Power control method of photovoltaic inverter, photovoltaic inverter, device and medium

Abstract

The application belongs to the technical field of photovoltaic inverter control, and particularly relates to a power control method of a photovoltaic inverter, the photovoltaic inverter, equipment and medium. The method collects the actual value of the direct-current bus voltage and the actual value of the output current of the photovoltaic inverter, and determines the power imbalance state in combination with the threshold value and the time length condition, and further determines the power imbalance level according to the bus voltage and the output current; according to the power imbalance level, the target control strategy including the first sub-strategy corresponding to the pre-stage boost circuit and the second sub-strategy corresponding to the post-stage inverter circuit is determined from multiple preset control strategies, and the first sub-strategy and the second sub-strategy are executed, the method can more accurately identify the power imbalance state, reduce the risk of misjudgment, match the control demand of different imbalance scenes, realize the targeted collaborative adjustment of the pre-stage and post-stage circuits, and further improve the reliability and stability of the direct-current bus voltage control.

Description

Technical Field

[0001] This application belongs to the field of photovoltaic inverter control technology, specifically relating to a power control method for a photovoltaic inverter, a photovoltaic inverter, equipment, and medium. Background Technology

[0002] Oversized two-stage photovoltaic inverters in photovoltaic power plants typically employ a control method combining maximum power point tracking (MPPT) and grid-connected voltage regulation to improve power generation utilization and system economy. However, under conditions of high irradiance or grid voltage and frequency fluctuations, a persistent deviation can easily occur between the photovoltaic input capability and the inverter output capability, leading to a slow accumulation or rapid increase in DC bus voltage. This can trigger overvoltage protection, causing system shutdown, or even damage power devices or capacitors, affecting equipment safety and lifespan.

[0003] In the existing technology, there is a power limiting control method based on power sampling and calculation, which uses sensors to detect the input power on the photovoltaic side and the output power on the grid side in real time, calculates the power difference, and adjusts the operating point of the upstream maximum power point tracking to limit the input.

[0004] However, the above method relies on power sampling calculation, and the sensor error is amplified during the power calculation process, which can easily lead to misjudgment of power imbalance state. At the same time, it cannot match the control requirements of different imbalance scenarios and has poor flexibility. Summary of the Invention

[0005] This application provides a power control method for a photovoltaic inverter, a photovoltaic inverter, equipment, and a medium to solve the problems that existing power control methods for photovoltaic inverters are prone to misjudging power imbalance states, and cannot match the control requirements of different imbalance scenarios, resulting in poor flexibility.

[0006] In a first aspect, embodiments of this application provide a power control method for a photovoltaic inverter. The photovoltaic inverter includes a front-end boost circuit and a rear-end inverter circuit. The input terminal of the front-end boost circuit is electrically connected to a photovoltaic array, and the output terminal of the rear-end inverter circuit is electrically connected to the power grid. The method includes:

[0007] Collect the actual values ​​of the DC bus voltage and output current of the photovoltaic inverter;

[0008] When the actual value of the DC bus voltage is greater than or equal to the first voltage threshold, the actual value of the output current is greater than or equal to the first current threshold, and the duration reaches the first duration, the power imbalance level of the photovoltaic inverter is determined based on the actual value of the DC bus voltage and the actual value of the output current.

[0009] Based on the power imbalance level of the photovoltaic inverter, a target control strategy is determined from multiple preset control strategies. The target control strategy includes the first sub-strategy corresponding to the front-end boost circuit and the second sub-strategy corresponding to the back-end inverter circuit.

[0010] Execute the first sub-policy and the second sub-policy.

[0011] In one possible embodiment, the subsequent inverter circuit further includes a heat sink. Before acquiring the actual values ​​of the DC bus voltage and output current of the photovoltaic inverter, the method further includes:

[0012] Obtain the temperature of the heat sink, the actual value of the grid voltage, and the operating temperature of the photovoltaic array;

[0013] The first voltage threshold and the first current threshold are determined based on the temperature of the heat sink, the actual value of the grid voltage, and the operating temperature of the photovoltaic array.

[0014] In one possible embodiment, determining a first voltage threshold and a first current threshold based on the temperature of the heat sink, the actual value of the grid voltage, and the operating temperature of the photovoltaic array includes:

[0015] The first correction value corresponding to the first voltage threshold is determined based on the difference between the actual grid voltage and the rated grid voltage.

[0016] The second correction value corresponding to the first voltage threshold is determined based on the difference between the operating temperature of the photovoltaic array and the preset operating temperature threshold.

[0017] The first voltage threshold is determined based on the first correction value, the second correction value, and the base voltage threshold.

[0018] Based on the difference between the radiator temperature and the preset radiator temperature threshold, determine the third correction value corresponding to the first current threshold.

[0019] The first current threshold is obtained by subtracting the sum of the base current deviation threshold and the third correction value from the maximum allowable output current of the photovoltaic inverter.

[0020] In one possible embodiment, the power imbalance level of the photovoltaic inverter is determined based on the actual value of the DC bus voltage and the actual value of the output current, including:

[0021] The rate of change of the actual DC bus voltage is determined based on the difference between the actual DC bus voltage value collected at the current moment and the actual DC bus voltage value collected at the previous moment, as well as the time interval between the current moment and the previous moment.

[0022] The power imbalance level of the photovoltaic inverter is determined based on the rate of change of the actual DC bus voltage and the ratio of the actual output current to the maximum allowable output current of the photovoltaic inverter.

[0023] In one possible embodiment, the power imbalance level of the photovoltaic inverter is determined based on the rate of change of the actual DC bus voltage and the ratio of the actual output current to the maximum permissible output current of the photovoltaic inverter, including:

[0024] If the rate of change of the actual value of the DC bus voltage is less than the first rate of change threshold and the ratio of the actual value of the output current to the maximum allowable output current of the photovoltaic inverter is less than the first ratio threshold, the power imbalance level of the photovoltaic inverter is determined to be the first power imbalance level.

[0025] If the rate of change of the actual value of the DC bus voltage is greater than or equal to the first rate of change threshold and less than the second rate of change threshold, and the ratio of the actual value of the output current to the maximum allowable output current of the photovoltaic inverter is greater than or equal to the first ratio threshold and less than the second ratio threshold, the power imbalance level of the photovoltaic inverter is determined to be the second power imbalance level.

