Photovoltaic power generation power automatic control method and system

Abstract

The present application belongs to the technical field of photovoltaic power generation control, and particularly relates to a photovoltaic power generation power automatic control method and system, which divides an inverter array into a functionally independent first subset and a second subset, according to a power difference, sequentially closes the inverters from low to high according to the inverter output power, combines a power compensation mechanism to effectively avoid power over-regulation and power grid oscillation, avoids the loss of power generation caused by the unjustified derating of high-efficiency inverters, evaluates the effective remaining regulation capacity of the second subset, calculates the individual energy gain potential of the inverters, preferentially improves the power of high-gain potential inverters or switches to a maximum power point tracking mode, realizes the optimal combination of regulation and power generation efficiency through intelligent distribution in the order of efficiency, dynamically updates the inverter subset division strategy library and optimizes the key parameters of the regulation efficiency control group based on historical operation data and actual regulation effect, and effectively guarantees the long-term effectiveness and superiority of the control strategy.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of photovoltaic power generation control, and particularly relates to a photovoltaic power generation power automatic control method and system. BACKGROUND

[0002] With the large-scale development of the photovoltaic industry, the volatility and intermittence of photovoltaic power generation power increasingly highlight the influence on the stable operation of the power grid, and the power grid dispatching needs to issue power instructions in real time, and requires photovoltaic power stations to accurately adjust the output power to match the load demand.

[0003] As the core equipment for realizing the conversion from direct current to alternating current in the photovoltaic power station, the inverter is naturally the main execution unit of power control.

[0004] At present, the inverter power control method of the photovoltaic power station mainly includes two categories: when the power is reduced, the output power is quickly reduced by the way of unified de-rating operation of the whole station or switching part of photovoltaic strings or inverters, and when the power is increased, the output power is quickly increased by the way of restoring all inverters in the de-rating or shutdown state to the maximum power point tracking mode (MPPT) at one time.

[0005] However, the prior art has the following limitations: 1. Although the unified de-rating operation of the whole station can reserve the adjustment margin, it forces all inverters to deviate from the optimal operation interval, causing non-discriminatory power generation loss. The way of switching part of photovoltaic strings or inverters can quickly reduce the power, but the inherent fixed sequence shutdown logic often causes high-efficiency inverters to be mistakenly shut down, while low-efficiency inverters are continuously running, reducing the overall operation economy of the power station.

[0006] 2. Although the simple inverter switching strategy responds quickly, it belongs to extensive regulation. When the power is slightly reduced, due to the limitation of the regulation granularity to the whole machine start-stop, it is easy to cause power over-regulation and oscillation. When the power is increased, the existing method generally restores all de-rating inverters to the MPPT mode, but does not consider the problem of the deviation of the actual optimal efficiency point of the inverter caused by the aging of the inverter or the change of the working condition, so that intelligent power distribution based on the maximum overall efficiency cannot be realized. SUMMARY

[0007] In order to overcome the shortcomings in the background art, the embodiments of the present application provide a photovoltaic power generation power automatic control method and system, which can effectively solve the problems involved in the above background art.

[0008] The purpose of the present application can be achieved by the following technical solutions: in a first aspect, the present application provides a photovoltaic power generation power automatic control method, comprising the following steps: S1: receiving a power grid power dispatching instruction to obtain a target power, if the target power is less than the actual output power of the power station, executing S2, otherwise executing S3.

[0009] S2: dividing the inverter array into a functionally independent first subset and a second subset, the first subset maintaining maximum power point tracking mode to provide base power, and the second subset switching to a subset capacity-reduced operation mode.

[0010] S3: evaluating the maximum available power of the current power station, and performing the following branch control: S31: if the maximum available power is greater than or equal to the target power, selecting and executing an adjustment strategy by evaluating the effective remaining adjustment capacity of the second subset, the adjustment strategy being locally increasing the power output value of the second subset or switching the second subset to the maximum power point tracking mode.

[0011] S32: if the maximum available power is less than the target power, controlling all inverters to operate in the maximum power point tracking mode, and calculating a power gap value.

[0012] S33: continuously monitoring the operation state of each inverter, recording power adjustment response parameters, and feeding back the power gap value and state information representing that the power generation capacity has reached the upper limit to the power grid dispatching platform.

[0013] In a second aspect, the present application also provides a photovoltaic power generation automatic control system, comprising: an information acquisition and processing module, an inverter grouping control module, and a power generation decision module.

