Control method and device, storable medium and photovoltaic energy storage equipment

Abstract

The invention provides a control method and device, a storable medium and photovoltaic energy storage equipment, and relates to the technical field of photovoltaic energy storage. The control method comprises the following steps: acquiring the power of a power grid and the current battery electric quantity of a battery module; determining a current working mode of the photovoltaic energy storage equipment according to a comparison result of the current battery electric quantity and the target standby power electric quantity; determining the target working power of the battery module according to the maximum working power of the battery module or the power of the power grid based on the current working mode; based on the current working mode, controlling the photovoltaic energy storage equipment to execute target operation according to the target working power; wherein the target operation comprises the steps of charging the battery module and supplying power to the load through the battery module. According to the invention, the battery module can keep sufficient standby power to deal with emergencies such as power failure, and the influence of power failure of a power grid on power utilization of users is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of photovoltaic energy storage, in particular to a control method and device, a readable storage medium and a photovoltaic energy storage device. BACKGROUND

[0002] In the related art, a photovoltaic energy storage device can generate electricity through a photovoltaic device and store the electricity generated by the photovoltaic device. When the stored energy reaches a certain amount of electricity or power grid fluctuations occur, the battery module of the photovoltaic energy storage device can supply power to the load.

[0003] For some areas where the power grid is frequently powered off, the electricity stored by the battery module can supply power to the load for a certain period of time when the power grid is powered off, reducing the impact of power grid power failure. The length of time that the battery can supply power depends on the battery capacity. How to improve the battery storage capacity while ensuring that the photovoltaic power generation capacity can be fully utilized is a problem to be solved. SUMMARY

[0004] The present application aims to at least solve one of the technical problems existing in the prior art or related art.

[0005] To this end, the first aspect of the present application provides a control method of a photovoltaic energy storage device.

[0006] The second aspect of the present application provides a control device of a photovoltaic energy storage device.

[0007] The third aspect of the present application provides a control device of a photovoltaic energy storage device.

[0008] The fourth aspect of the present application provides a readable storage medium.

[0009] The fifth aspect of the present application provides a photovoltaic energy storage device.

[0010] Therefore, the first aspect of the present application provides a control method of a photovoltaic energy storage device, the photovoltaic energy storage device being electrically connected with a power grid and a load, the photovoltaic energy storage device comprising a battery module, the control method comprising: obtaining a power grid power and a current battery capacity of the battery module; determining a current working mode of the photovoltaic energy storage device according to a comparison result of the current battery capacity and a target standby power; determining a target working power of the battery module based on the maximum working power of the battery module or the power grid power according to the current working mode; controlling the photovoltaic energy storage device to perform a target operation according to the target working power based on the current working mode; wherein the target operation comprises charging the battery module and supplying power to the load through the battery module.

[0011] In the technical solution, the photovoltaic energy storage device is electrically connected with the power grid and the load, the photovoltaic energy storage device includes a battery module, the battery module can include a plurality of battery cells, and the photovoltaic energy storage device also includes a photovoltaic (PV) power generation module, the photovoltaic energy storage device uses the phenomenon that a voltage is generated at a junction of a semiconductor and a metal when the semiconductor and the metal are combined to directly convert radiant energy of the sun into electric energy, and realizes photovoltaic power generation.

[0012] The electric energy generated by the photovoltaic power generation can be directly provided to the load for use, or can be charged to the battery module, so that the electric energy generated by the photovoltaic power generation is stored through the battery module, and in a suitable condition, the load is powered by the electric energy stored in the battery module, thereby reducing the amount of electricity taken from the power grid and reducing the electricity cost.

[0013] In some embodiments, the photovoltaic energy storage device can also realize grid connection, so as to deliver the surplus electric energy of the photovoltaic power generation to the power grid, realize power selling to the power grid, and further generate a benefit, which can also indirectly reduce the electricity cost of the household.

[0014] In order to better utilize the electric energy generated by the photovoltaic power generation, how to reasonably allocate the charging and discharging power of the battery is an important key to the utilization rate of the photovoltaic power generation, and at the same time, keeping the battery in a reasonable and healthy power range is also conducive to improving the battery life, and at the same time, when the power grid appears temporary power failure and other fluctuation faults, sufficient power is reserved to temporarily power the load, reducing the impact of power failure on power consumption.

[0015] Therefore, the technical solution of the present application proposes a control method of a photovoltaic energy storage device, which proposes a standby power operation mode, in which the photovoltaic energy storage device preferentially charges the battery module, so as to improve the SOC (State Of Charge) of the battery module to above the standby power SOC, that is, only when the remaining power of the battery module is above the target standby power, the battery module is discharged to the load for use.

[0016] For example, the standby power mode can be started when the electricity price is at the trough, at which time the power grid is mainly used to obtain electric energy for the load, and the remaining power of the battery module is kept above the target standby power, so that in the case of unexpected power failure of the power grid, the battery module has sufficient power for the load, which can reduce the impact of power failure.

[0017] Exemplarily, the photovoltaic energy storage device acquires the current battery power of the battery module, and determines whether the current battery power reaches the target standby power, and determines the current working mode of the photovoltaic energy storage device according to the comparison result, that is, the charging mode or the non-charging mode. In the charging mode, the battery module is not allowed to discharge, and at this time, the remaining power of the battery module needs to be charged to above the target standby power. In the non-charging mode, the battery module can discharge, and at this time, the power of the battery module is dynamically adjusted according to the remaining power of the battery module and the load condition.

[0018] Exemplarily, after the current working mode is determined, the target working power of the battery module is determined based on the maximum working power of the battery module or the grid-side power of the current photovoltaic energy storage device. It can be understood that the target working power includes the charging power of the battery module in the charging mode and the discharging power of the battery module in the discharging mode.

[0019] Exemplarily, whether the battery module is charging or supplying power to the load can be specified by the positive and negative values of the target working power. For example, assuming that the current direction in the photovoltaic energy storage device is the direction pointing to the AC busbar, the target working power is positive, and at this time, the battery module is in the discharging state. When the current direction in the photovoltaic energy storage device is the direction away from the AC busbar, the target working power is negative, and at this time, the battery module is in the charging state.

[0020] After the current working mode of the photovoltaic energy storage device and the target working power of the battery module in the current working mode are determined, the photovoltaic energy storage device automatically performs the corresponding target operation according to the current working mode and the target working power, wherein the target working power is the grid-side power. Exemplarily, when the target working mode is the charging mode, the photovoltaic energy storage device charges the battery module with the target working power as the charging power. Exemplarily, when the target working mode is the non-charging mode and the target working power is positive, the battery module is controlled to supply power to the load with the target working power as the discharging power.

[0021] The technical scheme provided in the present application divides the working mode of the photovoltaic energy storage device based on the comparison result of the remaining battery power and the target standby power, and dynamically adjusts the charging power or the discharging power of the battery module according to different working modes, so that the battery module can maintain sufficient standby power to cope with power failure and the like, and reduce the influence of power grid failure on user power consumption.

[0022] In addition, the control method of the photovoltaic energy storage device in the above technical scheme provided by the present application can further have the following additional technical features:

[0023] In some technical solutions of the present application, the current working mode of the photovoltaic energy storage device is determined according to the comparison result of the current battery power and the target standby power, including: in the case that the current battery power is less than the target standby power, the current working mode is determined as the charging mode; or in the case that the current battery power is greater than or equal to the target standby power, the current working mode is determined as the non-charging mode.

[0024] In this technical solution, the photovoltaic energy storage device includes a standby power running mode, in which the photovoltaic energy storage device needs to prioritize charging the battery module to ensure that the remaining power of the battery module is not less than the target standby power.

[0025] When the photovoltaic energy storage device is working, the photovoltaic energy storage device dynamically acquires the current battery power of the battery module and judges whether the current battery power reaches the target standby power. If the current battery power is less than the target standby power, the photovoltaic energy storage device needs to prioritize charging the battery module with the power generated by the photovoltaic power generation device, and at this time the working mode of the photovoltaic energy storage device is the charging mode.

[0026] If the current battery power is greater than or equal to the target standby power, i.e. the remaining power of the battery module meets the target standby power, the working mode of the photovoltaic energy storage device is determined as the non-charging mode.

[0027] Exemplarily, the user can set the target standby power according to his own needs.

[0028] Exemplarily, assuming that the SOC value is 100 when the battery module is in a full power state, and the SOC value is 0 when the battery module is in an empty power state, the target standby power can be set to any value between 0 and 100.

[0029] Exemplarily, the target standby power is 80, and when the current battery power of the battery module is less than 80, the working mode of the photovoltaic energy storage device is the charging mode.

[0030] Exemplarily, the target standby power is 100, and before the battery module is fully charged, the working mode of the photovoltaic energy storage device is the charging mode.

[0031] The technical solution of the present application can distinguish the working mode of the photovoltaic energy storage device by setting the target standby power, so as to keep the battery module with sufficient power and continuously provide power for user loads when the power grid is powered off.

[0032] In some technical solutions of the present application, optionally, based on the current working mode, the target working power of the battery module is determined according to the maximum working power of the battery module or the grid power, comprising: in the case that the current working mode is the charging mode, the first working power is determined according to the maximum charging power of the battery module; the target working power is determined according to the first working power.

[0033] In this technical solution, the current working mode is the charging mode, which means that the current battery capacity of the battery module has not reached the target standby power capacity. At this time, the electrical energy generated by photovoltaic power generation needs to be preferentially used to charge the battery module, while ensuring that the charging efficiency of the battery module is maximum. At this time, the maximum charging power of the battery module determines the first working power, which is used as the above-mentioned target working power.

[0034] Exemplarily, in order to ensure the charging efficiency of the battery module, when the battery module is in standby power, the target working power of the battery module can be set to the maximum charging power of the battery module if possible. However, since the power generation of photovoltaic power generation is greatly affected by the external environment, in some scenarios, the photovoltaic power generation power may not reach the maximum charging power of the battery module. At this time, it can be further judged whether it is allowed to take power from the grid side to charge the battery module.

[0035] Exemplarily, the user is not allowed to take power from the grid side to charge the battery module, and the photovoltaic power generation power is less than the maximum charging power of the battery module. At this time, the photovoltaic power generation power is used as the above-mentioned first working power.

[0036] Exemplarily, the user is allowed to take power from the grid side to charge the battery module, and the photovoltaic power generation power is less than the maximum charging power of the battery module. At this time, the difference between the maximum charging power and the photovoltaic power generation power is calculated, and the grid is used to compensate for this part of the difference. At this time, the maximum charging power of the battery module is used as the above-mentioned first working power.

[0037] Exemplarily, the photovoltaic power generation power is greater than or equal to the maximum charging power of the battery module. At this time, the maximum charging power of the battery module is used as the above-mentioned first working power.

[0038] The technical solutions of the present application can ensure that the charging power of the battery module is maintained at the highest possible charging power, thereby improving the charging efficiency in the standby power running mode.

[0039] In some technical solutions of the present application, optionally, based on the current working mode, the target working power of the battery module is determined according to the maximum working power of the battery module or the grid power, comprising: in the case that the current working mode is the charging mode, the first working power is determined according to the maximum charging power of the battery module; the target working power is determined according to the first working power.

