load mathematical model of the load of the energy storage inverter device, which is the load power consumption; According to the photovoltaic mathematical model, the battery mathematical model and the load mathematical model, an active power model of the energy storage inverter device interacting with the outside is obtained, which is the unmatched power.

9. The photovoltaic interconnection system according to claim 8, characterized in that: The energy storage inverter device is also used to obtain the current light intensity, ambient temperature and output power of the photovoltaic module, and transmit them to the grid-connected control device; The grid-connected control device is also used to obtain the photovoltaic mathematical model according to the light intensity, the ambient temperature, the output power and a preset comprehensive loss factor.

10. The photovoltaic interconnection system according to claim 8, characterized in that: The energy storage inverter device is also used to obtain the charge and discharge state, charge and discharge power, charge and discharge loss, storage loss, charge amount and charge amount range of the energy storage battery, and transmit them to the grid connection control device; The grid-connected control device is also used to obtain the battery mathematical model according to the charging and discharging state, the charging and discharging power, the charging and discharging loss, the storage loss, the charge amount and the charge amount range.

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