Photovoltaic power generation system control method and device, coordination controller, system and product

Abstract

The invention discloses a photovoltaic power generation system control method and device, a coordination controller, a system and a product, and relates to the technical field of photovoltaic power generation, and the method comprises the steps: obtaining the maximum power information of a first photovoltaic power generation unit in all photovoltaic power generation units through employing a maximum power tracking strategy; determining a direct current voltage and an active power set point of each photovoltaic power generation unit according to the maximum power information and a preset active power margin; and the direct current voltage and the active power set point are sent to a second photovoltaic power generation unit in the photovoltaic power generation units, so that the second photovoltaic power generation unit operates according to the direct current voltage and the active power set point, and the second photovoltaic power generation unit is a unit except the first photovoltaic power generation unit in the photovoltaic power generation units. According to the invention, tracking control of the maximum power point of the photovoltaic array can be considered while synchronous and stable operation of the power grid is realized, so that the operation stability of the photovoltaic power generation system is improved.

Description

Technical Field

[0001] The present application relates to the field of photovoltaic power generation technology, and in particular to photovoltaic power generation system control methods, devices, coordination controllers, systems and products. Background Art

[0002] As the penetration rate of new energy gradually increases, grid-connected photovoltaic power generation systems will become an important part of future new power systems.

[0003] In order to maximize the power generation potential of the photovoltaic array, the photovoltaic inverter usually needs to frequently adjust its output power to track and maintain it at the maximum power point. However, the grid-type photovoltaic power generation system mainly focuses on maintaining the constant output AC voltage and determining the output power according to the real-time status of the power grid. While achieving grid synchronization and stable operation, it is difficult to take into account the tracking and control of the maximum power point of the photovoltaic array.

[0004] In summary, how to achieve grid synchronization and stable operation while taking into account the tracking and control of the maximum power point of the photovoltaic array to improve the stability of the operation of the photovoltaic power generation system has become a technical problem that needs to be solved urgently in this field. Summary of the invention

[0005] The main purpose of this application is to provide a photovoltaic power generation system control method, device, coordinated controller, system and product, aiming to achieve grid synchronization and stable operation while taking into account the tracking and control of the maximum power point of the photovoltaic array to improve the stability of the operation of the photovoltaic power generation system.

[0006] To achieve the above-mentioned purpose, the present application proposes a photovoltaic power generation system control method, which is applied to a coordination controller in a photovoltaic power generation system, wherein the photovoltaic power generation system further includes photovoltaic power generation units;

[0007] The photovoltaic power generation system control method includes:

[0008] A maximum power tracking strategy is used to obtain the maximum power information of the first photovoltaic power generation unit in each of the photovoltaic power generation units;

[0009] Determining a DC voltage and an active power setting point of each photovoltaic power generation unit according to the maximum power information and a preset active power margin;

[0010] The DC voltage and the active power set point are sent to a second photovoltaic power generation unit in each of the photovoltaic power generation units, so that the second photovoltaic power generation unit operates according to the DC voltage and the active power set point, wherein the second photovoltaic power generation unit is a unit in each of the photovoltaic power generation units except the first photovoltaic power generation unit.

[0011] In one embodiment, the method further comprises:

[0012] Obtaining the current DC voltage of each photovoltaic power generation unit;

[0013] For each of the photovoltaic power generation units, the drop difference between the current DC voltage and the historical DC voltage is determined. When the drop difference exceeds a preset voltage drop threshold, the photovoltaic power generation unit is determined as the first photovoltaic power generation unit, and the first photovoltaic power generation unit is controlled by grid-following type and a maximum power tracking strategy is executed.

[0014] In one embodiment, after the step of obtaining the current DC voltage of each photovoltaic power generation unit, the method further includes:

[0015] For each of the photovoltaic power generation units, determining a drop difference between the current DC voltage and the historical DC voltage;

[0016] When each of the drop differences does not exceed the voltage drop threshold, each of the photovoltaic power generation units is determined as the first photovoltaic power generation unit in turn according to a preset order, and the first photovoltaic power generation unit is controlled by grid-following type and executes the maximum power tracking strategy.

[0017] In one embodiment, the step of adopting a maximum power tracking strategy to obtain the maximum power information of the first photovoltaic power generation unit in each of the photovoltaic power generation units includes:

[0018] Real-time monitoring of the output voltage and output current of the photovoltaic array of the first photovoltaic power generation unit in each of the photovoltaic power generation units;

[0019] Calculating the instantaneous power of the first photovoltaic power generation unit according to the output voltage and the output current;

[0020] By comparing the instantaneous power of the first photovoltaic power generation unit at different working points, the maximum power information of the first photovoltaic power generation unit is determined.

[0021] In one embodiment, the photovoltaic power generation system is connected to a power grid, and the step of determining the DC voltage and active power set point of each photovoltaic power generation unit according to the maximum power information and the preset active power margin includes:

[0022] Calculating the active power margin of each photovoltaic power generation unit according to the preset primary frequency regulation capacity requirement and the total power generation capacity of the photovoltaic power generation system;

[0023] The DC voltage and active power setting point of each photovoltaic power generation unit are calculated according to the maximum power information and the active power margin.

[0024] In one embodiment, the photovoltaic power generation system is connected to a power grid, and after the step of sending the DC voltage and the active power set point to the second photovoltaic power generation unit in each of the photovoltaic power generation units, the step further includes:

[0025] Acquiring frequency deviation information of the power grid in real time;

[0026] The frequency offset information is sent to each of the second photovoltaic power generation units, so that each of the second photovoltaic power generation units adjusts its own active power output according to the frequency offset information.

[0027] In one embodiment, the method further comprises:

[0028] Real-time monitoring of the operating status of each photovoltaic power generation unit;

[0029] When an abnormal photovoltaic power generation unit with an abnormal operating state is detected among the photovoltaic power generation units, the abnormal photovoltaic power generation unit is determined as the second photovoltaic power generation unit.