[0040] In the technical solution, when the current working mode is the non-charging mode, it indicates that the current battery power of the battery module has reached or is greater than the target standby power, at this time, whether the battery module discharges externally can be determined according to the specific load condition.

[0041] Exemplarily, the first working power is calculated by the following formula (1):

[0042] PObjabt1 = Pbat + Pgrid; (1)

[0043] Wherein, PObjabt1 is the first working power, Pbat is the current working power, and Pgrid is the grid power.

[0044] In the non-charging mode, the battery module can discharge externally, assuming that the battery module is in the discharging state, the current working power of the battery module is positive, and when the battery module is in the charging state, the current working power of the battery module is negative. Similarly, when the photovoltaic energy storage device is connected to the grid and outputs power to the grid, the grid power is negative, and when power is taken from the grid, the grid power is positive.

[0045] After calculation by formula (1), if the first working power is positive, the battery module is controlled to discharge according to the target working power finally determined, and if the first working power is negative, the battery module is controlled to charge according to the target working power finally determined.

[0046] The technical solution of the application can dynamically adjust the target working power of the battery module for charging or discharging in the non-charging mode according to the grid power and the current working power of the battery module, and can effectively improve the energy utilization rate of photovoltaic power generation.

[0047] In some technical solutions of the application, optionally, based on the current working mode, the target working power of the battery module is determined according to the maximum working power of the battery module or the grid power, comprising: in the case that the current working mode is the non-charging mode and the current battery power is greater than or equal to the power threshold, determining the first working power according to the grid power and the current working power of the battery module; wherein the power threshold is greater than the target standby power; determining the target working power according to the first working power.

[0048] In the technical solution, when the current working mode is the non-charging mode, it indicates that the current battery power of the battery module has reached or is greater than the target standby power, at this time, if the current battery power satisfies the preset power threshold, it is determined that the battery module satisfies the condition of discharging externally, that is, the battery module can discharge externally, and the first working power determined at this time is the target discharging power of the battery module.

[0049] Exemplarily, the power threshold is a sum of the target backup power and a backup power difference value. Assuming that the SOC value is 100 when the battery module is in a full power state, the SOC value is 0 when the battery module is in an empty power state, and the target backup power is 80, the power threshold is 85.

[0050] Exemplarily, the first working power can be calculated by the above formula (1).

[0051] Exemplarily, when the discharge condition of the battery module is met, it is determined whether the photovoltaic power generation power can cover the load power. If the photovoltaic power generation power cannot cover the load power, the insufficient power is supplemented by controlling the battery module to discharge, at this time, power is not taken from the power grid, and after the current battery power is lower than the above power threshold, the battery module no longer discharges.

[0052] Exemplarily, when the remaining power of the battery module is 100, that is, the power is full, if the photovoltaic power generation power is greater than the power required by the load, the surplus power after the photovoltaic power generation is used by the load can be sold to the power grid.

[0053] The technical scheme of the present application can dynamically adjust the target working power of the battery module according to the power grid power and the current working power of the battery module in the non-charging mode and under the condition that the discharge condition is met, and can improve the energy utilization rate of the battery photovoltaic power generation.

[0054] In some technical schemes of the present application, optionally, the target working power is determined according to the first working power, including: in the case that the first working power is less than or equal to the maximum working power of the battery module, the first working power is determined as the target working power; or in the case that the first working power is greater than the maximum working power of the battery module, the maximum working power is determined as the target working power.

[0055] In the technical scheme, the maximum working power of the battery module is the power threshold of the battery module when charging and discharging, and when the current working power of the battery module is greater than the maximum working power, the battery may be heated and other problems may be caused, affecting the safety of power consumption.

[0056] Therefore, after the first working power is calculated, the larger one between the first working power and the maximum working power is taken as the target power of the battery.

[0057] For example, when the first working power is the charging power (negative value) and the absolute value of the first working power is greater than the charging power threshold of the battery module (the absolute value of the maximum working power), the maximum working power of the battery module is set as the target working power, that is, the battery module is charged by the maximum charging power.

[0058] For example, when the first working power is a discharging power (a positive value) and the absolute value of the first working power is less than the discharging power threshold of the battery module (the absolute value of the maximum working power), the first working power is set as the target working power, that is, the battery module is controlled to supply power to the load by the first working power.

[0059] The technical solution of the present application can ensure the working safety of the battery module and improve the reliability of the photovoltaic energy storage device while ensuring the charging and discharging efficiency by selecting the larger one of the first working power and the maximum working power as the target working power.

[0060] In some technical solutions of the present application, the current working mode includes a charging mode and a non-charging mode. Based on the current working mode, the photovoltaic energy storage device is controlled to perform a target operation according to the target working power, including: when the current working mode is the charging mode and the current battery capacity is less than the maximum charging capacity, the photovoltaic energy storage device is controlled to charge the battery module according to the target working power; or when the current working mode is the non-charging mode and the current battery capacity is greater than the capacity threshold, the photovoltaic energy storage device is controlled to supply power to the load according to the target working power.

[0061] In this technical solution, the maximum charging capacity is the upper limit of the battery module. For example, the maximum charging capacity is greater than or equal to the target standby power.

[0062] In the charging mode, the photovoltaic energy storage device prioritizes the charging process of the battery module. When the current battery capacity does not reach the maximum charging capacity, that is, the battery module is not full, the battery module is charged by the determined target working power until the current battery capacity of the battery module is greater than or equal to the maximum charging capacity, and the charging stops. At this time, the power generated by the photovoltaic power generation module is used for the load, or when there is a surplus of power generated by the photovoltaic power generation module, the surplus part of the power is connected to the grid for power sales.

[0063] In the non-charging mode, the photovoltaic energy storage device can charge the battery module or use the stored power of the battery module to supply power to the load. Specifically, when the photovoltaic power generation capacity is greater than the load demand, the surplus power of the photovoltaic power generation is preferentially charged to the battery. When the photovoltaic power generation capacity is less than the load demand, whether the battery capacity is used to supply power to the load is selected.

[0064] Therefore, when the photovoltaic energy storage device is in the non-charging mode and the current battery power of the battery module is greater than the power threshold, the battery module supplies power to the load when the photovoltaic power generated by the photovoltaic power generation cannot cover the entire power demand of the load, until the current battery power of the battery module is less than or equal to the power threshold, the battery module stops discharging, and the battery module is charged when the condition allows.

[0065] The technical scheme of the present application can adaptively adjust the charging and discharging modes of the battery, avoid energy waste, and reduce the power taken from the power grid as much as possible to save electricity bills.

[0066] In some technical schemes of the present application, the photovoltaic energy storage device further includes a power conversion module and a photovoltaic inverter module. Before determining the target operating power of the battery module according to the maximum operating power of the battery module or the power grid power, the control method further includes: determining the load power of the photovoltaic energy storage device according to the power grid power, the inverter power of the power conversion module, and the inverter power of the photovoltaic inverter module; determining the maximum inverter power of the power conversion module according to the load power and the maximum feed-in power; wherein the maximum feed-in power is used to indicate the maximum power value of the photovoltaic energy storage device feeding into the power grid; and controlling the photovoltaic energy storage device to perform the target operation according to the target operating power, including: controlling the photovoltaic energy storage device to perform the target operation according to the target operating power and the maximum inverter power.

[0067] In this technical scheme, the photovoltaic energy storage device includes a power conversion module (PCS), which exemplarily includes a DC / AC bidirectional converter control unit and the like. The control unit receives a background control instruction through a communication unit, controls the charging or discharging of the battery module according to the sign and size of the power instruction, and adjusts the active power and reactive power of the microgrid.

[0068] The photovoltaic inverter module is used to convert the direct current signal generated by photovoltaic power generation into an alternating current signal to supply power to the load or sell electricity to the power grid.

[0069] Exemplarily, during the operation of the photovoltaic energy storage device, the power conversion module calculates the total load power according to the power grid power, the inverter power of the power conversion module, and the inverter power of the photovoltaic inverter module. Exemplarily, the load power can be calculated by the following formula (2):

[0070] Pload = Pgrid + Ppcs + Pacpv; (2)

[0071] wherein Pload is the load power, Pgrid is the power grid power, Ppcs is the inverter power of the power conversion module, and Pacpv is the inverter power of the photovoltaic inverter module.

[0072] After obtaining the load power, the maximum inverter power of the energy storage conversion module is calculated according to the load power and the maximum feeding power. For example, the maximum inverter power of the energy storage conversion module can be calculated by the following formula (3):

[0073] Ppcsmax = Pload + Pmaxsell - Pacpv (3)

[0074] Wherein, Ppcsmax is the maximum inverter power of the energy storage conversion module, Pload is the load power, Pacpv is the inverter power of the photovoltaic inverter module, Pmaxsell is the maximum feeding power, and the maximum feeding power is the maximum power of the photovoltaic energy storage device feeding the power grid. The maximum feeding power can be a fixed power value set in the program or a power value obtained by communicating with the upper device (such as a distribution box) of the power grid.

[0075] After obtaining the maximum inverter power of the energy storage conversion module, the maximum inverter power of the energy storage conversion module is used as a power instruction for controlling the operation of the energy storage conversion module. The photovoltaic energy storage device is controlled to work through the power instruction, which can accurately adjust the active power and the reactive power, and make the PCS keep the inverter power as matched as possible with the output power of the PV within the upper limit of the inverter power issued by the distribution box, thereby improving the energy efficiency of the photovoltaic energy storage device.

[0076] In some technical solutions of the present application, the control method further comprises updating the target working power and the maximum inverter power after the photovoltaic energy storage device performs the target operation according to the target working power and the maximum inverter power; and controlling the photovoltaic energy storage device to perform the target operation according to the updated target working power and the updated maximum inverter power when a preset condition is met. The preset condition includes at least one of the following: the difference between the updated target working power and the previous target working power is greater than a power difference threshold, and the difference between the updated maximum inverter power and the previous maximum inverter power is greater than a power difference threshold.

[0077] In the technical solution, the photovoltaic energy storage device continuously updates the target working power and the maximum inverter power of the energy storage converter module during operation. When the difference between the updated target working power and the last issued target working power (the target working power before updating) is greater than the power difference threshold, or when the difference between the updated maximum inverter power and the last issued maximum inverter power (the maximum inverter power before updating) is greater than the power difference threshold, it indicates that the system load or photovoltaic power generation has changed. At this time, the updated data is issued to the energy storage converter module PCS through the high-speed controller area network (CAN) bus, and the load and other parameters are recalculated according to the updated data to control the energy storage converter module PCS to adjust the power command and the charge and discharge power of the battery module.

[0078] When the difference between the updated target working power and the last issued target working power is not greater than the power difference threshold, and the difference between the updated maximum inverter power and the last issued maximum inverter power is not greater than the power difference threshold, it indicates that the system state has not changed significantly. At this time, the data change may come from collection errors or temporary fluctuations. Therefore, the energy storage converter module PCS is controlled to maintain the previous power adjustment command and the charge and discharge power of the battery module unchanged to avoid frequent adjustment of system control parameters and ensure system stability.