[0026] If the rate of change of the actual value of the DC bus voltage is greater than or equal to the second rate of change threshold, and the ratio of the actual value of the output current to the maximum allowable output current of the photovoltaic inverter is greater than or equal to the second ratio threshold, the power imbalance level of the photovoltaic inverter is determined to be the third power imbalance level.

[0027] Among them, the second rate of change threshold is greater than the first rate of change threshold, and the second ratio threshold is greater than the first ratio threshold.

[0028] In one possible embodiment, the multiple preset control strategies include: a first control strategy, a second control strategy, and a third control strategy;

[0029] Based on the power imbalance level of the photovoltaic inverter, a target control strategy is determined from multiple preset control strategies, including:

[0030] When the power imbalance level is the first power imbalance level, the first control strategy is determined as the target control strategy; in the first control strategy, the first sub-strategy is used to indicate the adjustment of the duty cycle of the front-stage boost circuit according to the first adjustment range, and the second sub-strategy is used to indicate the adjustment of the output power value of the rear-stage inverter circuit according to the first overload coefficient.

[0031] When the power imbalance level is the second power imbalance level, the second control strategy is determined as the target control strategy; in the second control strategy, the first sub-strategy is used to indicate the adjustment of the duty cycle of the front-stage boost circuit according to the second adjustment range, the second adjustment range is greater than the first adjustment range, and the second sub-strategy is used to indicate the adjustment of the output power value of the rear-stage inverter circuit according to the second overload coefficient, the second overload coefficient is greater than the first overload coefficient.

[0032] When the power imbalance level is the third power imbalance level, the third control strategy is determined as the target control strategy. In the third control strategy, the first sub-strategy is used to indicate the adjustment of the duty cycle of the front-stage boost circuit according to the third adjustment range, which is greater than the second adjustment range. The second sub-strategy is used to indicate the adjustment of the output power value of the rear-stage inverter circuit according to the third overload coefficient, which is greater than the second overload coefficient.

[0033] In one possible embodiment, the method further includes:

[0034] When the actual value of the DC bus voltage is less than the second voltage threshold and the duration reaches the second duration, the front-stage boost circuit is controlled to stop executing the first sub-strategy in the target control strategy, and the rear-stage inverter circuit is controlled to stop executing the second sub-strategy in the target control strategy, so that the photovoltaic inverter can be restored to normal operation mode.

[0035] The second voltage threshold and the second duration are determined based on the power imbalance level of the photovoltaic inverter. The higher the power imbalance level, the smaller the second voltage threshold and the longer the second duration. The second voltage threshold is less than the first voltage threshold and the second duration is greater than the first duration.

[0036] Secondly, embodiments of this application provide a photovoltaic inverter, which includes: a DC bus, a DC bus voltage sampling circuit, an output current sampling circuit, a front-stage boost circuit, a rear-stage inverter circuit, and a controller. The input terminal of the front-stage boost circuit is electrically connected to the photovoltaic array, the output terminal of the front-stage boost circuit is electrically connected to the DC bus, the input terminal of the rear-stage inverter circuit is electrically connected to the DC bus, and the output terminal of the rear-stage inverter circuit is electrically connected to the power grid.

[0037] A DC bus voltage sampling circuit is connected in parallel to the DC bus to collect the actual value of the DC bus voltage.

[0038] The output current sampling circuit is connected in series between the output terminal of the subsequent inverter circuit and the power grid to collect the actual value of the output current of the photovoltaic inverter.

[0039] The controller is electrically connected to the DC bus voltage sampling circuit and the output current sampling circuit, respectively.

[0040] The controller is used to determine the power imbalance level of the photovoltaic inverter based on the actual values ​​of the DC bus voltage and the actual value of the output current when the actual value of the DC bus voltage is greater than or equal to a first voltage threshold, the actual value of the output current is greater than or equal to a first current threshold, and the duration reaches a first time. Based on the power imbalance level of the photovoltaic inverter, the controller determines a target control strategy from multiple preset control strategies. The target control strategy includes a first sub-strategy corresponding to the front-end boost circuit and a second sub-strategy corresponding to the back-end inverter circuit. The controller then executes the first sub-strategy and the second sub-strategy.

[0041] Thirdly, embodiments of this application provide a power control device for a photovoltaic inverter. The photovoltaic inverter includes a front-end boost circuit and a rear-end inverter circuit. The input terminal of the front-end boost circuit is electrically connected to a photovoltaic array, and the output terminal of the rear-end inverter circuit is electrically connected to the power grid. The device includes:

[0042] The data acquisition module is used to acquire the actual values ​​of the DC bus voltage and the actual output current of the photovoltaic inverter.

[0043] The processing module is used to determine the power imbalance level of the photovoltaic inverter based on the actual value of the DC bus voltage and the actual value of the output current when the actual value of the DC bus voltage is greater than or equal to a first voltage threshold, the actual value of the output current is greater than or equal to a first current threshold, and the duration reaches a first duration.

[0044] The processing module is also used to determine the target control strategy from multiple preset control strategies based on the power imbalance level of the photovoltaic inverter. The target control strategy includes the first sub-strategy corresponding to the front-end boost circuit and the second sub-strategy corresponding to the back-end inverter circuit.

[0045] The control module is used to execute the first sub-policy and the second sub-policy.

[0046] Fourthly, embodiments of this application provide an electronic device, including: a memory and a processor;

[0047] The memory stores computer-executed instructions;

[0048] The processor executes computer execution instructions stored in the memory, causing the processor to perform the power control method for a photovoltaic inverter provided as described in the first aspect and / or various possible embodiments of the first aspect.

[0049] Fifthly, embodiments of this application provide a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement the power control method for a photovoltaic inverter provided in the first aspect and / or various possible embodiments of the first aspect.

[0050] In a sixth aspect, embodiments of this application provide a computer program product, including a computer program that, when executed by a processor, implements the power control method for a photovoltaic inverter provided in the first aspect and / or various possible implementations of the first aspect.

