Energy management method of photovoltaic energy storage system

Abstract

The invention provides an energy management method of a photovoltaic energy storage system, the photovoltaic energy storage system comprises a condensed state battery, a lithium ion flow battery, a super capacitor and a central control device, and the condensed state battery, the lithium ion flow battery and the super capacitor are connected with the central control device. The energy management method comprises the following steps: S1, establishing a photovoltaic power generation prediction model and an electricity load prediction model; s2, outputting a photovoltaic power generation power curve and an electricity load power curve through the prediction model; s3, determining a stable time period and a fluctuation time period according to the photovoltaic power generation power curve, and setting energy storage modes of the stable time period and the fluctuation time period; and S4, performing energy storage control based on the set energy storage mode. According to the invention, the photovoltaic energy storage system adopts a hybrid energy storage structure, the working state of the photovoltaic microgrid is predicted, and the corresponding energy storage mode is set in advance, so that the energy storage control is more timely and flexible.

Description

Technical Field

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

[0002] Microgrid is a small power generation and distribution system composed of distributed power sources, energy storage devices, energy conversion devices, related loads and monitoring and protection devices. It can achieve self-control, protection and management, and can operate with the external power grid or in isolation. Microgrid is a powerful supplement to the large power grid and an important part of the smart grid. It has broad application prospects in industrial and commercial areas, urban areas and remote areas. With the gradual advancement of the research and development of key microgrid technologies, microgrids will enter a period of rapid development.

[0003] Due to the widespread distribution of solar energy and the increasing maturity of photovoltaic power generation, photovoltaic microgrids occupy a very important position in microgrids. Photovoltaic power generation is affected by many factors such as weather, time, and season, and has strong volatility. For the electricity generated by photovoltaic power generation, it is necessary to rely on energy storage devices for storage and release to solve the volatility of photovoltaic power generation. However, the existing energy storage management method needs to be controlled based on real-time detection data, and the regulation control has lag, which cannot well absorb the electricity generated by photovoltaic power generation. Summary of the invention

[0004] In order to solve the technical problems that the regulation and control of the energy storage management method in the prior art has hysteresis and poor electric energy absorption capacity, the energy management method of the photovoltaic energy storage system proposed in the present invention includes the following steps: S1. Establishing photovoltaic power generation prediction model and power load prediction model; S2, outputting a photovoltaic power generation curve within a first preset time interval through a photovoltaic power generation prediction model, outputting a power load power curve within a first preset time interval through a power load prediction model, and starting timing from zero; S3. Determine the stable time period and the fluctuating time period according to the photovoltaic power generation power curve, and set the energy storage mode for the stable time period and the fluctuating time period; S4, performing energy storage control based on the set energy storage mode, collecting and recording the actual photovoltaic power generation and power load power, and determining whether the timing time is equal to the first preset time interval. If so, proceed to S5; S5. Use the recorded actual photovoltaic power generation power and power load power as training data to continue training the photovoltaic power generation prediction model and the power load prediction model. After the training is completed, return to S2.

[0005] Preferably, the condensed matter battery is composed of a plurality of condensed matter battery cells connected in parallel, each condensed matter battery cell has a specific condensed matter number, the lithium ion flow battery is composed of a plurality of lithium ion flow battery cells connected in parallel, each lithium ion flow battery cell has a specific flow battery number, and the supercapacitor is composed of a plurality of supercapacitor cells connected in parallel, each supercapacitor cell has a specific capacitance number.

[0006] Preferably, each condensed matter battery cell has a control switch that can control whether the condensed matter battery cell is connected to the condensed matter battery for operation, each lithium ion flow battery cell has a control switch that can control whether the lithium ion flow battery cell is connected to the lithium ion flow battery for operation, and each supercapacitor cell has a control switch that can control whether the supercapacitor cell is connected to the supercapacitor for operation.

[0007] Preferably, in S3, the specific process of determining the stable time period and the fluctuating time period according to the photovoltaic power generation power curve is to divide the photovoltaic power generation power curve into multiple unit time periods according to unit time intervals, mark each unit time period as power balance, power regulation, or power fluctuation, merge the unit time periods with the same mark to obtain the merged marked time periods, and use the marked time period marked as power regulation as the stable time period, and use the marked time period marked as power fluctuation as the fluctuating time period.

[0008] Preferably, in S3, the specific process of marking the unit time period is to calculate the average photovoltaic power generation power within the unit time period, calculate the percentage change of each power node relative to the average photovoltaic power generation power within the unit time period, select the maximum value of the absolute value of the change percentage, if the maximum value is greater than the first change threshold, then the unit time period is marked as power fluctuation, otherwise, obtain the power curve of the power load, select the part corresponding to the unit time period, calculate the corresponding average power of the power load, if the difference between the average photovoltaic power generation power and the average power of the power load is less than the second change threshold, the unit time period is marked as power balance, otherwise, the unit time period is marked as power regulation.