[0079] In some technical solutions of the present application, optionally, after the photovoltaic energy storage device performs the target operation according to the target working power and the maximum inverter power, the control method further comprises: determining the power difference between the current working power of the battery module and the target working power; and sending the power difference to the energy storage converter module when the power difference is greater than the difference threshold.

[0080] In the technical solution, there may be a certain power difference between the current working power of the battery and the target working power. For example, during standby power charging, it is desired that the current charging power of the battery module matches the maximum charging power, but the photovoltaic power generation power may not reach the maximum charging power, so there will be a certain power difference. For another example, during discharging, it is desired that the discharge power of the battery module matches the load demand power, but since the load power is variable and the battery discharge power may not completely cover the load demand, there may also be a power difference.

[0081] In view of the above situation, the present application determines the power difference between the actual current working power of the battery module and the desired target working power in real time. If the power difference is greater than the difference threshold, it indicates that the actual working power of the battery module does not match the set target working power. At this time, the power difference is sent to the energy storage converter module, and the energy storage converter module adjusts the power distribution between the power grid, photovoltaic power generation and the battery module according to the power difference.

[0082] Exemplarily, when the working mode of the photovoltaic energy storage device is the charging mode, the battery module is set to charge at the target working power, and the difference between the current working power of the battery module and the set target working power is greater than the difference threshold value, for example, the current working power is less than the target working power, the power difference is sent to the energy storage converter module, the energy storage converter module determines whether the user allows the battery module to be charged through the power grid, and if the user allows the battery module to be charged through the power grid, the insufficient charging power is compensated through the power grid.

[0083] Exemplarily, when the working mode of the photovoltaic energy storage device is the discharging mode, the battery module is set to discharge to the load at the target working power, and the difference between the current working power of the battery module and the set target working power is greater than the difference threshold value, for example, the current working power is greater than the target working power, the power difference is sent to the energy storage converter module, the energy storage converter module increases the power taken from the power grid, and the discharging power of the battery module is reduced under the condition of meeting the load demand.

[0084] Exemplarily, the difference threshold value is in the range of 50W to 200W.

[0085] Exemplarily, the difference threshold value is 100W.

[0086] Exemplarily, taking the difference threshold value of 100W as an example, when the power difference is less than 100W, the power difference is considered as 0.

[0087] The technical scheme of the present application updates the power difference between the actual power of the battery and the target power, thereby realizing reasonable distribution of the power of each part of the photovoltaic energy storage device and improving the energy utilization efficiency of the photovoltaic energy storage device.

[0088] The second aspect of the present application provides a control device of a photovoltaic energy storage device, the photovoltaic energy storage device is electrically connected with a power grid and a load, the photovoltaic energy storage device comprises a battery module, the control device comprises: an acquisition module for acquiring the power grid power and the current battery capacity of the battery module; a determination module for determining the current working mode of the photovoltaic energy storage device according to the comparison result of the current battery capacity and the target standby power; and determining the target working power of the battery module based on the maximum working power of the battery module or the power grid power based on the current working mode; a control module for controlling the photovoltaic energy storage device to perform a target operation according to the target working power based on the current working mode; wherein the target operation comprises charging the battery module and supplying power to the load through the battery module.

[0089] In the technical solution, the photovoltaic energy storage device is electrically connected to the power grid and the load, and includes a battery module which can include a plurality of battery cells. The photovoltaic energy storage device also includes a photovoltaic (PV) power generation module. The photovoltaic energy storage device uses the phenomenon that a semiconductor and a metal combined part generates a voltage to directly convert the radiant energy of the sun into electric energy, thereby realizing photovoltaic power generation.

[0090] The electric energy generated by the photovoltaic power generation can be directly provided to the load for use, or can be charged to the battery module, so that the electric energy generated by the photovoltaic power generation is stored through the battery module. In a suitable condition, the load is powered by the electric energy stored in the battery module, thereby reducing the amount of electricity taken from the power grid and reducing the electricity cost.

[0091] In some embodiments, the photovoltaic energy storage device can also realize grid connection to the power grid, so as to deliver the surplus electric energy of the photovoltaic power generation to the power grid, realize power selling to the power grid, and further generate a benefit, which can also indirectly reduce the electricity cost of the household.

[0092] In order to better utilize the electric energy generated by the photovoltaic power generation, how to reasonably allocate the charging and discharging power of the battery is an important key to the utilization rate of the photovoltaic power generation. At the same time, keeping the battery in a reasonable and healthy power range is also conducive to improving the battery life. At the same time, when the power grid appears temporary power failure and other fluctuation faults, sufficient power is reserved to temporarily power the load, thereby reducing the impact of power failure on electricity.

[0093] Therefore, the technical solution of the present application proposes a control method of a photovoltaic energy storage device. The method proposes a standby power operation mode. In the standby power operation mode, the photovoltaic energy storage device preferentially charges the battery module, thereby increasing the SOC (State Of Charge) of the battery module to above the standby power SOC. That is, only when the remaining power of the battery module is above the target standby power, the battery module is discharged to the load for use.

[0094] For example, the standby power mode can be started when the electricity price is at the trough. At this time, the power grid is mainly used to obtain electric energy for the load, and the remaining power of the battery module is kept above the target standby power. In this way, when the power grid is unexpectedly powered off, the battery module has sufficient power to power the load, thereby reducing the impact of power failure.

[0095] Exemplarily, the photovoltaic energy storage device acquires the current battery power of the battery module, and determines whether the current battery power reaches the target standby power, and determines the current working mode of the photovoltaic energy storage device according to the comparison result, which is the charging mode or the non-charging mode. In the charging mode, the battery module is not allowed to discharge, and the remaining power of the battery module needs to be charged to above the target standby power. In the non-charging mode, the battery module can discharge, and the power of the battery module is dynamically adjusted according to the remaining power of the battery module and the load condition.

[0096] Exemplarily, after determining the current working mode, the target working power of the battery module is determined based on the maximum working power of the battery module or the grid-side power of the current photovoltaic energy storage device. It can be understood that the target working power includes the charging power of the battery module in the charging mode and the discharging power of the battery module in the discharging mode.

[0097] Exemplarily, whether the battery module is charging or supplying power to the load can be determined by the positive or negative value of the target working power. For example, assuming that the current direction in the photovoltaic energy storage device is the direction pointing to the AC busbar, the target working power is positive, and the battery module is in the discharging state. When the current direction in the photovoltaic energy storage device is opposite to the direction of the AC busbar, the target working power is negative, and the battery module is in the charging state.

[0098] After determining the current working mode of the photovoltaic energy storage device and the target working power of the battery module in the current working mode, the photovoltaic energy storage device automatically performs the corresponding target operation according to the current working mode and the target working power, wherein the target working power is the grid-side power. Exemplarily, when the target working mode is the charging mode, the photovoltaic energy storage device charges the battery module with the target working power as the charging power. Exemplarily, when the target working mode is the non-charging mode and the target working power is positive, the battery module supplies power to the load with the target working power as the discharging power.

[0099] The technical scheme of the present application divides the working mode of the photovoltaic energy storage device based on the comparison result of the remaining battery power and the target standby power, and dynamically adjusts the charging power or discharging power of the battery module according to different working modes, so that the battery module can maintain sufficient standby power to cope with power failure and other emergencies, and reduce the impact of power failure on user power consumption.

[0100] The third aspect of the present application provides a control device of a photovoltaic energy storage device, the control device comprising: a memory for storing programs or instructions; and a processor for executing the programs or instructions to implement the steps of the control method of the photovoltaic energy storage device according to any one of the preceding aspects, thus also comprising all the beneficial effects of the control method of the photovoltaic energy storage device according to any one of the preceding aspects, which will not be repeated here to avoid repetition.

[0101] The fourth aspect of the present application provides a readable storage medium having programs or instructions stored thereon, the programs or instructions being executed by a processor to implement the steps of the control method of the photovoltaic energy storage device according to any one of the preceding aspects, thus also comprising all the beneficial effects of the control method of the photovoltaic energy storage device according to any one of the preceding aspects, which will not be repeated here to avoid repetition.

[0102] The fifth aspect of the present application provides a photovoltaic energy storage device comprising the control device of the photovoltaic energy storage device according to any one of the preceding aspects and / or the readable storage medium according to any one of the preceding aspects, thus also comprising all the beneficial effects of the control device of the photovoltaic energy storage device according to any one of the preceding aspects and / or the readable storage medium according to any one of the preceding aspects, which will not be repeated here to avoid repetition. BRIEF DESCRIPTION OF DRAWINGS

[0103] The above and / or additional aspects and advantages of the present application will become apparent and be readily appreciated from the following description, including the appended drawings, wherein:

[0104] Figure 1 A flow chart of the control method of the photovoltaic energy storage device of some embodiments of the present application is shown;

[0105] Figure 2 A charge-discharge logic diagram of the photovoltaic energy storage device of some embodiments of the present application is shown;

[0106] Figure 3 A flow chart of the control method of the photovoltaic energy storage device of some embodiments of the present application is shown;

[0107] Figure 4 A structural block diagram of the control device of the photovoltaic energy storage device of some embodiments of the present application is shown;

[0108] Figure 5 A structural block diagram of the control device of the photovoltaic energy storage device of some embodiments of the present application is shown. DETAILED DESCRIPTION

[0109] In order to enable a clearer understanding of the above-mentioned objects, features and advantages of the present application, the present application will be further described in detail below with reference to the drawings and specific embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0110] In the following description, a large number of specific details are set forth in order to facilitate a thorough understanding of the present application, but the present application can also be implemented in other ways different from those described herein, and therefore the scope of protection of the present application is not limited by the specific embodiments disclosed below.

[0111] The following refers to Figures 1 to 5 The control method and device, the storage medium and the photovoltaic energy storage device provided according to some embodiments of the present application are described.

[0112] In some embodiments of the present application, a control method of a photovoltaic energy storage device is provided, the photovoltaic energy storage device is electrically connected with a power grid and a load, the photovoltaic energy storage device includes a battery module, Figure 1 A flowchart of the control method of the photovoltaic energy storage device of some embodiments of the present application is shown as Figure 1 shown, Figure 1 A flowchart of the control method of the photovoltaic energy storage device of some embodiments of the present application is shown as Figure 1 shown, the control method includes:

[0113] Step 102, obtaining the power grid power and the current battery power of the battery module;

[0114] Step 104, determining the current working mode of the photovoltaic energy storage device according to the comparison result of the current battery power and the target standby power;

[0115] Step 106, determining the target working power of the battery module according to the maximum working power of the battery module or the power grid power based on the current working mode;

[0116] Step 108, controlling the photovoltaic energy storage device to perform a target operation according to the target working power based on the current working mode; wherein the target operation includes charging the battery module and supplying power to the load through the battery module.

[0117] In this embodiment, the photovoltaic energy storage device is electrically connected with a power grid and a load, the photovoltaic energy storage device includes a battery module, the battery module can include a plurality of battery cells, and the photovoltaic energy storage device also includes a photovoltaic (PV) power generation module, which utilizes the phenomenon that a semiconductor and a metal combined part generates a voltage when exposed to light to directly convert solar radiant energy into electrical energy, thereby realizing photovoltaic power generation.