[0014] The information acquisition and processing module is connected with the inverter grouping control module, and the inverter grouping control module is connected with the power generation decision module.

[0015] The information acquisition and processing module receives a power grid power dispatching instruction to obtain a target power, and executes the inverter grouping control module if the target power is less than the actual output power of the power station, otherwise executes the power generation decision module.

[0016] The inverter grouping control module divides the inverter array into a functionally independent first subset and a second subset, the first subset maintaining maximum power point tracking mode to provide base power, and the second subset switching to a subset capacity-reduced operation mode.

[0017] The power generation decision module evaluates the maximum available power of the current power station, and performs the following branch control: i. if the maximum available power is greater than or equal to the target power, selecting and executing an adjustment strategy by evaluating the effective remaining adjustment capacity of the second subset, the adjustment strategy being locally increasing the power output value of the second subset or switching the second subset to the maximum power point tracking mode.

[0018] ii. if the maximum available power is less than the target power, controlling all inverters to operate in the maximum power point tracking mode, and calculating a power gap value.

[0019] iii.Continuously monitor the operation state of each inverter, record the power regulation response parameters, and feed the power gap value and state information representing that the power generation capacity has reached the upper limit to the power grid dispatch platform.

[0020] Compared with the prior art, the embodiments of the present application have at least the following advantages or beneficial effects: (1) The present application divides the inverter array into a functionally independent first subset and a second subset, keeps the first subset inverters with high conversion efficiency and good operation in the maximum power point tracking mode at all times, and only regulates the power of the second subset with relatively low efficiency or poor working conditions. This differentiated division strategy avoids the loss of power generation caused by the unnecessary derating of high-efficiency inverters, and effectively improves the overall operation economy of the power station.

[0021] (2) The present application closes the inverters in order from low to high according to the power difference value, accumulates the closed power in real time, and effectively avoids power over-regulation and power grid oscillation in combination with the power compensation mechanism, until the down-regulation requirement is accurately met. By evaluating the effective remaining regulation capacity of the second subset and calculating the individual energy gain potential of the inverters, the high-gain-potential inverters are preferentially improved in power or switched back to the MPPT mode, and the regulation and power generation efficiency are combined optimally through intelligent distribution according to the efficiency order.

[0022] (3) The present application introduces an optimization mechanism, which can dynamically update the inverter subset division strategy library and optimize the key parameters of the efficiency loss comparison group based on historical operation data and actual regulation effect, continuously self-calibrates with the goal of minimizing efficiency loss, and effectively guarantees the long-term effectiveness and superiority of the control strategy. BRIEF DESCRIPTION OF DRAWINGS

[0023] The present application is further illustrated by the accompanying drawings, but the embodiments in the drawings do not constitute any limitation on the present application. For ordinary skilled persons in the art, other drawings can be obtained without creative labor based on the following drawings.

[0024] Figure 1 The present application is further illustrated by the accompanying drawings, but the embodiments in the drawings do not constitute any limitation on the present application. For ordinary skilled persons in the art, other drawings can be obtained without creative labor based on the following drawings.

[0025] Figure 2 The present application is further illustrated by the accompanying drawings, but the embodiments in the drawings do not constitute any limitation on the present application. For ordinary skilled persons in the art, other drawings can be obtained without creative labor based on the following drawings.

[0026] Figure 3 The present application is further illustrated by the accompanying drawings, but the embodiments in the drawings do not constitute any limitation on the present application. For ordinary skilled persons in the art, other drawings can be obtained without creative labor based on the following drawings. DETAILED DESCRIPTION

[0027] With reference to the drawings of the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described, obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0028] With reference to Figure 1 The first aspect of the present application provides a photovoltaic power generation power automatic control method and system, comprising the following steps: S1: receiving a power grid power scheduling instruction to obtain a target power, if it is less than the actual output power of the power station, then executing S2, otherwise executing S3.

[0029] S2: dividing the inverter array into a functionally independent first subset and a second subset, the first subset maintaining maximum power point tracking mode to provide basic power, and the second subset switching to subset capacity reduction operation mode.

[0030] Based on a preferred embodiment of the present application, the inverter array is divided into a functionally independent first subset and a second subset, specifically: obtaining the conversion efficiency of all inverters in the current power station.

[0031] According to the current received photovoltaic module input power of the inverter, the maximum conversion efficiency of the inverter in the current operating state is determined.