[0009] Preferably, in S3, the specific process of setting the energy storage mode for the stable time period is to screen the minimum photovoltaic power generation power within the stable time period, select the part corresponding to the stable time period in the power curve of the power load, screen the maximum power of the power load therein, calculate the absolute value of the difference between the minimum photovoltaic power generation power and the maximum power of the power load, use it as the power adjustment size, calculate the interval duration of the stable time period, if the interval duration is greater than the first time threshold, select the lithium-ion liquid flow battery as the energy storage adjustment module, and the lithium-ion liquid flow battery is controlled based on the power adjustment size, if the interval duration is less than or equal to the first time threshold, select the condensed matter battery and the lithium-ion liquid flow battery as the energy storage adjustment module, divide the power adjustment size equally into a first power adjustment size and a second power adjustment size, the condensed matter battery is controlled based on the first power adjustment size, and the lithium-ion liquid flow battery is controlled based on the second power adjustment size.

[0010] Preferably, in S3, the specific process of setting the energy storage mode for the fluctuation time period is to screen the maximum value, minimum value and average value of photovoltaic power generation power within the fluctuation time period, calculate the first difference between the maximum value and the average value of photovoltaic power generation power, calculate the second difference between the average value and the minimum value of photovoltaic power generation power, select the larger value of the first difference and the second difference as the fluctuation adjustment size, select the supercapacitor as the fluctuation adjustment module, and control the supercapacitor based on the fluctuation adjustment size, select the part corresponding to the stable time period in the power curve of the power load, calculate the corresponding average power of the power load, use the absolute value of the difference between the average value of photovoltaic power generation power and the average power of the power load as the power adjustment size, select the condensed matter battery as the energy storage adjustment module, and control the condensed matter battery based on the power adjustment size.

[0011] Preferably, in said S4, the process of controlling the condensed state battery based on the power regulation size is to divide the stable time period or the fluctuating time period into multiple unit time periods according to the unit time interval; when the time reaches the starting point of the unit time period, the average photovoltaic power generation power within the unit time period is calculated according to the photovoltaic power generation power curve; the average power load power within the unit time period is calculated according to the power load power curve; when the average photovoltaic power generation power is greater than the average power load power, the number of condensed state battery cells that need to be called is determined according to the power regulation size; if the number of cells in the non-working sequence of the condensed state battery cells is greater than or equal to the number of condensed state battery cells that need to be called, the condensed state battery cells are selected from the non-working sequence of the condensed state battery cells as working cells, the working cells are deleted from the non-working sequence of the condensed state battery cells, and energy is stored based on the working cells; if the number of cells in the non-working sequence of the condensed state battery cells is less than the number of condensed state battery cells that need to be called, the difference between the two is calculated as the number of cells to be supplemented, and the number of cells to be supplemented is calculated according to the amount of stored power less than the first A condensed state battery cell that meets the requirements is selected as a candidate cell from the condensed state battery cell working sequence according to a set threshold standard, until the number of candidate cells is equal to the number of cell supplements, the cells in the non-working sequence of the condensed state battery cell and the candidate cells are used as working cells, the working cells are deleted from the non-working sequence of the condensed state battery cell and the working sequence of the condensed state battery cell, energy is stored based on the working cells, when the average power of the photovoltaic power generation is less than the average power of the power load, the number of condensed state battery cells that need to be called is determined according to the power adjustment size, and the condensed state battery cell that meets the requirements is selected as a candidate cell from the condensed state battery cell working sequence according to the standard that the storage capacity is greater than the second set threshold, until the number of candidate cells is equal to the number of condensed state battery cells that need to be called, the candidate cells are used as working cells, the working cells are deleted from the condensed state battery cell working sequence, energy is supplemented based on the working cells, and when the time reaches the end point of the unit time period, the condensed state number of the working cell is added to the end of the condensed state battery cell working sequence.

