A Coordinated Control Method for Photovoltaic Power Generation and Energy Storage Based on Power Prediction

Abstract

This invention relates to a method for coordinated control of photovoltaic (PV) power generation and energy storage based on power prediction. This method achieves coordinated control of the PV power prediction system and the energy storage system under joint operation of the PV power plant and energy storage system. It considers both the PV power plant's operating status and the energy storage system's status in the PV power prediction process, and reduces power prediction requirements based on the energy storage system's charge and discharge control, while adapting to different operating modes of the power plant and reducing the amount of electricity supplied to the grid. Compared with existing technologies, this invention has the advantages of achieving efficient coordinated interaction between the PV power generation system and the energy storage system, while further improving the efficient utilization of the energy storage system in the PV power plant.

Description

Technical Field

[0001] This invention relates to the field of energy storage control technology, and in particular to a method for coordinated control of photovoltaic power generation and energy storage based on power prediction. Background Technology

[0002] Under the dual-carbon goals, photovoltaic (PV) power generation has developed rapidly across China in recent years due to its clean, efficient, and renewable nature. However, PV power generation is susceptible to external environmental influences, resulting in unstable and highly volatile output. The grid's absorption capacity and power system regulation resources, commensurate with its development scale, are facing increasing challenges. Introducing energy storage technology can achieve energy transfer, reduce power fluctuations, and smooth power output. The combined operation of PV and energy storage has become an effective means to address these issues. Currently, the application and control of energy storage in PV power generation systems mainly focus on reducing PV power fluctuations and collaboratively participating in grid ancillary services. The energy storage system and PV power generation are independent of each other, typically employing a control method where the energy storage system passively receives power prediction results and PV power generation data to calculate active or reactive power compensation. Furthermore, the short-term (24-hour) and ultra-short-term (4-hour) power predictions of PV power plant prediction systems are calculated using only meteorological forecast data and historical data from the plant, employing physical, statistical, and deep learning methods. Due to the influence of the prediction time scale, the accuracy of the two prediction methods differs significantly, and factors such as the operating status of the PV plant and the energy storage system are not taken into account. Currently, the integrated operation and control of photovoltaic and energy storage systems has not been able to achieve efficient synergy and interaction between the photovoltaic power generation system and the energy storage system. The efficient utilization of energy storage systems in photovoltaic power plants needs to be further improved. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the existing technology and provide a method for coordinated control of photovoltaic power generation and energy storage based on power prediction.

[0004] The objective of this invention can be achieved through the following technical solutions:

[0005] According to one aspect of the present invention, a method for coordinated control of photovoltaic power generation and energy storage based on power prediction is provided, which realizes coordinated control of photovoltaic power prediction system and energy storage system under the joint operation mode of photovoltaic power plant and energy storage system;

[0006] In photovoltaic power prediction, the operating status of photovoltaic power plants and the status of energy storage systems are considered together. Based on the charging and discharging control of energy storage systems, the power prediction assessment is reduced while adapting to the different operating modes of the power plants and reducing the amount of electricity sent to the grid from the power plants.

[0007] As a preferred technical solution, the method specifically includes the following steps:

[0008] Step 1: Calculate the average nighttime power consumption Q of the photovoltaic power station within the set time period;

[0009] Step 2: The power prediction system calculates the short-term power prediction data P for the next 24 hours. di The short-term power forecast data is revised based on the power plant's nighttime power demand and then reported to the power grid dispatch center.

[0010] Step 3: The power prediction system calculates the ultra-short-term power prediction data P for the next 4 hours. ci Based on the state of charge of the energy storage system and the correction of power based on short-term power forecasts, the ultra-short-term power forecast data is corrected and then reported to the grid dispatch.

[0011] Step 4: The energy storage system performs charge and discharge control based on the power prediction deviation. When the photovoltaic power generation is less than the plant power at night, it enters the plant power control mode.

[0012] As a preferred technical solution, the time set in step 1 is approximately one week.

[0013] As a preferred technical solution, the short-term power prediction data P di The correction process is as follows:

[0014]

[0015] in, P′ di P is the short-term predicted power actually reported at time i. m Δ is the maximum charging power for energy storage. di This is the correction amount for the short-term predicted power at time i.

[0016] As a preferred technical solution, the ultra-short-term power prediction data P ci The correction process is as follows:

[0017] P′ ci =P ci -Δ ci ;

[0018] in,

[0019] P′ ci for i The actual reported ultra-short-term power prediction data at any given time, P m Δ is the maximum charging power for energy storage. i-1 The ultra-short-term prediction bias Δ at time i-1 i-1 =P i-1 -P′ ci-1 P i-1 and P′ ci-1These represent the actual photovoltaic power generation at time i-1 and the actual reported ultra-short-term power prediction data, respectively, with SOC representing the state of charge of the energy storage system.

[0020] As a preferred technical solution, this method controls the power output according to a setting where the discharge power is equal to or greater than the plant's power consumption, thereby reducing the amount of electricity discharged from the photovoltaic power station.

[0021] As a preferred technical solution, this method stops energy storage discharge when the energy storage SOC is less than a set threshold in the energy storage power supply mode.

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] 1) This invention solves the problem of efficient coordinated control of photovoltaic and energy storage, realizes efficient coordinated interaction between photovoltaic power generation system and energy storage system, and further improves the efficient utilization of energy storage system in photovoltaic power station;

[0024] 2) This invention takes into account the operating status of the photovoltaic power plant and the status of the energy storage system in photovoltaic power prediction. While reducing the power prediction assessment based on the charging and discharging control of the energy storage system, it adapts to the different operating modes of the plant, reduces the amount of electricity sent to the grid in the plant's power consumption, and improves the overall operating economy of the photovoltaic plant.