[0032] Preferably, the difference between the current conversion efficiency and its own maximum conversion efficiency of the inverter is within a preset threshold, and the inverter is divided into the first subset, and the remaining inverters are divided into the second subset.

[0033] It should be noted that the setting of the preset threshold is based on the conventional definition of the high-efficiency operation range of inverters in the photovoltaic industry, for example, in the domestic inverter efficiency grade certification, high-efficiency inverters need to have an efficiency loss of less than 4% at rated power, to ensure that the threshold setting meets the basic requirements of the industry for power generation efficiency, and to avoid the loss of overall power generation efficiency caused by unreasonable threshold.

[0034] The present application divides the inverter array into a functionally independent first subset and a second subset, so that the first subset of inverters with high conversion efficiency and good operation always maintains maximum power point tracking mode, and only the second subset of inverters with relatively low efficiency or poor working conditions is adjusted in power. This differentiated division strategy avoids the loss of power generation caused by the unnecessary derating of high-efficiency inverters, and effectively improves the overall operation economy of the power station.

[0035] Based on a preferred embodiment of the present application, the conversion efficiency of all inverters in the current power station is obtained, specifically: real-time acquisition of the direct current side input power and the alternating current side output power of each inverter.

[0036] The conversion efficiency value of each inverter at present is obtained by calculating the ratio of output power to input power.

[0037] According to a preferred embodiment of the present application, the switching of the second subset to the subset capacity reduction operation mode is specifically as follows: when the target power is less than the actual output power, it is determined that the power adjustment direction is downward adjustment, and the number of inverters in the second subset that are put into operation is reduced according to the power difference, specifically as follows: a. The inverters in the second subset are sorted according to their current output power from low to high.

[0038] b. The inverter with the lowest current output power is sequentially turned off, and the sum of the power outputs of the turned-off inverters is accumulated.

[0039] c. When the accumulated power reaches the power difference, the subsequent inverter is stopped.

[0040] d. If the accumulated power exceeds the power difference, the subsequent inverter is stopped and the excess part is simultaneously taken as a power compensation value, and the power compensation value is compensated by locally increasing the power output value of the second subset.

[0041] The power difference is the difference between the actual output power of the power station at present and the target power, and the specific implementation steps of compensating the power compensation value by locally increasing the power output value of the second subset are as follows: first, the total output power of the accumulated turned-off inverters is calculated and the power difference to be adjusted downward is taken as the power compensation value, then, according to the power compensation value, the inverters in the second subset are selected in the order of energy gain potential from high to low, the power output set value of each inverter is calculated and increased in turn, then, the available upward adjustment space between the current output power of the first selected inverter and its safe operation upper limit is calculated, if the upward adjustment space is greater than or equal to the current power compensation value, the power output of the inverter is increased to exactly offset the power compensation value, and the process is ended, otherwise, the power of the inverter is increased to the safe operation upper limit, and the increment is deducted from the power compensation value, and then the next inverter is iterated until the compensation is completed.

[0042] It should be noted that the inverters in the second subset are sorted according to their current output power from low to high, and the inverter with the lowest current output power is sequentially turned off, and in this way, the inverter with higher output power can be retained as much as possible, which usually has higher operation stability or energy gain potential under the current input power, and when the power needs to be adjusted upward, there is no need to restart the low-power inverter that has been turned off, and the output of the retained high-power inverter can be increased to quickly respond, reducing the adjustment delay and efficiency fluctuation caused by the start and stop of the inverter.

[0043] S3: Assess the maximum power output of the current power plant and execute the following branch control: S31: If the maximum power output is greater than or equal to the target power, select and execute the regulation strategy by assessing the effective remaining regulation capacity of the second subset. The regulation strategy is to locally increase the power output value of the second subset or switch the second subset to the maximum power point tracking mode.

[0044] Based on a preferred embodiment of the present invention, the assessment of the maximum power generation capacity of the current power station specifically involves: estimating the theoretical maximum power generation capacity of the photovoltaic module array based on the current environmental conditions, and accumulating the maximum allowable output power of all inverters in the power station under their current state.

[0045] The theoretical maximum power generation capacity is compared with the maximum allowable output power of all inverters, and the smaller of the two is taken as the maximum power generation capacity of the current power station.