[0012] Preferably, in S4, the process of controlling the lithium-ion liquid flow battery based on the power regulation size is to divide the stable time period into multiple unit time periods according to the unit time interval; when the time reaches the starting point of the unit time period, the average photovoltaic power generation power within the unit time period is calculated according to the photovoltaic power generation power curve; the average power of the power load within the unit time period is calculated according to the power load power curve; when the average photovoltaic power generation power is greater than the average power of the power load, the number of lithium-ion liquid flow battery cells to be called is determined according to the power regulation size; if the number of cells in the non-working sequence of the lithium-ion liquid flow battery cells is greater than or equal to the number of lithium-ion liquid flow battery cells to be called, a lithium-ion liquid flow battery cell is selected from the non-working sequence of the lithium-ion liquid flow battery cells as a working cell, and the working cell is deleted from the non-working sequence of the lithium-ion liquid flow battery cells; energy is stored based on the working cell; if the number of cells in the non-working sequence of the lithium-ion liquid flow battery cells is less than the number of lithium-ion liquid flow battery cells to be called, the difference between the two is calculated as the number of cells to be supplemented, and the storage capacity is less than the first set threshold. The method comprises the following steps: selecting a lithium-ion liquid flow battery cell that meets the requirements from the lithium-ion liquid flow battery cell working sequence as a candidate cell according to the standard, until the number of the candidate cells is equal to the number of cell supplements, using the cells in the lithium-ion liquid flow battery cell non-working sequence and the candidate cells as working cells, deleting the working cells from the lithium-ion liquid flow battery cell non-working sequence and the lithium-ion liquid flow battery cell working sequence, storing energy based on the working cells, determining the number of lithium-ion liquid flow battery cells that need to be called according to the power adjustment size when the average photovoltaic power generation power is less than the average power of the power load, selecting a lithium-ion liquid flow battery cell that meets the requirements from the lithium-ion liquid flow battery cell working sequence as a candidate cell according to the standard that the storage capacity is greater than the second set threshold, until the number of the candidate cells is equal to the number of the lithium-ion liquid flow battery cells that need to be called, using the candidate cells as working cells, deleting the working cells from the lithium-ion liquid flow battery cell working sequence, replenishing energy based on the working cells, and adding the condensed state number of the working cell to the end of the lithium-ion liquid flow battery cell working sequence when the time reaches the end point of the unit time period.

[0013] Preferably, in S4, the process of controlling the supercapacitor based on the fluctuation adjustment size is to divide the stable time period into multiple unit time periods according to the unit time interval, when the time reaches the starting point of the unit time period, the average photovoltaic power generation power in the unit time period is calculated according to the photovoltaic power generation power curve, and the first proportion of nodes whose power is greater than the average photovoltaic power generation power in each power node in the unit time period is calculated. When the first proportion is greater than the judgment threshold, the number of supercapacitor cells to be called is determined according to the fluctuation adjustment size. If the number of cells in the supercapacitor cell non-working sequence is greater than or equal to the number of supercapacitor cells to be called, a supercapacitor cell is selected from the supercapacitor cell non-working sequence as a working cell, and the working cell is deleted from the supercapacitor cell non-working sequence. Energy is stored based on the working cell. If the number of cells in the supercapacitor cell non-working sequence is less than the number of supercapacitor cells to be called, the difference between the two is calculated as the number of cells to be supplemented, and the number of cells to be supplemented is calculated according to the small amount of stored electricity. Select supercapacitor cells that meet the requirements as candidate cells from the supercapacitor cell working sequence according to the standard of the first set threshold value, until the number of candidate cells is equal to the number of cell supplements, use the cells in the supercapacitor cell non-working sequence and the candidate cells as working cells, delete the working cells from the supercapacitor cell non-working sequence and the supercapacitor cell working sequence, store energy based on the working cells, and when the first ratio is less than the judgment threshold, determine the number of supercapacitor cells that need to be called according to the fluctuation adjustment size, select supercapacitor cells that meet the requirements as candidate cells from the supercapacitor cell working sequence according to the standard that the storage capacity is greater than the second set threshold value, until the number of candidate cells is equal to the number of supercapacitor cells that need to be called, use the candidate cells as working cells, delete the working cells from the supercapacitor cell working sequence, replenish energy based on the working cells, and when the time reaches the end point of the unit time period, add the condensed state number of the working cell to the end of the supercapacitor cell working sequence.

[0014] Compared with the prior art, the present invention has the following beneficial effects: The photovoltaic energy storage system adopts a hybrid energy storage structure, predicts the working status of the photovoltaic microgrid, and sets the corresponding energy storage mode in advance, making the energy storage control more timely and flexible. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a flow chart of the energy management method of the present invention. DETAILED DESCRIPTION

[0016] The technical solution of the present invention is described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0017] The photovoltaic microgrid includes a photovoltaic array and a photovoltaic energy storage system. The photovoltaic array is connected to the DC bus through a DC-DC module, and the photovoltaic energy storage system is connected to the DC bus. The DC bus is connected to the AC bus through a DC-AC module, and the power load module is connected to the AC bus. The photovoltaic energy storage system includes condensed matter batteries, lithium-ion liquid flow batteries, supercapacitors and a central control device. The condensed matter batteries, lithium-ion liquid flow batteries and supercapacitors are connected to the central control device through a DC-DC module, and the central control device is connected to the DC bus.