[0118] The electric energy generated by the photovoltaic power generation can be directly provided to the load for use, or can be charged to the battery module, so that the electric energy generated by the photovoltaic power generation is stored through the battery module, and in the case that the conditions are suitable, the load is powered by the electric energy stored in the battery module, thereby reducing the amount of electricity taken from the power grid and reducing the electricity cost.

[0119] In some embodiments, the photovoltaic energy storage device can also realize grid connection to the power grid, so as to deliver the excess electric energy generated by the photovoltaic power generation to the power grid, realize power selling to the power grid, and thus generate income, which can also indirectly reduce the electricity cost of the household.

[0120] In order to better utilize the electric energy generated by the photovoltaic power generation, how to reasonably allocate the charging and discharging power of the battery is an important key to the utilization rate of the photovoltaic power generation, and at the same time, keeping the battery in a reasonable and healthy power range is also beneficial to improving the battery life, and at the same time, when the power grid appears temporary power failure and other fluctuation faults, sufficient power is reserved to temporarily power the load, reducing the impact of power failure on electricity.

[0121] Therefore, an embodiment of the present application proposes a control method of a photovoltaic energy storage device, which proposes a standby power operation mode, in which the photovoltaic energy storage device preferentially ensures charging of the battery module, so as to improve the SOC (State Of Charge) of the battery module to above the standby power SOC, that is, only when the remaining power of the battery module is above the target standby power, the battery module is discharged to the load for use.

[0122] Illustratively, the standby power mode can be started when the electricity price is in the trough, at which time the power grid is mainly used to obtain electric energy for the load, and the remaining power of the battery module is kept above the target standby power, so that in the case of unexpected power failure of the power grid, the battery module has sufficient power for the load, which can reduce the impact of power failure.

[0123] Illustratively, the photovoltaic energy storage device obtains the current battery power of the battery module, and judges whether the current battery power reaches the target standby power, and determines whether the current working mode of the photovoltaic energy storage device is the charging mode or the non-charging mode according to the comparison result. In the charging mode, the battery module is not allowed to be discharged, at which time it is necessary to preferentially ensure that the remaining power of the battery module is charged to above the target standby power. In the non-charging mode, the battery module can be discharged, at which time the power of the battery module is dynamically adjusted according to the remaining power of the battery module and the load.

[0124] Exemplarily, after determining the current working mode, the target working power of the battery module is determined based on the maximum working power of the battery module or the grid-side power of the current photovoltaic energy storage device. It can be understood that the target working power includes the charging power of the battery module when charging and the discharging power of the battery module when discharging.

[0125] Exemplarily, whether the battery module is charging or supplying power to the load can be determined by the positive or negative value of the target working power. For example, assuming that the current direction in the photovoltaic energy storage device is the direction pointing to the AC busbar, the target working power is positive, and at this time the battery module is in the discharging state. When the current direction in the photovoltaic energy storage device is the direction away from the AC busbar, the target working power is negative, and at this time the battery module is in the charging state.

[0126] After determining the current working mode of the photovoltaic energy storage device and the target working power of the battery module in the current working mode, the photovoltaic energy storage device automatically performs the corresponding target operation according to the current working mode and the target working power, wherein the target working power is the grid-side power. Exemplarily, when the target working mode is the charging mode, the photovoltaic energy storage device charges the battery module with the target working power as the charging power. Exemplarily, when the target working mode is the non-charging mode and the target working power is positive, the battery module is controlled to supply power to the load with the target working power as the discharging power.

[0127] The embodiment of the present application divides the working mode of the photovoltaic energy storage device based on the comparison result of the battery remaining power and the target standby power, and dynamically adjusts the charging power or discharging power of the battery module according to different working modes, so that the battery module can maintain sufficient standby power to cope with power failure and the like, and reduce the impact of power failure on user power consumption.

[0128] In some embodiments of the present application, optionally, the current working mode of the photovoltaic energy storage device is determined according to the comparison result of the current battery power and the target standby power, including: in the case that the current battery power is less than the target standby power, determining that the current working mode is the charging mode; or in the case that the current battery power is greater than or equal to the target standby power, determining that the current working mode is the non-charging mode.

[0129] In this embodiment, the photovoltaic energy storage device includes a standby power running mode, in which the photovoltaic energy storage device needs to preferentially charge the battery module to ensure that the remaining power of the battery module is not lower than the target standby power.

[0130] When the photovoltaic energy storage device is working, the photovoltaic energy storage device dynamically acquires the current battery power of the battery module, and determines whether the current battery power reaches the target standby power. If the current battery power is less than the target standby power, the photovoltaic energy storage device needs to preferentially use the power generated by the photovoltaic power generation device to charge the battery module, and at this time, the working mode of the photovoltaic energy storage device is a charging mode.

[0131] If the current battery power is greater than or equal to the target standby power, that is, the remaining power of the battery module meets the target standby power, it is determined that the working mode of the photovoltaic energy storage device is a non-charging mode.

[0132] Exemplarily, the user can set the target standby power according to the own demand.

[0133] Exemplarily, assuming that the SOC value is 100 when the battery module is in a full power state, and the SOC value is 0 when the battery module is in an empty power state, the target standby power can be set to any value in 0-100.

[0134] Exemplarily, the target standby power is 80, and when the current battery power of the battery module is less than 80, the working mode of the photovoltaic energy storage device is a charging mode.

[0135] Exemplarily, the target standby power is 100, and before the battery module is fully charged, the working mode of the photovoltaic energy storage device is a charging mode.

[0136] The embodiment of the application can distinguish the working mode of the photovoltaic energy storage device by setting the target standby power, so that the battery module can maintain sufficient power and continuously provide power supply for the user load when the power grid is powered off.

[0137] In some embodiments of the application, optionally, based on the current working mode, the target working power of the battery module is determined according to the maximum working power of the battery module or the grid power, including: in the case that the current working mode is a charging mode, a first working power is determined according to the maximum charging power of the battery module; and the target working power is determined according to the first working power.

[0138] In this embodiment, the current working mode is a charging mode, which indicates that the current battery power of the battery module has not reached the target standby power, at this time, the power generated by the photovoltaic power generation needs to be preferentially used to charge the battery module, and at the same time, the charging efficiency of the battery module is ensured to be maximum, at this time, the maximum charging power of the battery module determines the first working power, and the first working power is used as the target working power.

[0139] Exemplarily, in order to ensure the charging efficiency of the battery module, in the case of backup power, the target working power of the battery module can be set as the maximum charging power of the battery module if possible. However, due to the fact that the power generation of photovoltaic power generation is greatly affected by the external environment, in some scenarios, the photovoltaic power generation power can not reach the maximum charging power of the battery module, at which time it can be further determined whether to allow the battery module to be charged from the grid side.

[0140] Exemplarily, in the case that the user is not allowed to charge the battery module from the grid side and the photovoltaic power generation power is less than the maximum charging power of the battery module, the photovoltaic power generation power is taken as the first working power.

[0141] Exemplarily, in the case that the user is allowed to charge the battery module from the grid side and the photovoltaic power generation power is less than the maximum charging power of the battery module, the difference between the maximum charging power and the photovoltaic power generation power is calculated, and the grid is used to compensate for the difference, at which time the maximum charging power of the battery module is taken as the first working power.

[0142] Exemplarily, in the case that the photovoltaic power generation power is greater than or equal to the maximum charging power of the battery module, the maximum charging power of the battery module is taken as the first working power.

[0143] The embodiments of the present application can ensure that the charging power of the battery module is maintained at the highest possible charging power as much as possible, thereby improving the charging efficiency in the backup power mode.

[0144] In some embodiments of the present application, optionally, based on the current working mode, the target working power of the battery module is determined according to the maximum working power of the battery module or the grid power, comprising: in the case that the current working mode is a non-charging mode, a first working power is determined according to the grid power and the current working power of the battery module; and the target working power is determined according to the first working power.

[0145] In this embodiment, when the current working mode is a non-charging mode, it indicates that the current battery power of the battery module has reached or is greater than the target backup power, at which time it can be determined according to the specific load condition whether the battery module discharges externally.

[0146] Exemplarily, the first working power is calculated by the following formula (1):

[0147] PObjabt1 = Pbat + Pgrid; (1)

[0148] Wherein, PObjabt1 is the first working power, Pbat is the current working power, and Pgrid is the grid power.

[0149] In the non-charging mode, the battery module can discharge to the outside, and the current working power of the battery module is positive if the battery module is in a discharging state, and the current working power of the battery module is negative if the battery module is in a charging state. Similarly, the grid power is negative when the photovoltaic energy storage device is connected to the grid and outputs power to the grid, and the grid power is positive when power is taken from the grid.

[0150] After calculation by formula (1), if the first working power is positive, the battery module is controlled to discharge according to the finally determined target working power, and if the first working power is negative, the battery module is controlled to charge according to the finally determined target working power.

[0151] The embodiment of the application can dynamically adjust the target working power of the battery module for charging or discharging in the non-charging mode according to the grid power and the current working power of the battery module, and can effectively improve the energy utilization rate of photovoltaic power generation.

[0152] In some embodiments of the application, optionally, based on the current working mode, the target working power of the battery module is determined according to the maximum working power of the battery module or the grid power, comprising: in the case that the current working mode is the non-charging mode and the current battery power is greater than or equal to the power threshold, determining the first working power according to the grid power and the current working power of the battery module; wherein the power threshold is greater than the target standby power; determining the target working power according to the first working power.

[0153] In this embodiment, when the current working mode is the non-charging mode, it means that the current battery power of the battery module has reached or is greater than the target standby power, and at this time, if the current battery power satisfies the preset power threshold, it is determined that the battery module satisfies the discharging condition, that is, the battery module can discharge to the outside, and the first working power determined at this time is specifically the target discharging power of the battery module.

[0154] Illustratively, the power threshold is the sum of the target standby power and the standby power difference. Assuming that the SOC value is 100 when the battery module is in a full power state, the SOC value is 0 when the battery module is in an empty power state, and the target standby power is 80, the power threshold is 85.

[0155] Illustratively, the first working power can be calculated by the above formula (1).

[0156] Illustratively, when the discharging condition of the battery module is satisfied, it is judged whether the photovoltaic power generation power can cover the load power. If the photovoltaic power generation power cannot cover the load power, the insufficient power is supplemented by controlling the battery module to discharge, at this time, power is not taken from the grid, and after the current battery power is lower than the above power threshold, the battery module no longer discharges.

[0157] Exemplarily, when the remaining power of the battery module is 100, i.e., the power is full, if the photovoltaic power generation power is greater than the required power of the load, the surplus power of the photovoltaic power generation power after being used by the load can be sold to the power grid.

[0158] The embodiment of the application can dynamically adjust the target working power of the battery module according to the grid power and the current working power of the battery module in the non-charging mode and under the condition of meeting the discharging condition, and can improve the energy utilization rate of the battery photovoltaic power generation.

[0159] In some embodiments of the application, optionally, the target working power is determined according to the first working power, including: in the case that the first working power is less than or equal to the maximum working power of the battery module, the first working power is determined as the target working power; or in the case that the first working power is greater than the maximum working power of the battery module, the maximum working power is determined as the target working power.

