Control method of photovoltaic energy storage system and photovoltaic energy storage system

Abstract

The invention discloses a control method of a photovoltaic energy storage system and the photovoltaic energy storage system. The method comprises the following steps: acquiring the generating capacity and power consumption of the photovoltaic energy storage system; when the generating capacity is greater than or equal to the power consumption, controlling the photovoltaic energy storage system to supply power or charge on the grid according to the relationship between the on-grid electricity price and the trough electricity price; and when the generating capacity is less than the power consumption, controlling the photovoltaic energy storage system to discharge, or controlling the photovoltaic energy storage system to charge according to the SOC value of the energy storage module or the predicted generating capacity of the photovoltaic energy storage system based on the relationship between the grid-connected electricity price and the trough electricity price. According to the technical scheme provided by the embodiment of the invention, on the basis of the generating capacity and the power consumption of the photovoltaic energy storage system, the utilization rate and the flexibility of photovoltaic energy are effectively improved by combining the SOC value and the predicted generating capacity of the energy storage module through the relationship between the on-grid electricity price and the trough electricity price, and the yield of photovoltaic storage and charging is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic power generation and energy storage, and in particular to a control method for a photovoltaic energy storage system and a photovoltaic energy storage system. Background Art

[0002] With the rapid development of new energy technologies, photovoltaic power generation accounts for an increasingly prominent proportion in the power system. At present, the traditional photovoltaic energy storage charging and discharging control method has not achieved refined management. When there is a difference between the on-grid electricity price and the off-peak electricity price, the surplus electricity is not connected to the grid reasonably, and there are problems such as overcharging during the off-peak period, which causes energy waste and cannot achieve efficient and flexible use of photovoltaic storage and charging resources. The photovoltaic storage and charging yield is low. Summary of the invention

[0003] The present invention provides a control method for a photovoltaic energy storage system and a photovoltaic energy storage system, so as to improve the utilization rate and flexibility of photovoltaic energy and enhance the yield rate of photovoltaic energy storage and charging.

[0004] According to one aspect of the present invention, a control method for a photovoltaic energy storage system is provided, wherein the photovoltaic energy storage system comprises a power generation module, a busbar and an energy storage module, wherein the power generation module is connected to the energy storage module via the busbar, the power generation module is used to convert solar energy into electrical energy and supply power to the Internet via the busbar, and the energy storage module is used to store electrical energy;

[0005] The control method of the photovoltaic energy storage system includes:

[0006] Obtain the power generation and power consumption of the photovoltaic energy storage system;

[0007] When the power generation is greater than or equal to the power consumption, the photovoltaic energy storage system is controlled to supply power or charge the power according to the relationship between the grid-connected power price and the valley power price;

[0008] When the power generation is less than the power consumption, the photovoltaic energy storage system is controlled to discharge, or the photovoltaic energy storage system is controlled to charge based on the relationship between the grid-connected electricity price and the valley electricity price according to the SOC value of the energy storage module or the predicted power generation of the photovoltaic energy storage system.

[0009] Optionally, when the power generation is greater than or equal to the power consumption, the photovoltaic energy storage system is controlled to supply power to the grid according to the relationship between the grid-connected power price and the valley power price, including:

[0010] When the on-grid electricity price is greater than the valley electricity price, controlling the power generation module to supply power to the grid;

[0011] When the grid-connected electricity price is less than or equal to the valley electricity price, the power generation module is controlled to supply power to the grid or the energy storage module is controlled to charge according to the relationship between the SOC value of the energy storage module and a first preset threshold.

[0012] Optionally, controlling the power generation module to supply power online or the energy storage module to charge according to the relationship between the SOC value of the energy storage module and a first preset threshold value includes:

[0013] When the SOC value of the energy storage module is less than the first preset threshold, controlling the energy storage module to charge;

[0014] When the SOC value of the energy storage module is greater than or equal to the first preset threshold, the power generation module is controlled to supply power online, and the output power of the energy storage module is adjusted to zero.

[0015] Optionally, when the power generation is less than the power consumption, the photovoltaic energy storage system is controlled to discharge, or the photovoltaic energy storage system is controlled to charge according to the SOC value of the energy storage module or the predicted power generation of the photovoltaic energy storage system based on the relationship between the grid-connected electricity price and the valley electricity price, including:

[0016] When the valley electricity price is less than the grid-connected electricity price, the energy storage module is controlled to charge according to the relationship between the SOC value of the energy storage module and a second preset threshold value;

[0017] When the valley electricity price is greater than or equal to the grid-connected electricity price, the energy storage module is controlled to charge according to the relationship between the predicted power generation and the predicted power consumption of the photovoltaic energy storage system.

[0018] Optionally, controlling the charging of the energy storage module according to the relationship between the SOC value of the energy storage module and the second preset threshold value includes:

[0019] When the SOC value of the energy storage module is less than the second preset threshold, controlling the energy storage module to charge;

[0020] When the SOC value of the energy storage module is greater than or equal to the second preset threshold, the energy storage module is controlled to stop charging.