[0051] The power control method for photovoltaic inverters provided in this application collects the actual values ​​of the DC bus voltage and output current of the photovoltaic inverter. When the actual value of the DC bus voltage is greater than or equal to a first voltage threshold and the actual value of the output current is greater than or equal to a first current threshold for a duration of a first time, the power imbalance level of the photovoltaic inverter is determined based on these values. This eliminates the need for power sampling calculations, avoiding the amplification effect of sensor errors in the power calculation process. This allows for more accurate identification of power imbalance states and reduces the risk of misjudgment. Furthermore, by determining a target control strategy from multiple preset control strategies based on the power imbalance level, including a first sub-strategy corresponding to the front-end boost circuit and a second sub-strategy corresponding to the rear-end inverter circuit, and executing both sub-strategies, differentiated control strategies can be implemented according to different imbalance levels. This matches the control requirements of different imbalance scenarios, achieving targeted coordinated adjustment of the front and rear circuits, thereby improving the reliability and stability of DC bus voltage control. Attached Figure Description

[0052] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0053] Figure 1 A flowchart illustrating the power control method for a photovoltaic inverter provided in this application embodiment. Figure 1 ;

[0054] Figure 2 A flowchart illustrating the power control method for a photovoltaic inverter provided in this application embodiment. Figure 2 ;

[0055] Figure 3 This is a schematic diagram of the structure of the power control device for a photovoltaic inverter provided in an embodiment of this application;

[0056] Figure 4 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application.

[0057] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0058] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0059] The terms “first,” “second,” “third,” “fourth,” etc., as used in this invention (if applicable), are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein.

[0060] In this application, the terms "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0061] Photovoltaic inverter control technology is widely used in grid-connected photovoltaic power plants employing oversizing design, and is particularly suitable for two-stage photovoltaic inverter systems consisting of a front-end boost circuit and a rear-end inverter circuit. In this type of system, the front-end boost circuit is connected to the photovoltaic array, and the rear-end inverter circuit is connected to the power grid, achieving energy transfer and voltage support through the DC bus.

[0062] Existing oversized two-stage photovoltaic inverters typically employ a control method that combines maximum power point tracking (MPPT) at the front end with grid-connected voltage regulation at the back end. Under normal sunlight conditions, this approach can balance power generation efficiency with grid-connected operation requirements. However, when sunlight intensity increases or grid voltage and frequency fluctuate, the input capacity of the photovoltaic side may consistently exceed the output capacity of the back end. Excess energy accumulates on the DC bus side, causing the bus voltage to rise slowly or even rapidly.

[0063] To address the above issues, existing solutions typically implement power limiting control by comparing the sampled photovoltaic input power with the grid-connected output power, or by executing protection based on bus voltage changes during grid fault scenarios. The former is highly dependent on the accuracy of voltage and current sensors and the real-time performance of power calculations; sensor errors are amplified during power calculations, easily leading to misjudgments of power imbalance states. The latter is mainly designed for abnormal operating conditions such as fault ride-through and is difficult to accurately identify persistent power imbalance states during normal operation.

[0064] Furthermore, the control methods described above are relatively simplistic, responding in the same way regardless of the severity of power imbalance. This fails to meet the control requirements of different imbalance scenarios, resulting in poor flexibility. These shortcomings can lead to control misjudgments or improper adjustments, leaving the DC bus voltage without effective intervention before it reaches a dangerous level. This not only affects the stable grid-connected operation of the inverter but may also trigger overvoltage shutdowns, and even adversely impact the safety and lifespan of the bus capacitors and power devices.

[0065] In view of this, how to promptly identify power imbalance and improve the reliability and stability of DC bus voltage control under normal operating conditions of oversized photovoltaic inverters has become an urgent technical problem to be solved.

[0066] To address the aforementioned issues, this application provides a power control method for a photovoltaic inverter. By collecting the actual values ​​of the DC bus voltage and output current, and considering that the actual DC bus voltage is greater than or equal to a first voltage threshold and the actual output current is greater than or equal to a first current threshold for a duration of a first time, a power imbalance level is determined based on these values. Then, a target control strategy is selected from multiple preset control strategies according to the power imbalance level. A first sub-strategy corresponding to the front-end boost circuit and a second sub-strategy corresponding to the rear-end inverter circuit are executed. This achieves targeted regulation of the power imbalance state, enabling the execution of differentiated control strategies based on different imbalance levels, matching the control requirements of different imbalance scenarios, and achieving targeted coordinated adjustment of the front and rear circuits, thereby improving the reliability and stability of DC bus voltage control.

[0067] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0068] Figure 1 A flowchart illustrating the power control method for a photovoltaic inverter provided in this application embodiment. Figure 1 The execution entity in this application embodiment can be, for example, the controller of a photovoltaic inverter. Figure 1 As shown, the power control method for a photovoltaic inverter provided in this embodiment includes:

[0069] S101. Collect the actual value of the DC bus voltage and the actual value of the output current of the photovoltaic inverter.

[0070] In this method, the photovoltaic inverter is the object of processing. It adopts a two-stage topology with a front-stage boost circuit and a rear-stage inverter circuit connected in series. The input terminal of the front-stage boost circuit is electrically connected to the photovoltaic array to receive the DC power output from the photovoltaic array and establish a DC bus voltage suitable for the rear stage. The output terminal of the rear-stage inverter circuit is electrically connected to the power grid to convert the power on the DC bus into grid-connected AC power.

[0071] The actual DC bus voltage value refers to the voltage sampling value across the DC bus capacitor inside the photovoltaic inverter, used to reflect the real-time voltage status of the DC bus; the actual output current value refers to the current sampling value on the AC output side of the subsequent inverter circuit, used to reflect the current output capacity utilization of the subsequent inverter circuit. Both serve as direct physical quantities for subsequent judgment of power imbalance status.

[0072] In this embodiment, the DC bus voltage and output current of the photovoltaic inverter are collected by a DC bus voltage sampling circuit and an output current sampling circuit, respectively. The controller receives the sampling signals to obtain the actual values ​​of the DC bus voltage and output current for control judgment. Through the above processing, the controller continuously obtains real-time updated actual values ​​of the DC bus voltage and output current, and uses them for subsequent state judgment.

