A wind-solar power storage station and an output control method thereof

Abstract

The application provides a wind-solar-storage power station and an output control method thereof. The method first acquires the power of each system and the SOC of the energy storage system, and determines the power upper limit reference value of the wind-solar-storage power station. Then, when the sum of the powers of each system is greater than the power upper limit reference value, the power of each system is reduced; and when the sum of the powers of each system is less than the power upper limit reference value, the power of each system is increased; until the difference between the sum of the powers of each system and the power upper limit reference value is within a preset range, so that the wind-solar-storage power station can reach the power upper limit reference value as much as possible, and the power is maximized. In addition, before adjusting the power of each system, the working mode allowed to enter by the energy storage system is determined according to the SOC, so as to avoid overcharging and overdischarging. Moreover, when the power is reduced, the energy storage system is given the highest priority, and when the power is increased, the energy storage system is given the lowest priority, so that the energy storage system can maintain a relatively high SOC as much as possible, and the SOC is ensured to be in a good state.

Description

Technical Field

[0001] This application relates to the field of new energy power generation technology, and in particular to a wind-solar-storage power station and its output control method. Background Technology

[0002] Wind and solar power generation are complementary, and power plants equipped with energy storage can further ensure grid connection stability. Low-voltage coupling of wind, solar, and energy storage can compensate for wasted power generation and save on transmission costs. However, there is currently a lack of corresponding control strategies to maximize the output of low-voltage coupling while ensuring the energy storage's State of Charge (SOC) remains in optimal condition. Summary of the Invention

[0003] In view of this, this application provides a wind-solar-storage power station and its output control method, so as to maximize the low-voltage coupling output of wind, solar and storage while ensuring that the SOC of energy storage is in a good state.

[0004] To achieve the above objectives, this application provides the following technical solution:

[0005] The first aspect of this application provides a power output control method for a wind-solar-storage power station, wherein a wind power system, a photovoltaic system, and an energy storage system are connected in parallel on the input side of a transformer in the wind-solar-storage power station, and the power output control method includes:

[0006] The power of each system and the state of charge (SOC) of the energy storage system are obtained, and the upper limit reference value of the power of the wind-solar-storage power station is determined.

[0007] The permitted operating modes of the energy storage system are determined based on the SOC.

[0008] When the sum of the power of all systems is greater than the power upper limit reference value, the energy storage system is given the highest priority and the power of each system is reduced; when the sum of the power of all systems is less than the power upper limit reference value, the energy storage system is given the lowest priority and the power of each system is increased.

[0009] Until the difference between the sum of the power of each system and the power upper limit reference value is within a preset range.

[0010] Optionally, when reducing the power of each system, the priority order of each system from high to low is: the energy storage system, the photovoltaic system, and the wind power system.

[0011] Optionally, prioritizing the energy storage system and reducing the power of each system, including:

[0012] When determining the power of the energy storage system to be the minimum output value under its current allowed operating mode, check whether the sum of the power of each system is greater than or equal to the power upper limit reference value.

[0013] If so, the energy storage system is controlled to exit the discharge mode or enter the charging mode;

[0014] Otherwise, the power of the energy storage system is reduced to the minimum output value, and the power of the photovoltaic system and the wind power system is further reduced.

[0015] Optionally, controlling the energy storage system to exit the discharge mode or enter the charging mode includes:

[0016] The difference between the power upper limit reference value and the power of the photovoltaic system and the power of the wind power system is determined as the charging value;

[0017] Control the power of the energy storage system to be reduced to zero and the smaller of the charging value.

[0018] Optionally, further reducing the power of the photovoltaic system and the wind power system includes:

[0019] Determine whether the power of the wind power system is greater than or equal to the difference between the upper limit reference value and the minimum output value;

[0020] If so, then control the power of the photovoltaic system to be reduced to zero, and control the power of the wind power system to be reduced to the difference between the upper limit reference value and the minimum output value;

[0021] Otherwise, the power of the photovoltaic system is controlled to be reduced to the difference between the upper limit reference value of the power and the minimum output value and the power of the wind power system.