[0030] In addition, to achieve the above purpose, the present application also proposes a coordination control device, which is applied to a coordination controller in a photovoltaic power generation system, wherein the photovoltaic power generation system also includes photovoltaic power generation units; the coordination control device includes:

[0031] A first photovoltaic power generation unit control module, used for acquiring maximum power information of a first photovoltaic power generation unit among the photovoltaic power generation units by adopting a maximum power tracking strategy;

[0032] A calculation module, used to determine the DC voltage and active power setting point of each photovoltaic power generation unit according to the maximum power information and the preset active power margin;

[0033] The second photovoltaic power generation unit control module is used to send the DC voltage and the active power set point to the second photovoltaic power generation unit in each of the photovoltaic power generation units, so that the second photovoltaic power generation unit operates according to the DC voltage and the active power set point, wherein the second photovoltaic power generation unit is a unit in each of the photovoltaic power generation units except the first photovoltaic power generation unit.

[0034] In addition, to achieve the above objectives, the present application also proposes a coordination controller, which includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, and the computer program is configured to implement the steps of the photovoltaic power generation system control method as described above.

[0035] In addition, to achieve the above objectives, the present application also proposes a photovoltaic power generation system, which includes each photovoltaic power generation unit and a coordination controller as described above, the photovoltaic power generation unit includes a photovoltaic array, an inverter and a transformer, and the photovoltaic power generation system is connected to a power grid.

[0036] In addition, to achieve the above-mentioned purpose, the present application also proposes a storage medium, which is a computer-readable storage medium, and a computer program is stored on the storage medium. When the computer program is executed by a processor, the steps of the photovoltaic power generation system control method as described above are implemented.

[0037] In addition, to achieve the above-mentioned purpose, the present application also provides a computer program product, which includes a computer program, and when the computer program is executed by a processor, the steps of the photovoltaic power generation system control method described above are implemented.

[0038] The present application proposes a photovoltaic power generation system control method, which is applied to a coordinated controller in a photovoltaic power generation system, and the photovoltaic power generation system also includes multiple photovoltaic power generation units; a maximum power tracking strategy is used to obtain the maximum power output information of the first photovoltaic power generation unit in the system, and then the DC voltage and active power set points of each photovoltaic power generation unit in the system are calculated based on the obtained maximum power information and the active power margin preset by the system; finally, the DC voltage and active power set points are sent to all other photovoltaic power generation units except the first photovoltaic power generation unit, that is, the second photovoltaic power generation unit, and the second photovoltaic power generation unit operates according to the received DC voltage and active power set points to ensure stable operation and efficient power generation of the entire system.

[0039] In summary, the present application ensures the power balance between the photovoltaic power generation units in the photovoltaic power generation system and the satisfaction of the grid demand by coordinating the calculation and real-time adjustment of the controller. At the same time, through the application of the maximum power tracking strategy, the maximum power point of the photovoltaic array in the system can be determined in real time, so that the system can make full use of solar energy resources and improve the power generation efficiency. This achieves the tracking and control of the maximum power point of the photovoltaic array while ensuring the synchronization and stable operation of the grid, thereby improving the stability of the operation of the photovoltaic power generation system. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0041] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0042] Figure 1 A schematic diagram of the power operating points provided for this application;

[0043] Figure 2 A schematic diagram of a flow chart provided for the first embodiment of the photovoltaic power generation system control method of the present application;

[0044] Figure 3 A schematic diagram of a photovoltaic power generation unit provided in Example 1 of the photovoltaic power generation system control method of the present application;

[0045] Figure 4 A schematic diagram of the structure of a photovoltaic power generation system provided in Example 1 of the photovoltaic power generation system control method of the present application;

[0046] Figure 5 A schematic diagram of a photovoltaic station structure provided in Example 1 of the photovoltaic power generation system control method of the present application;

[0047] Figure 6 Another schematic diagram of a photovoltaic station provided in Example 2 of the photovoltaic power generation system control method of the present application;

[0048] Figure 7 A schematic diagram of simulation results of a conventional solution provided in Example 2 of the photovoltaic power generation system control method of the present application;

[0049] Figure 8 A schematic diagram of simulation results of a first photovoltaic power generation unit provided in Embodiment 2 of the photovoltaic power generation system control method of the present application;

[0050] Fig. 9 A schematic diagram of simulation results of a second photovoltaic power generation unit provided in Embodiment 2 of the photovoltaic power generation system control method of the present application;

[0051] Fig.10 This is a schematic diagram of the module structure of the coordination control device according to an embodiment of the present application;

[0052] Fig.11 Schematic diagram of the equipment structure of the hardware operating environment involved in the photovoltaic power generation system control method in the embodiment of the present application.

[0053] The purpose, features and advantages of this application will be further described in conjunction with the embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0054] It should be understood that the specific embodiments described herein are only used to explain the technical solutions of the present application and are not used to limit the present application.

[0055] In order to better understand the technical solution of the present application, a detailed description will be given below in conjunction with the accompanying drawings and specific implementation methods.

[0056] The main solution of the embodiment of the present application is: a coordinated controller applied to a photovoltaic power generation system, the photovoltaic power generation system also includes various photovoltaic power generation units; a maximum power tracking strategy is adopted to obtain the maximum power information of the first photovoltaic power generation unit in each photovoltaic power generation unit; the DC voltage and active power set point of each photovoltaic power generation unit is determined according to the maximum power information and the preset active power margin; the DC voltage and active power set point are sent to the second photovoltaic power generation unit in each photovoltaic power generation unit, so that the second photovoltaic power generation unit operates according to the DC voltage and active power set point, wherein the second photovoltaic power generation unit is a unit in each photovoltaic power generation unit except the first photovoltaic power generation unit.