[0025] 3) This invention provides short-term power prediction data P di and ultra-short-term power prediction data P ci Modifications were made to further improve control precision;

[0026] 4) In the energy storage power supply mode of this invention, if the energy storage SOC is less than a certain value, the energy storage discharge will be stopped to ensure the life safety of the energy storage system. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the control system structure of the present invention. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0029] like Figure 1As shown, the control system corresponding to the photovoltaic power generation and energy storage coordinated control method based on power prediction of the present invention includes a power prediction system and an energy storage control system. In photovoltaic power prediction, the operating status of the photovoltaic power station and the status of the energy storage system are considered in a coordinated manner. While reducing the power prediction assessment based on the charging and discharging control of the energy storage system, it adapts to the needs of different operating modes of the power station, reduces the amount of electricity sent to the grid in the power station's plant power consumption, and improves the overall operating economy of the photovoltaic power station. Specific Implementation

[0031] A 100MW photovoltaic power station is equipped with a 5MW / 10MWh battery energy storage capacity, achieving coordinated operation of photovoltaic and energy storage systems.

[0032] 1) The average nighttime power consumption of the photovoltaic power station over the past week was 1000 kWh;

[0033] 2) The power prediction system calculates the short-term power prediction data P for the next 24 hours. di (P di for i The short-term power forecast data (at time m) is assumed to be zero since the photovoltaic power generation of the photovoltaic power station is zero at night. The short-term power forecast data from time m to n is corrected according to the following conditions, and the corrected short-term power forecast data is then reported to the grid dispatch center.

[0034]

[0035] in, P′ di for i The short-term forecast power actually reported at each moment, P m This represents the maximum charging power for energy storage.

[0036] 3) The power prediction system calculates the ultra-short-term power prediction data P for the next 4 hours. ci (P ci for i (Ultra-short-term power forecast at any given time). Based on the correction of power based on the state of charge of the energy storage system and short-term power forecast, the ultra-short-term power forecast data shall be corrected according to the following conditions, and the corrected ultra-short-term power forecast data shall be reported to the grid dispatch.

[0037] P′ ci =P ci -Δ ci

[0038] in,

[0039] Δ i-1 The ultra-short-term prediction bias Δ at the previous moment i-1 =P i-1 -P′ci-1 P i-1 This represents the actual photovoltaic power generation at the previous moment.

[0040] 4) The energy storage system controls charging and discharging based on power prediction deviations;

[0041] 5) When the photovoltaic power generation is less than the plant's power consumption at night, the energy storage enters the discharge mode and is controlled according to the setting that the discharge power is slightly greater than the plant's power consumption, thereby reducing the amount of electricity sent to the grid from the photovoltaic power station;

[0042] 6) In the energy storage power supply mode, if the energy storage SOC is less than 30%, the energy storage discharge will be stopped to ensure the life safety of the energy storage system.

[0043] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A power prediction based photovoltaic power generation and energy storage collaborative control method, characterized in that, The method realizes the coordinated control of the photovoltaic power prediction system and the energy storage system under the combined operation mode of the photovoltaic power station and the energy storage system; In the photovoltaic power prediction, the operation state of the photovoltaic power station and the state of the energy storage system are considered in coordination, and based on the charge and discharge control of the energy storage system, the power prediction examination is reduced, the demand of the station under different operation modes is adapted, and the off-grid power in the station auxiliary power is reduced; The method specifically comprises the following steps: Step 1, counting the average auxiliary power of the photovoltaic power station at night within a set time Q; Step 2, the power prediction system calculates short-term power prediction data P for the next 24 hours di , and reports the power grid dispatch after the short-term power prediction data is corrected according to the power plant night electricity demand; Step 3, the power prediction system calculates the ultra-short-term power prediction data P of the next 4h ci , according to the state of charge of the energy storage system and the short-term power prediction, the ultra-short-term power prediction data is corrected and reported to the grid dispatch; Step 4, the energy storage system performs charge and discharge control according to the power prediction deviation, and when the photovoltaic power at night is less than the auxiliary power, enters the auxiliary power control mode; The ultra-short-term power prediction data P ci The correction process is specifically: P' ci = P ci - Δ ci ; Wherein, P′ ci is the actual reported ultra-short-term power prediction data at time i, P m is the maximum charging power of the energy storage, Δ i-1 is the ultra-short-term prediction deviation at time i-1 i-1 = P i-1 -P′ ci-1 , P i-1 and P′ ci-1 are the actual power generation of the photovoltaic and the actual reported ultra-short-term power prediction data at time i-1, SOC is the state of charge of the energy storage system, Δ di is the correction amount of the short-term prediction power at time i.

2. The photovoltaic power generation and energy storage collaborative control method based on power prediction according to claim 1, characterized in that, The set time in step 1 is nearly a week. 3.The power prediction based photovoltaic power generation and energy storage collaborative control method according to claim 1, characterized in that, The short-term power prediction data P di The correction process is specifically: wherein, P′ di is the actual short-term predicted power reported at time i, P m is the maximum charging power of the energy storage, Δ di is the correction amount of the short-term predicted power at time i.

4. The photovoltaic power generation and energy storage collaborative control method based on power prediction according to claim 1, characterized in that, The method controls according to the setting that the discharge power is equal to or greater than the auxiliary power, so as to reduce the off-grid power of the photovoltaic station.

5. The photovoltaic power generation and energy storage collaborative control method based on power prediction according to claim 1, characterized in that, In the energy storage auxiliary power mode, if the SOC of the energy storage is less than the set threshold, the discharge of the energy storage is stopped.

Images