[0046] It should be noted that the estimation of the theoretical maximum power generation capacity of the photovoltaic module array based on the current environmental conditions specifically refers to: calculating the theoretical maximum power generation capacity that the photovoltaic module array can output under ideal conditions of no shading and no loss by combining real-time light intensity, ambient temperature, and module tilt angle.

[0047] The theoretical maximum power generation capacity is the upper limit of energy supply that can be provided under the current environment, i.e., the maximum DC input power that the power station can obtain, while the maximum allowable output power of all inverters is the upper limit of output power that the equipment can receive and convert into AC power.

[0048] Taking the smaller value as the maximum power output of the current power station can avoid operational instability caused by insufficient actual input power due to environmental changes, while setting the power output according to the equipment's upper limit, thus ensuring the safe and compliant operation of the power station.

[0049] Reference Figure 3 As shown, based on a preferred embodiment of the present invention, the step of selecting the regulation strategy by evaluating the effective remaining regulation capability of the second subset specifically involves: establishing the theoretical maximum conversion efficiency curves of each inverter under different photovoltaic input power, and determining the maximum conversion efficiency control group of each inverter.

[0050] It should be noted that the theoretical maximum conversion efficiency curve is obtained by the manufacturer for this model of inverter. In a laboratory environment, different photovoltaic input power conditions are simulated. The inverter is adjusted to operate under optimal control parameters, and the maximum conversion efficiency that the inverter can achieve at this time is measured. Different input power values ​​are correlated with the corresponding measured highest conversion efficiency values ​​to generate an input power-maximum conversion efficiency curve specific to this model of inverter.

[0051] Real-time monitoring of the actual input power and conversion efficiency of each inverter in the second subset, calculating the individual deviation of the current operating point of each inverter from the maximum conversion efficiency reference group.

[0052] Based on the individual deviation, the individual energy gain potential of each inverter by adjusting to the maximum conversion efficiency is evaluated, and the current regulation efficiency reference group is determined.

[0053] It should be noted that the maximum conversion efficiency reference group and the individual deviation are as follows: according to the currently monitored actual input power, the corresponding theoretical maximum conversion efficiency value under this input power is matched in the theoretical maximum conversion efficiency curve, which is the maximum conversion efficiency reference group, and the difference between the theoretical maximum conversion efficiency value and the current conversion efficiency value is calculated, which is the individual deviation of the current operating point of the inverter from the maximum efficiency. The larger the difference, the greater the deviation, and the higher the individual energy gain potential of the inverter to reach maximum efficiency through parameter adjustment. Conversely, the smaller the difference, the smaller the deviation, and the lower the individual energy gain potential.

[0054] It should also be noted that the regulation efficiency reference group is constructed as follows: based on the individual deviation calculated above, the inverters with efficiency improvement space are selected, and the efficiency reference corresponding to the inverters with larger deviation is preferentially retained. The historical efficiency data of each inverter is retrieved under various photovoltaic input power conditions in the past period of time, forming a historical efficiency data set for each inverter. The highest stable efficiency value that the inverter has ever achieved under various photovoltaic input power conditions is selected as the historical efficiency reference group of the inverter. The reference group is put into the current working condition for output power gain analysis. The analysis is specifically to limit the input power and calculate the output power of the inverter with its historical stable efficiency value under inverter duration compensation, and to retrieve the reference group corresponding to the maximum output power gain as the current regulation efficiency reference group of the inverter. It is essentially the highest efficiency reference that can be actually achieved based on the current state of the device, rather than a fixed theoretical curve.

[0055] The larger deviation means that the difference between the theoretical maximum conversion efficiency value and the current conversion efficiency value exceeds the preset permission threshold, which is defined as a larger deviation. The preset permission threshold can be set in advance in combination with the inverter model and the power station efficiency target.

[0056] The difference between the total upper limit of the safe operation of all inverters in the second subset and the current total power output value of the second subset is calculated as the basic remaining regulation capacity.

[0057] Aggregate the individual energy gain potential of each inverter in the second subset, and combine the basic residual regulation capability to obtain the effective residual regulation capability of the second subset as a whole.

[0058] It should be noted that the effective residual regulation capability refers to the maximum power up-regulation space that the inverters in the second subset can achieve as a whole under the premise of considering the efficiency optimization potential and the equipment safety boundary, and the specific definition and calculation logic are as follows: first, the individual energy gain potential of all inverters in the second subset is counted to obtain the total gain potential, then the basic residual regulation capability is combined, and finally the smaller value of the two is taken as the effective residual regulation capability of the second subset as a whole.

