A power factor control method, device, apparatus and storage medium

Abstract

This invention discloses a power factor control method, apparatus, device, and storage medium. The method is applied to a photovoltaic-storage integrated power generation system, which includes a photovoltaic inverter, an energy storage converter, and a preset reactive power compensation device. The method includes: acquiring active power and reactive power; determining a predicted time when the power factor equals a preset threshold based on the active and reactive power; determining at least one of a first time for the photovoltaic inverter, a second time for the energy storage converter to start, and a third time for the preset reactive power compensation device based on the predicted time and the expected end time of photovoltaic power generation; and performing reactive power compensation on the system at at least one of the first, second, and third times to control the system's power factor to be greater than the preset threshold. The technical solution of this invention enables the photovoltaic inverter, energy storage converter, and reactive power compensation device to work collaboratively, achieving a dynamic and continuous reactive power compensation effect for the system.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic energy storage, and particularly to a method, device, equipment and storage medium for controlling power factor. Background Art

[0002] With the large-scale construction of industrial and commercial distributed new energy projects, the problem of non-compliance of the power factor at the grid assessment point due to distributed new energy power generation has become increasingly common. When distributed power sources are connected, the user load consumes new energy power generation, and the active power obtained from the grid decreases. Since new energy power generation is all active power, reactive power still needs to be obtained from the grid, resulting in a decrease in the measured active power at the grid assessment point, the reactive power remaining unchanged, and a decrease in the measured average power factor at the grid assessment point.

[0003] Currently, the solutions for distributed photovoltaic reactive power compensation can be divided into two categories. One category is to use a reactive power regulation device配套 with the photovoltaic power station inverter to compensate reactive power, thereby solving the problem of low power factor. This solution is applicable to the case where the power factor deviation is not large. The other category is to add a reactive power compensation correction device to enable the original capacitor cabinet to still work properly after the distributed power source is connected.

[0004] However, using a reactive power regulation device配套 with the photovoltaic power station inverter to compensate reactive power will affect the conversion efficiency and lifespan of the inverter, while the reactive power compensation correction device has a slow response speed and discontinuous regulation. The existing reactive power compensation solutions cannot well solve the problem of decreased power factor. Summary of the Invention

[0005] The present invention provides a method, device, equipment and storage medium for controlling power factor to solve the problem of poor effects of conventional reactive power compensation methods.

[0006] In a first aspect, an embodiment of the present invention provides a method for controlling power factor, which is applied to a photovoltaic and energy storage integrated power generation system. The system includes a photovoltaic inverter, an energy storage converter, and a preset reactive power compensation device. The method includes:

[0007] Obtain active power and reactive power, where the active power includes current instantaneous active power and cumulative active power, the reactive power includes current instantaneous reactive power and cumulative reactive power, the cumulative active power is determined based on the instantaneous active power within a preset period, and the cumulative reactive power is determined based on the instantaneous reactive power within the preset period;

[0008] According to the active power and the reactive power, determine the prediction time when the power factor is equal to a preset threshold;

[0009] Based on the predicted time and the expected photovoltaic power generation end time, at least one of the following is determined: a first time when the photovoltaic inverter starts to perform reactive power compensation on the system, a second time when the energy storage converter starts to perform reactive power compensation on the system, and a third time when the preset reactive power compensation device starts to perform reactive power compensation on the system. The third time is earlier than the second time, the second time is earlier than the first time, and the expected photovoltaic power generation end time is determined based on the historical time when the photovoltaic power generation in the system stops.

[0010] At least one of the first time, the second time, and the third time, reactive power compensation is performed on the system to control the power factor of the system to be greater than the preset threshold.

[0011] Secondly, embodiments of the present invention provide a power factor control device configured in a photovoltaic-storage integrated power generation system, the system including a photovoltaic inverter, an energy storage converter, and a preset reactive power compensation device, the device comprising:

[0012] The power acquisition module is used to acquire active power and reactive power, wherein the active power includes the current instantaneous active power and the cumulative active power, and the reactive power includes the current instantaneous reactive power and the cumulative reactive power. The cumulative active power is determined based on the instantaneous active power within a preset period, and the cumulative reactive power is determined based on the instantaneous reactive power within the preset period.

[0013] The prediction time determination module is used to determine the prediction time when the power factor is equal to a preset threshold based on the active power and the reactive power.

[0014] The compensation time determination module is used to determine, based on the predicted time and the expected photovoltaic power generation end time, at least one of the following: a first time when the photovoltaic inverter starts to perform reactive power compensation on the system, a second time when the energy storage converter starts to perform reactive power compensation on the system, and a third time when the preset reactive power compensation device starts to perform reactive power compensation on the system, wherein the third time is earlier than the second time, the second time is earlier than the first time, and the expected photovoltaic power generation end time is determined based on the historical time when the photovoltaic power generation in the system stops;

[0015] The reactive power compensation module is used to perform reactive power compensation on the system at at least one of the first time, the second time, and the third time, so as to control the power factor of the system to be greater than the preset threshold.

[0016] Thirdly, embodiments of the present invention provide an electronic device, the electronic device comprising:

[0017] At least one processor;

[0018] and memory that is communicatively connected to at least one processor;

[0019] The memory stores a computer program that can be executed by at least one processor, which enables the at least one processor to perform the power factor control method described in the first aspect.

[0020] Fourthly, embodiments of the present invention provide a computer-readable storage medium storing computer instructions for causing a processor to execute the power factor control method of the first aspect described above.