[0057] In order to maximize the power generation potential of the photovoltaic array, the photovoltaic inverter usually needs to frequently adjust its output power to track and maintain it at the maximum power point. However, the grid-type photovoltaic power generation system mainly focuses on maintaining the constant output AC voltage and determining the output power according to the real-time status of the power grid. While achieving grid synchronization and stable operation, it is difficult to take into account the tracking and control of the maximum power point of the photovoltaic array.

[0058] It should also be noted that although a control method for switching the grid-following switch has been proposed, that is, obtaining the maximum output power under grid-following control and then switching to grid-following control, this method requires frequent switching between the grid-following mode and the grid-following mode, and has the following defects: First, when the maximum power point changes but is not known in time, the power operation point will work to the point where the maximum power point is too high. Figure 1 The left area 1 shown in the figure causes the photovoltaic power generation system to operate unstably; second, if the grid needs the inverter to provide inertia support in the grid-following control mode, the photovoltaic power generation system has no control capability at this time; third, if in the grid-building control mode, when the grid frequency is higher than the rated value (i.e., positive frequency deviation), the photovoltaic power generation system will reduce its power output to reduce power injection into the grid, reduce the grid frequency and restore it to near the rated value, but when the grid frequency is lower than the rated value (i.e., negative frequency deviation), the photovoltaic power generation system cannot increase its active output to adjust this deviation, which eventually leads to a voltage drop on the DC side or even a system crash.

[0059] The present application provides a solution, which ensures the power balance between each photovoltaic power generation unit in the photovoltaic power generation system and the satisfaction of the power grid demand by coordinating the calculation and real-time adjustment of the controller. At the same time, through the application of the maximum power tracking strategy, the maximum power point of the photovoltaic array in the system can be determined in real time, so that the system can make full use of solar energy resources and improve the power generation efficiency. Thus, while ensuring the synchronization and stable operation of the power grid, the tracking and control of the maximum power point of the photovoltaic array is taken into account, thereby improving the stability of the operation of the photovoltaic power generation system.

[0060] It should be noted that the execution subject of this embodiment can be an electronic device with data processing, network communication and program running functions, such as a computer, a server, etc., or an electronic device capable of realizing the above functions, etc. The following takes the coordination controller as an example to illustrate this embodiment and the following embodiments.

[0061] Based on this, the embodiment of the present application provides a photovoltaic power generation system control method, referring to Figure 2 , Figure 2 This is a flow chart of the first embodiment of the photovoltaic power generation system control method of the present application.

[0062] In this embodiment, the photovoltaic power generation system control method is applied to a coordination controller in the photovoltaic power generation system, and the photovoltaic power generation system also includes photovoltaic power generation units.

[0063] For example, the photovoltaic power generation unit has a structure as follows: Figure 3 As shown, the photovoltaic power generation unit includes a photovoltaic array, an inverter and a transformer. The photovoltaic power generation unit is connected to the power grid. Multiple photovoltaic power generation units are combined into a photovoltaic power generation system. The combined photovoltaic power generation system is as shown in Figure 4 shown.

[0064] Based on this, in this embodiment, the photovoltaic power generation system control method includes steps S10 to S30:

[0065] Step S10, using a maximum power tracking strategy to obtain maximum power information of a first photovoltaic power generation unit among the photovoltaic power generation units;

[0066] It should be noted that the maximum power point tracking strategy is an intelligent control algorithm for photovoltaic power generation systems. It adjusts the operating point of photovoltaic modules in real time so that they always operate under the voltage and current conditions that can output maximum power, thereby maximizing the power generation efficiency of the photovoltaic power generation system.

[0067] The maximum power tracking strategy is adopted to optimize the control of the first photovoltaic power generation unit in the system. The first photovoltaic power generation unit is controlled by the MPPT (Maximum Power Point Tracking) strategy to ensure that it operates at the maximum power point that the photovoltaic component can provide. Among them, the photovoltaic power generation unit with the physical center of the photovoltaic array in the system is preferably used as the first photovoltaic power generation unit.

[0068] Step S20, determining the DC voltage and active power setting point of each photovoltaic power generation unit according to the maximum power information and the preset active power margin;

[0069] It should be noted that active power margin refers to the power buffer reserved for stable system operation, which can reduce the risk of system failure due to insufficient power, help improve the overall reliability of the system and ensure the continuity of power supply.

[0070] According to the obtained maximum power information of the first photovoltaic power generation unit and the preset active power margin, the target values ​​of DC voltage and active power, i.e., DC voltage set point and active power set point, are set for each photovoltaic power generation unit to ensure that the entire photovoltaic power generation system can operate efficiently and stably.

[0071] Step S30, sending the DC voltage and active power set point to the second photovoltaic power generation unit in each photovoltaic power generation unit, so that the second photovoltaic power generation unit operates according to the DC voltage and active power set point, wherein the second photovoltaic power generation unit is a unit in each photovoltaic power generation unit except the first photovoltaic power generation unit.

[0072] The calculated DC voltage set point and active power set point information are transmitted to all other photovoltaic power generation units in the system except the first photovoltaic power generation unit, i.e., the second photovoltaic power generation unit. The DC voltage and active power set point information are used to guide the operation of the second photovoltaic power generation unit, ensuring that each second photovoltaic power generation unit can operate according to the set DC voltage and active power, thereby maintaining the coordination and efficiency of the entire photovoltaic power generation system.

[0073] For example, Figure 5As shown, the power generation unit 1 in the photovoltaic station serves as the first photovoltaic power generation unit, wherein the inverter adopts the grid-following control and executes the maximum power tracking algorithm to obtain the maximum power point of the photovoltaic array, and sends the maximum power information to the coordination controller in real time through communication. The coordination controller calculates the active margin of each photovoltaic power generation unit according to the primary frequency regulation capability given by the upper scheduling system, and specifically designs the DC voltage and active power setting point of each power generation unit. The coordination controller sends the corresponding DC voltage and active power reference to the power generation unit 2 to the power generation unit n, that is, each second photovoltaic power generation unit, through communication. The photovoltaic power generation unit 2 to the power generation unit n receive the coordination controller information to perform the grid-building control, that is, the photovoltaic power generation system proposed in this embodiment is a grid-building hybrid photovoltaic power generation system, in which the first photovoltaic power generation unit in the system adopts the grid-following control, and the second photovoltaic power generation unit adopts the grid-building control.