[0160] In this embodiment, the maximum working power of the battery module is the power threshold of the battery module in charging and discharging, and when the current working power of the battery module is greater than the maximum working power, the battery may be heated and other problems may be caused, affecting the safety of power consumption.

[0161] Therefore, after the first working power is calculated, the greater one between the first working power and the maximum working power is taken as the target power of the battery.

[0162] For example, when the first working power is the charging power (a negative value) and the absolute value of the first working power is greater than the charging power threshold of the battery module (the absolute value of the maximum working power), the maximum working power of the battery module is set as the target working power, i.e., the battery module is charged by the maximum charging power.

[0163] For example, when the first working power is the discharging power (a positive value) and the absolute value of the first working power is less than the discharging power threshold of the battery module (the absolute value of the maximum working power), the first working power is set as the target working power, i.e., the battery module is controlled to supply power to the load by the first working power.

[0164] The embodiment of the application can select the greater one between the first working power and the maximum working power as the target working power, which can ensure the working safety of the battery module while ensuring the charging and discharging efficiency, and improve the reliability of the photovoltaic energy storage device.

[0165] In some embodiments of the present application, optionally, the current working mode includes a charging mode and a non-charging mode; based on the current working mode, the target operation of the photovoltaic energy storage device according to the target working power includes: in the case that the current working mode is the charging mode and the current battery power is less than the maximum charging power, controlling the photovoltaic energy storage device to charge the battery module according to the target working power; or in the case that the current working mode is the non-charging mode and the current battery power is greater than the power threshold, controlling the photovoltaic energy storage device to supply power to the load according to the target working power.

[0166] In this embodiment, the maximum charging power is the upper limit of the power of the battery module, and exemplarily, the maximum charging power is greater than or equal to the target standby power.

[0167] In the charging mode, the photovoltaic energy storage device preferentially ensures the charging process of the battery module, at this time, if the current battery power does not reach the maximum charging power, that is, the battery module is not full, then the battery module is charged through the determined target working power, until the current battery power of the battery module is greater than or equal to the maximum charging power, the charging stops, at this time, the power generated by the photovoltaic power generation module will be used for the load, or when there is a surplus of power generated by the photovoltaic power generation module after supplying power to the load, the surplus part of the power is connected to the grid for power selling.

[0168] In the non-charging mode, the photovoltaic energy storage device can charge the battery module, or use the power stored in the battery module to supply power to the load. Specifically, when the photovoltaic power generation is greater than the load demand, the surplus power of the photovoltaic power generation preferentially charges the battery. When the photovoltaic power generation is less than the load demand, whether the battery power is used to supply power to the load is selected according to the remaining battery power.

[0169] Therefore, when the photovoltaic energy storage device is in the non-charging mode and the current battery power of the battery module is greater than the power threshold, the battery module supplies power to the load when the power generated by the photovoltaic power generation cannot cover the entire power demand of the load, until the current battery power of the battery module is less than or equal to the power threshold, the battery module stops discharging, and charges the battery module when the condition allows.

[0170] The embodiments of the present application can adaptively adjust the charging and discharging modes of the battery, can avoid energy waste, and at the same time, can reduce the power taken from the grid as much as possible to save electricity bills.

[0171] In some embodiments of the present application, the photovoltaic energy storage device further comprises a storage power conversion module and a photovoltaic inverter module; before determining the target operating power of the battery module according to the maximum operating power of the battery module or the grid power, the control method further comprises: determining the load power of the photovoltaic energy storage device according to the grid power, the inverter power of the storage power conversion module and the inverter power of the photovoltaic inverter module; determining the maximum inverter power of the storage power conversion module according to the load power and the maximum feed-in power; wherein the maximum feed-in power is used to indicate the maximum power value of the photovoltaic energy storage device feeding into the grid; controlling the photovoltaic energy storage device to perform the target operation according to the target operating power, comprising: controlling the photovoltaic energy storage device to perform the target operation according to the target operating power and the maximum inverter power.

[0172] In this embodiment, the photovoltaic energy storage device comprises a storage power conversion module (PCS), which exemplarily comprises a DC / AC bidirectional converter control unit and the like, wherein the control unit receives the background control instruction through the communication unit, controls the charging or discharging of the battery module according to the sign and size of the power instruction, and realizes the adjustment of the active power and the reactive power of the microgrid.

[0173] The photovoltaic inverter module is used to convert the direct current signal generated by photovoltaic power generation into an alternating current signal to supply power to the load or sell electricity to the grid.

[0174] Exemplarily, during the operation of the photovoltaic energy storage device, the storage power converter calculates the total load power according to the grid power, the inverter power of the storage power conversion module and the inverter power of the photovoltaic inverter module. Exemplarily, the load power can be calculated by the following formula (2):

[0175] Pload = Pgrid + Ppcs + Pacpv; (2)

[0176] Wherein, Pload is the load power, Pgrid is the grid power, Ppcs is the inverter power of the storage power conversion module, and Pacpv is the inverter power of the photovoltaic inverter module.

[0177] After obtaining the load power, the maximum inverter power of the storage power conversion module is calculated according to the load power and the maximum feed-in power, which exemplarily can be calculated by the following formula (3):

[0178] Ppcsmax = Pload + Pmaxsell - Pacpv; (3)

[0179] Wherein, Ppcsmax is the maximum inverter power of the energy storage converter module, Pload is the load power, Pacpv is the inverter power of the photovoltaic inverter module, Pmaxsell is the maximum feeding power, the maximum feeding power is the maximum power of the photovoltaic energy storage device feeding the power grid, and Pmaxsell can be a fixed power value set in the program or a power value obtained by communicating with the upper device (such as a distribution box) of the power grid.

[0180] After obtaining the maximum inverter power of the energy storage converter module, the maximum inverter power of the energy storage converter module is used as the power instruction for controlling the operation of the energy storage converter module. By controlling the photovoltaic energy storage device to work through the power instruction, accurate adjustment of active power and reactive power can be realized, and the inverter power can be matched with the output power of the PV as much as possible within the range of the upper limit of the inverter power issued by the distribution box, thereby improving the energy efficiency of the photovoltaic energy storage device.

[0181] In some embodiments of the present application, optionally, after the photovoltaic energy storage device performs the target operation according to the target working power and the maximum inverter power, the control method further comprises: updating the target working power and the maximum inverter power; and in the case that a preset condition is met, controlling the photovoltaic energy storage device to perform the target operation according to the updated target working power and the updated maximum inverter power; wherein the preset condition comprises at least one of the following: a difference between the updated target working power and the previous target working power is greater than a power difference threshold, and a difference between the updated maximum inverter power and the previous maximum inverter power is greater than the power difference threshold.

[0182] In this embodiment, the photovoltaic energy storage device continuously updates the target working power and the maximum inverter power of the energy storage converter module during the working process. When the difference between the updated target working power and the target working power issued last time (the target working power before updating) is greater than the power difference threshold, or when the difference between the updated maximum inverter power and the maximum inverter power issued last time (the maximum inverter power before updating) is greater than the power difference threshold, it indicates that the system load or the photovoltaic power generation condition has changed. At this time, the updated data is issued to the energy storage converter module PCS through the Controller Area Network (CAN) bus, and the load and the like are recalculated according to the updated data, so as to control the energy storage converter module PCS to adjust the power instruction and the charging and discharging power of the battery module.

[0183] When the difference between the updated target working power and the last issued target working power is not greater than the power difference threshold, and the difference between the updated inverter maximum power and the last issued inverter maximum power is not greater than the power difference threshold, it is indicated that the system state has not changed greatly, and the data change at this time may come from the collection error or temporary fluctuation. Therefore, the control control energy storage converter module PCS maintains the previous power regulation instruction and the charge and discharge power of the battery module unchanged, so as to avoid frequent adjustment of the system control parameter and ensure the system stability.

[0184] In some embodiments of the present application, optionally, after the control photovoltaic energy storage device performs the target operation according to the target working power and the inverter maximum power, the control method further comprises: determining the power difference between the current working power of the battery module and the target working power; and sending the power difference to the energy storage converter module when the power difference is greater than the difference threshold.

[0185] In this embodiment, there may be a certain power difference between the current working power of the battery and the target working power. For example, when the battery is charged, it is expected that the current charging power of the battery module matches the maximum charging power, but the photovoltaic power generation power may not reach the maximum charging power, so there will be a certain power difference. For another example, when discharging, it is expected that the discharge power of the battery module matches the load demand power, but since the load power is variable and the battery discharge power may not completely cover the load demand, there may also be a power difference.

[0186] In view of the above situation, the embodiments of the present application determine the power difference between the actual current working power of the battery module and the target working power in real time. If the power difference is greater than the difference threshold, it is indicated that the actual working power of the battery module does not match the set target working power, and the power difference is sent to the energy storage converter module at this time. The energy storage converter module adjusts the power distribution between the power grid, photovoltaic power generation and the battery module according to the power difference.

[0187] For example, the working mode of the photovoltaic energy storage device is the charging mode, and the battery module is set to charge at the target working power. At this time, the difference between the current working power of the battery module and the set target working power is greater than the difference threshold, for example, the current working power is less than the target working power. The power difference is sent to the energy storage converter module, the energy storage converter module judges whether the user allows the battery module to be charged by the power grid, and if the user allows the battery module to be charged by the power grid, the insufficient charging power is compensated by the power grid.

[0188] Exemplarily, when the working mode of the photovoltaic energy storage device is the discharging mode, the battery module is set to discharge to the load at a target working power, and the difference between the current working power of the battery module and the set target working power is greater than a difference threshold value, for example, the current working power is greater than the target working power, the power difference is sent to the energy storage converter module, the energy storage converter module increases the power taken from the power grid, and the discharging power of the battery module is reduced under the condition of meeting the load demand.

[0189] Exemplarily, the difference threshold value is in the range of 50W to 200W.

[0190] Exemplarily, the difference threshold value is 100W.

[0191] Exemplarily, taking the difference threshold value of 100W as an example, when the power difference is less than 100W, the power difference is considered as 0.

[0192] The power difference between the actual power of the battery and the target power is updated, so that the power of each part in the photovoltaic energy storage device is reasonably distributed, and the energy utilization efficiency of the photovoltaic energy storage device is improved.

[0193] In some embodiments of the present application, Figure 2 The charging and discharging logic diagram of the photovoltaic energy storage device of some embodiments of the present application is shown as follows: Figure 2 As shown in the figure, in the standby power mode, when the current SOC of the battery module is less than the standby power SOC, the battery module cannot be discharged. When the current SOC of the battery module is greater than the standby power SOC, the excess power is discharged according to Figure 2 The logic is shown in the figure.