[0018] Condensed matter batteries are composed of multiple condensed matter battery cells connected in parallel, each condensed matter battery cell has a specific condensed matter number, and each condensed matter battery cell has a control switch that can control whether the condensed matter battery cell is connected to the condensed matter battery for operation. Lithium-ion flow batteries are composed of multiple lithium-ion flow battery cells connected in parallel, each lithium-ion flow battery cell has a specific flow battery number, and each lithium-ion flow battery cell has a control switch that can control whether the lithium-ion flow battery cell is connected to the lithium-ion flow battery for operation. Supercapacitors are composed of multiple supercapacitor cells connected in parallel, each supercapacitor cell has a specific capacitor number, and each supercapacitor cell has a control switch that can control whether the supercapacitor cell is connected to the supercapacitor for operation.

[0019] The central control device is internally provided with a condensed state battery cell non-working sequence, a condensed state battery cell working sequence, a lithium ion flow battery cell non-working sequence, a lithium ion flow battery cell working sequence, a supercapacitor cell non-working sequence and a supercapacitor cell working sequence. The condensed state battery cell non-working sequence is used to record the condensed state numbers of the condensed state battery cells that have never worked among the condensed state battery cells, and the condensed state battery cell working sequence records the condensed state numbers of the condensed state battery cells in the order of working. The lithium ion flow battery cell non-working sequence is used to record the flow battery numbers of the lithium ion flow battery cells that have never worked among the lithium ion flow battery cells, and the lithium ion flow battery cell working sequence records the flow battery numbers of the lithium ion flow battery cells in the order of working. The supercapacitor cell non-working sequence is used to record the capacitance numbers of the supercapacitor cells that have never worked among the supercapacitor cells, and the supercapacitor cell working sequence records the capacitance numbers of the supercapacitor cells in the order of working.

[0020] The energy management method of the photovoltaic energy storage system includes the following steps: S1. Establish a photovoltaic power generation prediction model and a power load prediction model. The photovoltaic power generation prediction model fits the nonlinear relationship between environmental factors such as light and temperature and photovoltaic power generation through a polynomial function. The power load prediction adopts an autoregressive integral moving average model, which can obtain the trend and seasonality in the historical power consumption data. By analyzing the historical power consumption data, the power consumption at a certain point in the future can be predicted.

[0021] S2. Outputting the photovoltaic power generation power curve within a first preset time interval (eg, 4 hours) through the photovoltaic power generation prediction model, outputting the power load power curve within a first preset time interval (eg, 4 hours) through the power load prediction model, and starting the timing from zero.

[0022] S3. Determine a stable time period and a fluctuating time period according to the photovoltaic power generation power curve, and set energy storage modes for the stable time period and the fluctuating time period.

[0023] The specific process of determining the stable time period and the fluctuating time period according to the photovoltaic power generation curve is to divide the photovoltaic power generation curve into multiple unit time periods according to the unit time interval (for example, 10 minutes), mark each unit time period as power balance, power regulation, or power fluctuation, merge the unit time periods with the same mark, obtain the merged marked time period, and use the marked time period marked as power regulation as the stable time period, and use the marked time period marked as power fluctuation as the fluctuating time period. The specific process of marking the unit time period is to calculate the average photovoltaic power generation power within the unit time period, calculate the percentage change of each power node relative to the average photovoltaic power generation power within the unit time period, select the maximum value of the absolute value of the percentage change, if the maximum value is greater than the first change threshold (for example, 50%), then mark the unit time period as power fluctuation, otherwise, obtain the power curve of the power load, select the part corresponding to the unit time period, calculate the corresponding power average of the power load, if the difference between the average photovoltaic power generation power and the average power of the power load is less than the second change threshold, mark the unit time period as power balance, otherwise, mark the unit time period as power regulation.

[0024] The specific process of setting the energy storage mode for the stable time period is to screen the minimum photovoltaic power generation power within the stable time period, select the part corresponding to the stable time period in the power curve of the power load, screen the maximum power of the power load therein, calculate the absolute value of the difference between the minimum photovoltaic power generation power and the maximum power of the power load, use it as the power adjustment size, calculate the interval length of the stable time period, if the interval length is greater than the first time threshold, select the lithium-ion liquid flow battery as the energy storage adjustment module, and the lithium-ion liquid flow battery is controlled based on the power adjustment size, if the interval length is less than or equal to the first time threshold, select the condensed matter battery and the lithium-ion liquid flow battery as the energy storage adjustment module, divide the power adjustment size into a first power adjustment size and a second power adjustment size, the condensed matter battery is controlled based on the first power adjustment size, and the lithium-ion liquid flow battery is controlled based on the second power adjustment size.

[0025] The specific process of setting the energy storage mode for the fluctuation time period is to screen the maximum photovoltaic power generation power, the minimum photovoltaic power generation power and the average photovoltaic power generation power within the fluctuation time period, calculate the first difference between the maximum photovoltaic power generation power and the average photovoltaic power generation power, calculate the second difference between the average photovoltaic power generation power and the minimum photovoltaic power generation power, select the larger value of the first difference and the second difference as the fluctuation adjustment size, select the supercapacitor as the fluctuation adjustment module, and control the supercapacitor based on the fluctuation adjustment size, select the part corresponding to the stable time period in the power curve of the power load, calculate the corresponding average power of the power load, and use the absolute value of the difference between the average photovoltaic power generation power and the average power of the power load as the power adjustment size, select the condensed matter battery as the energy storage adjustment module, and control the condensed matter battery based on the power adjustment size.