[0073] Based on the above analysis, this step establishes a dual-variable sampling basis for DC-side voltage and grid-connected output capability, so that the subsequent identification of persistent power imbalance under normal operating conditions does not rely on the direct calculation of input power and output power, thereby reducing the impact of sensor error accumulation and power calculation delay on the control results.

[0074] S102. When the actual value of the DC bus voltage is greater than or equal to the first voltage threshold, the actual value of the output current is greater than or equal to the first current threshold, and the duration reaches the first duration, the power imbalance level of the photovoltaic inverter is determined based on the actual value of the DC bus voltage and the actual value of the output current.

[0075] The first voltage threshold is used to determine the boundary when the DC bus voltage enters the abnormal rise trend identification range; the first current threshold is used to determine the boundary when the inverter output current has reached the preset judgment range; and the first duration is used to distinguish between instantaneous fluctuations and continuous imbalance states. The power imbalance level is used to characterize the severity of the current system's upstream input capability continuously exceeding the downstream output capability, and serves as a direct basis for subsequent control strategy selection.

[0076] In this embodiment, the controller reads the actual value of the DC bus voltage and the actual value of the output current obtained in step S101 during each control cycle, and compares them with the first voltage threshold and the first current threshold, respectively. When the actual value of the DC bus voltage is greater than or equal to the first voltage threshold and the actual value of the output current is greater than or equal to the first current threshold, a continuous timer is started; when either condition is not met, the continuous timer is reset to zero and the power imbalance determination state is exited. Only when the above two conditions are met consecutively and the duration reaches the first duration, does the controller enter the power imbalance level calculation process.

[0077] The first duration can be achieved through a timer / counter. The cumulative time of the counter is equal to the number of control cycles that meet the conditions multiplied by the length of the control cycle. For example, if the control cycle is 100 microseconds and the first duration is set to 20 milliseconds, the grading judgment will be entered after 200 consecutive cycles of meeting the conditions.

[0078] In specific classification, a joint evaluation can be performed based on the difference ΔV between the actual DC bus voltage and the first voltage threshold, and the difference ΔI between the actual output current and the first current threshold, where ΔV = actual DC bus voltage - first voltage threshold, and ΔI = actual output current - first current threshold. The controller pre-stores multiple level ranges. When ΔV and ΔI are in the lower range, it is determined to be a low power imbalance level; when ΔV and ΔI further increase, it is determined to be a medium power imbalance level; when ΔV reaches a higher range and ΔI remains large, it is determined to be a high power imbalance level.

[0079] In one possible embodiment, the power imbalance level can be divided into three or four levels, with the number of levels determined by the controller software configuration; for example, level one corresponds to mild imbalance, level two corresponds to moderate imbalance, and level three corresponds to severe imbalance.

[0080] Based on the above analysis, this step uses the actual value of DC bus voltage, the actual value of output current, and duration to form a joint criterion, and classifies the levels accordingly. This enables the controller to identify continuous power imbalances under normal operating conditions, rather than waiting until it enters the protection zone to respond, thus providing subsequent control with clear triggering timing and adjustment intensity basis.

[0081] S103. Based on the power imbalance level of the photovoltaic inverter, determine the target control strategy from multiple preset control strategies. The target control strategy includes the first sub-strategy corresponding to the front-end boost circuit and the second sub-strategy corresponding to the rear-end inverter circuit.

[0082] The preset control strategy stores a set of control schemes corresponding to different power imbalance levels. The target control strategy is the current execution strategy selected from this set based on the current power imbalance level. The first sub-strategy is directed to the front-end boost circuit and is used to adjust the energy extraction method of the photovoltaic array. The second sub-strategy is directed to the back-end inverter circuit and is used to adjust the power command or current command output by the grid-connected circuit. The two sub-strategies work together to form a complete power imbalance handling action.

[0083] In this embodiment, the controller establishes a mapping relationship of "power imbalance level - target control strategy" in the memory. Each strategy record in the mapping relationship includes the control content corresponding to the front-end boost circuit and the control content corresponding to the back-end inverter circuit.

[0084] After obtaining the current power imbalance level in step S102, the controller reads the corresponding strategy record and generates a target control strategy. In specific implementation, for different power imbalance levels, the first and second sub-strategies in the target control strategy can have different adjustment strengths, so that the front-end boost circuit and the back-end inverter circuit can perform coordinated control according to the current imbalance level.

[0085] For example, multiple preset control strategies can form a hierarchical relationship according to the power imbalance level, ensuring that the actions invoked by the controller under different severity levels match the current state. In another possible implementation, the target control strategy may also include an exit condition, such as when the actual value of the DC bus voltage falls below a first voltage threshold and continues for a preset recovery time, the controller cancels the current target control strategy and resumes normal control mode.

[0086] Based on the above analysis, this step establishes a clear correspondence between the power imbalance level and the linkage control actions of the preceding and following stages, enabling the system to allocate the input suppression amount of the preceding stage and the output boost amount of the following stage according to the current severity of the imbalance, thereby ensuring that the control actions match the field conditions.

[0087] S104, Execute the first sub-policy and the second sub-policy.

[0088] The first sub-strategy is executed on the front-end boost circuit, and the second sub-strategy is executed on the back-end inverter circuit. The execution process is used to convert the target control strategy determined in step S103 into control commands that can be directly applied to the power converter.

[0089] In this embodiment, the controller sends the first sub-strategy to the front-end boost control module and the second sub-strategy to the back-end grid-connected control module within the same control cycle, so that the front and back stages can coordinate and regulate the DC bus energy balance.

[0090] For the front-end boost circuit, when executing the first sub-strategy, the controller adjusts the energy harvested from the front-end according to the target control strategy to reduce the input power of the front-end. For the rear-end inverter circuit, when executing the second sub-strategy, the controller adjusts the output of the rear-end according to the target control strategy to increase the energy delivered to the grid within the allowable range.

[0091] To ensure stable execution, the controller can also introduce a ramp transition mechanism when implementing the first and second sub-strategies. That is, the relevant control quantity changes gradually according to the preset slope, rather than abruptly changing in a single cycle, thereby suppressing additional oscillations.

[0092] In one possible implementation, the first sub-strategy and the second sub-strategy can be executed in parallel, that is, the control instructions of the preceding and following levels are updated simultaneously immediately after the same target control strategy is determined; in another possible implementation, the execution order can also be adopted, and the specific order is set by the controller.