[0021] Optionally, controlling the charging of the energy storage module according to the relationship between the predicted power generation and the predicted power consumption of the photovoltaic energy storage system includes:

[0022] When the predicted power generation is less than or equal to the predicted power consumption, controlling the energy storage module to charge to an SOC increment, wherein the SOC increment is a ratio of a difference between the predicted power consumption and the predicted power generation to a capacity of the energy storage module;

[0023] When the predicted power generation is greater than the power consumption, the energy storage module is controlled not to be charged.

[0024] Optionally, when the power generation is less than the power consumption, the photovoltaic energy storage system is controlled to discharge, or the photovoltaic energy storage system is controlled to charge according to the SOC value of the energy storage module or the predicted power generation of the photovoltaic energy storage system based on the relationship between the grid-connected electricity price and the valley electricity price, further comprising:

[0025] When the SOC value of the energy storage module is greater than a third preset threshold, the energy storage module is controlled to discharge.

[0026] Optionally, when the power generation is greater than or equal to the power consumption, before controlling the photovoltaic energy storage system to supply power or charge the power grid according to the relationship between the grid-connected power price and the valley power price, the method further includes:

[0027] Detecting whether the voltage and / or current of the bus is at a first safety threshold;

[0028] When the power generation is less than the power consumption, the photovoltaic energy storage system is controlled to discharge, or before the photovoltaic energy storage system is controlled to charge according to the SOC value of the energy storage module or the predicted power generation of the photovoltaic energy storage system based on the relationship between the grid-connected electricity price and the valley electricity price, the method further includes:

[0029] Detect whether the voltage and / or current of the energy storage module is within a second safety threshold

[0030] According to another aspect of the present invention, there is provided a photovoltaic energy storage system including an energy management platform, wherein the energy management platform adopts the control method of the photovoltaic energy storage system described in any one of the above aspects to perform charging and discharging control and grid power supply control.

[0031] Optionally, the photovoltaic energy storage system further includes a meteorological service module, an inverter, a first circuit breaker, a second circuit breaker and a measurement module;

[0032] The meteorological service module is connected to the energy management platform, and the meteorological service module is used to predict the solar radiation of the photovoltaic energy storage system;

[0033] The power generation module is connected to the energy storage module and the busbar respectively through the inverter;

[0034] The busbar is connected to the power grid through the first circuit breaker, the energy storage module is connected to the busbar through the second circuit breaker, and the first circuit breaker and the second circuit breaker are respectively connected to the energy management platform; the closing and opening of the first circuit breaker and the second circuit breaker are controlled by the energy management platform;

[0035] The measuring modules are connected to the busbar and the energy storage module respectively, and are used to measure the voltage and / or current of the busbar and the energy storage module.

[0036] The technical solution provided by the embodiment of the present invention obtains the power generation and power consumption of the photovoltaic energy storage system. When the power generation is greater than or equal to the power consumption, the excess power generation of the photovoltaic energy storage system is selected to be connected to the grid or temporarily stored in the energy storage module according to the price difference between the grid-connected power price and the valley power price, thereby improving the utilization rate of photovoltaic energy. When the power generation is less than the power consumption, the energy storage module in the photovoltaic energy storage system is controlled to discharge to provide electric energy, and the energy storage module is charged when the SOC value of the energy storage module is small based on the price difference between the grid-connected power price and the valley power price, thereby improving the flexibility of photovoltaic energy, or the photovoltaic energy storage system is controlled to charge appropriately according to the predicted power generation of the photovoltaic energy storage system based on the price difference between the grid-connected power price and the valley power price, thereby saving charging costs while replenishing the energy storage module in time, and improving the yield rate of photovoltaic storage and charging. The technical solution provided by the embodiment of the present invention is based on the power generation and power consumption of the photovoltaic energy storage system, and through the relationship between the grid-connected power price and the valley power price, combined with the SOC value and predicted power generation of the energy storage module, effectively improves the utilization rate and flexibility of photovoltaic energy, controls the charging cost, and improves the yield rate of photovoltaic storage and charging.

[0037] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0039] Figure 1 A schematic diagram of the structure of a photovoltaic energy storage system provided by an embodiment of the present invention;

[0040] Figure 2 A flow chart of a control method for a photovoltaic energy storage system provided by an embodiment of the present invention;

[0041] Figure 3 A flow chart of another control method of a photovoltaic energy storage system provided by an embodiment of the present invention;

[0042] Figure 4 A flow chart of another control method of a photovoltaic energy storage system provided by an embodiment of the present invention;

[0043] Figure 5 A flow chart of another control method of a photovoltaic energy storage system provided by an embodiment of the present invention;

[0044] Figure 6 A flow chart of another control method of a photovoltaic energy storage system provided by an embodiment of the present invention;

[0045] Figure 7 A flow chart of another control method of a photovoltaic energy storage system provided by an embodiment of the present invention;

[0046] Figure 8 A flow chart of another control method of a photovoltaic energy storage system provided by an embodiment of the present invention;

[0047] Fig. 9 A flow chart of another control method of a photovoltaic energy storage system provided by an embodiment of the present invention;

[0048] Fig.10 A schematic diagram of the structure of another photovoltaic energy storage system provided by an embodiment of the present invention;