[0022] Optionally, when increasing the power of each system, the priority order of each system from high to low is: the wind power system, the photovoltaic system, and the energy storage system.

[0023] Optionally, prioritizing the energy storage system as the least important, the power of each system is increased, including:

[0024] Increase the power output of the wind power system and the photovoltaic system;

[0025] When determining the power of the energy storage system to be its maximum output value under its current allowed operating mode, check whether the sum of the power of each system is greater than or equal to the power upper limit reference value.

[0026] If so, then control the power of the energy storage system to be increased to the upper limit reference value minus the difference between the power of the photovoltaic system and the power of the wind power system;

[0027] Otherwise, control the energy storage system to exit charging mode or enter discharging mode.

[0028] Optionally, increasing the power output of the wind power system and the photovoltaic system includes:

[0029] The power increase of the wind power system is controlled by subtracting the power of the energy storage system and the power of the photovoltaic system from the power upper limit reference value.

[0030] Determine whether the sum of the power of each system is still less than the power upper limit reference value;

[0031] If so, the upper limit is determined by subtracting the power of the energy storage system and the power of the wind power system from the power upper limit reference value, and the power increase of the photovoltaic system is controlled accordingly.

[0032] Optionally, controlling the energy storage system to exit charging mode or enter discharging mode includes:

[0033] Determine whether the difference between the power upper limit reference value and the power of the photovoltaic system and the power of the wind power system is greater than the under-operation threshold value of the energy storage system.

[0034] If so, then control the power of the energy storage system to be increased to the power upper limit reference value minus the difference between the power of the photovoltaic system, the power of the wind power system and the under-action threshold value;

[0035] Otherwise, the power of the energy storage system is controlled to be zero.

[0036] Optionally, determining the upper limit reference value of the power of the wind-solar-storage power station includes:

[0037] Obtain the upper-layer scheduling power command value;

[0038] The smaller of the upper-level dispatch power command value and the transformer operation protection setting value is used as the upper limit power reference value.

[0039] Optionally, the permitted operating modes of the energy storage system are determined based on the SOC, including:

[0040] When the SOC is less than or equal to the discharge threshold, the energy storage system is determined to be allowed to enter the charging mode.

[0041] When the SOC is greater than or equal to the charging threshold, the energy storage system is determined to be allowed to enter the discharge mode.

[0042] When the SOC is between the discharge threshold and the charge threshold, the operating modes that the energy storage system is allowed to enter include the charging mode and the discharging mode.

[0043] Optionally, when the energy storage system is allowed to enter the charging mode, its minimum output value is the power corresponding to the negative rated capacity, and its maximum output value is zero.

[0044] The energy storage system is allowed to operate in discharge mode, with a minimum output of zero and a maximum output of the power corresponding to the rated capacity.

[0045] The energy storage system is allowed to operate in two modes: charging mode and discharging mode. Its minimum output value is the power corresponding to the negative rated capacity, and its maximum output value is the power corresponding to the rated capacity.

[0046] A second aspect of this application also provides a wind-solar-energy storage power station, comprising: a controller, a transformer, a wind power system, a photovoltaic system, and an energy storage system; wherein...

[0047] Each system is connected in parallel to the input side of the transformer;

[0048] The output side of the transformer is connected to the power grid via a step-up substation;

[0049] The controller is communicatively connected to the transformer and each system, and is used to execute the power output control method of the wind-solar-storage power station as described in any of the first aspects above.