[0059] When the power difference is less than the effective residual regulation capability, the local power output value of the second subset is preferentially adjusted, and the inverter with high energy gain potential is preferentially selected in the adjustment process.

[0060] When the power difference is greater than or equal to the effective residual regulation capability, the mode of switching to the maximum efficiency point tracking mode is preferentially used for rapid adjustment.

[0061] It should be noted that when the power difference is less than the effective residual regulation capability, it means that the difference can be filled by local power up-regulation only, without the need to switch to the maximum efficiency point tracking mode, which avoids the complication of the adjustment process caused by switching modes, strictly controls the power regulation without breaking the equipment safety operation boundary, ensures the stability and safety of the adjustment process, preferentially adjusts the inverter with high energy gain potential, fills the power difference at the lowest efficiency loss cost, maximizes the overall power generation efficiency of the second subset, and further reduces the impact on the overall output stability of the power station, ensuring that the power target is met while maintaining the stability of the core power generation capacity of the power station when responding to the grid dispatching instruction.

[0062] Referring to Figure 3 Based on a preferred embodiment of the present application, the local power output value of the second subset is specifically calculated as follows: the ratio of the power difference to the effective residual regulation capability is calculated as an adjustment ratio.

[0063] According to the adjustment ratio, the number of inverters in the second subset that need to increase the power output value is determined.

[0064] It should be noted that the essence of the adjustment ratio is the ratio between the power gap to be filled and the maximum adjustable capacity of the second subset, and the number of inverters that need to call the second subset adjustment capacity can be determined by adjusting the ratio, specifically: first, count the total number of inverters in the second subset that currently have individual energy gain potential, then multiply the total number by the adjustment ratio, and round up the calculation result to the nearest integer, which is the final number of inverters that need to participate in power boost.

[0065] When the power gap is small, the number of inverters calculated is also small, thereby avoiding the calling of a large number of devices for a small power change, reducing unnecessary operation and system disturbance, and when the power gap is large, more inverters are automatically allocated to participate in adjustment to ensure sufficient aggregated power output capacity, providing a quantitative basis for subsequent determination of the number of inverters to boost power, ensuring that the final cumulative boost is just enough to fill the power difference, and achieving accurate matching of the target power.

[0066] According to the order of energy gain potential from high to low, the inverters in the second subset that need to boost the power output value are changed to the photovoltaic input power in the current adjustment efficiency reference group, and the cumulative power output is calculated.

[0067] The inverters in the second subset that have not yet run at the optimal efficiency point are adjusted according to the order of energy gain potential from high to low, and the photovoltaic input power is changed to the corresponding optimal value in the current adjustment efficiency reference group. This stage aims to increase the total output by boosting the single machine efficiency to fill the power gap as small as possible.

[0068] It should be noted that using energy gain potential as the basis for sorting can prioritize the scheduling of inverters with the largest current efficiency improvement space, thereby achieving higher overall power boost with the same number of device actions, reducing the number of inverters that need to be adjusted, reducing system control complexity, and avoiding redundant operations caused by frequently switching adjustment objects due to adjusting inverters with small margins.

[0069] If there is a deviation between the cumulative power output and the target power, the power output value of the last inverter that has been boosted is adjusted back to the value that just meets the required power adjustment target.

[0070] Based on a preferred embodiment of the present application, the calculation logic of the power output value rollback is as follows: calculate the total power output of the inverters that have been boosted to the set value under the safe running upper limit except for the last inverter that has been boosted, and record it as the pre-sequential cumulative power.

[0071] Calculate the difference between the pre-sequential cumulative power and the required power adjustment target, which is the power output target that the last boosted inverter needs to bear.

[0072] Set the power output target as the post-recovery power output value of the last boosted inverter.

[0073] It should be noted that the recovery process is as follows: by calculating the deviation value of the cumulative power output and the target power, the pre-recovery power output value of the last boosted power inverter is retrieved, and the new power output value of the inverter is set as the difference between the pre-recovery power output value and the recovery amount, for example, the pre-recovery cumulative power output is 1050kW, the target power is 1000kW, the deviation value is 50kW, and the pre-recovery power output value of the last inverter is 300kW, then the new power output value is 250kW.