[0049] Fig.11 A control flow chart of a photovoltaic energy storage system provided by an embodiment of the present invention;

[0050] Fig.12 A schematic diagram of an interface of an energy storage module in a photovoltaic energy storage system provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0051] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0052] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0053] Figure 1 A schematic diagram of the structure of a photovoltaic energy storage system provided by an embodiment of the present invention is shown in FIG. Figure 2A flow chart of a control method for a photovoltaic energy storage system provided by an embodiment of the present invention. Figure 1 and Figure 2 The photovoltaic energy storage system includes a power generation module 100, a busbar 200 and an energy storage module 300. The power generation module 100 is connected to the energy storage module 300 through the busbar 200. The power generation module 100 is used to convert solar energy into electrical energy and supply power to the grid through the busbar 200. The energy storage module 300 is used to store electrical energy.

[0054] Specifically, the power generation module 100 may be a photovoltaic panel, which may convert solar energy into electrical energy, and the converted electrical energy may be transmitted to the power grid through the bus 200 for supplying electricity, or transmitted to the energy storage module 300 for storage through the bus 200. The energy storage module 300 may be charged through the power generation module 100 or the power grid, and may be discharged to supply energy when the photovoltaic energy storage system is short of power.

[0055] The control method of the photovoltaic energy storage system includes:

[0056] S110, obtaining power generation and power consumption of the photovoltaic energy storage system.

[0057] Specifically, the power generation of the photovoltaic energy storage system can be the value of electric energy that can be converted by the photovoltaic panel within a certain period of time. The power consumption of the photovoltaic energy storage system can be the value of electric energy that each load in the photovoltaic energy storage system needs to consume within a certain period of time.

[0058] S120: When the power generation is greater than or equal to the power consumption, the photovoltaic energy storage system is controlled to supply power or charge the power according to the relationship between the grid-connected power price and the valley power price.

[0059] Specifically, the grid-connected electricity price can be the price at which the photovoltaic energy storage system transmits the electricity it generates to the grid. The peak-valley time-of-use electricity price is an electricity price system in which the power grid calculates electricity charges based on peak electricity consumption and valley electricity consumption. Peak electricity consumption can refer to electricity consumption when electricity users are concentrated and power supply is tight, such as during the day, when the peak electricity price is higher; valley electricity consumption can refer to electricity consumption when there are fewer electricity users and power supply is more sufficient, such as at night, when the valley electricity price is lower. When the power generation of the photovoltaic energy storage system is greater than or equal to the power consumption of the photovoltaic energy storage system, the photovoltaic energy storage system can choose to supply the excess power generation of the photovoltaic energy storage system to the grid or temporarily store it in the energy storage module based on the price difference between the grid-connected electricity price and the valley electricity price, thereby improving the utilization rate and flexibility of photovoltaic energy and increasing the rate of return of photovoltaic storage and charging.

[0060] S130. When the power generation is less than the power consumption, control the photovoltaic energy storage system to discharge, or control the photovoltaic energy storage system to charge based on the relationship between the grid-connected electricity price and the valley electricity price according to the SOC value of the energy storage module or the predicted power generation of the photovoltaic energy storage system.

[0061] Specifically, the SOC (State of Charge) value of the energy storage module may be the proportional relationship between the current power of the energy storage module and the full power. When the energy storage module is fully charged, the SOC value of the energy storage module is 1. As the energy storage module is gradually discharged, the SOC value of the energy storage module gradually decreases. The predicted power generation of the photovoltaic energy storage system may be the power generation of the photovoltaic energy storage system in the future period obtained based on the solar radiation intensity predicted by the meteorological server of the photovoltaic power station. When the power generation of the photovoltaic energy storage system is less than the power consumption of the photovoltaic energy storage system, the power generation of the photovoltaic energy storage system itself is insufficient to support the operation of various loads in the photovoltaic energy storage system. The energy storage modules in the photovoltaic energy storage system may be controlled to discharge to provide electrical energy, thereby improving the utilization rate and flexibility of photovoltaic energy. At the same time, since the discharge of the energy storage module also needs to be charged when the SOC value of the energy storage module is small based on the price difference between the grid-connected electricity price and the valley electricity price, or the photovoltaic energy storage system is controlled to be appropriately charged according to the predicted power generation of the photovoltaic energy storage system based on the price difference between the grid-connected electricity price and the valley electricity price, so as to control the charging cost while replenishing the energy storage module in time, and improve the yield of photovoltaic storage and charging.

[0062] The technical solution provided by the embodiment of the present invention obtains the power generation and power consumption of the photovoltaic energy storage system. When the power generation is greater than or equal to the power consumption, the excess power generation of the photovoltaic energy storage system is selected to be connected to the grid or temporarily stored in the energy storage module according to the price difference between the grid-connected power price and the valley power price, thereby improving the utilization rate of photovoltaic energy. When the power generation is less than the power consumption, the energy storage module in the photovoltaic energy storage system is controlled to discharge to provide electric energy, and the energy storage module is charged when the SOC value of the energy storage module is small based on the price difference between the grid-connected power price and the valley power price, thereby improving the flexibility of photovoltaic energy, or the photovoltaic energy storage system is controlled to charge appropriately according to the predicted power generation of the photovoltaic energy storage system based on the price difference between the grid-connected power price and the valley power price, thereby saving the charging cost while replenishing the energy storage module in time, and improving the yield rate of photovoltaic storage and charging. The technical solution provided by the embodiment of the present invention is based on the power generation and power consumption of the photovoltaic energy storage system, and through the relationship between the grid-connected power price and the valley power price, combined with the SOC value and predicted power generation of the energy storage module, effectively improves the utilization rate and flexibility of photovoltaic energy, controls the charging cost, and improves the yield rate of photovoltaic storage and charging.