[0050] The power output control method for a wind-solar-storage power station provided in this application, when a wind power system, a photovoltaic system, and an energy storage system are connected in parallel to the input side of the transformer in the wind-solar-storage power station, first obtains the power of each system and the SOC of the energy storage system, and determines the upper limit reference value of the power of the wind-solar-storage power station; then, when the sum of the power of each system is greater than the upper limit reference value, the power of each system is reduced; and when the sum of the power of each system is less than the upper limit reference value, the power of each system is increased; until the difference between the sum of the power of each system and the upper limit reference value is within a preset range, thereby enabling the wind-solar-storage power station to reach its upper limit reference value as much as possible, achieving power maximization. Furthermore, this method not only determines the allowed operating mode of the energy storage system based on the SOC before adjusting the power of each system to avoid overcharging and over-discharging of the energy storage system; but also prioritizes the energy storage system when reducing the power of each system and prioritizes the energy storage system last when increasing the power of each system, so as to maintain the energy storage system at a relatively high SOC and ensure that the SOC of the energy storage system is in a good state. Attached Figure Description

[0051] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0052] Figure 1 This is a schematic diagram of the structure of a wind-solar-storage power station provided in an embodiment of this application;

[0053] Figure 2 A flowchart illustrating the power output control method for a wind-solar-storage power station provided in this application embodiment;

[0054] Figure 3 and Figure 4 These are partial flowcharts of the power output control method for wind-solar-storage power stations provided in the embodiments of this application;

[0055] Figure 5 A schematic diagram of the specific structure of the wind-solar-storage power station provided in the embodiments of this application. Detailed Implementation

[0056] 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 embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0057] In this application, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0058] This application provides a power output control method for a wind-solar-storage power station, which maximizes the low-voltage coupled power output of wind, solar and storage while ensuring that the SOC of the energy storage is in a good state.

[0059] See Figure 1In this wind-solar-storage power station, the input side of the transformer is connected in parallel to the wind power system, the photovoltaic system, and the energy storage system. Each system is equipped with a corresponding power source and its converter. For example, the wind power system is equipped with at least one wind turbine and its wind power converter, the photovoltaic system is equipped with at least one photovoltaic string and its inverter, and the energy storage system is equipped with at least one battery cluster and its bidirectional inverter. The structure and connection relationship of each system can be found in the prior art, and will not be described in detail here.

[0060] The output control method of this wind-solar-storage power station is executed by the controller of the wind-solar-storage power station, such as... Figure 2 As shown, it mainly includes:

[0061] S101. Obtain the power of each system and the SOC of the energy storage system, and determine the upper limit reference value of the power of the wind-solar-storage power station.

[0062] In practical applications, the controller of this wind-solar-storage power station can collect the SOC of the energy storage system and the power values ​​Pwi, Pso, and Pst of each system in real time. Pwi represents the real-time power of the wind power system, Pso represents the real-time power of the photovoltaic system, and Pst represents the real-time power of the energy storage system. This process can be achieved either by the controller directly communicating with the converters in each system, or by the controller collecting the current and transformer input voltage of each system for separate calculations; the choice depends on the specific application environment, and both are within the scope of this application.

[0063] Simultaneously, the controller typically receives power commands from higher-level systems such as AGC (Automatic Generation Control) to obtain the upper-level dispatch power command value Pagc. Subsequently, the controller can directly use this upper-level dispatch power command value Pagc as a reference value for the sum of wind, solar, and energy storage power, i.e., the upper limit reference value for the power of the wind-solar-energy storage power station; or, more preferably, after obtaining the upper-level dispatch power command value Pagc, the controller compares it with its internally set transformer operation protection setting Str, and then takes the smaller of the two as the upper limit reference value to ensure the safety of system operation.

[0064] In addition, the settings parameters inside the controller can also include other parameters for use in subsequent steps, such as: the SOC charging threshold Socu, the SOC discharging threshold Socl, the discharge under-action threshold Pdisunrea, and the rated capacities of each system Swi, Sso, and Sst; where Swi is the rated capacity of the wind power system, Sso is the rated capacity of the photovoltaic system, and Sst is the rated capacity of the energy storage system.

[0065] S102. Determine the permitted operating modes of the energy storage system based on the SOC.