[0074] In summary, the embodiment of the present application ensures the power balance between the photovoltaic power generation units in the photovoltaic power generation system and the satisfaction of the power grid demand by coordinating the calculation and real-time adjustment of the controller. At the same time, through the application of the maximum power tracking strategy, the maximum power point of the photovoltaic array in the system can be determined in real time, so that the system can make full use of solar energy resources and improve the power generation efficiency. This achieves the tracking and control of the maximum power point of the photovoltaic array while ensuring the synchronization and stable operation of the power grid, thereby improving the stability of the operation of the photovoltaic power generation system.

[0075] Based on the first embodiment of the present application, in the second embodiment of the present application, the same or similar contents as those in the above-mentioned embodiment 1 can be referred to the above introduction, and will not be repeated in the following. On this basis, the photovoltaic power generation system control method of the present application can also include steps A10 to A20:

[0076] Step A10, obtaining the current DC voltage of each photovoltaic power generation unit;

[0077] All photovoltaic power generation units in the system are periodically traversed at preset time intervals and the current DC voltage of each photovoltaic power generation unit is recorded, wherein the time interval can be set based on the actual application scenario and is not specifically limited in this embodiment.

[0078] Step A20, for each photovoltaic power generation unit, determine the drop difference between the current DC voltage and the historical DC voltage. When the drop difference exceeds the preset voltage drop threshold, determine the photovoltaic power generation unit as the first photovoltaic power generation unit, adopt grid-following control for the first photovoltaic power generation unit and execute the maximum power tracking strategy.

[0079] For each photovoltaic power generation unit, the drop difference between its current DC voltage and the historical DC voltage (referring to the last recorded DC voltage) is calculated. The drop difference reflects the drop amplitude of the voltage of the photovoltaic power generation unit. The drop difference is compared with the preset voltage drop threshold. The voltage drop threshold is set based on comprehensive consideration of multiple factors such as system stability, safety and power generation efficiency. When the voltage drop difference of a photovoltaic power generation unit exceeds the voltage drop threshold, it is determined as the first photovoltaic power generation unit, and grid-following control is performed on the first photovoltaic power generation unit, and the maximum power tracking strategy is executed to obtain the maximum power point of the photovoltaic array.

[0080] In addition, when the voltage drop difference of a plurality of photovoltaic power generation units exceeds the voltage drop threshold, a unit with the largest voltage drop difference is selected from the plurality of photovoltaic power generation units as the first photovoltaic power generation unit.

[0081] In a feasible embodiment, step A10 may further include steps A30 to A40:

[0082] Step A30, for each photovoltaic power generation unit, determining a drop difference between a current DC voltage and a historical DC voltage;

[0083] For each photovoltaic power generation unit, the difference between its current DC voltage and the historical DC voltage (referring to the last recorded DC voltage) is calculated. The difference reflects the drop in voltage of the photovoltaic power generation unit. The difference is compared with the preset voltage drop threshold, which is set based on comprehensive consideration of multiple factors such as system stability, safety and power generation efficiency.

[0084] Step A40, when each drop difference does not exceed the voltage drop threshold, each photovoltaic power generation unit is determined as the first photovoltaic power generation unit in turn according to a preset order, and the first photovoltaic power generation unit is controlled by grid-following type and executes the maximum power tracking strategy.

[0085] When the voltage drop difference of all photovoltaic power generation units exceeds the voltage drop threshold, each photovoltaic power generation unit is designated as the current first photovoltaic power generation unit in turn according to a predetermined order. For the selected first photovoltaic power generation unit, grid-following control is adopted and a maximum power tracking strategy is executed to maximize the utilization of its light energy conversion efficiency and ensure the overall performance and power generation efficiency of the entire photovoltaic power generation system.

[0086] For example, when the photovoltaic station area is relatively large, there are local photovoltaic array illumination changes, such as cloud occlusion, which causes insufficient power of the blocked power generation unit and causes system disturbances. Figure 6As shown in the figure, each power generation unit in the system communicates bidirectionally with the coordination controller. The power generation unit that executes the maximum power point tracking algorithm is changed at fixed intervals. At the same time, when the DC voltage drop of a power generation unit exceeds the set rate, the coordination controller preferentially designates the power generation unit to perform the maximum power point tracking.

[0087] In a feasible embodiment, step S10 may include steps S101 to S103:

[0088] Step S101, real-time monitoring of the output voltage and output current of the photovoltaic array of the first photovoltaic power generation unit among the photovoltaic power generation units;

[0089] Step S102, calculating the instantaneous power of the first photovoltaic power generation unit according to the output voltage and the output current;

[0090] The output voltage and output current of the photovoltaic array of the first photovoltaic power generation unit in each photovoltaic power generation unit are monitored in real time, and the instantaneous power of the first photovoltaic power generation unit is calculated according to the output voltage and output current, so as to timely understand the working condition of the photovoltaic array in the first photovoltaic power generation unit.

[0091] Step S103: determining the maximum power information of the first photovoltaic power generation unit by comparing the instantaneous power of the first photovoltaic power generation unit at different working points.

[0092] By comparing and analyzing the instantaneous power of the first photovoltaic power generation unit under different working states (ie, different output voltage and output current combinations), the working state that makes the output power of the first photovoltaic power generation unit reach the maximum, ie, the maximum power point, is determined.