[0063] Optionally, Figure 3 A flow chart of another control method of a photovoltaic energy storage system provided by an embodiment of the present invention. Figure 3 When the power generation is greater than or equal to the power consumption, the photovoltaic energy storage system is controlled to supply power to the grid according to the relationship between the grid-connected power price and the valley power price, including:

[0064] S210, obtaining power generation and power consumption of the photovoltaic energy storage system.

[0065] S220: When the on-grid electricity price is greater than the valley electricity price, the power generation module is controlled to supply power to the grid.

[0066] Specifically, the on-grid electricity price is greater than the valley electricity price, which means that the price of the photovoltaic energy storage system for on-grid power supply is better than the price of electricity consumption through the power grid. Therefore, when the photovoltaic energy storage system has redundant power generation and the on-grid electricity price is greater than the valley electricity price, the excess power generation of the photovoltaic energy storage system can be supplied to the grid without storage, so as to improve the utilization rate of photovoltaic energy and the yield rate of photovoltaic storage and charging.

[0067] S230: When the grid-connected electricity price is less than or equal to the valley electricity price, the power generation module is controlled to supply power to the grid or the energy storage module is controlled to charge according to the relationship between the SOC value of the energy storage module and the first preset threshold.

[0068] Specifically, the on-grid electricity price being less than or equal to the valley electricity price may mean that the price of electricity used by the photovoltaic energy storage system through the power grid is better than the price of power supply to the grid. At this time, according to the relationship between the SOC value of the energy storage module and the first preset threshold, when the remaining power of the energy storage module does not reach the ideal remaining power, it is possible to choose to use the redundant electric energy when the photovoltaic energy storage system generates electricity to charge the energy storage module of the photovoltaic energy storage system, or when the remaining power of the energy storage module reaches the ideal remaining power, the redundant electric energy when the photovoltaic energy storage system generates electricity is transmitted to the grid end for power supply to the grid. The first preset threshold may be the SOC value when the energy storage module reaches the ideal remaining power, and the first preset threshold is greater than zero and less than 1. Exemplarily, the first preset threshold may be 95%.

[0069] S240: When the power generation is less than the power consumption, the photovoltaic energy storage system is controlled to discharge, or the photovoltaic energy storage system is controlled to charge according to the SOC value of the energy storage module or the predicted power generation of the photovoltaic energy storage system based on the relationship between the grid-connected electricity price and the valley electricity price.

[0070] Optionally, Figure 4 A flow chart of another control method of a photovoltaic energy storage system provided by an embodiment of the present invention. Figure 4 Controlling the power generation module to supply power to the grid or the energy storage module to charge according to the relationship between the SOC value of the energy storage module and the first preset threshold value includes:

[0071] S310, obtaining power generation and power consumption of the photovoltaic energy storage system.

[0072] S320: When the on-grid electricity price is greater than the valley electricity price, the power generation module is controlled to supply power to the grid.

[0073] S330: When the SOC value of the energy storage module is less than a first preset threshold, control the energy storage module to charge.

[0074] Specifically, the SOC value of the energy storage module being less than the first preset threshold value may be a situation where the remaining power of the energy storage module has not reached the ideal remaining power. To ensure that the energy storage module has sufficient power to use during discharge, the energy storage module of the photovoltaic energy storage system may be charged using redundant power generated by the photovoltaic energy storage system when the on-grid electricity price is less than the valley electricity price and the SOC value of the energy storage module is less than the first preset threshold value.

[0075] S340: When the SOC value of the energy storage module is greater than or equal to a first preset threshold, the power generation module is controlled to supply power online, and the output power of the energy storage module is adjusted to zero.

[0076] Specifically, the output power of the energy storage module may be the working power of the energy storage module when discharging. The output power of the energy storage module being zero may be a working condition in which the energy storage module is not discharging. The SOC value of the energy storage module being greater than or equal to the first preset threshold may be a condition in which the remaining power of the energy storage module meets the ideal remaining power, and at this time the power of the energy storage module is sufficient for use when discharging. Therefore, when the on-grid electricity price is less than the valley electricity price, and the SOC value of the energy storage module is greater than or equal to the first preset threshold, the redundant electric energy generated by the photovoltaic energy storage system during power generation can be transmitted to the grid end for power supply to the grid, and at the same time, the energy storage module is controlled not to discharge, that is, at this time, only the redundant electric energy generated by the photovoltaic energy storage system is used for power supply to the grid.