[0066] To prevent the energy storage system from being overcharged or over-discharged, the allowable operating modes can be set in advance, such as:

[0067] When SOC ≤ Socl, it is determined that the allowable operating mode of the energy storage system is the charging mode, that is, only charging is allowed and discharging is not allowed; since the current directions during charging and discharging of the energy storage system are different, the power during discharging can be defined as a positive value, and the power during charging as a negative value; when only charging is allowed, the minimum output value of the energy storage system is the power corresponding to the negative rated capacity, and its maximum output value is zero, that is, the lower limit of the energy storage power at this time is Pstmin = -Sst, and the upper limit is Pstmax = 0.

[0068] When SOC ≥ Socu charging threshold, it is determined that the allowable operating mode of the energy storage system is the discharging mode, that is, only discharging is allowed and charging is not allowed; at this time, the minimum output value of the energy storage system is zero, and its maximum output value is the power corresponding to the rated capacity, that is, the lower limit of the energy storage power at this time is Pstmin = 0, and the upper limit is Pstmax = Sst.

[0069] Only when Socu < SOC < Socl, it is determined that the allowable operating modes of the energy storage system include both the charging mode and the discharging mode, that is, both charging and discharging are allowed; at this time, the minimum output value of the energy storage system is the power corresponding to the negative rated capacity, and its maximum output value is the power corresponding to the rated capacity, that is, the lower limit of the energy storage power at this time is Pstmin = -Sst, and the upper limit is Pstmax = Sst.

[0070] After determining the allowable operating mode of the energy storage system, the adjustment direction of the power of the power station can be determined according to the relationship between the overall power of the wind-solar-storage power station and the reference value of the power upper limit; for example, when the sum of the powers of the wind-solar-storage is greater than the reference value of the power upper limit, the overall power needs to be reduced, and vice versa, the overall power should be increased until the sum of the powers of the wind-solar-storage is close to the reference value of the power upper limit. Specifically, the following steps S103 and S104 can be executed.

[0071] S103. When the sum of the powers of each system is greater than the reference value of the power upper limit, taking the energy storage system as the top priority, reduce the powers of each system; until the difference between the sum of the powers of each system and the reference value of the power upper limit is within the preset range.

[0072] In practical applications, in order to keep the SOC of the energy storage system in a good state, the discharge of the energy storage system can be minimized. Therefore, when it is necessary to reduce the overall power of the wind-solar-storage power station, the energy storage system can be given the highest priority, and the power of each system can be reduced accordingly. That is, whenever it is necessary to reduce the overall power, the power of the energy storage system should be reduced first. For example, the discharge power of the energy storage system can be reduced, or the charging power of the energy storage system can be increased, depending on the operating mode it is allowed to enter.

[0073] Preferably, when reducing the power of each system, the priority order of the systems from high to low is: energy storage system, photovoltaic system, and wind power system. That is, when executing step S103, the power of each system can be reduced in order of priority from high to low, namely energy storage system, photovoltaic system, and wind power system. Specifically, when it is necessary to reduce the overall power of wind, solar, and energy storage, the controller first shuts down the discharge power of the energy storage system or turns on the charging power of the energy storage system; then reduces the power of the photovoltaic system, and finally reduces the power of the wind power system, until the overall power of wind, solar, and energy storage is less than the upper limit reference value.

[0074] It should be noted that adopting the above priority settings can minimize power curtailment losses. Moreover, since photovoltaic and energy storage systems have faster adjustment speeds, they can protect transformers and prevent power exceeding limits from incurring grid penalties. However, in practical applications, the priority order is not limited to the above sequence. As long as the power of the energy storage system is reduced first, other power reduction sequences are also within the scope of protection of this application.

[0075] S104. When the sum of the power of each system is less than the upper limit reference value, the power of each system is increased with the energy storage system as the last priority; until the difference between the sum of the power of each system and the upper limit reference value is within the preset range.

[0076] When it is necessary to increase the overall power of the wind-solar-storage power station, the power of the photovoltaic system and the wind power system can be increased first. If the overall power of the power station still cannot reach the upper limit reference value, the power of the energy storage system can be increased. For example, the charging power of the energy storage system can be reduced, or the discharging power of the energy storage system can be increased, depending on the operating mode it is allowed to enter.