[0021] The power factor control scheme provided in this embodiment of the invention obtains active power and reactive power, wherein the active power includes current instantaneous active power and cumulative active power, and the reactive power includes current instantaneous reactive power and cumulative reactive power. The cumulative active power is determined based on the instantaneous active power within a preset period, and the cumulative reactive power is determined based on the instantaneous reactive power within the preset period. Based on the active power and the reactive power, a predicted time when the power factor equals a preset threshold is determined. Based on the predicted time and the expected photovoltaic power generation end time, at least one of the following is determined: a first time when the photovoltaic inverter starts reactive power compensation for the system, a second time when the energy storage converter starts reactive power compensation for the system, and a third time when the preset reactive power compensation device starts reactive power compensation for the system. The third time is earlier than the second time, the second time is earlier than the first time, and the expected photovoltaic power generation end time is determined based on the historical time when photovoltaic power generation stops in the system. Reactive power compensation is performed on the system at at least one of the first time, the second time, and the third time to control the power factor of the system to be greater than the preset threshold. By adopting the above technical solution, the obtained active and reactive power are used to determine the predicted time when the power factor equals the preset threshold. Then, based on the expected end time of photovoltaic power generation and this predicted time, the time when the photovoltaic inverter, energy storage converter, and preset reactive power compensation equipment start reactive power compensation operations is determined. Reactive power compensation is performed on the power generation system at this time to achieve the purpose of controlling the power factor. This allows the photovoltaic inverter, energy storage converter, and reactive power compensation equipment to work together, which can not only complete the reactive power compensation task well, but also achieve the effect of dynamic response and continuous reactive power compensation of the system. At the same time, it also reduces the probability of affecting the photoelectric conversion efficiency due to the use of photovoltaic inverters for reactive power compensation of the system during the photovoltaic power generation period.

[0022] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a flowchart of a power factor control method according to Embodiment 1 of the present invention;

[0025] Figure 2 This is a schematic diagram of a photovoltaic-storage integrated power generation system according to Embodiment 1 of the present invention;

[0026] Figure 3 This is a flowchart of a power factor control method according to Embodiment 2 of the present invention;

[0027] Figure 4 This is a schematic diagram of the structure of a power factor control device according to Embodiment 3 of the present invention;

[0028] Figure 5 This is a schematic diagram of the structure of an electronic device provided according to Embodiment 4 of the present invention. Detailed Implementation

[0029] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. 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 should fall within the scope of protection of the present invention.

[0030] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. In the description of this invention, unless otherwise stated, "a plurality of" means two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist; for example, A and / or B can represent: A alone, A and B simultaneously, and B alone. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or devices.

[0031] Example 1

[0032] Figure 1 The flowchart of a power factor control method provided in Embodiment 1 of the present invention is applicable to reactive power compensation of a photovoltaic-storage integrated power generation system to control the power factor of the system. The method can be executed by a power factor control device, which can be implemented in hardware and / or software. The power factor control device can be configured in the photovoltaic-storage integrated power generation system, which includes a photovoltaic inverter, an energy storage converter, and preset reactive power compensation equipment, etc. The photovoltaic-storage integrated power generation system can operate in an electronic device, which can be composed of two or more physical entities or a single physical entity.

[0033] like Figure 1 As shown, the power factor control method provided in Embodiment 1 of the present invention specifically includes the following steps:

[0034] S101. Obtain active power and reactive power, wherein the active power includes current instantaneous active power and cumulative active power, the reactive power includes current instantaneous reactive power and cumulative reactive power, the cumulative active power is determined based on the instantaneous active power within a preset period, and the cumulative reactive power is determined based on the instantaneous reactive power within the preset period.

[0035] In this embodiment, Figure 2 This is a schematic diagram of a photovoltaic-storage integrated power generation system, such as... Figure 2As shown, power acquisition devices, such as smart meters, can be installed near the grid assessment point to collect the current instantaneous reactive power, cumulative reactive power, and total reactive power. In a typical on-site photovoltaic-storage integrated power generation system (hereinafter referred to as the system), the electricity generated by the photovoltaic system is mainly used by user loads, and the remaining electricity can be stored in the energy storage section, such as lithium batteries, without being fed back to the shared grid. The energy storage section typically operates by charging at night when electricity prices are low and discharging during peak daytime hours. All the electricity flowing through the energy storage section can be grid electricity. At night, the photovoltaic system does not generate electricity, so its impact on the power factor is negligible. During the day, when the photovoltaic system generates electricity, the active power generated is used by user loads, resulting in a decrease in the active power flowing through the grid assessment point, i.e., a decrease in the amount of electricity obtained from the grid, but the reactive power obtained from the grid remains unchanged. If reactive power compensation is not provided to the system, it will lead to a decrease in the power factor at the grid assessment point. The location of the power grid assessment point is generally set by the power grid company. The power grid company can obtain the average power factor of the power grid assessment point for a certain period of time, such as one month. Based on the average power factor, it can be determined whether the power factor of the system meets the relevant regulations, such as the "Technical Guidelines for Voltage and Reactive Power of Power Systems" (GB / T40427-2021). The cumulative time for cumulative reactive power and cumulative active power, i.e., the preset period, can be set according to the preset period, such as seven days. The cumulative active power can be obtained by accumulating the instantaneous active power for seven days. Correspondingly, the cumulative reactive power can be obtained by accumulating the instantaneous reactive power for seven days. The preset reactive power compensation equipment can be reactive power compensation equipment such as capacitor banks.

[0036] S102. Based on the active power and the reactive power, determine the prediction time when the power factor equals a preset threshold.

[0037] In this embodiment, based on the collected active and reactive power, not only can the current instantaneous power factor and the average active power within a preset period be calculated, but also, since photovoltaic power generation depends on the intensity of sunlight, and the intensity of sunlight has seasonal and temporal patterns, the active and reactive power within the system also have certain patterns. Using a set expression, the time when the power factor reaches a preset threshold can also be predicted, i.e., the prediction time. The preset threshold can be set according to national standards, and the preset threshold can be less than or equal to the national standards, such as 0.9 or 0.95, etc. For example, it can be set to 0.9.