[0093] During execution, the controller continuously returns to step S101 for a new round of sampling and then loops into step S102 to determine whether the power imbalance level has changed. If the level decreases, a lower-intensity target control strategy is invoked. If the level is resolved, the controller gradually exits the current target control strategy and resumes normal control.

[0094] Based on the above analysis, this step implements the target control strategy as actual control actions that limit the input power of the front stage and enhance the output capability of the back stage, so that the excess energy in the DC bus can be released in time or the input can be suppressed, thereby bringing the DC bus voltage back from a continuously rising state to a controllable range and maintaining the continuity of grid-connected operation.

[0095] This application provides a power control method for a photovoltaic inverter. The method involves collecting the actual values ​​of the DC bus voltage and output current of the photovoltaic inverter. When the actual value of the DC bus voltage is greater than or equal to a first voltage threshold and the actual value of the output current is greater than or equal to a first current threshold for a duration of a first time, the method determines the power imbalance level of the photovoltaic inverter based on these values. According to the power imbalance level, a target control strategy is determined from multiple preset control strategies. The target control strategy includes a first sub-strategy corresponding to the front-end boost circuit and a second sub-strategy corresponding to the rear-end inverter circuit. The first and second sub-strategies are then executed. In this application, a persistent power imbalance identification mechanism is constructed by using the actual value of DC bus voltage and the actual value of output current. Based on the power imbalance level, hierarchical coordinated control is implemented on the front-end boost circuit and the back-end inverter circuit. This enables the over-saturated photovoltaic inverter to intervene in advance when the input capacity is continuously higher than the output capacity under normal operating conditions. This makes the bus voltage control no longer dependent on direct comparison of input and output power or only responding during the fault protection stage, thereby achieving timely suppression of the rising trend of DC bus voltage and maintaining the stability of grid-connected operation.

[0096] Figure 2 A flowchart illustrating the power control method for the photovoltaic inverter provided in this application. Figure 2 ,like Figure 2 As shown, in this embodiment... Figure 1 Based on the embodiments, the power control method of the photovoltaic inverter is described in detail. The power control method of the photovoltaic inverter provided in this embodiment includes:

[0097] S201. Obtain the temperature of the heat sink, the actual value of the grid voltage, and the operating temperature of the photovoltaic array.

[0098] The photovoltaic inverter's downstream inverter circuit also includes a heat sink. In practice, the heat sink temperature can be acquired by a temperature acquisition unit attached to the heat sink substrate or heat sink fins, the actual grid voltage value can be obtained by a grid-connected sampling circuit, and the photovoltaic array's operating temperature can be acquired by a temperature sensor located on the photovoltaic array's back panel or frame.

[0099] In this embodiment of the application, the collected data can be processed by low-pass filtering or moving average before being sent to the threshold calculation unit to reduce the impact of instantaneous disturbances on the judgment result.

[0100] S202. Determine the first voltage threshold and the first current threshold based on the temperature of the radiator, the actual value of the grid voltage, and the operating temperature of the photovoltaic array.

[0101] The first voltage threshold can be obtained by superimposing the grid voltage correction and temperature correction on the base voltage threshold, and the first current threshold can be obtained by subtracting the current correction corresponding to the heat sink temperature from the maximum allowable output current of the photovoltaic inverter, thus forming a judgment benchmark that changes with the operating state.

[0102] During operation, the threshold calculation unit first determines the first voltage threshold based on the deviation between the actual grid voltage and the rated grid voltage, and the deviation between the photovoltaic array operating temperature and the preset temperature threshold. Then, it determines the first current threshold based on the deviation between the radiator temperature and the preset radiator temperature threshold.

[0103] Subsequently, when the controller collects the actual values ​​of the DC bus voltage and the actual values ​​of the output current, it can use this threshold as the criterion for subsequent power imbalance identification.

[0104] Since the first voltage threshold and the first current threshold can be dynamically determined by combining the thermal state of the heat sink, the grid voltage state, and the temperature state of the photovoltaic array, the threshold setting can be consistent with the current grid connection conditions and the thermal state of the device. This makes the input boundary of the subsequent power imbalance level judgment more in line with the actual operating conditions and improves the stability and adaptability of the threshold judgment.

[0105] For example, determining a first voltage threshold and a first current threshold based on the temperature of the heat sink, the actual value of the grid voltage, and the operating temperature of the photovoltaic array includes: determining a first correction value corresponding to the first voltage threshold based on the difference between the actual grid voltage and the rated grid voltage; determining a second correction value corresponding to the first voltage threshold based on the difference between the operating temperature of the photovoltaic array and a preset operating temperature threshold; determining the first voltage threshold based on the first correction value, the second correction value, and the base voltage threshold; determining a third correction value corresponding to the first current threshold based on the difference between the temperature of the heat sink and a preset heat sink temperature threshold; and subtracting the sum of the base current deviation threshold and the third correction value from the maximum allowable output current of the photovoltaic inverter to obtain the first current threshold.

[0106] Among them, the base voltage threshold is the default judgment voltage without the introduction of operating condition correction, the preset operating temperature threshold is the reference temperature base of the photovoltaic array, the preset heat sink temperature threshold is the reference temperature base of the heat sink, and the base current deviation threshold is the base deduction amount of the output current limit. The first correction value, the second correction value, and the third correction value are all intermediate correction amounts associated with the corresponding difference, used for adaptive compensation of the threshold.

[0107] Understandably, when the grid voltage is below the rated value, the inverter's output capability decreases, requiring a higher voltage threshold to prevent false triggering of protection when the bus voltage rises slightly. Conversely, when the grid voltage is above the rated value, the threshold can be appropriately lowered to respond more sensitively to overvoltage.

[0108] In the specific implementation, the actual value of the grid voltage can be obtained by the grid-connected side voltage sampling circuit. The sampling signal is isolated, amplified and converted from analog to digital and then input to the controller. The controller filters the sampled value and compares it with the rated grid voltage. When the actual value of the grid voltage is higher or lower than the rated value, a first correction value is generated according to the preset mapping relationship. The mapping relationship can be determined by linear proportion, piecewise function or lookup table method.