[0074] Taking the actual deviation value as the recovery amount can not only ensure that the cumulative output meets the standard, but also avoid excessive recovery that causes the cumulative output to be lower than the target, so as to realize accurate recovery and reduce the efficiency loss of repeated adjustment.

[0075] According to the power difference, the inverter output power is sequentially closed from low to high, the closed power is accumulated in real time, and the power compensation mechanism is combined to effectively avoid power over-adjustment and grid oscillation, until the down-regulation demand is accurately met, the effective remaining adjustment capacity of the second subset is evaluated, and the individual energy gain potential of the inverter is calculated, the high gain potential inverter power is preferentially boosted or the MPPT mode is cut back, and the adjustment and power generation benefit are combined to realize the intelligent distribution of the efficiency order.

[0076] S32: If the maximum available power is less than the target power, control all inverters to operate in the maximum power point tracking mode, and calculate the power gap value.

[0077] S33: Continuously monitor the operating state of each inverter, record the power adjustment response parameters, and feed back the power gap value and the state information representing that the power generation capacity has reached the upper limit to the grid dispatching platform.

[0078] It should be noted that the power gap value is the difference between the target power and the maximum available power.

[0079] The system continuously tracks the operating state of each inverter and records the power regulation response parameters, which are the basis for evaluating the effectiveness of the control logic of the power station and provide a basis for subsequent optimization. On the one hand, the power gap value can help the power grid quickly grasp the size of the power gap of the power station, so as to facilitate the dispatching center to timely coordinate other power sources to supplement the gap. On the other hand, the state information that the power generation capacity reaches the upper limit can prevent the power grid from continuously issuing higher power instructions due to misjudgment of the regulation potential of the power station, avoid equipment failure caused by forced overload operation of the power station, and provide a real power station capacity reference for the power grid to subsequently develop a more realistic dispatching plan.

[0080] Based on a preferred embodiment of the application, the method further comprises an optimization mechanism, specifically: based on the power regulation records in the historical operation data and the corresponding environmental condition data, a sub-set division strategy library for different light intensities and temperature conditions is established and dynamically updated.

[0081] It should be noted that the conversion efficiency and operating stability of the inverter are not fixed values, but will dynamically change with environmental conditions such as light intensity and temperature, and the efficiency characteristics of some inverters will change after long-term operation. By obtaining the power regulation records and corresponding environmental condition data in the historical data, analyzing different combinations of working conditions, and determining which sub-set division method can ensure basic power generation efficiency while making the second sub-set exhibit better regulation response characteristics and energy gain potential, when similar environmental conditions occur again, the system preferentially calls the optimized division scheme verified in the strategy library, and simultaneously performs confidence evaluation and iterative updating of the schemes in the strategy library according to the newly generated regulation effect data, thereby realizing continuous evolution of the division strategy.

[0082] Based on this rule to establish the strategy library, it can avoid fixed division that is not based on actual working conditions, making the sub-set division more scientific and ensuring the basic power generation efficiency and regulation response capability of the power station from the source.

[0083] By comparing the expected effect of power regulation with the actual response result, the adjustment efficiency reference group involved in the optimization evaluation of the effective remaining regulation capacity is optimized to minimize the efficiency loss in the regulation process.

[0084] It should be noted that the adjustment efficiency reference group involved in the optimization evaluation of the effective remaining regulation capacity is based on making the adjustment efficiency reference group more consistent with the actual operating state of the power station, avoiding inaccurate evaluation of the effective remaining regulation capacity due to reference deviation, and thereby causing efficiency waste or regulation failure.

[0085] Periodically perform performance evaluation based on regulation response time, tracking accuracy, and overall power generation efficiency indicators, and automatically calibrate the control parameters in the sub-set division strategy and power regulation logic according to the evaluation results.

[0086] The application can dynamically update the inverter subset division strategy library and optimize the key parameters of the efficiency adjustment efficiency control group based on the historical operation data and the actual adjustment effect, continuously self-calibrates with the goal of minimizing efficiency loss, and effectively guarantees the long-term effectiveness and superiority of the control strategy.

[0087] Referring to Figure 2 The second aspect of the application provides a photovoltaic power generation power automatic control system, comprising: an information acquisition and processing module, an inverter grouping control module and a power generation decision module.

[0088] The information acquisition and processing module is connected with the inverter grouping control module, and the inverter grouping control module is connected with the power generation decision module.