[0038] S103. Based on the predicted time and the expected photovoltaic power generation end time, determine at least one of the following: a first time when the photovoltaic inverter starts to perform reactive power compensation on the system, a second time when the energy storage converter starts to perform reactive power compensation on the system, and a third time when the preset reactive power compensation device starts to perform reactive power compensation on the system, wherein the third time is earlier than the second time, the second time is earlier than the first time, and the expected photovoltaic power generation end time is determined based on the historical time when the photovoltaic power generation in the system stops.

[0039] In this embodiment, based on historical photovoltaic (PV) power generation data, the daily start and stop times of PV power generation can be summarized, allowing for the prediction of preset times, such as the expected end time of PV power generation on a given day. Based on this predicted time, the start times for reactive power compensation of the PV inverter, energy storage converter, and preset reactive power compensation device can be set. The preset reactive power compensation device can be used first, and this compensation time is designated as the third time. If the reactive power output of the preset device is insufficient and the power factor remains low, both the energy storage converter and the preset device can be used simultaneously for reactive power compensation, with the energy storage converter's compensation time designated as the second time. Finally, if the reactive power output of the energy storage converter and the preset device is still insufficient, the PV inverter can also begin reactive power compensation, with its compensation time designated as the first time.

[0040] S104. At at least one of the first time, the second time, and the third time, reactive power compensation is performed on the system to control the power factor of the system to be greater than the preset threshold.

[0041] In this embodiment, by sequentially using a preset reactive power compensation device, an energy storage converter, and a photovoltaic inverter to perform reactive power compensation on the photovoltaic-energy storage integrated power generation system, the power factor of the system can be guaranteed to be greater than a preset threshold.

[0042] The power factor control method provided in this invention obtains active power and reactive power, wherein the active power includes current instantaneous active power and cumulative active power, and the reactive power includes current instantaneous reactive power and cumulative reactive power. The cumulative active power is determined based on the instantaneous active power within a preset period, and the cumulative reactive power is determined based on the instantaneous reactive power within the preset period. Based on the active power and the reactive power, a predicted time when the power factor equals a preset threshold is determined. Based on the predicted time and the expected photovoltaic power generation end time, at least one of the following is determined: a first time when the photovoltaic inverter starts reactive power compensation for the system, a second time when the energy storage converter starts reactive power compensation for the system, and a third time when the preset reactive power compensation device starts reactive power compensation for the system. The third time is earlier than the second time, the second time is earlier than the first time, and the expected photovoltaic power generation end time is determined based on the historical time when photovoltaic power generation stops in the system. Reactive power compensation is performed on the system at at least one of the first time, the second time, and the third time to control the power factor of the system to be greater than the preset threshold. The technical solution of this invention utilizes the acquired active and reactive power to determine the predicted time when the power factor equals a preset threshold. Then, based on the expected end time of photovoltaic power generation and this predicted time, the time when the photovoltaic inverter, energy storage converter, and preset reactive power compensation equipment begin reactive power compensation operations is determined. Reactive power compensation is performed on the power generation system at this time to control the power factor. This allows the photovoltaic inverter, energy storage converter, and reactive power compensation equipment to work collaboratively, effectively completing the reactive power compensation task and achieving dynamic and continuous reactive power compensation for the system. At the same time, it reduces the probability of affecting the photoelectric conversion efficiency due to reactive power compensation of the system by using the photovoltaic inverter during the photovoltaic power generation period.

[0043] Example 2

[0044] Figure 3 This is a flowchart of a power factor control method provided in Embodiment 2 of the present invention. The technical solution of the present invention is further optimized based on the above optional technical solutions, and a specific method for controlling the power factor is given.

[0045] Optionally, determining at least one of the following based on the predicted time and the expected end time of photovoltaic power generation—namely, the first time when the photovoltaic inverter begins reactive power compensation, the second time when the energy storage converter begins reactive power compensation, and the third time when the preset reactive power compensation device begins reactive power compensation—includes: if the predicted time is earlier than or equal to the expected end time of photovoltaic power generation, then determining at least one of the following: if the predicted time is later than the expected end time of photovoltaic power generation, then determining the third time when the preset reactive power compensation device begins reactive power compensation. The advantage of this setting is that before determining a specific reactive power compensation strategy, the preset time can be determined by judging the order of the predicted time and the expected end time of photovoltaic power generation. For example, on that day, it can be considered whether a situation with an excessively low power factor will occur, thereby eliminating times when reactive power compensation by the energy storage converter and photovoltaic inverter is unnecessary.

[0046] Optionally, the method further includes: determining the correspondence between a second target power factor and a target time based on the current instantaneous active power and the current instantaneous reactive power; determining a fourth target time corresponding to the second target power factor being greater than a third value, and defining the fourth target time as the time when the photovoltaic inverter stops providing reactive power compensation to the system; determining a fifth target time corresponding to the second target power factor being greater than a second value, and defining the fifth target time as the time when the energy storage converter stops providing reactive power compensation to the system, wherein the second value is greater than the third value; and wherein the fourth target time and the fifth target time belong to the target time. The advantage of this configuration is that by determining the specific changes in the power factor, the time when the energy storage converter and the photovoltaic inverter stop generating reactive power can be accurately determined, avoiding the overuse of the energy storage converter and the photovoltaic inverter.

[0047] like Figure 3 As shown in Embodiment 2 of the present invention, a power factor control method specifically includes the following steps:

[0048] S201. Obtain active power and reactive power.

[0049] S202. Based on the active power and the reactive power, determine the prediction time when the power factor equals a preset threshold.