[0109] In one possible implementation, the first correction value can be determined using a piecewise linear correction method. For example, when At that time, the first correction value It can be calculated using the following formula: , This is the difference between the actual grid voltage and the rated grid voltage. This is the voltage correction factor. For example, 0.5; when When, the first correction value is taken as a fixed upper limit of 15V, when When this happens, the first correction value can be calculated using the following formula: .

[0110] The operating temperature of the photovoltaic array can be collected by a temperature sensor attached to the back of the module. The controller obtains a second correction value based on the difference between the operating temperature of the photovoltaic array and the preset operating temperature threshold, and then adds it to the first correction value to correct the base voltage threshold, thereby forming a first voltage threshold that adapts to the current grid voltage and the thermal state of the array.

[0111] Understandably, as the operating temperature of a photovoltaic array increases, its output capacity decreases, and the normal operating range of the bus voltage shifts downward, necessitating a reduction in the voltage threshold to allow for earlier protection intervention. Conversely, as the operating temperature of the photovoltaic array decreases, its output voltage increases with the temperature drop, and the normal operating range of the bus voltage shifts upward accordingly, allowing for an appropriate increase in the voltage threshold to avoid oversensitivity.

[0112] In one possible implementation, the second correction value can be determined using a piecewise linear correction method. For example, when At that time, the second correction value It can be calculated using the following formula: , This is the voltage-temperature correction factor, which can be 0.3. This is the difference between the operating temperature of the photovoltaic array and the preset operating temperature threshold; when At that time, the second correction value Take a fixed lower limit value of -9V, when Second correction value Set to 0V. The first voltage threshold can be the base voltage threshold plus a first correction value. Second correction value The sum of .

[0113] The temperature of the radiator can be obtained by a temperature sensor installed on the radiator body. The controller calculates a third correction value based on the deviation of the radiator temperature from the preset radiator temperature threshold. Then, the maximum allowable output current is subtracted from the sum of the basic current deviation threshold and the third correction value to obtain the first current threshold.

[0114] Understandably, as the heatsink temperature rises, the heat dissipation conditions of power devices deteriorate, and the overload capacity decreases. Therefore, it's necessary to tighten the current threshold (i.e., increase the correction amount in the deviation threshold) to trigger system protection earlier. Conversely, when the heatsink temperature is low, the current threshold can be appropriately relaxed.

[0115] In one possible implementation, the third correction value can be determined using a piecewise linear correction method. For example, when At that time, the third correction value , This is the current-temperature correction factor, which can be taken as 0.2. This is the difference between the radiator temperature and the preset radiator temperature threshold; when At that time, the third correction value A fixed upper limit of 4.5A can be taken; when At that time, the third correction value It is 0A.

[0116] Basic current deviation threshold It can be 5A, total current deviation threshold. Basic current deviation threshold and the third correction value The sum. The first current threshold is the maximum allowable output current. Subtract the total deviation threshold .

[0117] This implementation incorporates the actual grid voltage, photovoltaic array operating temperature, and radiator temperature into threshold calculations, enabling the first voltage threshold and first current threshold to change synchronously with external grid conditions, component thermal state, and heat dissipation conditions. When the controller subsequently acquires the actual DC bus voltage and output current values, it can identify power imbalance based on the determined thresholds, ensuring that the threshold determination matches the current operating conditions.

[0118] With this approach, the first voltage threshold and the first current threshold are no longer fixed, but are corrected by combining grid voltage fluctuations, photovoltaic array temperature rise and radiator temperature. This can improve the pertinence and stability of power imbalance detection and provide a more reliable basis for the selection of subsequent control strategies.

[0119] S203. Collect the actual value of the DC bus voltage and the actual value of the output current of the photovoltaic inverter.

[0120] Step S203 is similar to step S101 above, and will not be repeated here.

[0121] S204. When the actual value of the DC bus voltage is greater than or equal to the first voltage threshold, the actual value of the output current is greater than or equal to the first current threshold, and the duration reaches the first time period, the rate of change of the actual value of the DC bus voltage is determined based on the difference between the actual value of the DC bus voltage collected at the current time and the actual value of the DC bus voltage collected at the previous time, and the time interval between the current time and the previous time.

[0122] In practical implementation, the controller continuously acquires the actual value of the DC bus voltage within a preset sampling period, performs difference calculation between the current sampled value and the previous sampled value, and then calculates the rate of change of the actual value of the DC bus voltage by combining the time interval between the two samplings. The rate of change of the actual value of the DC bus voltage can be characterized by the quotient of the voltage difference and the time interval.

[0123] The controller simultaneously reads the actual value of the output current and calculates the ratio of this current value to the pre-calibrated maximum allowable output current to obtain the output load ratio.

[0124] S205. Determine the power imbalance level of the photovoltaic inverter based on the rate of change of the actual value of the DC bus voltage and the ratio of the actual value of the output current to the maximum allowable output current of the photovoltaic inverter.

[0125] Subsequently, the controller matches the rate of change and ratio of the actual DC bus voltage with the corresponding preset intervals. When the rate of change of the actual DC bus voltage is in a high-rising interval and the output load ratio is high, the power imbalance level is determined to be high; when the rate of change of the actual DC bus voltage is low or the output load ratio is low, it is determined to be low. This determination result is output to the subsequent control module to drive the corresponding power limiting or voltage regulation control strategy. In practical applications, the preset sampling period, interval threshold, and maximum allowable output current calibration values ​​can also be configured according to different photovoltaic inverter models; this application does not limit this.

[0126] By jointly determining the power imbalance level based on the rate of change of the actual DC bus voltage and the proportion of output current, the system can not only reflect the dynamic trend of DC bus voltage changes, but also the proximity of the inverter output load, thus making the identification of power imbalance more closely resemble the actual operating process. Since this level is directly determined by both voltage change characteristics and current load characteristics, it can provide a more accurate basis for subsequent control strategy selection.

[0127] By adopting the above method, the determination of the power imbalance level does not rely on a single instantaneous power calculation, but is comprehensively identified by combining the bus voltage change trend and the output current load status. Therefore, the accuracy and stability of the imbalance level determination can be improved, and a reliable input can be provided for subsequent targeted control.