[0089] The information acquisition and processing module receives the target power of the power grid power dispatching instruction to obtain the target power, and if it is less than the actual output power of the power station, the inverter grouping control module is executed, otherwise the power generation decision module is executed.

[0090] The inverter grouping control module divides the inverter array into a functionally independent first subset and a second subset, the first subset maintains the maximum power point tracking mode to provide basic power, and the second subset switches to the subset capacity reduction operation mode.

[0091] The power generation decision module evaluates the maximum available power of the current power station, and executes the following branch control: i. if the maximum available power is greater than or equal to the target power, select and execute the adjustment strategy by evaluating the effective remaining adjustment capacity of the second subset, the adjustment strategy is to locally increase the power output value of the second subset or switch the second subset to the maximum power point tracking mode.

[0092] ii. If the maximum available power is less than the target power, control all inverters to operate in the maximum power point tracking mode, and calculate the power gap value.

[0093] iii. Continuously monitor the operating state of each inverter, record the power adjustment response parameters, and feed back the power gap value and the state information representing that the power generation capacity has reached the upper limit to the power grid dispatching platform.

[0094] The above embodiments can be realized in whole or in part by software, hardware, firmware or any combination thereof. When realized by software, the above embodiments can be realized in whole or in part in the form of a computer program product.

[0095] Those skilled in the art can understand that the modules and algorithm steps of each example described in combination with the embodiments disclosed herein can be realized in electronic hardware or a combination of computer software and electronic hardware. Whether the functions are realized 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 realize the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0096] In addition, each functional module in each embodiment of the present application can be integrated in one processing module, or each module can exist physically alone, or two or more modules can be integrated in one module.

[0097] The above description is merely specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any modification or replacement within the technical scope disclosed by the present application can be easily thought by those skilled in the art, and should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

[0098] Finally, the above description is only the preferred embodiments of the present application, and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A method for automatic control of photovoltaic power generation, characterized in that, Includes the following steps: S1: Receive the power dispatch command from the power grid and obtain the target power. If it is less than the actual output power of the power station, execute S2; otherwise, execute S3. S2: Divide the inverter array into a functionally independent first subset and a second subset. The first subset maintains the maximum power point tracking mode to provide basic power, while the second subset switches to the subset reduced capacity operation mode. S3: Assess the current maximum generating capacity of the power plant and execute the following branch control: S31: If the maximum power output is greater than or equal to the target power, an adjustment strategy is selected and executed by evaluating the effective remaining adjustment capability of the second subset. The adjustment strategy is to locally increase the power output value of the second subset or switch the second subset to the maximum power point tracking mode. S32: If the maximum power output is less than the target power, control all inverters to operate in maximum power point tracking mode and calculate the power deficit value; S33: Continuously monitor the operating status of each inverter, record the power regulation response parameters, and feed back the power gap value and status information indicating that the power generation capacity has reached its limit to the grid dispatch platform. Obtain the conversion efficiency of all inverters in the current power station; determine the maximum conversion efficiency of the inverter under the current operating state based on the photovoltaic module input power currently received by the inverter; Inverters whose current conversion efficiency is within a preset threshold difference from their maximum conversion efficiency are prioritized and assigned to the first subset, while the remaining inverters are assigned to the second subset. Establish the theoretical maximum conversion efficiency curves of each inverter under different photovoltaic input power, and determine the maximum conversion efficiency control group of each inverter; monitor the actual input power and conversion efficiency of each inverter in the second subset in real time, and calculate the individual deviation of each inverter's current operating point from its own maximum conversion efficiency control group. Based on the degree of individual deviation, assess the individual energy gain potential of each inverter by adjusting to maximum conversion efficiency, and determine the current adjustment efficiency control group; The difference between the total safe operating limit of all inverters in the second subset and the current total power output value of the second subset is calculated as the basic residual regulation capacity. The individual energy gain potential of each inverter in the second subset is aggregated and combined with the basic residual regulation capacity to obtain the overall effective residual regulation capacity of the second subset. When the power difference is less than the effective residual regulation capacity, the regulation is preferentially carried out by locally increasing the power output value of the second subset, and inverters with high energy gain potential are preferentially selected during the regulation process. When the power difference is greater than or equal to the effective remaining regulation capacity, the method of switching to the maximum efficiency point tracking mode is preferred for rapid regulation.