[0050] Optionally, determining the prediction time when the power factor equals a preset threshold based on the active power and the reactive power includes: determining the prediction duration when the power factor equals the preset threshold based on the preset threshold, the active power, and the reactive power; and determining the prediction time when the power factor equals the preset threshold based on the prediction duration and the current time.

[0051] For example, the prediction duration ΔT when the power factor equals a preset threshold can be determined using the following expression:

[0052]

[0053] Wherein, PF represents a preset power factor with a value of a preset threshold, P is the current instantaneous active power, P0 is the cumulative active power, Q is the current instantaneous reactive power, and Q0 is the cumulative reactive power. Based on the prediction duration and the current time, the prediction time when the power factor equals the preset threshold can be determined. For example, if the preset threshold is 0.9 and the current time is 9:00, using the above formula, the time ΔT from the current time when the power factor equals 0.9 can be calculated, i.e., the prediction duration. If the prediction duration is 5 hours, then the prediction time when the power factor equals 0.9 can be determined to be 14:00.

[0054] Optionally, determining the prediction time when the power factor equals a preset threshold based on the active power and the reactive power includes: determining the predicted power factor within the preset time based on a preset duration, the active power, and the reactive power; and determining the prediction time when the power factor equals a preset threshold based on the power factor and the current time.

[0055] For example, the predicted power factor within a preset time period ΔT' can be determined using the following expression:

[0056]

[0057] Wherein, PF' is the predicted power factor, P is the current instantaneous active power, P0 is the cumulative active power, Q is the current instantaneous reactive power, and Q0 is the cumulative reactive power. Based on the power factor and the current time, the prediction time when the power factor equals a preset threshold can be determined. For example, if the current time is 9:00, the preset threshold is 0.9, and the preset duration ΔT' is 10 hours, then using the above formula, the power factor for the next ten hours can be calculated, thus obtaining multiple predicted power factors. By plotting points, the changes in the predicted power factor over the next ten hours can be observed intuitively. If the prediction duration corresponding to a predicted power factor of 0.9 is 6.5 hours, then the prediction time can be determined to be 15:30.

[0058] S203. Determine whether the predicted time is earlier than or equal to the expected photovoltaic power generation end time. If yes, proceed to step 204; otherwise, proceed to step 205.

[0059] S204. Determine at least one of the following: the first time when the photovoltaic inverter starts to perform reactive power compensation on the system, the second time when the energy storage converter starts to perform reactive power compensation on the system, and the third time when the preset reactive power compensation device starts to perform reactive power compensation on the system, and execute 206.

[0060] For example, if the predicted time is 3 PM and the expected end time of photovoltaic power generation is 6 PM, it indicates that the predicted time is earlier than the expected end time of photovoltaic power generation. That is, before the end of photovoltaic power generation, the power factor may be lower than the preset threshold. In this case, it is necessary to determine the time when the photovoltaic inverter and / or energy storage converter and / or preset reactive power compensation device start to perform reactive power compensation on the system.

[0061] Optionally, determining at least one of the following: the first time when the photovoltaic inverter begins reactive power compensation of the system, the second time when the energy storage converter begins reactive power compensation of the system, and the third time when the preset reactive power compensation device begins reactive power compensation of the system, includes:

[0062] 1) Based on the current instantaneous active power and the current instantaneous reactive power, determine the correspondence between the first target power factor and the target time.

[0063] For example, based on the conventional calculation expression of the power factor, the current instantaneous power factor, i.e. the first target power factor, can be calculated using the current instantaneous active power and the current instantaneous reactive power. The current time, i.e. the target time, is recorded, and a correspondence between the first target power factor and the target time is formed.

[0064] 2) Determine the first target time corresponding to the first target power factor being less than the first value and greater than the second value, and determine the third time when the preset reactive power compensation device starts to perform reactive power compensation on the system as the first target time.

[0065] For example, if the first target power factor is 0.94, the first value is 0.95, and the second value is 0.93, that is, the first target power factor is less than the first value and greater than the second value, the time when the power factor is 0.94 can be determined according to the correspondence between the first target power factor and the target time, that is, the first target time. If the first target time is 11 o'clock, then the time when the preset reactive power compensation device starts to perform reactive power compensation on the system can be determined as 11 o'clock, that is, the third time.

[0066] 3) Determine the second target time corresponding to the first target power factor being less than the second value and greater than the third value, and determine the second time when the energy storage converter starts to perform reactive power compensation on the system and the third time when the preset reactive power compensation device starts to perform reactive power compensation on the system as the second target time.

[0067] For example, if the first target power factor is 0.92, the second value is 0.93, and the third value is 0.91, that is, the first target power factor is less than the second value and greater than the third value, the time when the power factor is 0.92 can be determined according to the correspondence between the first target power factor and the target time, that is, the second target time. If the second target time is 12 o'clock, then the time when the energy storage converter starts to perform reactive power compensation on the system can be determined as 12 o'clock, that is, the second time. If the preset reactive power compensation device is already in the working state of performing reactive power compensation on the system, then it will continue to maintain this state. If the preset reactive power compensation device is not in the working state of performing reactive power compensation on the system, then the third time of the preset reactive power compensation device will also be determined as 12 o'clock.

[0068] 3) Determine the third target time corresponding to the first target power factor being less than the third value and greater than the preset threshold, and determine the first time when the photovoltaic inverter starts to perform reactive power compensation on the system, the second time when the energy storage converter starts to perform reactive power compensation on the system, and the third time when the preset reactive power compensation device starts to perform reactive power compensation on the system as the third target time;

[0069] The target time includes the first target time, the second target time, and the third target time, wherein the first value is greater than the second value, the second value is greater than the third value, and the third value is greater than the preset threshold. The advantage of setting 1) to 3) above is that by setting different values, the preset times for the reactive power compensation device, energy storage converter, and photovoltaic inverter to begin reactive power compensation of the system are determined, enabling the three to work together more rationally and avoiding the overuse of a single device for reactive power compensation.