[0026] S4. Perform energy storage control based on the set energy storage mode, collect and record the actual photovoltaic power generation power and electrical load power, and determine whether the timing time is equal to the first preset time interval. If so, enter S5.

[0027] The process of controlling the condensed state battery based on the power regulation size is to divide the stable time period or the fluctuating time period into multiple unit time periods according to the unit time interval. When the time reaches the starting point of the unit time period, the average photovoltaic power generation power within the unit time period is calculated according to the photovoltaic power generation power curve, and the average power load power within the unit time period is calculated according to the power load power curve. When the average photovoltaic power generation power is greater than the average power load power, the number of condensed state battery cells that need to be called is determined according to the power regulation size. If the number of cells in the non-working sequence of the condensed state battery cells is greater than or equal to the number of condensed state battery cells that need to be called, the condensed state battery cells are selected from the non-working sequence of the condensed state battery cells as working cells, and the working cells are deleted from the non-working sequence of the condensed state battery cells. Energy is stored based on the working cells. If the number of cells in the non-working sequence of the condensed state battery cells is less than the number of condensed state battery cells that need to be called, the difference between the two is calculated as the number of cells to be supplemented, and the cells are removed from the non-working sequence of the condensed state battery cells according to the standard that the stored power is less than the first set threshold. In the condensed state battery monomer working sequence, the condensed state battery monomers that meet the requirements are selected as candidate monomers until the number of candidate monomers is equal to the number of monomer supplements, the monomers in the condensed state battery monomer non-working sequence and the candidate monomers are used as working monomers, the working monomers are deleted from the condensed state battery monomer non-working sequence and the condensed state battery monomer working sequence, and energy is stored based on the working monomers. When the average power of photovoltaic power generation is less than the average power of the power load, the number of condensed state battery monomers that need to be called is determined according to the power adjustment size, and the condensed state battery monomers that meet the requirements are selected from the condensed state battery monomer working sequence according to the standard that the storage capacity is greater than the second set threshold value as candidate monomers, until the number of candidate monomers is equal to the number of condensed state battery monomers that need to be called, the candidate monomers are used as working monomers, the working monomers are deleted from the condensed state battery monomer working sequence, and energy is supplemented based on the working monomers. When the time reaches the end point of the unit time period, the condensed state number of the working monomer is added to the end of the condensed state battery monomer working sequence.

[0028] The process of controlling the lithium-ion liquid flow battery based on the power regulation size is to divide the stable time period into multiple unit time periods according to the unit time interval. When the time reaches the starting point of the unit time period, the average photovoltaic power generation power in the unit time period is calculated according to the photovoltaic power generation power curve, and the average power of the power load in the unit time period is calculated according to the power load power curve. When the average photovoltaic power generation power is greater than the average power of the power load, the number of lithium-ion liquid flow battery cells that need to be called is determined according to the power regulation size. If the number of cells in the non-working sequence of lithium-ion liquid flow battery cells is greater than or equal to the number of lithium-ion liquid flow battery cells that need to be called, the lithium-ion liquid flow battery cells are selected from the non-working sequence of lithium-ion liquid flow battery cells as working cells, and the working cells are deleted from the non-working sequence of lithium-ion liquid flow battery cells. Energy storage is performed based on the working cells. If the number of cells in the non-working sequence of lithium-ion liquid flow battery cells is less than the number of lithium-ion liquid flow battery cells that need to be called, the difference between the two is calculated as the number of cells to be supplemented, and the lithium-ion liquid flow battery cells are selected according to the standard that the storage capacity is less than the first set threshold. Select lithium-ion liquid flow battery cells that meet the requirements from the working sequence of the sub-liquid flow battery cells as candidate cells until the number of candidate cells is equal to the number of cell supplements, use the cells in the non-working sequence of the lithium-ion liquid flow battery cells and the candidate cells as working cells, delete the working cells from the non-working sequence of the lithium-ion liquid flow battery cells and the working sequence of the lithium-ion liquid flow battery cells, store energy based on the working cells, and determine the number of lithium-ion liquid flow battery cells that need to be called according to the power adjustment size when the average photovoltaic power generation power is less than the average power of the power load, select lithium-ion liquid flow battery cells that meet the requirements from the working sequence of the lithium-ion liquid flow battery cells according to the standard that the storage capacity is greater than the second set threshold value as candidate cells until the number of candidate cells is equal to the number of lithium-ion liquid flow battery cells that need to be called, use the candidate cells as working cells, delete the working cells from the working sequence of the lithium-ion liquid flow battery cells, and replenish energy based on the working cells. When the time reaches the end point of the unit time period, add the condensed state number of the working cell to the end of the working sequence of the lithium-ion liquid flow battery cells.