[0077] Preferably, when increasing the power of each system, the priority order of the systems from high to low is: wind power system, photovoltaic system, and energy storage system. That is, when executing step S104, the power of each system can be reduced in descending order of priority: wind power system, photovoltaic system, and energy storage system. Specifically, when it is necessary to increase the overall power of wind, solar, and energy storage, the power of the wind power system is increased first, followed by the power of the photovoltaic system, and finally the charging power of the energy storage system is reduced, or the energy storage discharge mode is activated, until the sum of the power of wind, solar, and energy storage approaches the reference value.

[0078] It should be noted that the order of increasing the power of each system is not limited to the priority order mentioned above. As long as the SOC of the energy storage system is kept in a good state, such as the charging threshold Socu and the discharging threshold Socl, it can be determined according to the specific application environment, and all of them are within the protection scope of this application.

[0079] The power output control method provided in this embodiment, based on the aforementioned principles, enables wind-solar-storage power stations to reach their maximum power reference value, thereby maximizing power output. Furthermore, this method not only determines the permissible operating mode of the energy storage system based on its State of Charge (SOC) before adjusting the power of each system to prevent overcharging and over-discharging, but also prioritizes the energy storage system when reducing its power and lowers it when increasing its power, thus maintaining a relatively high SOC and ensuring the energy storage system remains in a healthy state.

[0080] Based on the previous embodiment, this embodiment provides some specific implementation examples of the power output control method for the wind-solar-storage power station, such as:

[0081] In step S103, the energy storage system is given top priority, and the power of each system is reduced. This process may specifically include... Figure 3 As shown:

[0082] S201. When determining the power of the energy storage system to be the minimum output value under its current allowable operating mode, check whether the sum of the power of each system is greater than or equal to the upper limit reference value of the power.

[0083] Regardless of the current permitted operating mode of the energy storage system, its minimum output value is recorded as the lower limit of energy storage power Pstmin described in the various operating modes of the above embodiments; and taking the smaller of the upper-level scheduling power command value Pagc and the transformer operation protection setting value Str as min{Str, Pagc} as the upper limit reference value of the power, in this case, step S201 specifically determines whether Pwi+Pso+Pstmin≥min{Str, Pagc} is true; if it is true, it means that the judgment condition of step S201 is met, and step S202 can be executed; otherwise, step S203 is executed.

[0084] S202, Control the energy storage system to exit the discharge mode or enter the charging mode.

[0085] This step S202 may specifically include:

[0086] (1) The difference between the upper limit reference value of power and the power of the photovoltaic system and the power of the wind power system is determined and used as the charging value.

[0087] That is, the formula for calculating the charging value is min{Str,Pagc}-Pwi-Pso.

[0088] (2) Control the power of the energy storage system to decrease to zero and the smaller of the charge value.

[0089] In practical applications, the controller can send a power adjustment command to the energy storage system, so that its power is adjusted to min{min{Str,Pagc}-Pwi-Pso,0}.

[0090] S203. Control the power of the energy storage system to reduce to the minimum output value, and continue to reduce the power of the photovoltaic system and the wind power system.

[0091] Preferably, the power output of photovoltaic and wind power systems will be further reduced, specifically including... Figure 3 As shown:

[0092] S301. Determine whether the power of the wind power system is greater than or equal to the difference between the upper limit reference value and the minimum output value.

[0093] The power of the energy storage system is reduced to the minimum output value Pstmin. Step S301 is to determine whether Pwi≥min{Str,Pagc}-Pstmin is true. If it is true, then proceed to step S302; otherwise, proceed to step S303.

[0094] S302. Control the power of the photovoltaic system to reduce to zero, and control the power of the wind power system to reduce to the difference between the upper limit reference value and the minimum output value.

[0095] In practical applications, the controller can send power reduction commands to the photovoltaic system and the wind power system respectively, so that the power of the photovoltaic system is adjusted to 0 and the power of the wind power system is adjusted to min{Str,Pagc}-Pstmin.