[0194] Figure 3 The flow chart of the control method of the photovoltaic energy storage device of some embodiments of the present application is shown as follows: Figure 3 As shown in the figure, the control method comprises:

[0195] Step 302, calculating the load power;

[0196] Step 304, calculating the maximum inverter power;

[0197] Step 306, judging whether the current battery SOC is less than the standby power SOC; if yes, go to step 308, otherwise go to step 310;

[0198] Step 308, the first working power is the maximum charging power of the battery;

[0199] Step 310, the first working power is the sum of the current working power and the grid power;

[0200] Step 312, the first target working power is the larger one of the first working power and the maximum working power;

[0201] Step 314, determine whether it can be discharged; yes, go to step 316, otherwise go to step 318;

[0202] Step 316, the second target working power takes the smaller value of the first target working power and the maximum discharge power;

[0203] Step 318, the second target working power takes the smaller value of the first target working power and 0;

[0204] Step 320, calculate the power difference between the current working power and the target working power;

[0205] Step 322, determine whether the power difference is greater than the difference threshold; yes, go to step 326, otherwise go to step 324;

[0206] Step 324, set the power difference to 0;

[0207] Step 326, send the power difference and the maximum inverter power to the PCS.

[0208] Wherein, step one: according to the law of conservation of energy, calculate the total load power Pload = grid power (Pgrid, collected) + PCS inverter power (Ppcs, PCS reported) + AC inverter power (Pacpv, collected).

[0209] Step two: calculate the upper limit of PCS inverter power (Ppcsmax) = load (Pload) + electricity selling quota Pmaxsell, APP configuration) - AC inverter power (Pacpv, collected).

[0210] Step three: determine whether the current SOC of the battery is less than the standby power SOC, if yes, go to step five, otherwise go to step four.

[0211] Step four: battery target power = battery current power + grid power, go to step six.

[0212] Step five: still in the standby power not full stage, battery target power = battery charging upper limit.

[0213] Step six: make lower limit judgment on the battery target power, take the larger value of the battery target power and the battery charging power upper limit (charging power is negative) as the battery target power.

[0214] Step seven: determine whether the battery can be discharged, the logic is as follows:

[0215] If the standby power SOC is 100: the battery discharge flag bit is always 0 (not dischargeable).

[0216] If the standby power SOC is not 100:

[0217] 1) Current battery SOC ≤ standby battery SOC, battery discharge flag is 0 (not dischargeable)

[0218] 2) Current battery SOC ≥

standby battery SOC + standby battery difference value (default 5), 100

[0219] Step eight: limit the battery target power.

[0220] Battery not allowed to discharge: the smaller of the battery target power and 0 is the final target power;

[0221] Battery allowed to discharge: the smaller of the battery target power and the battery discharge upper limit is the final target power of the battery.

[0222] Step nine: calculate the battery power difference = battery target power - battery power, if the difference is not more than 100w, then the battery power difference is 0.

[0223] Step ten: command sequence number + 1, and send the PCS inverter power upper limit and battery power difference to the PCS through high-speed CAN, sleep for 100ms, and go to step one.

[0224] In some embodiments of the present application, a control device of a photovoltaic energy storage device is provided, the photovoltaic energy storage device is electrically connected with a power grid and a load, the photovoltaic energy storage device includes a battery module, Figure 4 The structure block diagram of the control device of the photovoltaic energy storage device of some embodiments of the present application is shown as Figure 4 As shown in the figure, the control device 400 includes:

[0225] The acquisition module 402 is configured to acquire the power grid power and the current battery capacity of the battery module; the determination module 404 is configured to determine the current working mode of the photovoltaic energy storage device according to the comparison result of the current battery capacity and the target standby battery capacity, and determine the target working power of the battery module according to the maximum working power of the battery module or the power grid power based on the current working mode; and the control module 406 is configured to control the photovoltaic energy storage device to perform a target operation according to the target working power based on the current working mode; wherein the target operation includes charging the battery module and supplying power to the load through the battery module.

[0226] In this embodiment, the photovoltaic energy storage device is electrically connected with a power grid and a load, the photovoltaic energy storage device includes a battery module, the battery module can include a plurality of battery cells, and the photovoltaic energy storage device also includes a photovoltaic (PV) power generation module, which utilizes the phenomenon that a semiconductor and a metal combined part generates a voltage to directly convert solar radiant energy into electrical energy, realizing photovoltaic power generation.

[0227] The electricity generated by photovoltaic power generation can be directly supplied to the load or used to charge the battery module. The electricity generated by photovoltaic power generation can be stored in the battery module. Under suitable conditions, the electricity stored in the battery module can be used to supply power to the load, thereby reducing the amount of electricity drawn from the grid and reducing electricity costs.

[0228] In some implementations, photovoltaic energy storage devices can also be connected to the grid, thereby transmitting surplus electricity generated by photovoltaic power generation to the grid and selling electricity to the grid to generate revenue, which can also indirectly reduce household electricity costs.

[0229] To better utilize the electricity generated by photovoltaic power generation, the rational allocation of battery charging and discharging power is a crucial factor affecting the utilization rate of photovoltaic power generation. At the same time, maintaining the battery within a reasonable and healthy power range is beneficial to improving battery life. Furthermore, reserving sufficient power to temporarily supply power to the load during power grid outages or other fluctuations can reduce the impact of power outages on electricity consumption.

[0230] Therefore, this application proposes a control method for a photovoltaic energy storage device. The method proposes a backup power operation mode. In the backup power operation mode, the photovoltaic energy storage device will prioritize charging the battery module, thereby increasing the SOC (State of Charge) of the battery module to above the backup power SOC. That is, the battery module will only discharge to the load when the remaining power of the battery module is above the target backup power.

[0231] For example, the above-mentioned backup power mode can be activated when the electricity price is at a low point. At this time, the power is mainly obtained from the grid to supply the load, and the remaining power of the battery module is kept above the target backup power. In this way, in the event of an unexpected power outage, the battery module will have sufficient power to supply the load, which can reduce the impact of the power outage.

[0232] For example, the photovoltaic energy storage device acquires the current battery level of the battery module, determines whether the current battery level has reached the target backup power level, and determines whether the photovoltaic energy storage device is currently operating in charging mode or non-charging mode based on the comparison result. In charging mode, the battery module is not allowed to discharge; priority must be given to charging the remaining battery level to above the target backup power level. In non-charging mode, the battery module can discharge, and its power is dynamically adjusted based on the remaining battery level and load conditions.

[0233] Exemplarily, after determining the current working mode, the target working power of the battery module is determined based on the maximum working power of the battery module or the grid-side power of the current photovoltaic energy storage device. It can be understood that the target working power includes the charging power of the battery module when charging and the discharging power of the battery module when discharging.

[0234] Exemplarily, whether the battery module is charging or supplying power to the load can be determined by the positive or negative value of the target working power. For example, assuming that the current direction in the photovoltaic energy storage device is the direction pointing to the AC busbar, the target working power is positive, and at this time, the battery module is in the discharging state. When the current direction in the photovoltaic energy storage device is the direction away from the AC busbar, the target working power is negative, and at this time, the battery module is in the charging state.

[0235] After determining the current working mode of the photovoltaic energy storage device and the target working power of the battery module in the current working mode, the photovoltaic energy storage device automatically performs the corresponding target operation according to the current working mode and the target working power, wherein the target working power is the grid-side power. Exemplarily, when the target working mode is the charging mode, the photovoltaic energy storage device charges the battery module with the target working power as the charging power. Exemplarily, when the target working mode is the non-charging mode and the target working power is positive, the battery module is controlled to supply power to the load with the target working power as the discharging power.

[0236] The embodiment of the present application divides the working mode of the photovoltaic energy storage device based on the comparison result of the battery remaining power and the target standby power, and dynamically adjusts the charging power or discharging power of the battery module according to different working modes, so that the battery module can maintain sufficient standby power to cope with power failure and the like, and reduce the influence of power grid failure on user power consumption.

[0237] In some embodiments of the present application, optionally, the determining module is further configured to determine that the current working mode is the charging mode when the current battery power is less than the target standby power; or determine that the current working mode is the non-charging mode when the current battery power is greater than or equal to the target standby power.

[0238] In this embodiment, the photovoltaic energy storage device includes a standby power running mode, in which the photovoltaic energy storage device needs to preferentially charge the battery module to ensure that the remaining power of the battery module is not less than the target standby power.

[0239] When the photovoltaic energy storage device is working, the photovoltaic energy storage device dynamically acquires the current battery power of the battery module, and determines whether the current battery power reaches the target standby power. If the current battery power is less than the target standby power, the photovoltaic energy storage device needs to preferentially use the power generated by the photovoltaic power generation device to charge the battery module, and at this time, the working mode of the photovoltaic energy storage device is a charging mode.

[0240] If the current battery power is greater than or equal to the target standby power, that is, the remaining power of the battery module meets the target standby power, it is determined that the working mode of the photovoltaic energy storage device is a non-charging mode.

[0241] Exemplarily, the user can set the target standby power according to the own demand.

[0242] Exemplarily, assuming that the SOC value is 100 when the battery module is in a full power state, and the SOC value is 0 when the battery module is in an empty power state, the target standby power can be set to any value in 0-100.

[0243] Exemplarily, the target standby power is 80, and when the current battery power of the battery module is less than 80, the working mode of the photovoltaic energy storage device is a charging mode.

[0244] Exemplarily, the target standby power is 100, and before the battery module is fully charged, the working mode of the photovoltaic energy storage device is a charging mode.

[0245] The embodiment of the application can distinguish the working mode of the photovoltaic energy storage device by setting the target standby power, so that the battery module can maintain sufficient power and continuously provide power supply for the user load when the power grid is powered off.

[0246] In some embodiments of the application, optionally, the determining module is further configured to, when the current working mode is the charging mode, determine a first working power according to the maximum charging power of the battery module; and determine the target working power according to the first working power.

[0247] In this embodiment, when the current working mode is the charging mode, it indicates that the current battery power of the battery module has not reached the target standby power, and at this time, the power generated by the photovoltaic power generation needs to be preferentially used to charge the battery module, while ensuring that the charging efficiency of the battery module is maximum, and at this time, the maximum charging power of the battery module determines the first working power, and the first working power is used as the target working power.

[0248] Exemplarily, in order to ensure the charging efficiency of the battery module, in the case of power backup, the target working power of the battery module can be set as the maximum charging power of the battery module if possible. However, due to the fact that the power generation of photovoltaic power generation is greatly affected by the external environment, in some scenarios, the photovoltaic power generation power can not reach the maximum charging power of the battery module, at which time it can be further determined whether to allow the battery module to be charged from the grid side.

[0249] Exemplarily, in the case that the user is not allowed to charge the battery module from the grid side and the photovoltaic power generation power is less than the maximum charging power of the battery module, the photovoltaic power generation power is taken as the first working power.

[0250] Exemplarily, in the case that the user is allowed to charge the battery module from the grid side and the photovoltaic power generation power is less than the maximum charging power of the battery module, the difference between the maximum charging power and the photovoltaic power generation power is calculated, and the grid is used to compensate for the difference, and the maximum charging power of the battery module is taken as the first working power.

[0251] Exemplarily, in the case that the photovoltaic power generation power is greater than or equal to the maximum charging power of the battery module, the maximum charging power of the battery module is taken as the first working power.

[0252] The embodiment of the present application can ensure that the charging power of the battery module is maintained at the highest possible charging power as much as possible, thereby improving the charging efficiency in the power backup mode.