[0070] For example, if the first target power factor is 0.915, the third value is 0.91, and the preset threshold is 0.90, that is, the first target power factor is less than the third value and greater than the preset threshold, the time when the power factor is 0.915 can be determined according to the correspondence between the first target power factor and the target time, that is, the third target time. If the third target time is 2 PM, then the time when the photovoltaic inverter starts to perform reactive power compensation on the system can be determined as 2 PM, that is, the first time. At this time, if the preset reactive power compensation device energy storage converter is already in the working state of performing reactive power compensation on the system, then it continues to maintain this state. At this time, if the preset reactive power compensation device energy storage converter is not in the working state of performing reactive power compensation on the system, then the second time of the preset reactive power compensation device energy storage converter is also determined as 2 PM.

[0071] S205. Determine the third time when the preset reactive power compensation device starts to perform reactive power compensation on the system.

[0072] For example, if the predicted time is 7 PM and the expected end time of photovoltaic power generation is 6 PM, it indicates that the predicted time is later than the expected end time of photovoltaic power generation. That is, before the end of photovoltaic power generation, it is highly unlikely that the power factor will fall below the preset threshold. In this case, it is only necessary to determine the time when the preset reactive power compensation device starts to perform reactive power compensation on the system. On the same day, there is no need to start the reactive power compensation function of the photovoltaic inverter and the energy storage converter. The preset reactive power compensation device can be in a standby state for a long time. When the system needs reactive power compensation, it can be woken up in time and the preset reactive power compensation device can be used to perform reactive power compensation on the system first. This time is the third time.

[0073] S206. At at least one of the first time, the second time, and the third time, reactive power compensation is performed on the system to control the power factor of the system to be greater than the preset threshold.

[0074] S207. Based on the current instantaneous active power and the current instantaneous reactive power, determine the correspondence between the second target power factor and the target time.

[0075] Specifically, the second target power factor determined in this step can be understood as the instantaneous power factor determined after the first target power factor is determined, and the corresponding time is recorded. This time is also the target time, thus establishing a correspondence between the second target power factor and the target time.

[0076] S208. Determine the fourth target time corresponding to the second target power factor being greater than the third value, and determine the fourth target time as the time when the photovoltaic inverter stops performing reactive power compensation on the system.

[0077] For example, as described above, if after a period of reactive power compensation, the instantaneous power factor increases from 0.915 to 0.921, meaning the second target power factor is greater than the third value, the time when the power factor is 0.921 can be determined based on the correspondence between the second target power factor and the target time, which is the fourth target time. If the fourth target time is 14:30, then the fourth time when the photovoltaic inverter stops performing reactive power compensation on the system can be determined as 14:30.

[0078] S209. Determine the fifth target time corresponding to the second target power factor being greater than the second value, and determine the fifth time when the energy storage converter stops performing reactive power compensation on the system as the fifth target time.

[0079] Wherein, the second value is greater than the third value, and the fourth target time and the fifth target time belong to the target time.

[0080] For example, as described above, if after a period of reactive power compensation, the instantaneous power factor rises from 0.921 to 0.931, meaning the second target power factor is greater than the second value, the time when the power factor is 0.931 can be determined based on the correspondence between the second target power factor and the target time. This is the fifth target time. If the fifth target time is 3 PM, then the fifth time when the energy storage converter stops performing reactive power compensation on the system can be determined as 3 PM.

[0081] The power factor control method provided in this invention utilizes the acquired active and reactive power to determine the prediction time when the power factor equals a preset threshold. When the prediction time is later than the expected photovoltaic power generation end time, reactive power compensation can be performed on the system solely by a preset reactive power compensation device. When the prediction time is earlier than the expected photovoltaic power generation end time, the timing for reactive power compensation by the photovoltaic inverter, energy storage converter, and preset reactive power compensation device can be determined based on the instantaneous power factor. Reactive power compensation is performed on the power generation system at this time to achieve the purpose of controlling the power factor. By adjusting the reactive power compensation time of the photovoltaic inverter, energy storage converter, and preset reactive power compensation device in real time, the three can work in an orderly and coordinated manner, avoiding the overuse of a single device for reactive power compensation or the disorderly use of devices within the system for reactive power compensation. This extends the service life of the reactive power compensation device, photovoltaic inverter, and energy storage converter within the system and improves the system's economy.

[0082] Optionally, based on the above embodiments, the method further includes: stopping the reactive power compensation of the system by the energy storage converter and the photovoltaic inverter within a preset time period, and controlling the preset reactive power compensation device to perform reactive power compensation of the system, so as to maintain the power factor within a preset range within the preset time period, wherein the preset time period is determined based on the time period corresponding to when the photovoltaic in the system stops emitting active power.

[0083] Specifically, the preset time period can be set to the period when photovoltaic power generation is stopped, such as from 7 PM to 5 AM the next day. During this period, the reactive power compensation functions of the energy storage converter and the photovoltaic inverter can be turned off. Since the demand for reactive power is lower at night, only the preset reactive power compensation equipment can be turned on to maintain the system's power factor within a preset range, such as greater than 0.99 and less than or equal to 1. The advantage of this setting is that, since the State Grid requires the power factor of the grid assessment points to be the average power factor, improving the power factor within the preset time period can reduce the demand for reactive power during daytime photovoltaic power generation, thereby reducing the time that the equipment in the system needs to perform reactive power compensation and extending the service life of the equipment in the system.