[0093] In a feasible embodiment, the photovoltaic power generation system is connected to the power grid, and step S20 may include:

[0094] Step S201, calculating the active power margin of each photovoltaic power generation unit according to the preset primary frequency regulation capacity requirement and the total power generation capacity of the photovoltaic power generation system;

[0095] According to the preset primary frequency regulation capacity requirements and the total power generation capacity of the entire photovoltaic power generation system, the active power margin required to be reserved for each photovoltaic power generation unit is calculated to ensure that the system can quickly and effectively adjust its output power when facing grid frequency fluctuations to maintain stable operation of the grid.

[0096] Step S202: Calculate the DC voltage and active power setting point of each photovoltaic power generation unit according to the maximum power information and the active power margin.

[0097] The maximum power information and active power margin calculated previously are used to calculate the DC voltage set point and active power set point of each photovoltaic power generation unit. By accurately adjusting the DC voltage and output power of each photovoltaic power generation unit, it is ensured that the entire photovoltaic power generation system can operate efficiently in the optimal state. At the same time, it also meets the grid's immediate demand for frequency regulation, achieving a dual improvement in the flexibility and stability of the photovoltaic power generation system.

[0098] In a feasible embodiment, the photovoltaic power generation system is connected to the power grid, and steps S40 to S50 may be included after step S30:

[0099] Step S40, acquiring frequency offset information of the power grid in real time;

[0100] Obtain frequency deviation information of the power grid in real time to monitor the stability of the power grid and respond to possible frequency fluctuations in real time.

[0101] Step S50: sending the frequency offset information to each second photovoltaic power generation unit, so that each second photovoltaic power generation unit can adjust its own active power output according to the frequency offset information.

[0102] The acquired frequency offset information is sent to each second photovoltaic power generation unit. Each second photovoltaic power generation unit will dynamically adjust its own active output according to the received frequency offset information to respond more flexibly to the frequency change of the power grid, which helps to maintain the stable operation of the power grid.

[0103] In a feasible embodiment, the photovoltaic power generation system control method of the present application may further include steps A50 to A60:

[0104] Step A50, real-time monitoring of the operating status of each photovoltaic power generation unit;

[0105] Real-time monitoring of the operating status of each photovoltaic power generation unit in the system, including monitoring of key parameters such as power generation efficiency, operating temperature, connection status, etc. of each unit, to ensure that they are operating within the normal range.

[0106] Step A60: When it is detected that there is an abnormal photovoltaic power generation unit with an abnormal operating state among the photovoltaic power generation units, the abnormal photovoltaic power generation unit is determined as the second photovoltaic power generation unit.

[0107] If any photovoltaic power generation unit is found to have an abnormal operating state during the monitoring process (for example, a decrease in output power, an overly high temperature, or a disconnected connection, etc.), these abnormal units are immediately identified as second photovoltaic power generation units.

[0108] For example, in order to help understand the implementation process of the photovoltaic power generation system control method obtained by combining this embodiment with the above-mentioned embodiment 1, this example provides a scenario schematic diagram of executing the photovoltaic power generation system control method, specifically:

[0109] Grid-following control is performed through at least one photovoltaic power generation unit (i.e., the first photovoltaic power generation unit) in the photovoltaic station, and a maximum power tracking strategy is executed to obtain the maximum power point of the photovoltaic array. The first photovoltaic power generation unit sends the maximum power information, including DC voltage and power, to the coordination controller in real time through communication.

[0110] The coordination controller calculates and sets the DC voltage and active power set points of each photovoltaic power generation unit based on the primary frequency regulation capability requirements given by the upper-level dispatching system and the collected maximum power information, combined with the frequency and voltage requirements of the power grid and the physical parameters of each photovoltaic power generation unit; specifically, the coordination controller can determine the active output amount that needs to be adjusted for each photovoltaic power generation unit based on the deviation between the current frequency of the power grid and the target frequency, as well as the response speed and frequency regulation capability of the photovoltaic power generation unit, and then set the corresponding DC voltage and active power set points.

[0111] In addition to the first photovoltaic power generation unit that performs grid-following control, other photovoltaic power generation units (i.e., the second photovoltaic power generation unit) receive the DC voltage and active power set point information sent by the coordination controller to perform grid-forming control; when performing grid-forming control, the second photovoltaic power generation unit also detects the frequency deviation of the power grid in real time. Specifically, it can obtain the power grid frequency information through the built-in power grid frequency detection module or through continuous communication with the coordination controller, and automatically adjust its own active output according to the deviation direction and size of the power grid frequency to realize the primary frequency regulation function of the power grid. If the power grid frequency is higher than the target frequency, the active output is reduced; if the power grid frequency is lower than the target frequency, the active output is increased.

[0112] In the traditional grid-type photovoltaic power generation system, when the light changes and the photovoltaic array power decreases, the simulation results are as follows: Figure 7 As shown, Figure 7 The line on the left shows how the light intensity changes over time. Figure 7 The right side shows the change curve of the DC side voltage standard Vdc_INV and angular frequency wr at the same time. From the simulation results, it can be seen that when the light change causes the photovoltaic array power to decrease and the grid needs a frequency modulation, the DC voltage will oscillate and become unstable.

[0113] In the photovoltaic power generation system proposed in this embodiment, if Figure 1 As shown, the active power operating point Pset of the photovoltaic power generation system is set at a position on the right side of the maximum power point MPP in area 2, leaving a part of the active power regulation margin Psevup between the maximum power point and the active power margin. This part of the active power margin is used for the primary frequency modulation of the photovoltaic inverter, thereby ensuring the stability of the system.

[0114] When the change in light intensity causes the photovoltaic array power to decrease, the simulation results of the first photovoltaic power generation unit are as follows: Figure 8 As shown, Figure 8 The line graph marked with number ① shows the change of light intensity over time. Figure 8 The line graph marked with number ② shows the variation curve of the maximum power point obtained at the same time. Figure 8 The line graph with the mark ③ shows the change curve of the DC side voltage standard Vdc_INV_pu of the first photovoltaic power generation unit at the same time; the simulation results of the second photovoltaic power generation unit are as follows: Fig. 9 As shown, Fig. 9 The line graph marked with number ①' shows the change of light intensity over time. Fig. 9 The line graph marked with number ②' shows the change curve of active power Pe and reactive power Qe obtained at the same time. Fig. 9 The line graph with the mark ③' represents the change curve of the DC side voltage standard Vdc_INV_pu of the second photovoltaic power generation unit at the same time. When the light changes, the photovoltaic power generation units in the photovoltaic station can achieve fast and stable operation.