[0029] The process of controlling the supercapacitor based on the fluctuation adjustment size is to divide the stable time period into multiple unit time periods according to the unit time interval. When the time reaches the starting point of the unit time period, the average photovoltaic power generation power in the unit time period is calculated according to the photovoltaic power generation power curve, and the first proportion of nodes with power greater than the average photovoltaic power generation power in each power node in the unit time period is calculated. When the first proportion is greater than the judgment threshold, the number of supercapacitor cells that need to be called is determined according to the fluctuation adjustment size. If the number of cells in the supercapacitor cell non-working sequence is greater than or equal to the number of supercapacitor cells that need to be called, a supercapacitor cell is selected from the supercapacitor cell non-working sequence as a working cell, and the working cell is deleted from the supercapacitor cell non-working sequence. Energy is stored based on the working cell. If the number of cells in the supercapacitor cell non-working sequence is less than the number of supercapacitor cells that need to be called, the difference between the two is calculated as the number of cells to be supplemented, and the storage capacity is less than the first set threshold. The standard of the value is to select supercapacitor monomers that meet the requirements from the supercapacitor monomer working sequence as candidate monomers until the number of candidate monomers is equal to the number of monomer supplements, and the monomers in the supercapacitor monomer non-working sequence and the candidate monomers are used as working monomers, and the working monomers are deleted from the supercapacitor monomer non-working sequence and the supercapacitor monomer working sequence. Energy storage is performed based on the working monomers. When the first ratio is less than the judgment threshold, the number of supercapacitor monomers to be called is determined according to the fluctuation adjustment size, and the supercapacitor monomers that meet the requirements are selected from the supercapacitor monomer working sequence according to the standard that the storage capacity is greater than the second set threshold as candidate monomers, until the number of candidate monomers is equal to the number of supercapacitor monomers to be called, and the candidate monomers are used as working monomers, and the working monomers are deleted from the supercapacitor monomer working sequence, and energy is supplemented based on the working monomers. When the time reaches the end point of the unit time period, the condensed state number of the working monomer is added to the end of the supercapacitor monomer working sequence.

[0030] S5. Use the recorded actual photovoltaic power generation power and power load power as training data to continue training the photovoltaic power generation prediction model and the power load prediction model. After the training is completed, return to S2.

[0031] The above disclosure is only the preferred embodiment of the present invention, and certainly cannot be used to limit the scope of the present invention. It should be pointed out that for those skilled in the art, any equivalent changes made to the scheme of the present invention without departing from the design structure and principle of the present invention are considered to be within the protection scope of the present invention.

Claims

1. An energy management method for a photovoltaic energy storage system, characterized in that: The photovoltaic energy storage system comprises a condensed state battery, a lithium ion flow battery, a super capacitor and a central control device, wherein the condensed state battery, the lithium ion flow battery and the super capacitor are connected to the central control device, and the central control device is internally provided with a condensed state battery monomer non-working sequence, a condensed state battery monomer working sequence, a lithium ion flow battery monomer non-working sequence, a lithium ion flow battery monomer working sequence, a super capacitor monomer non-working sequence and a super capacitor monomer working sequence; The energy management method of the photovoltaic energy storage system includes the following steps: S1. Establishing photovoltaic power generation prediction model and power load prediction model; S2, outputting a photovoltaic power generation curve within a first preset time interval through a photovoltaic power generation prediction model, outputting a power load power curve within a first preset time interval through a power load prediction model, and starting timing from zero; S3. Determine the stable time period and the fluctuating time period according to the photovoltaic power generation power curve, and set the energy storage mode for the stable time period and the fluctuating time period; S4, performing energy storage control based on the set energy storage mode, collecting and recording the actual photovoltaic power generation and power load power, and determining whether the timing time is equal to the first preset time interval. If so, proceed to S5; S5. Use the recorded actual photovoltaic power generation power and power load power as training data to continue training the photovoltaic power generation prediction model and the power load prediction model. After the training is completed, return to S2.

2. The energy management method according to claim 1, characterized in that: The condensed matter battery is composed of a plurality of condensed matter battery cells connected in parallel, each condensed matter battery cell has a specific condensed matter number, the lithium ion liquid flow battery is composed of a plurality of lithium ion liquid flow battery cells connected in parallel, each lithium ion liquid flow battery cell has a specific liquid flow battery number, and the supercapacitor is composed of a plurality of supercapacitor cells connected in parallel, each supercapacitor cell has a specific capacitance number.