[0077] S350: When the power generation is less than the power consumption, the photovoltaic energy storage system is controlled to discharge, or the photovoltaic energy storage system is controlled to charge according to the SOC value of the energy storage module or the predicted power generation of the photovoltaic energy storage system based on the relationship between the on-grid electricity price and the valley electricity price.

[0078] Optionally, Figure 5 A flow chart of another control method of a photovoltaic energy storage system provided by an embodiment of the present invention. Figure 5 When the power generation is less than the power consumption, the photovoltaic energy storage system is controlled to discharge, or the photovoltaic energy storage system is controlled to charge based on the relationship between the grid-connected electricity price and the valley electricity price according to the SOC value of the energy storage module or the predicted power generation of the photovoltaic energy storage system, including:

[0079] S410, obtaining power generation and power consumption of the photovoltaic energy storage system.

[0080] S420: When the on-grid electricity price is greater than the valley electricity price, the power generation module is controlled to supply power to the grid.

[0081] S430: When the SOC value of the energy storage module is less than a first preset threshold, control the energy storage module to charge.

[0082] S440: When the SOC value of the energy storage module is greater than or equal to a first preset threshold, the power generation module is controlled to supply power to the grid, and the output power of the energy storage module is adjusted to zero.

[0083] S450: When the valley electricity price is less than the grid-connected electricity price, the energy storage module is controlled to charge according to the relationship between the SOC value of the energy storage module and the second preset threshold value.

[0084] Specifically, the valley electricity price being less than the grid-connected electricity price may refer to a situation where the price of electricity used by the photovoltaic energy storage system through the grid is better than the price of grid-connected electricity supply. When the power generation of the photovoltaic energy storage system is less than the power consumption, it is necessary to perform the discharge function through the energy storage module, and correspondingly, the energy storage module needs to be charged and supplemented. At this time, since the valley electricity price is relatively low, it is possible to directly choose to charge the energy storage module of the photovoltaic energy storage system through the power of the grid when the power of the energy storage module is not charged to the ideal remaining power based on the relationship between the SOC value of the energy storage module and the second preset threshold. The second preset threshold may be the SOC value when the energy storage module is charged to the ideal power, and the second preset threshold is greater than zero and less than 1. Exemplarily, the second preset threshold may be 95%

[0085] S460: When the valley electricity price is greater than or equal to the grid-connected electricity price, the charging of the energy storage module is controlled according to the relationship between the predicted power generation and the predicted power consumption of the photovoltaic energy storage system.

[0086] Specifically, the valley electricity price being greater than or equal to the grid-connected electricity price may refer to a situation where the price of grid-connected power supply by the photovoltaic energy storage system is better than the price of electricity through the power grid. When the power generation of the photovoltaic energy storage system is less than the power consumption, the energy storage module needs to be discharged, and correspondingly, the energy storage module needs to be charged and supplemented. At this time, due to the high valley electricity price, the energy storage module can be charged to an appropriate degree based on the relationship between the predicted power generation and predicted power consumption of the photovoltaic energy storage system, thereby saving charging costs and improving the rate of return of photovoltaic storage and charging. The predicted power consumption of the photovoltaic energy storage system can be the value of electric energy required to be consumed by various loads in the photovoltaic energy storage system in the future.

[0087] Optionally, Figure 6 A flow chart of another control method of a photovoltaic energy storage system provided by an embodiment of the present invention. Figure 6 Controlling the charging of the energy storage module according to the relationship between the SOC value of the energy storage module and the second preset threshold value includes:

[0088] S510: Obtain power generation and power consumption of the photovoltaic energy storage system.

[0089] S520: When the on-grid electricity price is greater than the valley electricity price, the power generation module is controlled to supply power to the grid.

[0090] S530: When the SOC value of the energy storage module is less than a first preset threshold, control the energy storage module to charge.

[0091] S540: When the SOC value of the energy storage module is greater than or equal to a first preset threshold, the power generation module is controlled to supply power to the grid, and the output power of the energy storage module is adjusted to zero.

[0092] S550: When the SOC value of the energy storage module is less than a second preset threshold, control the energy storage module to charge.

[0093] Specifically, the SOC value of the energy storage module being less than the second preset threshold value may be a situation where the remaining power of the energy storage module has not reached the ideal power SOC value. At this time, since the valley electricity price is less than the grid electricity price, the power of the grid can be used to charge and store energy in the energy storage module of the photovoltaic energy storage system.

[0094] S560: When the SOC value of the energy storage module is greater than or equal to a second preset threshold, control the energy storage module to stop charging.

[0095] Specifically, the SOC value of the energy storage module being greater than or equal to the second preset threshold value may be a situation where the remaining power of the energy storage module reaches the ideal power SOC value during the charging process. At this time, the energy storage module stops charging and does not need to be charged and supplemented.

[0096] S570: When the valley electricity price is greater than or equal to the grid-connected electricity price, the charging of the energy storage module is controlled according to the relationship between the predicted power generation and the predicted power consumption of the photovoltaic energy storage system.

[0097] Optionally, Figure 7 A flow chart of another control method of a photovoltaic energy storage system provided by an embodiment of the present invention. Figure 7 The charging of the energy storage module is controlled according to the relationship between the predicted power generation and the predicted power consumption of the photovoltaic energy storage system, including:

[0098] S610: Obtain power generation and power consumption of the photovoltaic energy storage system.