[0084] Example 3

[0085] Figure 4 This is a schematic diagram of a power factor control device provided in Embodiment 3 of the present invention. Figure 4 As shown, the device includes: a power acquisition module 301, a prediction time determination module 302, a compensation time determination module 303, and a reactive power compensation module 304, wherein:

[0086] The power acquisition module is used to acquire active power and reactive power, wherein the active power includes the current instantaneous active power and the cumulative active power, and the reactive power includes the current instantaneous reactive power and the cumulative reactive power. The cumulative active power is determined based on the instantaneous active power within a preset period, and the cumulative reactive power is determined based on the instantaneous reactive power within the preset period.

[0087] The prediction time determination module is used to determine the prediction time when the power factor is equal to a preset threshold based on the active power and the reactive power.

[0088] The compensation time determination module is used to determine, based on the predicted time and the expected photovoltaic power generation end time, at least one of the following: a first time when the photovoltaic inverter starts to perform reactive power compensation on the system, a second time when the energy storage converter starts to perform reactive power compensation on the system, and a third time when the preset reactive power compensation device starts to perform reactive power compensation on the system, wherein the third time is earlier than the second time, the second time is earlier than the first time, and the expected photovoltaic power generation end time is determined based on the historical time when the photovoltaic power generation in the system stops;

[0089] The reactive power compensation module is used to perform reactive power compensation on the system at at least one of the first time, the second time, and the third time, so as to control the power factor of the system to be greater than the preset threshold.

[0090] The power factor control device provided in this embodiment of the invention uses the acquired active and reactive power to determine the predicted time when the power factor equals a preset threshold. Then, based on the expected end time of photovoltaic power generation and the predicted time, it determines the time when the photovoltaic inverter, energy storage converter, and preset reactive power compensation equipment will begin reactive power compensation operations. Reactive power compensation is performed on the power generation system at this time to achieve the purpose of controlling the power factor. This allows the photovoltaic inverter, energy storage converter, and reactive power compensation equipment to work together, which can not only complete the reactive power compensation task well, but also achieve the effect of dynamic response and continuous reactive power compensation of the system. At the same time, it also reduces the probability of affecting the photoelectric conversion efficiency due to the use of photovoltaic inverters for reactive power compensation of the system during the photovoltaic power generation period.

[0091] Optionally, the prediction time determination module includes:

[0092] The prediction duration determination unit is used to determine the prediction duration when the power factor is equal to the preset threshold based on the preset threshold, the active power, and the reactive power;

[0093] The prediction time determination unit is used to determine the prediction time when the power factor is equal to the preset threshold based on the prediction duration and the current time.

[0094] Optionally, the prediction time determination module includes:

[0095] A power factor prediction unit is used to determine the predicted power factor within the preset time period based on a preset time period, the active power, and the reactive power.

[0096] The prediction time determination unit is used to determine the prediction time when the power factor is equal to a preset threshold based on the power factor and the current time.

[0097] Optionally, the compensation time determination module includes:

[0098] The first compensation time determination unit is used to determine at least one of the following if the predicted time is earlier than or equal to the expected photovoltaic power generation end time: the first time when the photovoltaic inverter starts to perform reactive power compensation on the system, the second time when the energy storage converter starts to perform reactive power compensation on the system, and the third time when the preset reactive power compensation device starts to perform reactive power compensation on the system.

[0099] The second compensation time determination unit is used to determine a third time when the preset reactive power compensation device starts to perform reactive power compensation on the system if the predicted time is later than the expected photovoltaic power generation end time.

[0100] Furthermore, determining at least one of the following: the first time when the photovoltaic inverter begins reactive power compensation of the system, the second time when the energy storage converter begins reactive power compensation of the system, and the third time when the preset reactive power compensation device begins reactive power compensation of the system, includes: determining the correspondence between a first target power factor and a target time based on the current instantaneous active power and the current instantaneous reactive power; determining the first target time corresponding to the first target power factor being less than a first value and greater than a second value, and determining the third time when the preset reactive power compensation device begins reactive power compensation of the system as the first target time; determining the second target time corresponding to the first target power factor being less than the second value and greater than the third value, and determining the third time when the energy storage converter begins reactive power compensation of the system as the first target time; and determining the second target time corresponding to the first target power factor being less than the second value and greater than the third value, and determining the third time when the energy storage converter begins reactive power compensation of the system as the first target time. The second time when reactive power compensation is performed and the third time when the preset reactive power compensation device begins to perform reactive power compensation on the system are determined as the second target time; the third target time corresponding to the first target power factor being less than the third value and greater than the preset threshold is determined, and the first time when the photovoltaic inverter begins to perform reactive power compensation on the system, the second time when the energy storage converter begins to perform reactive power compensation on the system, and the third time when the preset reactive power compensation device begins to perform reactive power compensation on the system are determined as the third target time; wherein, the target time includes the first target time, the second target time, and the third target time, the first value is greater than the second value, the second value is greater than the third value, and the third value is greater than the preset threshold.

[0101] Optionally, the device may also include:

[0102] The correspondence determination module is used to determine the correspondence between the second target power factor and the target time based on the current instantaneous active power and the current instantaneous reactive power.

[0103] The first stop time determination module is used to determine the fourth target time corresponding to the second target power factor being greater than the third value, and to determine the fourth target time as the fourth time when the photovoltaic inverter stops performing reactive power compensation on the system.

[0104] The second stop time determination module is used to determine the fifth target time corresponding to the second target power factor being greater than the second value, and to determine the fifth target time as the fifth time when the energy storage converter stops performing reactive power compensation on the system, wherein the second value is greater than the third value;

[0105] The fourth target time and the fifth target time are both target times.

[0106] Optionally, the device may also include:

[0107] The equipment control module is used to stop the reactive power compensation of the system by the energy storage converter and the photovoltaic inverter within a preset time period, and to control the preset reactive power compensation device to perform reactive power compensation of the system, so as to maintain the power factor within a preset range within the preset time period, wherein the preset time period is determined based on the time period corresponding to when the photovoltaic in the system stops emitting active power.