[0096] S303, Control the power of the photovoltaic system to be reduced to the difference between the upper limit reference value of the power and the minimum output value and the power of the wind power system.

[0097] In practical applications, the controller can send a command to the wind power system to reduce its power output, adjusting its power to min{Str,Pagc}-Pstmin-Pwi.

[0098] Furthermore, in step S104 of this power control method, the power of each system is increased with the energy storage system as the lowest priority. Specifically, this may include... Figure 4 As shown:

[0099] S401, Increase the power output of wind power systems and photovoltaic systems.

[0100] This step S401 may specifically include Figure 4 as shown in

[0101] S501: Use the difference between the power upper limit reference value and the sum of the power of the energy storage system and the power of the photovoltaic system as the upper limit to control the power increase of the wind power system.

[0102] In practical applications, the controller can send a command to increase the power to the wind power system, so that its power is adjusted to min{Str, Pagc}-Pso-Pst.

[0103] S502: Determine whether the sum of the powers of each system is still less than the power upper limit reference value.

[0104] That is, determine whether Pwi+Pso+Pst<min{Str, Pagc} holds. If it holds, execute step S503; otherwise, directly complete step S104.

[0105] S503: Use the difference between the power upper limit reference value and the sum of the power of the energy storage system and the power of the wind power system as the upper limit to control the power increase of the photovoltaic system.

[0106] In practical applications, the controller can send a command to increase the power to the photovoltaic, and its upper limit is min{Str, Pagc}-Pwi-Pst.

[0107] After completing step S401, step S402 can be executed.

[0108] S402: Determine whether the sum of the powers of each system is greater than or equal to the power upper limit reference value when the power of the energy storage system is the maximum output value in its current allowed working mode.

[0109] That is, determine whether Pwi+Pso+Pstmax≥min{Str, Pagc} holds; if it holds, execute step S403; otherwise, execute step S404.

[0110] S403: Control the power of the energy storage system to increase to the difference between the power upper limit reference value and the sum of the power of the photovoltaic system and the power of the wind power system.

[0111] In practical applications, the controller can send a power adjustment command to the energy storage, and the power magnitude is min{Str, Pagc}-Pwi-Pso.

[0112] S404: Control the energy storage system to exit the charging mode or enter the discharging mode.

[0113] This step S404 specifically includes Figure 4 as shown in

[0114] S601. Determine whether the difference between the power upper limit reference value minus the power of the photovoltaic system and the power of the wind power system is greater than the under-action threshold value of the energy storage system.

[0115] That is, determine whether Pwi + Pso < min{Str, Pagc} - Pdisunrea holds; if it holds, execute step S602; otherwise, execute step S603.

[0116] S602. Control the power of the energy storage system to increase to the difference between the power upper limit reference value minus the power of the photovoltaic system, the power of the wind power system, and the under-action threshold value.

[0117] In practical applications, the controller can send an instruction to the energy storage to adjust the power, and the power magnitude is min{Str, Pagc} - Pwi - Pso - Pdisunrea.

[0118] S603. Control the power of the energy storage system to be zero.

[0119] At this time, the controller can also send an instruction to the energy storage to adjust the power, and the power magnitude is 0.

[0120] It should be noted that this embodiment only gives an optional example of power adjustment in steps S103 and S104. In practical applications, it is not limited to this. Not only can the power adjustment of the photovoltaic system and the wind power system be interchanged in order or executed simultaneously, but also the parameters in the above adjustment process can be set differently according to the actual situation. No specific limitations are made here. Any solution that can achieve the maximum power of wind-solar-storage and a good SOC state is within the protection scope of this application.

[0121] Another embodiment of this application also provides a wind-solar-storage power station, as Figure 1 shown, specifically including: a controller 50, a transformer 40, a wind power system 10, a photovoltaic system 20, and an energy storage system 30; where:

[0122] Each system is connected in parallel to the input side of the transformer 40; the output side of this transformer 40 is connected to the power grid through a booster station.