3. The energy management method according to claim 2, characterized in that: Each condensed matter battery cell has a control switch that can control whether the condensed matter battery cell is connected to the condensed matter battery for operation. Each lithium ion flow battery cell has a control switch that can control whether the lithium ion flow battery cell is connected to the lithium ion flow battery for operation. Each supercapacitor cell has a control switch that can control whether the supercapacitor cell is connected to the supercapacitor for operation.

4. The energy management method according to claim 1, characterized in that: In S3, the specific process of determining the stable time period and the fluctuating time period according to the photovoltaic power generation power curve is to divide the photovoltaic power generation power curve into multiple unit time periods according to the unit time interval, mark each unit time period as power balance, power regulation, or power fluctuation, merge the unit time periods with the same mark to obtain the merged marked time periods, and use the marked time period marked as power regulation as the stable time period, and use the marked time period marked as power fluctuation as the fluctuating time period.

5. The energy management method according to claim 4, characterized in that: In the S3, the specific process of marking the unit time period is to calculate the average photovoltaic power generation power within the unit time period, calculate the change percentage of each power node relative to the average photovoltaic power generation power within the unit time period, select the maximum value of the absolute value of the change percentage, if the maximum value is greater than the first change threshold, then the unit time period is marked as power fluctuation, otherwise, obtain the power curve of the power load, select the part corresponding to the unit time period, calculate the corresponding power average of the power load, if the difference between the average photovoltaic power generation power and the average power of the power load is less than the second change threshold, the unit time period is marked as power balance, otherwise, the unit time period is marked as power regulation.

6. The energy management method according to claim 1, characterized in that: In the S3, the specific process of setting the energy storage mode of the stable time period is to screen the minimum photovoltaic power generation power within the stable time period, select the part corresponding to the stable time period in the power curve of the power load, screen the maximum power of the power load therein, calculate the absolute value of the difference between the minimum photovoltaic power generation power and the maximum power of the power load, use it as the power adjustment size, calculate the interval length of the stable time period, if the interval length is greater than the first time threshold, select the lithium ion liquid flow battery as the energy storage adjustment module, and the lithium ion liquid flow battery is controlled based on the power adjustment size, if the interval length is less than or equal to the first time threshold, select the condensed state battery and the lithium ion liquid flow battery as the energy storage adjustment module, divide the power adjustment size into a first power adjustment size and a second power adjustment size, the condensed state battery is controlled based on the first power adjustment size, and the lithium ion liquid flow battery is controlled based on the second power adjustment size.

7. The energy management method according to claim 6, characterized in that: In the S3, the specific process of setting the energy storage mode for the fluctuation time period is to screen the maximum value, minimum value and average value of photovoltaic power generation power within the fluctuation time period, calculate the first difference between the maximum value and the average value of photovoltaic power generation power, calculate the second difference between the average value and the minimum value of photovoltaic power generation power, select the larger value of the first difference and the second difference as the fluctuation adjustment size, select the supercapacitor as the fluctuation adjustment module, and control the supercapacitor based on the fluctuation adjustment size, select the part corresponding to the stable time period in the power curve of the power load, calculate the corresponding average power of the power load, use the absolute value of the difference between the average value of photovoltaic power generation power and the average power of the power load as the power adjustment size, select the condensed matter battery as the energy storage adjustment module, and control the condensed matter battery based on the power adjustment size.

8. The energy management method according to claim 7, characterized in that: In the S4, the process of controlling the condensed state battery based on the power regulation size is to divide the stable time period or the fluctuating time period into multiple unit time periods according to the unit time interval. When the time reaches the starting point of the unit time period, the average photovoltaic power generation power in the unit time period is calculated according to the photovoltaic power generation power curve, and the average power load power in the unit time period is calculated according to the power load power curve. When the average photovoltaic power generation power is greater than the average power load power, the number of condensed state battery cells that need to be called is determined according to the power regulation size. If the number of cells in the non-working sequence of the condensed state battery cells is greater than or equal to the number of condensed state battery cells that need to be called, the condensed state battery cells are selected from the non-working sequence of the condensed state battery cells as working cells, and the working cells are deleted from the non-working sequence of the condensed state battery cells. Energy is stored based on the working cells. If the number of cells in the non-working sequence of the condensed state battery cells is less than the number of condensed state battery cells that need to be called, the difference between the two is calculated as the number of cells to be supplemented, and the storage capacity is less than the first setting. According to the standard of a certain threshold, condensed state battery cells that meet the requirements are selected as candidate cells from the condensed state battery cell working sequence, until the number of candidate cells is equal to the number of cell supplements, the cells in the non-working sequence of the condensed state battery cells and the candidate cells are used as working cells, the working cells are deleted from the non-working sequence of the condensed state battery cells and the working sequence of the condensed state battery cells, energy storage is performed based on the working cells, when the average power of photovoltaic power generation is less than the average power of the power load, the number of condensed state battery cells that need to be called is determined according to the power adjustment size, and the condensed state battery cells that meet the requirements are selected as candidate cells from the condensed state battery cell working sequence according to the standard that the storage capacity is greater than the second set threshold, until the number of candidate cells is equal to the number of condensed state battery cells that need to be called, the candidate cells are used as working cells, the working cells are deleted from the condensed state battery cell working sequence, energy is supplemented based on the working cells, and when the time reaches the end point of the unit time period, the condensed state number of the working cell is added to the end of the condensed state battery cell working sequence.