[0108] The power factor control device provided in the embodiments of the present invention can execute the power factor control method provided in any embodiment of the present invention, and has the corresponding functional modules and beneficial effects of the method.

[0109] Example 4

[0110] Figure 5 A schematic diagram of an electronic device 40 that can be used to implement embodiments of the present invention is shown. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The components shown herein, their connections and relationships, and their functions are merely illustrative and are not intended to limit the implementation of the invention described and / or claimed herein.

[0111] like Figure 5As shown, the electronic device 40 includes at least one processor 41 and a memory, such as a read-only memory (ROM) 42 or a random access memory (RAM) 43, communicatively connected to the at least one processor 41. The memory stores computer programs executable by the at least one processor. The processor 41 can perform various appropriate actions and processes based on the computer program stored in the ROM 42 or loaded into the RAM 43 from storage unit 48. The RAM 43 may also store various programs and data required for the operation of the electronic device 40. The processor 41, ROM 42, and RAM 43 are interconnected via a bus 44. An input / output (I / O) interface 45 is also connected to the bus 44.

[0112] Multiple components in electronic device 40 are connected to I / O interface 45, including: input unit 46, such as keyboard, mouse, etc.; output unit 47, such as various types of monitors, speakers, etc.; storage unit 48, such as disk, optical disk, etc.; and communication unit 49, such as network card, modem, wireless transceiver, etc. Communication unit 49 allows electronic device 40 to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks.

[0113] Processor 41 can be a variety of general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of processor 41 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various special-purpose artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any suitable processor, controller, microcontroller, etc. Processor 41 performs the various methods and processes described above, such as power factor control methods.

[0114] In some embodiments, the power factor control method may be implemented as a computer program tangibly contained in a computer-readable storage medium, such as storage unit 48. In some embodiments, part or all of the computer program may be loaded into and / or installed on electronic device 40 via ROM 42 and / or communication unit 49. When the computer program is loaded into RAM 43 and executed by processor 41, one or more steps of the power factor control method described above may be performed. Alternatively, in other embodiments, processor 41 may be configured to perform the power factor control method by any other suitable means (e.g., by means of firmware).

[0115] Various embodiments of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), systems-on-a-chip (SoCs), payload-programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments may include implementations in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which may be a dedicated or general-purpose programmable processor, capable of receiving data and instructions from a storage system, at least one input device, and at least one output device, and transmitting data and instructions to the storage system, the at least one input device, and the at least one output device.

[0116] Computer programs used to implement the methods of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, such that when executed by the processor, the computer programs cause the functions / operations specified in the flowcharts and / or block diagrams to be performed. The computer programs may be executed entirely on a machine, partially on a machine, or as a standalone software package, partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0117] The computer equipment provided above can be used to execute the power factor control method provided in any of the above embodiments, and has corresponding functions and beneficial effects.

[0118] Example 5

[0119] In the context of this invention, a computer-readable storage medium may be a tangible medium, and the computer-executable instructions, when executed by a computer processor, are used to perform a power factor control method applicable to a photovoltaic-storage integrated power generation system, which includes a photovoltaic inverter, an energy storage converter, and a pre-set reactive power compensation device. The method includes:

[0120] The active power and reactive power are obtained, wherein the active power includes the current instantaneous active power and the cumulative active power, and the reactive power includes the current instantaneous reactive power and the cumulative reactive power. The cumulative active power is determined based on the instantaneous active power within a preset period, and the cumulative reactive power is determined based on the instantaneous reactive power within the preset period.

[0121] Based on the active power and the reactive power, determine the prediction time when the power factor equals a preset threshold;

[0122] Based on the predicted time and the expected photovoltaic power generation end time, at least one of the following is determined: a first time when the photovoltaic inverter starts to perform reactive power compensation on the system, a second time when the energy storage converter starts to perform reactive power compensation on the system, and a third time when the preset reactive power compensation device starts to perform reactive power compensation on the system. The third time is earlier than the second time, the second time is earlier than the first time, and the expected photovoltaic power generation end time is determined based on the historical time when the photovoltaic power generation in the system stops.

[0123] At least one of the first time, the second time, and the third time, reactive power compensation is performed on the system to control the power factor of the system to be greater than the preset threshold.

[0124] In the context of this invention, a computer-readable storage medium can be a tangible medium that may contain or store a computer program for use by, or in conjunction with, an instruction execution system, apparatus, or device. A computer-readable storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination thereof. Alternatively, a computer-readable storage medium may be a machine-readable signal medium. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0125] The computer equipment provided above can be used to execute the power factor control method provided in any of the above embodiments, and has corresponding functions and beneficial effects.

[0126] It is worth noting that in the embodiments of the power factor control device described above, the various units and modules included are only divided according to functional logic, but are not limited to the above division, as long as the corresponding functions can be achieved; in addition, the specific names of each functional unit are only for easy differentiation and are not used to limit the scope of protection of the present invention.

[0127] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A method of controlling power factor, characterized by, The method is applied to a photovoltaic-energy storage integrated power generation system, the system including a photovoltaic inverter, an energy storage converter, and a pre-set reactive power compensation device, and includes: The active power and reactive power are obtained, wherein the active power includes the current instantaneous active power and the cumulative active power, and the reactive power includes the current instantaneous reactive power and the cumulative reactive power. The cumulative active power is determined based on the instantaneous active power within a preset period, and the cumulative reactive power is determined based on the instantaneous reactive power within the preset period. Based on the active power and the reactive power, determine the prediction time when the power factor equals a preset threshold; Based on the predicted time and the expected photovoltaic power generation end time, at least one of the following is determined: a first time when the photovoltaic inverter starts to perform reactive power compensation on the system, a second time when the energy storage converter starts to perform reactive power compensation on the system, and a third time when the preset reactive power compensation device starts to perform reactive power compensation on the system. The third time is earlier than the second time, the second time is earlier than the first time, and the expected photovoltaic power generation end time is determined based on the historical time when the photovoltaic power generation in the system stops. At least one of the first time, the second time, and the third time, reactive power compensation is performed on the system to control the power factor of the system to be greater than the preset threshold.