[0123] This transformer 30 can specifically be a box-type transformer, such as the box transformer shown in the figure.

[0124] In practical applications, corresponding power supplies and their converters are respectively set in each system. The power supply can specifically refer to a wind turbine in the wind power system 10, a photovoltaic string in the photovoltaic system 20, or a battery cluster in the energy storage system 30; the photovoltaic string includes one or at least two serially connected photovoltaic modules, and the battery cluster includes one or at least two serially connected battery modules.

[0125] For example, refer to Figure 5 The wind power system 10 includes at least one wind turbine 101 and its wind power converter 102. The input side of each wind power converter 102 is connected to the corresponding wind turbine 101, and the output side of each wind power converter 102 is connected to the input side of the transformer 40. The photovoltaic system 20 includes at least one photovoltaic string 201 and its inverter 202. The DC side of each inverter 202 is connected to the corresponding photovoltaic string 201, and the AC side of each inverter 202 is connected to the input side of the transformer 40. The energy storage system 30 includes at least one battery cluster 301 and its bidirectional inverter 302. The DC side of each bidirectional inverter 302 is connected to the corresponding battery cluster in the battery system, and the AC side of each bidirectional inverter 302 is connected to the input side of the transformer 40. The specific structure and connection relationship of the converters in each system can be found in the prior art, and will not be described in detail here.

[0126] The controller 50 is communicatively connected to the transformer 40 and each system, and is used to execute the power output control method of the wind-solar-storage power station as described in any of the above embodiments. The process and principle of this power output control method can be found in the above embodiments, and will not be repeated here.

[0127] This wind-solar-storage power station, through its low-voltage coupling structure, can compensate for the waste of power generation and reduce transmission costs. Furthermore, the controller 50 collects real-time power status data of the wind, solar, and storage systems, the state of charge (SOC) of the storage system 30, and power commands from the upper-level dispatch center. This allows for real-time adjustment of the output of the wind, solar, and storage systems, maximizing their output while ensuring the SOC of the storage system remains at a healthy level, thus reducing the risk of overcharging and over-discharging.

[0128] Similar or identical parts between the various embodiments in this specification can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for system or system embodiments, since they are basically similar to method embodiments, the description is relatively simple, and relevant parts can be referred to the description of the method embodiments. The systems and system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment solution according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0129] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0130] The features described above in the disclosed embodiments can be substituted for or combined with each other to enable those skilled in the art to implement or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for controlling the output of a wind-solar-storage power station, characterized in that, In a wind-solar-storage power station, the input side of the transformer is connected in parallel to a wind power system, a photovoltaic system, and an energy storage system. The output control method includes: The power of each system and the state of charge (SOC) of the energy storage system are obtained, and the upper limit reference value of the power of the wind-solar-storage power station is determined. The permitted operating modes of the energy storage system are determined based on the SOC. When the sum of the power of each system is greater than the power upper limit reference value, if the power of the energy storage system is the minimum output value in its current allowed operating mode, and the sum of the power of each system is greater than or equal to the power upper limit reference value, then the energy storage system is controlled to exit the discharge mode or enter the charging mode; otherwise, the power of the energy storage system is controlled to decrease to the minimum output value, and the power of the photovoltaic system and the wind power system continues to decrease. When the sum of the power of each system is less than the power upper limit reference value, the power of the wind power system and the photovoltaic system is first increased. Then, if the power of the energy storage system is the maximum output value in its current allowed operating mode, and the sum of the power of each system is greater than or equal to the power upper limit reference value, then the power of the energy storage system is controlled to increase to the power upper limit reference value minus the difference between the power of the photovoltaic system and the power of the wind power system; otherwise, the energy storage system is controlled to exit the charging mode or enter the discharge mode. Until the difference between the sum of the power of each system and the power upper limit reference value is within a preset range.

2. The power output control method for a wind-solar-storage power station according to claim 1, characterized in that, When reducing the power of each system, the priority order of each system from high to low is: the energy storage system, the photovoltaic system, and the wind power system.