[0128] For example, when the rate of change of the actual value of the DC bus voltage is less than a first rate of change threshold and the ratio of the actual value of the output current to the maximum allowable output current of the photovoltaic inverter is less than a first ratio threshold, the power imbalance level of the photovoltaic inverter is determined to be the first power imbalance level.

[0129] If the rate of change of the actual value of the DC bus voltage is greater than or equal to the first rate of change threshold and less than the second rate of change threshold, and the ratio of the actual value of the output current to the maximum allowable output current of the photovoltaic inverter is greater than or equal to the first ratio threshold and less than the second ratio threshold, the power imbalance level of the photovoltaic inverter is determined to be the second power imbalance level.

[0130] If the rate of change of the actual value of the DC bus voltage is greater than or equal to the second rate of change threshold, and the ratio of the actual value of the output current to the maximum allowable output current of the photovoltaic inverter is greater than or equal to the second ratio threshold, the power imbalance level of the photovoltaic inverter is determined to be the third power imbalance level; wherein, the second rate of change threshold is greater than the first rate of change threshold, and the second ratio threshold is greater than the first ratio threshold.

[0131] Specifically, the first rate of change threshold is used to divide the lower-level range of the rate of change of the actual value of the DC bus voltage, and the second rate of change threshold is used to divide the higher-level range of the rate of change; the first ratio threshold is used to divide the lower-level range of the ratio of the output current to the maximum allowable output current, and the second ratio threshold is used to divide the higher-level range of the ratio. For example, the first rate of change threshold can be 10V / s, the second rate of change threshold can be 30V / s, the first ratio threshold can be 0.7, and the second ratio threshold can be 0.9.

[0132] The first power imbalance level represents the lowest level of power imbalance. Its determination boundary is jointly determined by the first rate of change threshold and the first ratio threshold. For example, when the rate of change is less than 10V / s per second and the ratio is less than 0.7, it is determined to be the first power imbalance level.

[0133] The second power imbalance level indicates a moderate level of power imbalance. For example, when the rate of change is greater than or equal to 10V / s and less than 30V / s, and the ratio is greater than or equal to 0.7 and less than 0.9, it is judged as the second power imbalance level.

[0134] The third power imbalance level indicates the highest degree of power imbalance. For example, when the rate of change is greater than or equal to 30V / s and the ratio is greater than or equal to 0.9, it is judged as the third power imbalance level.

[0135] In the specific implementation, the controller periodically acquires the DC bus voltage sample value, and calculates the rate of change of the actual DC bus voltage value based on the voltage difference and time interval between two adjacent sampling times. The rate of change of the actual DC bus voltage value can be obtained by the ratio of the absolute change to the preset sampling period.

[0136] The controller simultaneously acquires the actual output current value and pre-stores the maximum allowable output current of the photovoltaic inverter. When the ratio of the actual output current value to the maximum allowable output current is less than a first ratio threshold and the rate of change of the actual DC bus voltage is small, the current state is mapped to the first power imbalance level. When both values ​​are in the middle range, it is mapped to the second power imbalance level. When both values ​​reach a higher range, it is mapped to the third power imbalance level. Based on this, the controller outputs the corresponding target power imbalance level and transmits this level to the subsequent control module to match the corresponding adjustment parameters of the front-end boost circuit and the back-end inverter circuit.

[0137] During operation, the rate of change of the actual DC bus voltage reflects the speed of energy accumulation on the bus, while the output current ratio reflects the degree to which the inverter approaches its maximum output capacity. The combination of these two metrics classifies the imbalance state into three levels: mild, moderate, and severe. After completing calculations and determinations within the same sampling period, the controller directly obtains the power imbalance level corresponding to the current operating state, providing a basis for subsequent control strategy selection.

[0138] With this implementation, the power imbalance level can simultaneously characterize the bus voltage evolution trend and the output current load level, so that different imbalance states correspond to different level boundaries, thereby providing clearer criteria for subsequent control strategies and improving the classification accuracy of imbalance identification and control matching.

[0139] S206. Determine the target control strategy from multiple preset control strategies based on the power imbalance level of the photovoltaic inverter.

[0140] In one possible implementation, the multiple preset control strategies include: a first control strategy, a second control strategy, and a third control strategy; based on the power imbalance level of the photovoltaic inverter, a target control strategy is determined from the multiple preset control strategies, including: when the power imbalance level is a first power imbalance level, determining the first control strategy as the target control strategy; in the first control strategy, a first sub-strategy is used to instruct the adjustment of the duty cycle of the front-end boost circuit according to a first adjustment range, and a second sub-strategy is used to instruct the adjustment of the output power value of the rear-end inverter circuit according to a first overload factor;

[0141] When the power imbalance level is the second power imbalance level, the second control strategy is determined as the target control strategy; in the second control strategy, the first sub-strategy is used to indicate the adjustment of the duty cycle of the front-stage boost circuit according to the second adjustment range, the second adjustment range is greater than the first adjustment range, and the second sub-strategy is used to indicate the adjustment of the output power value of the rear-stage inverter circuit according to the second overload coefficient, the second overload coefficient is greater than the first overload coefficient.

[0142] When the power imbalance level is the third power imbalance level, the third control strategy is determined as the target control strategy. In the third control strategy, the first sub-strategy is used to indicate the adjustment of the duty cycle of the front-stage boost circuit according to the third adjustment range, which is greater than the second adjustment range. The second sub-strategy is used to indicate the adjustment of the output power value of the rear-stage inverter circuit according to the third overload coefficient, which is greater than the second overload coefficient.

[0143] The second voltage threshold is used as the exit threshold for restoring normal operation mode, the second duration is used to limit the duration of low voltage state, and the normal operation mode is used to represent the normal operating state when there is no power imbalance.

[0144] In practical implementation, multiple preset control strategies are pre-stored in the controller's parameter table. The parameter table records the mapping relationship between each power imbalance level and the duty cycle adjustment of the preceding stage and the output power derating of the following stage. For example, assume that the first adjustment range D1 = 2%, the second adjustment range D2 = 5%, and the third adjustment range D3 = 8%; the first overload coefficient K1 = 1.02, the second overload coefficient K2 = 1.05, and the third overload coefficient K3 = 1.10.