2. The method according to claim 1, characterized in that, The step of determining the prediction time when the power factor equals a preset threshold based on the active power and the reactive power includes: Based on the preset threshold, the active power, and the reactive power, determine the prediction duration for which the power factor equals the preset threshold; Based on the predicted duration and the current time, determine the prediction time when the power factor equals the preset threshold.

3. The method according to claim 1, characterized in that, The step of determining the prediction time when the power factor equals a preset threshold based on the active power and the reactive power includes: Based on the preset duration, the active power, and the reactive power, determine the predicted power factor within the preset duration; Based on the power factor and the current time, determine the prediction time when the power factor equals a preset threshold.

4. The method according to any one of claims 1-3, characterized in that, The step of determining at least one of the following based on the predicted time and the expected end time of photovoltaic power generation: a first time when the photovoltaic inverter begins reactive power compensation of the system, a second time when the energy storage converter begins reactive power compensation of the system, and a third time when the preset reactive power compensation device begins reactive power compensation of the system, includes: If the predicted time is earlier than or equal to the expected photovoltaic power generation end time, then at least one of the following is determined: the first time when the photovoltaic inverter starts to perform reactive power compensation on the system, the second time when the energy storage converter starts to perform reactive power compensation on the system, and the third time when the preset reactive power compensation device starts to perform reactive power compensation on the system. If the predicted time is later than the expected photovoltaic power generation end time, then the third time when the preset reactive power compensation device starts to perform reactive power compensation on the system is determined.

5. The method according to claim 4, characterized in that, The determination of at least one of the following: the first time when the photovoltaic inverter begins reactive power compensation of the system, the second time when the energy storage converter begins reactive power compensation of the system, and the third time when the preset reactive power compensation device begins reactive power compensation of the system, includes: Based on the current instantaneous active power and the current instantaneous reactive power, determine the correspondence between the first target power factor and the target time; Determine the first target time when the first target power factor is less than the first value and greater than the second value, and determine the third time when the preset reactive power compensation device starts to perform reactive power compensation on the system as the first target time; The second target time is determined to be when the first target power factor is less than the second value and greater than the third value. The second time when the energy storage converter starts to perform reactive power compensation on the system and the third time when the preset reactive power compensation device starts to perform reactive power compensation on the system are determined as the second target time. The third target time is determined to be the time when the first target power factor is less than the third value and greater than the preset threshold. The first time when the photovoltaic inverter starts to perform reactive power compensation on the system, the second time when the energy storage converter starts to perform reactive power compensation on the system, and the third time when the preset reactive power compensation device starts to perform reactive power compensation on the system are determined as the third target time. The target time includes the first target time, the second target time, and the third target time, wherein the first value is greater than the second value, the second value is greater than the third value, and the third value is greater than the preset threshold.

6. The method according to claim 1, characterized in that, Also includes: Based on the current instantaneous active power and the current instantaneous reactive power, determine the correspondence between the second target power factor and the target time; Determine the fourth target time corresponding to the second target power factor being greater than the third value, and determine the fourth target time as the fourth time when the photovoltaic inverter stops performing reactive power compensation on the system. The fifth target time is determined to be when the second target power factor is greater than the second value, and the fifth time when the energy storage converter stops performing reactive power compensation on the system is determined as the fifth target time, wherein the second value is greater than the third value; The fourth target time and the fifth target time are both target times.

7. The method according to claim 1, characterized in that, Also includes: Within a preset time period, the reactive power compensation of the system by the energy storage converter and the photovoltaic inverter is stopped, and the preset reactive power compensation device is controlled to perform reactive power compensation of the system, so that the power factor is maintained within a preset range within the preset time period, wherein the preset time period is determined based on the time period corresponding to when the photovoltaic in the system stops emitting active power.

8. A power factor control device, characterized in that, Configured in a photovoltaic-energy storage integrated power generation system, the system includes a photovoltaic inverter, an energy storage converter, and a pre-set reactive power compensation device, the device comprising: The power acquisition module is used to acquire active power and reactive power, wherein the active power includes the current instantaneous active power and the cumulative active power, and the reactive power includes the current instantaneous reactive power and the cumulative reactive power. The cumulative active power is determined based on the instantaneous active power within a preset period, and the cumulative reactive power is determined based on the instantaneous reactive power within the preset period. The prediction time determination module is used to determine the prediction time when the power factor is equal to a preset threshold based on the active power and the reactive power. The compensation time determination module is used to determine, based on the predicted time and the expected photovoltaic power generation end time, at least one of the following: a first time when the photovoltaic inverter starts to perform reactive power compensation on the system, a second time when the energy storage converter starts to perform reactive power compensation on the system, and a third time when the preset reactive power compensation device starts to perform reactive power compensation on the system, wherein the third time is earlier than the second time, the second time is earlier than the first time, and the expected photovoltaic power generation end time is determined based on the historical time when the photovoltaic power generation in the system stops; The reactive power compensation module is used to perform reactive power compensation on the system at at least one of the first time, the second time, and the third time, so as to control the power factor of the system to be greater than the preset threshold.

9. An electronic device, characterized in that, The electronic device includes: At least one processor; and A memory communicatively connected to the at least one processor; wherein, The memory stores a computer program that can be executed by the at least one processor to enable the at least one processor to perform the power factor control method according to any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions that, when executed by a processor, implement the power factor control method according to any one of claims 1-7.

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