[0099] S620: When the on-grid electricity price is greater than the valley electricity price, the power generation module is controlled to supply power to the grid.

[0100] S630: When the SOC value of the energy storage module is less than a first preset threshold, control the energy storage module to charge.

[0101] S640: When the SOC value of the energy storage module is greater than or equal to a first preset threshold, the power generation module is controlled to supply power to the grid, and the output power of the energy storage module is adjusted to zero.

[0102] S650: When the SOC value of the energy storage module is less than a second preset threshold, control the energy storage module to charge.

[0103] S660: When the SOC value of the energy storage module is greater than or equal to a second preset threshold, control the energy storage module to stop charging.

[0104] S670: When the predicted power generation is less than or equal to the predicted power consumption, the energy storage module is controlled to charge to an SOC increment, where the SOC increment is a ratio of a difference between the predicted power consumption and the predicted power generation to the capacity of the energy storage module.

[0105] Specifically, the predicted power generation is less than or equal to the predicted power consumption, which can be a situation where the power consumed by various loads in the photovoltaic energy storage system in the future is greater than the power converted by the photovoltaic energy storage system itself. However, since the valley electricity price for charging the energy storage module is more expensive than the grid-connected electricity price, the charging degree of the energy storage module can be controlled at this time, that is, the SOC value of the energy storage module is controlled to be charged to the SOC increment, so that the photovoltaic energy storage system can be self-sufficient in the future, so as to save charging costs and improve the rate of return of photovoltaic storage and charging. The SOC increment can be obtained by comprehensive calculation based on the predicted power consumption and the predicted power generation, and the SOC increment is greater than or equal to zero and less than or equal to 1. Exemplarily, the SOC increment can be obtained by the following formula:

[0106]

[0107] S680: When the predicted power generation is greater than the power consumption, the energy storage module is controlled not to be charged.

[0108] Specifically, the predicted power generation being greater than the predicted power consumption can be a situation where the power consumed by various loads in the photovoltaic energy storage system in the future is less than the power converted by the photovoltaic energy storage system itself, that is, the photovoltaic energy storage system can be self-sufficient and does not need to charge the energy storage module.

[0109] Optionally, Figure 8 A flow chart of another control method of a photovoltaic energy storage system provided by an embodiment of the present invention. Figure 8 When the power generation is less than the power consumption, the photovoltaic energy storage system is controlled to discharge, or the photovoltaic energy storage system is controlled to charge according to the SOC value of the energy storage module or the predicted power generation of the photovoltaic energy storage system based on the relationship between the grid-connected power price and the valley power price, and also includes:

[0110] S710. Obtain power generation and power consumption of the photovoltaic energy storage system.

[0111] S720: When the on-grid electricity price is greater than the valley electricity price, the power generation module is controlled to supply power to the grid.

[0112] S730: When the SOC value of the energy storage module is less than a first preset threshold, control the energy storage module to charge.

[0113] S740: When the SOC value of the energy storage module is greater than or equal to a first preset threshold, the power generation module is controlled to supply power to the grid, and the output power of the energy storage module is adjusted to zero.

[0114] S750: When the SOC value of the energy storage module is greater than a third preset threshold, control the energy storage module to discharge.

[0115] Specifically, the third preset threshold value may be the SOC value when the remaining power of the energy storage module is about to be exhausted. When the power generation of the photovoltaic energy storage module is less than the power consumption and the SOC value of the energy storage module is greater than the third preset threshold value, the energy storage module can be controlled to discharge to supply power to various loads of the photovoltaic energy storage system. When the SOC value of the energy storage module is not greater than the third preset threshold value, the electric energy of the energy storage module is about to be exhausted. In order to avoid over-discharge of the energy storage module and affect its life, the energy storage module can be controlled to stop discharging. Exemplarily, the third preset threshold value may be 5%.

[0116] Optionally, Fig. 9 A flow chart of another control method of a photovoltaic energy storage system provided by an embodiment of the present invention. Fig. 9 When the power generation is greater than or equal to the power consumption, before the photovoltaic energy storage system is controlled to supply power or charge the power on the grid according to the relationship between the grid-connected power price and the valley power price, it also includes:

[0117] S810. Obtain power generation and power consumption of the photovoltaic energy storage system.

[0118] S820: Detect whether the voltage and / or current of the bus is at a first safety threshold.

[0119] Specifically, the photovoltaic energy storage system needs to be tested for safety before it is powered on or charged. Whether the photovoltaic energy storage system is in a safe working state can be determined based on the voltage and / or current of the busbar in the photovoltaic energy storage system. When the voltage and / or current of the busbar is within the first safety threshold range, the photovoltaic energy storage system can be considered to be in a normal working state, and the photovoltaic energy storage system can be controlled to charge or power on.

[0120] S830: When the power generation is greater than or equal to the power consumption, the photovoltaic energy storage system is controlled to supply power or charge the power according to the relationship between the grid-connected power price and the valley power price.