3. The power output control method for a wind-solar-storage power station according to claim 1, characterized in that, Controlling the energy storage system to exit the discharge mode or enter the charging mode includes: The difference between the power upper limit reference value and the power of the photovoltaic system and the power of the wind power system is determined as the charging value; Control the power of the energy storage system to be reduced to zero and the smaller of the charging value.

4. The power output control method for a wind-solar-storage power station according to claim 1, characterized in that, Further reduce the power of the photovoltaic system and the wind power system, including: Determine whether the power of the wind power system is greater than or equal to the difference between the upper limit reference value and the minimum output value; If so, then control the power of the photovoltaic system to be reduced to zero, and control the power of the wind power system to be reduced to the difference between the upper limit reference value and the minimum output value; Otherwise, the power of the photovoltaic system is controlled to be reduced to the difference between the upper limit reference value of the power and the minimum output value and the power of the wind power system.

5. The power output control method for a wind-solar-storage power station according to claim 1, characterized in that, When increasing the power of each system, the priority order of each system from high to low is: the wind power system, the photovoltaic system, and the energy storage system.

6. The power output control method for a wind-solar-storage power station according to claim 1, characterized in that, Increasing the power output of the wind power system and the photovoltaic system includes: The power increase of the wind power system is controlled by subtracting the power of the energy storage system and the power of the photovoltaic system from the power upper limit reference value. Determine whether the sum of the power of each system is still less than the power upper limit reference value; If so, the upper limit is determined by subtracting the power of the energy storage system and the power of the wind power system from the power upper limit reference value, and the power increase of the photovoltaic system is controlled accordingly.

7. The power output control method for a wind-solar-storage power station according to claim 1, characterized in that, Controlling the energy storage system to exit charging mode or enter discharging mode includes: Determine whether the difference between the power upper limit reference value and the power of the photovoltaic system and the power of the wind power system is greater than the under-operation threshold value of the energy storage system. If so, then control the power of the energy storage system to be increased to the power upper limit reference value minus the difference between the power of the photovoltaic system, the power of the wind power system and the under-action threshold value; Otherwise, the power of the energy storage system is controlled to be zero.

8. The power output control method for a wind-solar-storage power station according to any one of claims 1 to 7, characterized in that, Determining the upper limit reference value of the power of the wind-solar-storage power station includes: Obtain the upper-layer scheduling power command value; The smaller of the upper-level dispatch power command value and the transformer operation protection setting value is used as the upper limit power reference value.

9. The power output control method for a wind-solar-storage power station according to any one of claims 1 to 7, characterized in that, The permitted operating modes of the energy storage system are determined based on the State of Charge (SOC), including: When the SOC is less than or equal to the discharge threshold, the energy storage system is determined to be allowed to enter the charging mode. When the SOC is greater than or equal to the charging threshold, the energy storage system is determined to be allowed to enter the discharge mode. When the SOC is between the discharge threshold and the charge threshold, the operating modes that the energy storage system is allowed to enter include the charging mode and the discharging mode.

10. The power output control method for a wind-solar-storage power station according to claim 9, characterized in that, When the energy storage system is allowed to enter the charging mode, its minimum output value is the power corresponding to the negative rated capacity, and its maximum output value is zero. The energy storage system is allowed to operate in discharge mode, with a minimum output of zero and a maximum output of the power corresponding to the rated capacity. The energy storage system is allowed to operate in two modes: charging mode and discharging mode. Its minimum output value is the power corresponding to the negative rated capacity, and its maximum output value is the power corresponding to the rated capacity.

11. A wind-solar-storage power station, characterized in that, include: Controllers, transformers, wind power systems, photovoltaic systems, and energy storage systems; among which, Each system is connected in parallel to the input side of the transformer; The output side of the transformer is connected to the power grid via a step-up substation; The controller is communicatively connected to the transformer and each system, and is used to execute the power output control method of the wind-solar-storage power station as described in any one of claims 1 to 10.

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