2. The method for automatic control of photovoltaic power generation according to claim 1, characterized in that: The specific steps for obtaining the conversion efficiency of all inverters in the current power station are as follows: Real-time acquisition of DC-side input power and AC-side output power of each inverter; The current conversion efficiency value of each inverter is obtained by calculating the ratio of output power to input power.

3. The automatic control method for photovoltaic power generation according to claim 1, characterized in that: The second subset switches to subset reduction operation mode as follows: When the target power is less than the actual output power, the power adjustment direction is determined to be downward. Based on the power difference, the number of inverters put into operation in the second subset is reduced, specifically: a. Sort the inverters in the second subset from low to high according to their current output power; b. Sequentially shut down the inverters with the lowest current output power, and sum the power output of the shut-down inverters; c. When the accumulated power reaches the power difference value, stop shutting down the subsequent inverters; d. If the cumulative power exceeds the power difference, stop shutting down subsequent inverters and synchronously use the excess as a power compensation value, and compensate for the power compensation value by locally increasing the power output value of the second subset.

4. The automatic control method for photovoltaic power generation according to claim 1, characterized in that: The assessment of the current power plant's maximum generating capacity specifically refers to: Estimate the theoretical maximum power generation capacity of the photovoltaic module array based on the current environmental conditions, and accumulate the maximum allowable output power of all inverters in the power station under the current state; The theoretical maximum power generation capacity is compared with the maximum allowable output power of all inverters, and the smaller of the two is taken as the maximum power generation capacity of the current power station.

5. The automatic control method for photovoltaic power generation according to claim 4, characterized in that: The specific steps of locally boosting the power output value of the second subset are as follows: The ratio of the power difference to the effective remaining regulation capacity is calculated as the regulation ratio; Based on the aforementioned adjustment ratio, determine the number of inverters in the second subset that require an increase in power output value; In order of energy gain potential from high to low, the inverters in the second subset that need to increase their power output value are sequentially changed to the photovoltaic input power in their respective current regulation efficiency control group, and the cumulative power output is calculated. If there is a deviation between the cumulative power output and the target power, the power output value of the last inverter whose power output value has been increased will be adjusted back to adjust its output power to just meet the required power regulation target.

6. The automatic control method for photovoltaic power generation according to claim 5, characterized in that: The calculation logic for the power output value callback is as follows: Calculate the total power output of the remaining inverters (excluding the last one whose power output value has been increased) under the safe operating limit, and record it as the previous cumulative power. Calculate the difference between the preceding cumulative power and the required power adjustment target. This difference is the power output target that the last inverter to be boosted needs to bear. The power output target is set to the power output value after the callback of the last boosted inverter.

7. The automatic control method for photovoltaic power generation according to claim 1, characterized in that: The method also includes an optimization mechanism, specifically: Based on the power regulation records and corresponding environmental condition data in the historical operation data, an inverter subset partitioning strategy library is established and dynamically updated for different light intensity and temperature conditions. By comparing the expected effect of power regulation with the actual response results, and with the goal of minimizing efficiency loss during the regulation process, the regulation efficiency control group involved in evaluating the effective residual regulation capacity is optimized. Regular performance evaluations are performed based on adjustment response time, tracking accuracy, and overall power generation efficiency indicators. Based on the evaluation results, the subset partitioning strategy and control parameters in the power regulation logic are automatically calibrated.

8. A photovoltaic power generation automatic control system, used to execute the steps of the photovoltaic power generation automatic control method as described in any one of claims 1-7, characterized in that: include: Information acquisition and processing module: Receives power dispatch instructions from the power grid to obtain the target power. If the target power is less than the actual output power of the power station, the inverter group control module is executed; otherwise, the power generation decision module is executed. Inverter group control module: Divides the inverter array into a first subset and a second subset with independent functions. The first subset maintains the maximum power point tracking mode to provide basic power, while the second subset switches to the subset reduction operation mode. Power generation decision module: Assess the maximum power output of the current power plant and execute the following branch controls: i. If the maximum power output is greater than or equal to the target power, an adjustment strategy is selected and executed by evaluating the effective remaining adjustment capability of the second subset. The adjustment strategy is to locally increase the power output value of the second subset or switch the second subset to the maximum power point tracking mode. ii. If the maximum power output is less than the target power, control all inverters to operate in maximum power point tracking mode and calculate the power deficit value; iii. Continuously monitor the operating status of each inverter, record the power regulation response parameters, and feed back the power deficit value and status information indicating that the power generation capacity has reached its limit to the grid dispatch platform.

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