[0115] It should be noted that the above examples are only used to understand the present application and do not constitute a limitation on the photovoltaic power generation system control method of the present application. More simple transformations based on this technical concept are all within the protection scope of the present application.

[0116] The present application also provides a coordination control device, which is applied to a coordination controller in a photovoltaic power generation system. The photovoltaic power generation system also includes photovoltaic power generation units; please refer to Fig.10 , the coordinated control device includes:

[0117] The first photovoltaic power generation unit control module 10 is used to obtain the maximum power information of the first photovoltaic power generation unit among the photovoltaic power generation units by adopting the maximum power tracking strategy;

[0118] A calculation module 20, for determining a DC voltage and an active power setting point of each photovoltaic power generation unit according to the maximum power information and a preset active power margin;

[0119] The second photovoltaic power generation unit control module 30 is used to send the DC voltage and active power set point to the second photovoltaic power generation unit in each photovoltaic power generation unit so that the second photovoltaic power generation unit can operate according to the DC voltage and active power set point, wherein the second photovoltaic power generation unit is a unit in each photovoltaic power generation unit except the first photovoltaic power generation unit.

[0120] Optionally, the coordination control device further includes a first photovoltaic power generation unit determination module (not shown), and the first photovoltaic power generation unit determination module is used to:

[0121] Obtain the current DC voltage of each photovoltaic power generation unit;

[0122] For each photovoltaic power generation unit, the drop difference between the current DC voltage and the historical DC voltage is determined. When the drop difference exceeds a preset voltage drop threshold, the photovoltaic power generation unit is determined as the first photovoltaic power generation unit, and the first photovoltaic power generation unit is controlled by grid-following type and executes the maximum power tracking strategy.

[0123] Optionally, the first photovoltaic power generation unit determination module is used to:

[0124] For each photovoltaic power generation unit, determining a drop difference between a current DC voltage and a historical DC voltage;

[0125] When each drop difference does not exceed the voltage drop threshold, each photovoltaic power generation unit is determined as the first photovoltaic power generation unit in turn according to a preset sequence, and the first photovoltaic power generation unit is controlled by a grid-following control and executes a maximum power tracking strategy.

[0126] Optionally, the first photovoltaic power generation unit control module 10 is further used for:

[0127] Real-time monitoring of the output voltage and output current of the photovoltaic array of the first photovoltaic power generation unit in each photovoltaic power generation unit;

[0128] Calculating the instantaneous power of the first photovoltaic power generation unit according to the output voltage and the output current;

[0129] By comparing the instantaneous power of the first photovoltaic power generation unit at different working points, the maximum power information of the first photovoltaic power generation unit is determined.

[0130] Optionally, the photovoltaic power generation system is connected to a power grid, and the computing module 20 is further used for:

[0131] Calculate the active power margin of each photovoltaic power generation unit according to the preset primary frequency regulation capacity requirement and the total power generation capacity of the photovoltaic power generation system;

[0132] The DC voltage and active power set point of each photovoltaic power generation unit are calculated based on the maximum power information and active power margin.

[0133] Optionally, the photovoltaic power generation system is connected to the power grid, and the coordinated control device further includes an active output adjustment module (not shown), which is used to:

[0134] Obtain frequency deviation information of the power grid in real time;

[0135] The frequency offset information is sent to each second photovoltaic power generation unit, so that each second photovoltaic power generation unit adjusts its own active power output according to the frequency offset information.

[0136] Optionally, the coordination control device further includes an operation status monitoring module (not shown), and the operation status monitoring module is used to:

[0137] Real-time monitoring of the operating status of each photovoltaic power generation unit;

[0138] When an abnormal photovoltaic power generation unit having an abnormal operation state is detected among the photovoltaic power generation units, the abnormal photovoltaic power generation unit is determined as the second photovoltaic power generation unit.

[0139] The coordinated control device provided in the embodiment of the present application adopts the photovoltaic power generation system control method in the above embodiment, and can achieve grid synchronization and stable operation while taking into account the tracking control of the maximum power point of the photovoltaic array to improve the stability of the operation of the photovoltaic power generation system. Compared with the prior art, the beneficial effects of the coordinated control device provided in the embodiment of the present application are the same as the beneficial effects of the photovoltaic power generation system control method provided in the above embodiment, and other technical features in the coordinated control device are the same as the features disclosed in the photovoltaic power generation system control method in the above embodiment, which will not be repeated here.

[0140] An embodiment of the present application provides a coordination controller, which includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the photovoltaic power generation system control method in the above-mentioned embodiment one.

[0141] Reference below Fig.11 , which shows a schematic diagram of the structure of a coordination controller suitable for implementing an embodiment of the present application. Fig.11 The coordination controller shown is merely an example and should not bring any limitation to the functions and scope of use of the embodiments of the present application.

[0142] like Fig.11As shown, the coordination controller may include a processing device 1001 (e.g., a central processing unit, a graphics processor, etc.), which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM: Read Only Memory) 1002 or a program loaded from a storage device 1003 to a random access memory (RAM: Random Access Memory) 1004. In RAM1004, various programs and data required for the operation of the coordination controller are also stored. The processing device 1001, ROM1002, and RAM1004 are connected to each other through a bus 1005. An input / output (I / O) interface 1006 is also connected to the bus. Generally, the following systems can be connected to the I / O interface 1006: an input device 1007 including, for example, a touch screen, a touch pad, a keyboard, a mouse, an image sensor, a microphone, an accelerometer, a gyroscope, etc.; an output device 1008 including, for example, a liquid crystal display (LCD: Liquid Crystal Display), a speaker, a vibrator, etc.; a storage device 1003 including, for example, a magnetic tape, a hard disk, etc.; and a communication device 1009. The communication device 1009 can allow the coordination controller to communicate with other devices wirelessly or by wire to exchange data. Although the coordination controller with various systems is shown in the figure, it should be understood that it is not required to implement or have all the systems shown. More or fewer systems can be implemented or have alternatively.