9. The energy management method according to claim 7, characterized in that: In the S4, the process of controlling the lithium-ion liquid flow battery based on the power regulation size is to divide the stable time period into multiple unit time periods according to the unit time interval. When the time reaches the starting point of the unit time period, the average photovoltaic power generation power in the unit time period is calculated according to the photovoltaic power generation power curve, and the average power of the power load in the unit time period is calculated according to the power load power curve. When the average photovoltaic power generation power is greater than the average power of the power load, the number of lithium-ion liquid flow battery cells that need to be called is determined according to the power regulation size. If the number of cells in the non-working sequence of lithium-ion liquid flow battery cells is greater than or equal to the number of lithium-ion liquid flow battery cells that need to be called, a lithium-ion liquid flow battery cell is selected from the non-working sequence of lithium-ion liquid flow battery cells as a working cell, and the working cell is deleted from the non-working sequence of lithium-ion liquid flow battery cells. Energy is stored based on the working cell. If the number of cells in the non-working sequence of lithium-ion liquid flow battery cells is less than the number of lithium-ion liquid flow battery cells that need to be called, the difference between the two is calculated as the number of cells to be supplemented, and the standard that the storage capacity is less than the first set threshold is used. Select lithium-ion liquid flow battery cells that meet the requirements from the lithium-ion liquid flow battery cell working sequence as candidate cells until the number of candidate cells is equal to the number of cell supplements, use the cells in the lithium-ion liquid flow battery cell non-working sequence and the candidate cells as working cells, delete the working cells from the lithium-ion liquid flow battery cell non-working sequence and the lithium-ion liquid flow battery cell working sequence, store energy based on the working cells, and determine the number of lithium-ion liquid flow battery cells that need to be called according to the power adjustment size when the average photovoltaic power generation power is less than the average power of the power load, select lithium-ion liquid flow battery cells that meet the requirements from the lithium-ion liquid flow battery cell working sequence according to the standard that the storage capacity is greater than the second set threshold value as candidate cells, until the number of candidate cells is equal to the number of lithium-ion liquid flow battery cells that need to be called, use the candidate cells as working cells, delete the working cells from the lithium-ion liquid flow battery cell working sequence, replenish energy based on the working cells, and when the time reaches the end point of the unit time period, add the condensed state number of the working cell to the end of the lithium-ion liquid flow battery cell working sequence.

10. The energy management method according to claim 7, characterized in that: In the S4, the process of controlling the supercapacitor based on the fluctuation adjustment size is to divide the stable time period into multiple unit time periods according to the unit time interval, when the time reaches the starting point of the unit time period, the average photovoltaic power generation power in the unit time period is calculated according to the photovoltaic power generation power curve, and the first proportion of nodes with power greater than the average photovoltaic power generation power in each power node in the unit time period is calculated. When the first proportion is greater than the judgment threshold, the number of supercapacitor cells that need to be called is determined according to the fluctuation adjustment size. If the number of cells in the supercapacitor cell non-working sequence is greater than or equal to the number of supercapacitor cells that need to be called, a supercapacitor cell is selected from the supercapacitor cell non-working sequence as a working cell, and the working cell is deleted from the supercapacitor cell non-working sequence. Energy is stored based on the working cell. If the number of cells in the supercapacitor cell non-working sequence is less than the number of supercapacitor cells that need to be called, the difference between the two is calculated as the number of cells to be supplemented, and the storage capacity is less than the first A supercapacitor cell that meets the requirements is selected as an alternative cell from the supercapacitor cell working sequence according to a set threshold standard, until the number of alternative cells is equal to the number of cells to be supplemented, the cells in the supercapacitor cell non-working sequence and the alternative cells are used as working cells, the working cells are deleted from the supercapacitor cell non-working sequence and the supercapacitor cell working sequence, energy is stored based on the working cells, when the first ratio is less than the judgment threshold, the number of supercapacitor cells to be called is determined according to the fluctuation adjustment size, and supercapacitor cells that meet the requirements are selected as alternative cells from the supercapacitor cell working sequence according to the standard that the storage capacity is greater than the second set threshold, until the number of alternative cells is equal to the number of supercapacitor cells to be called, the alternative cells are used as working cells, the working cells are deleted from the supercapacitor cell working sequence, energy is supplemented based on the working cells, and when the time reaches the end point of the unit time period, the condensed state number of the working cell is added to the end of the supercapacitor cell working sequence.

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