[0121] When the power generation is less than the power consumption, the photovoltaic energy storage system is controlled to discharge, or the photovoltaic energy storage system is controlled to charge according to the SOC value of the energy storage module or the predicted power generation of the photovoltaic energy storage system based on the relationship between the grid-connected power price and the valley power price, and also includes:

[0122] S840: Detect whether the voltage and / or current of the energy storage module is at a second safety threshold.

[0123] Specifically, the energy storage module needs to be tested for safety before charging and discharging. Whether the energy storage module is in a safe working state can be judged based on the voltage and / or current of the energy storage module when it is working. When the voltage and / or current of the energy storage module is within the second safety threshold range, it can be considered that the energy storage module is in a normal working state, and the energy storage module can be controlled to charge and discharge.

[0124] S850: When the power generation is less than the power consumption, the photovoltaic energy storage system is controlled to discharge, or the photovoltaic energy storage system is controlled to charge based on the relationship between the grid-connected electricity price and the valley electricity price according to the SOC value of the energy storage module or the predicted power generation of the photovoltaic energy storage system.

[0125] Fig.10 A schematic diagram of the structure of another photovoltaic energy storage system provided by an embodiment of the present invention is shown in FIG. Fig.11 A control flow chart of a photovoltaic energy storage system provided by an embodiment of the present invention, Fig.12 This is a schematic diagram of an interface of an energy storage module in a photovoltaic energy storage system provided by an embodiment of the present invention. Fig.10 , Fig.11 and Fig.12 The photovoltaic energy storage system includes a capacity management platform 400, and the energy management platform 400 adopts the control method of the photovoltaic energy storage system provided by any of the above embodiments to perform charging and discharging control and grid power supply control.

[0126] Optionally, based on the above embodiment, continue to refer to Fig.10 , Fig.11 and Fig.12 The photovoltaic energy storage system also includes a meteorological service module 500, an inverter 600, a second circuit breaker 700, a first circuit breaker 800 and a measurement module 900; the meteorological service module 500 is connected to the energy management platform 400, and the meteorological service module 500 is used to predict the predicted power generation of the photovoltaic energy storage system; the power generation module 100 is connected to the energy storage module 300 and the bus 200 respectively through the inverter 600; the bus 200 is connected to the power grid through the first circuit breaker 800, the energy storage module 300 is connected to the bus 200 through the second circuit breaker 700, and the second circuit breaker 700 and the first circuit breaker 800 are respectively connected to the energy management platform 400; the measurement module 900 is connected to the bus 200 and the energy storage module 300 respectively, and the measurement module 900 is used to measure the voltage and / or current of the bus 200 and the energy storage module 300.

[0127] Specifically, the meteorological service module 500 can be a meteorological server for a photovoltaic power station. The meteorological service module 500 can predict the intensity of solar radiation in the future, and predict the power generation of the photovoltaic energy storage system through comprehensive calculations such as solar radiation, the inclination and direction of the photovoltaic panel, conversion efficiency, climate and temperature. The inverter 600 can convert the direct current generated by the power generation module 100 into alternating current and transmit it to the power grid through the bus 200 for online power supply, or transmit it to the energy storage module 3 for storage. The bus 200 is connected to the power grid through the first circuit breaker 800. When it is detected that the voltage and / or current of the bus 200 is within the range of the first safety threshold, it can be considered that the photovoltaic energy storage system is in a normal working state, and the first circuit breaker 800 can be controlled by controlling the energy management platform 400 to conduct, so that the photovoltaic energy storage system is connected to the power grid for charging or online power supply. The energy storage module 300 is connected to the bus 200 through the second circuit breaker 700. When it is detected that the voltage and / or current of the energy storage module 300 is within the range of the second safety threshold, it can be considered that the energy storage module 300 is in a normal working state, and the second circuit breaker 700 can be controlled to be turned on through the energy management platform 400, so that the energy storage module 300 is connected to the bus 200 for charging or discharging. The measurement module 900 can measure the voltage and / or current of the bus 200 and the energy storage module 300, and transmit it to the energy management platform 400 through the energy storage module 300. The energy management platform 400 can control the conduction and disconnection of the second circuit breaker 700 and the first circuit breaker 800 according to the voltage and / or current of the bus 200 and the energy storage module 300, and control the charging and discharging state of the energy storage module 300 according to the operating status of the load. The predicted total load power in the energy storage module 300 interface is the predicted power consumption, and the total load power can be obtained through the load curve; the on-grid electricity price, load electricity price, valley electricity price and valley time period can be obtained through the power supply bureau on the grid side, and the valley charging SOC can be calculated using the above parameters.

[0128] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0129] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A control method for a photovoltaic energy storage system, characterized in that: The photovoltaic energy storage system comprises a power generation module, a busbar and an energy storage module. The power generation module is connected to the energy storage module via the busbar. The power generation module is used to convert solar energy into electrical energy and supply power to the Internet via the busbar. The energy storage module is used to store electrical energy. The control method of the photovoltaic energy storage system includes: Obtain the power generation and power consumption of the photovoltaic energy storage system; When the power generation is greater than or equal to the power consumption, the photovoltaic energy storage system is controlled to supply power or charge the power according to the relationship between the grid-connected power price and the valley power price; When the power generation is less than the power consumption, the photovoltaic energy storage system is controlled to discharge, or the photovoltaic energy storage system is controlled to charge based on the relationship between the grid-connected electricity price and the valley electricity price according to the SOC value of the energy storage module or the predicted power generation of the photovoltaic energy storage system.