[0143] In particular, according to the embodiments disclosed in the present application, the process described above with reference to the flowchart can be implemented as a computer software program. For example, the embodiments disclosed in the present application include a computer program product, which includes a computer program carried on a computer-readable medium, and the computer program includes a program code for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from a network through a communication device, or installed from a storage device 1003, or installed from a ROM 1002. When the computer program is executed by the processing device 1001, the above-mentioned functions defined in the method of the embodiment disclosed in the present application are executed.

[0144] The coordination controller provided in the embodiment of the present application adopts the photovoltaic power generation system control method in the above embodiment, which can achieve grid synchronization and stable operation while taking into account the tracking control of the maximum power point of the photovoltaic array to improve the stability of the operation of the photovoltaic power generation system. Compared with the prior art, the beneficial effects of the coordination controller provided in the embodiment of the present application are the same as the beneficial effects of the photovoltaic power generation system control method provided in the above embodiment, and the other technical features in the coordination controller are the same as the features disclosed in the photovoltaic power generation system control method in the previous embodiment, which will not be repeated here.

[0145] It should be understood that the various parts disclosed in the embodiments of the present application can be implemented by hardware, software, firmware or a combination thereof. In the description of the above embodiments, specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0146] The above are only specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

[0147] The embodiment of the present application provides a photovoltaic power generation system, which includes photovoltaic power generation units and the coordination controller described above, the photovoltaic power generation units include photovoltaic arrays, inverters and transformers, and the photovoltaic power generation system is connected to the power grid. The photovoltaic power generation system control method described in the above embodiment can achieve power grid synchronization and stable operation while taking into account the tracking and control of the maximum power point of the photovoltaic array to improve the stability of the operation of the photovoltaic power generation system. Compared with the prior art, the beneficial effects of the photovoltaic power generation system provided by the embodiment of the present application are the same as the beneficial effects of the photovoltaic power generation system control method provided by the above embodiment, and other technical features in the photovoltaic power generation system are the same as the features disclosed in the photovoltaic power generation system control method described in the above embodiment, which will not be described in detail here.

[0148] An embodiment of the present application provides a computer-readable storage medium having computer-readable program instructions (ie, computer programs) stored thereon, and the computer-readable program instructions are used to execute the photovoltaic power generation system control method in the above-mentioned embodiment.

[0149] The computer-readable storage medium provided in the embodiment of the present application may be, for example, a USB flash drive, but is not limited to electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems or devices, or any combination of the above. More specific examples of computer-readable storage media may include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM: Random Access Memory), a read-only memory (ROM: Read Only Memory), an erasable programmable read-only memory (EPROM: Erasable Programmable Read Only Memory or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM: CD-Read Only Memory), an optical storage device, a magnetic storage device, or any suitable combination of the above. In this embodiment, the computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in combination with an instruction execution system or device. The program code contained on the computer-readable storage medium may be transmitted using any appropriate medium, including but not limited to: wires, optical cables, RF (Radio Frequency: Radio Frequency), etc., or any suitable combination of the above.

[0150] The computer-readable storage medium may be included in the coordination controller; or may exist independently without being assembled into the coordination controller.

[0151] The computer-readable storage medium carries one or more programs. When the one or more programs are executed by the coordination controller, the coordination controller: adopts a maximum power tracking strategy to obtain the maximum power information of the first photovoltaic power generation unit in each photovoltaic power generation unit; determines the DC voltage and active power set point of each photovoltaic power generation unit according to the maximum power information and the preset active power margin; sends the DC voltage and active power set point to the second photovoltaic power generation unit in each photovoltaic power generation unit, so that the second photovoltaic power generation unit operates according to the DC voltage and active power set point, wherein the second photovoltaic power generation unit is a unit in each photovoltaic power generation unit except the first photovoltaic power generation unit.

[0152] The computer program code for performing the operation of the embodiment of the present application can be written in one or more programming languages ​​or a combination thereof, and the above-mentioned programming languages ​​include object-oriented programming languages, such as Java, Smalltalk, C++, and also include conventional procedural programming languages, such as "C" language or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as an independent software package, partially on the user's computer and partially on the remote computer, or completely on the remote computer or server. In the case of a remote computer, the remote computer can be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or can be connected to an external computer (e.g., using an Internet service provider to connect through the Internet).

[0153] The flow chart and block diagram in the accompanying drawings illustrate the possible architecture, function and operation of the system, method and computer program product according to various embodiments of the present application. In this regard, each square box in the flow chart or block diagram can represent a module, a program segment or a part of a code, and the module, the program segment or a part of the code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the square box can also occur in a sequence different from that marked in the accompanying drawings. For example, two square boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each square box in the block diagram and / or flow chart, and the combination of the square boxes in the block diagram and / or flow chart can be implemented with a dedicated hardware-based system that performs a specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0154] The modules involved in the embodiments described in this application may be implemented by software or hardware, wherein the name of the module does not constitute a limitation on the unit itself in some cases.

[0155] The readable storage medium provided in the embodiment of the present application is a computer-readable storage medium, which stores computer-readable program instructions (i.e., computer programs) for executing the above-mentioned photovoltaic power generation system control method, and can track and control the maximum power point of the photovoltaic array while achieving grid synchronization and stable operation, so as to improve the stability of the operation of the photovoltaic power generation system. Compared with the prior art, the beneficial effects of the computer-readable storage medium provided in the embodiment of the present application are the same as the beneficial effects of the photovoltaic power generation system control method provided in the above-mentioned embodiment, and will not be repeated here.