[0253] In some embodiments of the present application, the determination module is further configured to, in the case that the current working mode is a non-charging mode, determine the first working power according to the grid power and the current working power of the battery module, and determine the target working power according to the first working power.

[0254] In this embodiment, when the current working mode is a non-charging mode, it indicates that the current battery power of the battery module has reached or is greater than the target backup power, at which time it can be determined according to the specific load whether the battery module discharges externally.

[0255] Exemplarily, the first working power is calculated by the following formula (1):

[0256] PObjabt1 = Pbat + Pgrid; (1)

[0257] Wherein, PObjabt1 is the first working power, Pbat is the current working power, and Pgrid is the grid power.

[0258] In the non-charging mode, the battery module can discharge to the outside, and the current working power of the battery module is positive if the battery module is in a discharging state, and the current working power of the battery module is negative if the battery module is in a charging state. Similarly, the grid power is negative when the photovoltaic energy storage device is connected to the grid and outputs power to the grid, and the grid power is positive when power is taken from the grid.

[0259] After calculation by formula (1), if the first working power is positive, the battery module is controlled to discharge according to the finally determined target working power, and if the first working power is negative, the battery module is controlled to charge according to the finally determined target working power.

[0260] The embodiment of the application can dynamically adjust the target working power of the battery module to charge or discharge in the non-charging mode according to the grid power and the current working power of the battery module, and can effectively improve the energy utilization rate of photovoltaic power generation.

[0261] In some embodiments of the application, optionally, the determining module is further configured to, in a case where the current working mode is the non-charging mode and the current battery power is greater than or equal to the power threshold, determine the first working power according to the grid power and the current working power of the battery module; wherein the power threshold is greater than the target standby power; and determine the target working power according to the first working power.

[0262] In this embodiment, when the current working mode is the non-charging mode, it indicates that the current battery power of the battery module has reached or is greater than the target standby power, and at this time, if the current battery power satisfies the preset power threshold, it is determined that the battery module satisfies the discharging condition, that is, the battery module can discharge to the outside, and the first working power determined at this time is specifically the target discharging power of the battery module.

[0263] For example, the power threshold is the sum of the target standby power and the standby power difference. Assuming that the SOC value is 100 when the battery module is in a full power state, the SOC value is 0 when the battery module is in an empty power state, and the target standby power is 80, the power threshold is 85.

[0264] For example, the first working power can be calculated by the above formula (1).

[0265] For example, when the discharging condition of the battery module is satisfied, it is determined whether the photovoltaic power generation power can cover the load power. If the photovoltaic power generation power cannot cover the load power, the insufficient power is supplemented by controlling the battery module to discharge, at this time, power is not taken from the grid, and after the current battery power is lower than the above power threshold, the battery module no longer discharges.

[0266] Exemplarily, when the remaining power of the battery module is 100, i.e., the power is full, if the photovoltaic power generation power is greater than the required power of the load, the surplus power of the photovoltaic power generation after being used by the load can be sold to the power grid.

[0267] The embodiment of the application can dynamically adjust the target working power of the battery module according to the grid power and the current working power of the battery module in the non-charging mode and under the condition of meeting the discharging condition, and can improve the energy utilization rate of the battery photovoltaic power generation.

[0268] In some embodiments of the application, optionally, the determining module is further configured to determine the first working power as the target working power when the first working power is less than or equal to the maximum working power of the battery module, or determine the maximum working power as the target working power when the first working power is greater than the maximum working power of the battery module.

[0269] In this embodiment, the maximum working power of the battery module is the power threshold of the battery module in charging and discharging, and when the current working power of the battery module is greater than the maximum working power, the battery may be heated and other problems may occur, affecting the safety of power consumption.

[0270] Therefore, after the first working power is calculated, the greater one between the first working power and the maximum working power is taken as the target power of the battery.

[0271] For example, when the first working power is the charging power (a negative value) and the absolute value of the first working power is greater than the charging power threshold of the battery module (the absolute value of the maximum working power), the maximum working power of the battery module is set as the target working power, i.e., the battery module is charged by the maximum charging power.

[0272] For example, when the first working power is the discharging power (a positive value) and the absolute value of the first working power is less than the discharging power threshold of the battery module (the absolute value of the maximum working power), the first working power is set as the target working power, i.e., the battery module is controlled to supply power to the load by the first working power.

[0273] The embodiment of the application can select the greater one between the first working power and the maximum working power as the target working power, which can ensure the working safety of the battery module while ensuring the charging and discharging efficiency, and improve the reliability of the photovoltaic energy storage device.

[0274] In some embodiments of the present application, optionally, the current working mode includes a charging mode and a non-charging mode; the control module is further configured to, in a case where the current working mode is the charging mode and the current battery power is less than the maximum charging power, control the photovoltaic energy storage device to charge the battery module according to the target working power; or in a case where the current working mode is the non-charging mode and the current battery power is greater than the power threshold, control the photovoltaic energy storage device to supply power to the load according to the target working power.

[0275] In this embodiment, the maximum charging power is the upper limit of the power of the battery module, and exemplarily, the maximum charging power is greater than or equal to the target standby power.

[0276] In the charging mode, the photovoltaic energy storage device gives priority to ensuring the charging process of the battery module, and at this time, if the current battery power does not reach the maximum charging power, that is, the battery module is not full, then the battery module is charged by the determined target working power until the current battery power of the battery module is greater than or equal to the maximum charging power, and the charging stops at this time, at which time the power generated by the photovoltaic power generation module is entirely used for the load, or when there is a surplus of the power generated by the photovoltaic power generation module after supplying power to the load, the surplus part of the power is grid-connected for power selling.

[0277] In the non-charging mode, the photovoltaic energy storage device can charge the battery module, or use the power stored in the battery module to supply power to the load. Specifically, when the photovoltaic power generation power is greater than the load demand, the surplus power of the photovoltaic power generation is preferentially charged to the battery. When the photovoltaic power generation power is less than the load demand, whether the battery power is used to supply power to the load is selected according to the remaining battery power.

[0278] Therefore, when the photovoltaic energy storage device is in the non-charging mode and the current battery power of the battery module is greater than the power threshold, the battery module is used to supply power to the load when the power generated by the photovoltaic power generation cannot cover the entire power demand of the load, until the current battery power of the battery module is less than or equal to the power threshold, the battery module stops discharging, and the battery module is charged when the condition allows.

[0279] The embodiments of the present application can adaptively adjust the charging and discharging modes of the battery, can avoid energy waste, and at the same time, can reduce the power taken from the power grid as much as possible to save electricity bills.

[0280] In some embodiments of the present application, the photovoltaic energy storage device further comprises a power storage conversion module and a photovoltaic inversion module; the determining module is further configured to determine a load power of the photovoltaic energy storage device according to the grid power, the inversion power of the power storage conversion module, and the inversion power of the photovoltaic inversion module; determine an inversion power maximum value of the power storage conversion module according to the load power and a feed-in power maximum value; wherein the feed-in power maximum value is used to indicate a maximum power value of the photovoltaic energy storage device feeding into the grid; and the control module is further configured to control the photovoltaic energy storage device to perform a target operation according to the target operating power and the inversion power maximum value.

[0281] In this embodiment, the photovoltaic energy storage device comprises a power storage conversion module (PCS), which exemplarily comprises a DC / AC bidirectional converter control unit and the like, wherein the control unit receives a background control instruction through a communication unit, controls the charging or discharging of the battery module according to the sign and size of the power instruction, and realizes the adjustment of the active power and the reactive power of the microgrid.

[0282] The photovoltaic inversion module is used to convert the direct current signal generated by photovoltaic power generation into an alternating current signal to supply power to the load or sell electricity to the grid.

[0283] Exemplarily, during the operation of the photovoltaic energy storage device, the power storage converter calculates the total load power according to the grid power, the inversion power of the power storage conversion module, and the inversion power of the photovoltaic inversion module. Exemplarily, the load power can be calculated by the following formula (2):

[0284] Pload = Pgrid + Ppcs + Pacpv; (2)

[0285] Wherein, Pload is the load power, Pgrid is the grid power, Ppcs is the inversion power of the power storage conversion module, and Pacpv is the inversion power of the photovoltaic inversion module.

[0286] After obtaining the load power, the inversion power maximum value of the power storage conversion module is calculated according to the load power and the feed-in power maximum value. Exemplarily, the inversion power maximum value of the power storage conversion module can be calculated by the following formula (3):

[0287] Ppcsmax = Pload + Pmaxsell - Pacpv; (3)

[0288] Wherein, Ppcsmax is the maximum inverter power of the energy storage converter module, Pload is the load power, Pacpv is the inverter power of the photovoltaic inverter module, Pmaxsell is the maximum feeding power, the maximum feeding power is the maximum power of the photovoltaic energy storage device feeding to the power grid, and Pmaxsell can be a fixed power value set in the program or a power value obtained by communicating with the upper device (such as a distribution box) of the power grid.

[0289] After obtaining the maximum inverter power of the energy storage converter module, the maximum inverter power of the energy storage converter module is used as a power instruction for controlling the operation of the energy storage converter module. By controlling the photovoltaic energy storage device to operate through the power instruction, accurate adjustment of active power and reactive power can be realized, and the inverter power of the PCS can be kept as much as possible to match the output power of the PV within the upper limit of the inverter power issued by the distribution box, thereby improving the energy efficiency of the photovoltaic energy storage device.

[0290] In some embodiments of the present application, the control device further comprises an updating module for updating the target operating power and the maximum inverter power; and the control module is further configured to control the photovoltaic energy storage device to perform a target operation according to the updated target operating power and the updated maximum inverter power when a preset condition is met; wherein the preset condition includes at least one of the following: the difference between the updated target operating power and the target operating power before the update is greater than a power difference threshold, and the difference between the updated maximum inverter power and the maximum inverter power before the update is greater than the power difference threshold.

[0291] In this embodiment, the photovoltaic energy storage device continuously updates the target operating power and the maximum inverter power of the energy storage converter module during operation. When the difference between the updated target operating power and the target operating power issued last time (the target operating power before the update) is greater than the power difference threshold, or when the difference between the updated maximum inverter power and the maximum inverter power issued last time (the maximum inverter power before the update) is greater than the power difference threshold, it indicates that the system load or the photovoltaic power generation condition has changed. At this time, the updated data is issued to the energy storage converter module PCS through the Controller Area Network (CAN), and the load and the like are recalculated according to the updated data, so as to control the energy storage converter module PCS to adjust the power instruction and the charging and discharging power of the battery module.

[0292] When the difference between the updated target working power and the last issued target working power is not greater than the power difference threshold, and the difference between the updated inverter power maximum value and the last issued inverter power maximum value is not greater than the power difference threshold, it is indicated that the system state has not changed greatly, and the data change at this time may come from the collection error or temporary fluctuation. Therefore, the control control energy storage converter module PCS maintains the previous power regulation instruction and the charge and discharge power of the battery module unchanged, so as to avoid frequent adjustment of the system control parameter and ensure the system stability.

[0293] In some embodiments of the present application, the determining module is further configured to determine a power difference between the current working power and the target working power of the battery module, and the control module is further configured to send the power difference to the energy storage converter module when the power difference is greater than the difference threshold.