2. The control method of the photovoltaic energy storage system according to claim 1, characterized in that: When the power generation is greater than or equal to the power consumption, the photovoltaic energy storage system is controlled to supply power to the grid according to the relationship between the grid-connected power price and the valley power price, including: When the on-grid electricity price is greater than the valley electricity price, controlling the power generation module to supply power to the grid; When the grid-connected electricity price is less than or equal to the valley electricity price, the power generation module is controlled to supply power to the grid or the energy storage module is controlled to charge according to the relationship between the SOC value of the energy storage module and a first preset threshold.

3. The control method of the photovoltaic energy storage system according to claim 2, characterized in that: Controlling the power generation module to supply power online or the energy storage module to charge according to the relationship between the SOC value of the energy storage module and the first preset threshold value includes: When the SOC value of the energy storage module is less than the first preset threshold, controlling the energy storage module to charge; When the SOC value of the energy storage module is greater than or equal to the first preset threshold, the power generation module is controlled to supply power online, and the output power of the energy storage module is adjusted to zero.

4. The control method of the photovoltaic energy storage system according to claim 1, characterized in that: When the power generation is less than the power consumption, the photovoltaic energy storage system is controlled to discharge, or the photovoltaic energy storage system is controlled to charge according to the SOC value of the energy storage module or the predicted power generation of the photovoltaic energy storage system based on the relationship between the grid-connected electricity price and the valley electricity price, including: When the valley electricity price is less than the grid-connected electricity price, the energy storage module is controlled to charge according to the relationship between the SOC value of the energy storage module and a second preset threshold value; When the valley electricity price is greater than or equal to the grid-connected electricity price, the energy storage module is controlled to charge according to the relationship between the predicted power generation and the predicted power consumption of the photovoltaic energy storage system.

5. The control method of the photovoltaic energy storage system according to claim 4, characterized in that: Controlling the charging of the energy storage module according to the relationship between the SOC value of the energy storage module and the second preset threshold value includes: When the SOC value of the energy storage module is less than the second preset threshold, controlling the energy storage module to charge; When the SOC value of the energy storage module is greater than or equal to the second preset threshold, the energy storage module is controlled to stop charging.

6. The control method of the photovoltaic energy storage system according to claim 4, characterized in that: Controlling the charging of the energy storage module according to the relationship between the predicted power generation and the predicted power consumption of the photovoltaic energy storage system includes: When the predicted power generation is less than or equal to the predicted power consumption, controlling the energy storage module to charge to an SOC increment, wherein the SOC increment is a ratio of a difference between the predicted power consumption and the predicted power generation to a capacity of the energy storage module; When the predicted power generation is greater than the power consumption, the energy storage module is controlled not to be charged.

7. The control method of the photovoltaic energy storage system according to claim 4, characterized in that: When the power generation is less than the power consumption, the photovoltaic energy storage system is controlled to discharge, or the photovoltaic energy storage system is controlled to charge according to the SOC value of the energy storage module or the predicted power generation of the photovoltaic energy storage system based on the relationship between the grid-connected electricity price and the valley electricity price, further comprising: When the SOC value of the energy storage module is greater than a third preset threshold, the energy storage module is controlled to discharge.

8. The control method of the photovoltaic energy storage system according to claim 1, characterized in that: When the power generation is greater than or equal to the power consumption, before controlling the photovoltaic energy storage system to supply power or charge the power on the grid according to the relationship between the grid-connected power price and the valley power price, the method further includes: Detecting whether the voltage and / or current of the bus is at a first safety threshold; When the power generation is less than the power consumption, the photovoltaic energy storage system is controlled to discharge, or before the photovoltaic energy storage system is controlled to charge according to the SOC value of the energy storage module or the predicted power generation of the photovoltaic energy storage system based on the relationship between the grid-connected electricity price and the valley electricity price, the method further includes: Detect whether the voltage and / or current of the energy storage module is at a second safety threshold.

9. A photovoltaic energy storage system, characterized in that: It comprises an energy management platform, and the energy management platform adopts the control method of the photovoltaic energy storage system described in any one of claims 1-8 to perform charging and discharging control and online power supply control.

10. The photovoltaic energy storage system according to claim 9, characterized in that: Also includes a weather service module, an inverter, a first circuit breaker, a second circuit breaker and a measurement module; The meteorological service module is connected to the energy management platform, and the meteorological service module is used to predict the solar radiation of the photovoltaic energy storage system; The power generation module is connected to the energy storage module and the busbar respectively through the inverter; The busbar is connected to the power grid through the first circuit breaker, the energy storage module is connected to the busbar through the second circuit breaker, the first circuit breaker and the second circuit breaker are respectively connected to the energy management platform, and the energy management platform is used to control the closing and opening of the first circuit breaker and the second circuit breaker; The measuring modules are connected to the busbar and the energy storage module respectively, and are used to measure the voltage and / or current of the busbar and the energy storage module.

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