[0156] The present application also provides a computer program product, including a computer program, which implements the steps of the photovoltaic power generation system control method as described above when the computer program is executed by a processor.

[0157] The computer program product provided in this application can solve the technical problem of photovoltaic power generation system control. Compared with the prior art, the beneficial effects of the computer program product provided in this application are the same as the beneficial effects of the photovoltaic power generation system control method provided in the above embodiment, which will not be repeated here.

[0158] The above are only some embodiments of the present application, and are not intended to limit the patent scope of the present application. All equivalent structural changes made using the contents of the present application specification and drawings under the technical concept of the present application, or direct / indirect application in other related technical fields are included in the patent protection scope of the present application.

Claims

1. A photovoltaic power generation system control method, characterized in that: A coordination controller applied to a photovoltaic power generation system, wherein the photovoltaic power generation system further comprises photovoltaic power generation units; The method comprises: A maximum power tracking strategy is used to obtain the maximum power information of the first photovoltaic power generation unit in each of the photovoltaic power generation units; Determining a DC voltage and an active power setting point of each photovoltaic power generation unit according to the maximum power information and a preset active power margin; The DC voltage and the active power set point are sent to a second photovoltaic power generation unit in each of the photovoltaic power generation units, so that the second photovoltaic power generation unit operates according to the DC voltage and the active power set point, wherein the second photovoltaic power generation unit is a unit in each of the photovoltaic power generation units except the first photovoltaic power generation unit.

2. The photovoltaic power generation system control method according to claim 1, characterized in that: The method further comprises: Obtaining the current DC voltage of each photovoltaic power generation unit; For each of the photovoltaic power generation units, the drop difference between the current DC voltage and the historical DC voltage is determined. When the drop difference exceeds a preset voltage drop threshold, the photovoltaic power generation unit is determined as the first photovoltaic power generation unit, and the first photovoltaic power generation unit is controlled by grid-following type and a maximum power tracking strategy is executed.

3. The photovoltaic power generation system control method according to claim 2, characterized in that: After the step of obtaining the current DC voltage of each photovoltaic power generation unit, the method further includes: For each of the photovoltaic power generation units, determining a drop difference between the current DC voltage and the historical DC voltage; When each of the drop differences does not exceed the voltage drop threshold, each of the photovoltaic power generation units is determined as the first photovoltaic power generation unit in turn according to a preset order, and the first photovoltaic power generation unit is controlled by grid-following type and executes the maximum power tracking strategy.

4. The photovoltaic power generation system control method according to claim 1, characterized in that: The step of adopting the maximum power tracking strategy to obtain the maximum power information of the first photovoltaic power generation unit in each of the photovoltaic power generation units includes: Real-time monitoring of the output voltage and output current of the photovoltaic array of the first photovoltaic power generation unit in each of the photovoltaic power generation units; Calculating the instantaneous power of the first photovoltaic power generation unit according to the output voltage and the output current; By comparing the instantaneous power of the first photovoltaic power generation unit at different working points, the maximum power information of the first photovoltaic power generation unit is determined.

5. The photovoltaic power generation system control method according to claim 1, characterized in that: The photovoltaic power generation system is connected to a power grid, and the step of determining the DC voltage and active power setting point of each photovoltaic power generation unit according to the maximum power information and the preset active power margin includes: Calculating the active power margin of each photovoltaic power generation unit according to the preset primary frequency regulation capacity requirement and the total power generation capacity of the photovoltaic power generation system; The DC voltage and active power setting point of each photovoltaic power generation unit are calculated according to the maximum power information and the active power margin.

6. The photovoltaic power generation system control method according to claim 1, characterized in that: The photovoltaic power generation system is connected to a power grid, and after the step of sending the DC voltage and the active power set point to the second photovoltaic power generation unit in each of the photovoltaic power generation units, the step further includes: Acquiring frequency deviation information of the power grid in real time; The frequency offset information is sent to each of the second photovoltaic power generation units, so that each of the second photovoltaic power generation units adjusts its own active power output according to the frequency offset information.

7. The photovoltaic power generation system control method according to claim 1, characterized in that: The method further comprises: Real-time monitoring of the operating status of each photovoltaic power generation unit; When an abnormal photovoltaic power generation unit with an abnormal operating state is detected among the photovoltaic power generation units, the abnormal photovoltaic power generation unit is determined as the second photovoltaic power generation unit.

8. A coordination control device, applied to a coordination controller in a photovoltaic power generation system, wherein the photovoltaic power generation system further comprises photovoltaic power generation units; the coordination control device comprises: A first photovoltaic power generation unit control module, used for acquiring maximum power information of a first photovoltaic power generation unit among the photovoltaic power generation units by adopting a maximum power tracking strategy; A calculation module, used to determine the DC voltage and active power setting point of each photovoltaic power generation unit according to the maximum power information and the preset active power margin; The second photovoltaic power generation unit control module is used to send the DC voltage and the active power set point to the second photovoltaic power generation unit in each of the photovoltaic power generation units, so that the second photovoltaic power generation unit operates according to the DC voltage and the active power set point, wherein the second photovoltaic power generation unit is a unit in each of the photovoltaic power generation units except the first photovoltaic power generation unit.

9. A coordination controller, characterized in that: The coordination controller includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the computer program is configured to implement the steps of the photovoltaic power generation system control method according to any one of claims 1 to 7.

10. A photovoltaic power generation system, characterized in that: The photovoltaic power generation system comprises photovoltaic power generation units and the coordination controller as claimed in claim 9, the photovoltaic power generation units comprise photovoltaic arrays, inverters and transformers, and the photovoltaic power generation system is connected to a power grid.

11. A computer program product, characterized in that The computer program product comprises a computer program, and when the computer program is executed by a processor, the steps of the photovoltaic power generation system control method according to any one of claims 1 to 7 are implemented.

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