[0294] In this embodiment, there may be a certain power difference between the current working power and the target working power of the battery. For example, when the battery is charged, it is expected that the current charging power of the battery module matches the maximum charging power. However, the photovoltaic power generation power may not reach the maximum charging power, and thus there is a certain power difference. For another example, when the battery is discharged, it is expected that the discharge power of the battery module matches the load demand power. However, the load power is variable, and the battery discharge power may not completely cover the load demand, and thus there may be a power difference.

[0295] In view of the above situation, the power difference between the actual current working power of the battery module and the target working power is determined in real time. If the power difference is greater than the difference threshold, it is indicated that the actual working power of the battery module does not match the set target working power. At this time, the power difference is sent to the energy storage converter module, and the energy storage converter module adjusts the power distribution among the power grid, photovoltaic power generation and the battery module according to the power difference.

[0296] For example, the working mode of the photovoltaic energy storage device is the charging mode, and the battery module is set to charge at the target working power. At this time, the difference between the current working power of the battery module and the set target working power is greater than the difference threshold. For example, the current working power is less than the target working power. The power difference is sent to the energy storage converter module. The energy storage converter module determines whether the user allows the battery module to be charged by the power grid. If the user allows the battery module to be charged by the power grid, the insufficient charging power is compensated by the power grid.

[0297] Exemplarily, when the working mode of the photovoltaic energy storage device is the discharging mode, the battery module is set to discharge to the load at a target working power, and a difference between the current working power of the battery module and the target working power is greater than a difference threshold value, for example, the current working power is greater than the target working power, the power difference is sent to the energy storage converter module, the energy storage converter module increases the power taken from the power grid, and the discharging power of the battery module is reduced under the condition of meeting the load demand.

[0298] Exemplarily, the difference threshold value is in a range of 50W to 200W.

[0299] Exemplarily, the difference threshold value is 100W.

[0300] Exemplarily, taking the difference threshold value of 100W as an example, when the power difference is less than 100W, the power difference is regarded as 0.

[0301] The power difference between the actual power and the target power of the battery is updated, so that the power of each part of the photovoltaic energy storage device is reasonably distributed, and the energy utilization efficiency of the photovoltaic energy storage device is improved.

[0302] In some embodiments of the present application, a control device of a photovoltaic energy storage device is provided, Figure 5 A structural block diagram of the control device of the photovoltaic energy storage device of some embodiments of the present application is shown as Figure 5 As shown, the control device 500 includes a memory 502 for storing programs or instructions, and a processor 504 for executing the programs or instructions to implement the steps of the control method of the photovoltaic energy storage device provided in any of the above embodiments, and therefore also includes all the beneficial effects of the control method of the photovoltaic energy storage device provided in any of the above embodiments, and to avoid repetition, details are not described herein.

[0303] In some embodiments of the present application, a readable storage medium is provided, and the readable storage medium stores programs or instructions, and the programs or instructions are executed by a processor to implement the steps of the control method of the photovoltaic energy storage device provided in any of the above embodiments, and therefore also includes all the beneficial effects of the control method of the photovoltaic energy storage device provided in any of the above embodiments, and to avoid repetition, details are not described herein.

[0304] In some embodiments of the present application, a photovoltaic energy storage device is provided, which includes the control device of the photovoltaic energy storage device provided in any of the above embodiments and / or the readable storage medium provided in any of the above embodiments, and therefore also includes the control device of the photovoltaic energy storage device provided in any of the above embodiments and / or all the beneficial effects of the control device of the photovoltaic energy storage device provided in any of the above embodiments, and to avoid repetition, details are not described herein.

[0305] The methods can be implemented in various ways, and with various features and / or applications in view of the particular implementation. For example, these methods can be implemented by hardware, firmware, and / or software. For example, in a hardware implementation, the processors can be implemented within one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), controllers, micro-controllers, microprocessors, electronic devices, other devices for executing the above-described functions, and / or any combination thereof.

[0306] The computer readable storage medium can be a tangible device that can retain and store instructions for use by an instruction execution device. The computer readable storage medium can be, for example, but is not limited to, an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. A non-exhaustive list of more specific examples of the computer readable storage medium includes the following: a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), a static random access memory (SRAM), a portable compact disc read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanically encoded device such as punch-cards or raised structures in a groove having instructions recorded thereon, and any suitable combination of the foregoing. A computer readable storage medium, as used herein, is not to be construed as being transitory signals per se, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through a waveguide or other transmission media, or electrical signals transmitted through a wire cable or optical cable, and the like.

[0307] In the description of the present application, the term "a plurality of" means two or more, unless otherwise explicitly defined, and the terms "upper", "lower", and the like indicate the orientation or positional relationship based on the drawings, and are merely used to facilitate the description of the present application and simplify the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application; the terms "connection", "mounting", "fixing" and the like should be understood broadly, for example, "connection" can be fixed connection, can also be detachable connection, or integral connection; can be direct connection, or indirect connection through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0308] In the description of the application, the terms "one embodiment", "some embodiments", "certain embodiments", etc. mean that the particular feature, structure, material or characteristic being described is included in at least one embodiment or example of the application. The illustrative appearances of the above-mentioned terms in various places in the specification are not necessarily intended to refer to the same embodiment or example, unless otherwise indicated. Furthermore, the description is not intended to limit the application to the particular forms and examples disclosed. Rather, any modifications and variations of the application that are apparent to those skilled in the art are intended to be covered by the descriptions and claims.

[0309] The above description is merely illustrative of the application, and is not intended to limit the application. The application can be modified and varied greatly without departing from the spirit or scope of the application, as set forth in the following claims.

Claims

1. A control method of a photovoltaic energy storage device, characterized in that, The photovoltaic energy storage device is electrically connected with a power grid and a load, and the control method comprises: obtaining a grid power and a current battery capacity of the battery module; determining a current working mode of the photovoltaic energy storage device according to a comparison result of the current battery capacity and a target standby power; determining a target working power of the battery module according to a maximum working power of the battery module or the grid power based on the current working mode; controlling the photovoltaic energy storage device to perform a target operation according to the target working power based on the current working mode; wherein the target operation comprises charging the battery module or supplying power to the load through the battery module.

2. The control method according to claim 1, characterized by, The determination of the current working mode of the photovoltaic energy storage device according to the comparison result of the current battery capacity and the target standby power comprises: determining the current working mode as a charging mode when the current battery capacity is less than the target standby power; or determining the current working mode as a non-charging mode when the current battery capacity is greater than or equal to the target standby power.

3. The control method according to claim 2, characterized by, The determination of the target working power of the battery module according to the maximum working power of the battery module or the grid power based on the current working mode comprises: determining a first working power according to a maximum charging power of the battery module when the current working mode is the charging mode; determining the target working power according to the first working power.

4. The control method according to claim 2, characterized by, The determination of the target working power of the battery module according to the maximum working power of the battery module or the grid power based on the current working mode comprises: determining a first working power according to the grid power and a current working power of the battery module when the current working mode is the non-charging mode; determining the target working power according to the first working power.

5. The control method according to claim 2, characterized by, The determination of the target working power of the battery module according to the maximum working power of the battery module or the grid power based on the current working mode comprises: determining a first working power according to the grid power and a current working power of the battery module when the current working mode is the non-charging mode and the current battery capacity is greater than or equal to a capacity threshold; wherein the capacity threshold is greater than the target standby power; determining the target working power according to the first working power.

6. The control method according to any one of claims 3 to 5, characterized by, The determination of the target working power according to the first working power comprises: determining the first working power as the target working power when the first working power is less than or equal to a maximum working power of the battery module; or determining the maximum working power of the battery module as the target working power when the first working power is greater than the maximum working power of the battery module.

7. The control method according to any one of claims 1 to 5, characterized by, The current working mode comprises a charging mode and a non-charging mode; and the control of the photovoltaic energy storage device to perform a target operation according to the target working power based on the current working mode comprises: In a case where the current working mode is the charging mode and the current battery power is less than the maximum charging power, the photovoltaic energy storage device is controlled to charge the battery module according to the target working power; or In a case where the current working mode is the non-charging mode and the current battery power is greater than the power threshold, the photovoltaic energy storage device is controlled to supply power to the load according to the target working power.

8. The control method according to any one of claims 1 to 5, characterized by, The photovoltaic energy storage device further comprises an energy storage converter module and a photovoltaic inverter module. Before the target working power of the battery module is determined according to the maximum working power of the battery module or the grid power, the control method further comprises: determining a load power of the photovoltaic energy storage device according to the grid power, an inverter power of the energy storage converter module and an inverter power of the photovoltaic inverter module; determining an inverter power maximum value of the energy storage converter module according to the load power and a maximum feeding power value; wherein the maximum feeding power value indicates a maximum power value of power fed to the grid by the photovoltaic energy storage device; the control of the photovoltaic energy storage device to perform the target operation according to the target working power and the inverter power maximum value. the control of the photovoltaic energy storage device to perform the target operation according to the target working power and the inverter power maximum value.

9. The control method according to claim 8, characterized by, After the control of the photovoltaic energy storage device to perform the target operation according to the target working power and the inverter power maximum value, the control method further comprises: updating the target working power and the inverter power maximum value; in a case where a preset condition is met, controlling the photovoltaic energy storage device to perform the target operation according to the updated target working power and the updated inverter power maximum value; wherein the preset condition comprises at least one of the following: a difference between the updated target working power and the previous target working power is greater than a power difference threshold, and a difference between the updated inverter power maximum value and the previous inverter power maximum value is greater than the power difference threshold.

10. The control method according to claim 8, characterized by, After the control of the photovoltaic energy storage device to perform the target operation according to the target working power and the inverter power maximum value, the control method further comprises: determining a power difference between the current working power of the battery module and the target working power; and in a case where the power difference is greater than a difference threshold, sending the power difference to the energy storage converter module.

11. A control device for a photovoltaic energy storage apparatus, characterized by The photovoltaic energy storage device is electrically connected with a grid and a load, and comprises a battery module, and the control device comprises: an acquisition module configured to acquire a grid power and a current battery power of the battery module; a determination module configured to determine a current working mode of the photovoltaic energy storage device according to a comparison result of the current battery power and a target standby power; and determine a target working power of the battery module according to the maximum working power of the battery module or the grid power based on the current working mode; a control module configured to control the photovoltaic energy storage device to perform a target operation according to the target working power based on the current working mode; wherein the target operation comprises charging the battery module or supplying power to the load through the battery module.

12. A control device for a photovoltaic energy storage apparatus, characterized by The control device comprises: a memory for storing a program or instructions; a processor for executing the program or instructions to implement the steps of the control method of the photovoltaic energy storage device according to any one of claims 1 to 10.

13. A readable storage medium, on which a program or instructions are stored, characterized in that, The program or instructions, when executed by the processor, implement the steps of the control method of the photovoltaic energy storage device according to any one of claims 1 to 10.

14. A photovoltaic energy storage device, characterized by, comprise: a control device of a photovoltaic energy storage device according to claim 11 or 12; and / or a readable storage medium according to claim 13.

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