[0145] When the current power imbalance level is determined to be the first power imbalance level, the controller invokes the first control strategy. Based on the first sub-strategy, it adjusts the duty cycle of the front-end boost circuit to a preset increment, thereby changing the boost ratio and suppressing the continued rise of the bus voltage. Simultaneously, it generates the power limit value of the downstream inverter circuit according to the first overload factor, ensuring that the grid-connected output power is maintained at a level that matches the current power imbalance level. For example, the first sub-strategy is used to instruct the adjustment of the duty cycle of the front-end boost circuit according to the first adjustment range D1 (e.g., 2%), that is, to increase the duty cycle of the front-end boost circuit by 2% based on the current duty cycle of the front-end boost circuit; the second sub-strategy is used to instruct the adjustment of the output power value of the downstream inverter circuit according to the first overload factor K1 (e.g., 1.02), that is, to control the downstream inverter circuit to deliver power to the grid at 1.02 times its rated power.

[0146] At this level, the rate of change of DC bus voltage and the current ratio are both in a low range, indicating a mild power imbalance. This typically occurs when the solar irradiance just exceeds the inverter's output capacity or when there are slight fluctuations in grid voltage. The controller primarily uses power limiting at the upstream stage and secondarily uses slight overload at the downstream stage to regulate the bus voltage, allowing it to gradually return to a safe range while avoiding excessive intervention that could significantly impact the normal power generation efficiency of the photovoltaic array.

[0147] When the current power imbalance level is determined to be the second power imbalance level, the controller switches to the second control strategy and adjusts the duty cycle with a second adjustment range greater than the first adjustment range, and limits the output power with a second overload factor greater than the first overload factor, thereby enhancing the regulation intensity. For example, the first sub-strategy is used to instruct the adjustment of the duty cycle of the front-end boost circuit according to the second adjustment range D2 (e.g., 5%), where D2 is greater than D1; the second sub-strategy is used to instruct the adjustment of the output power value of the rear-end inverter circuit according to the second overload factor K2 (e.g., 1.05), where K2 is greater than K1.

[0148] At this level, the rate of change of DC bus voltage and the current ratio are both in the medium range, indicating a worsening of power imbalance. This typically occurs in scenarios where the solar irradiance is consistently higher than the inverter's output capacity or where the grid voltage fluctuates significantly. Both the upstream power limiting and downstream power boosting efforts need to be strengthened. A 5% duty cycle adjustment should be used to further reduce the input power of the photovoltaic array, while a 1.05 overload factor should be applied to enable the downstream inverter circuit to output more power, accelerating the dissipation of excess energy accumulated on the DC bus side.

[0149] When the current power imbalance level is determined to be the third power imbalance level, the controller executes a third control strategy, applying stronger control to the upstream and downstream stages with a third adjustment range and a third overload factor, respectively. For example, in the third control strategy, the first sub-strategy is used to instruct the adjustment of the duty cycle of the upstream boost circuit according to the third adjustment range D3 (e.g., 8%), where D3 is greater than D2; the second sub-strategy is used to instruct the adjustment of the output power value of the downstream inverter circuit according to the third overload factor K3 (e.g., 1.10), where K3 is greater than K2.

[0150] At this level, the DC bus voltage is rising rapidly, and the current ratio is close to or reaches its upper limit, indicating the most severe power imbalance. This typically occurs in scenarios with a sudden increase in sunlight or significant fluctuations in grid voltage. The controller rapidly reduces the input power of the photovoltaic array with an 8% duty cycle adjustment, while simultaneously using an overload factor of 1.10 to cause the downstream inverter circuit to output power significantly exceeding its rated power for a short period. This allows the DC bus voltage to quickly drop back to a safe range, preventing overvoltage protection from being triggered or damage to power devices.

[0151] This control method maps power imbalance levels to control strategies of varying intensities, enabling synchronized adjustment of the duty cycle in the front-end boost circuit and the output power regulation in the rear-end inverter circuit. When the power imbalance is minor, the controller employs a smaller adjustment range and a lower overload coefficient; as the power imbalance worsens, the adjustment range and overload coefficient are gradually increased, thus achieving graded suppression of DC bus energy accumulation. When the control values ​​of the front and rear stages return to a range matching the normal operating mode, the system can exit the target control strategy and return to the normal operating mode after the DC bus voltage falls below the second voltage threshold for a second duration.

[0152] With this implementation method, the target control strategy corresponds one-to-one with the power imbalance level. The duty cycle of the front stage and the output power of the back stage can be adjusted in stages according to the degree of power imbalance. The control action has stronger pertinence and consistency, which can improve the stability of DC bus voltage regulation and reduce the probability of control mismatch under power imbalance conditions.

[0153] S207, Execute the first sub-policy and the second sub-policy.

[0154] Step S207 is similar to step S104 above, and will not be repeated here.

[0155] S208. When the actual value of the DC bus voltage is less than the second voltage threshold and the duration reaches the second duration, control the front-stage boost circuit to stop executing the first sub-strategy in the target control strategy, and control the rear-stage inverter circuit to stop executing the second sub-strategy in the target control strategy.

[0156] The second voltage threshold and the second duration are determined based on the power imbalance level of the photovoltaic inverter. The higher the power imbalance level, the smaller the second voltage threshold and the longer the second duration. The second voltage threshold is smaller than the first voltage threshold, and the second duration is longer than the first duration. The second voltage threshold can be obtained by subtracting the recovery margin from the rated DC bus voltage. The second duration can be set from several hundred milliseconds to several seconds to ensure that short-term fluctuations in the bus voltage do not trigger false recovery.

[0157] For example, the first voltage threshold V1 is 825V, and the first duration T1 is 100ms. When the power imbalance level is the first power imbalance level, the second voltage threshold V2 is set to 790V, and the second duration T... 21 The time limit is 300ms. This is because a slight imbalance has a smaller impact on the system, the bus voltage recovers faster, and the exit condition requirement is lower: the voltage drops below 790V and remains below 300ms to determine whether the system can exit.

[0158] When the power imbalance level is the second power imbalance level (moderate), the second voltage threshold V2 is set to 780V, and the second duration T is... 22The time limit is 500ms. This is because a moderate imbalance has a greater impact on the system, requiring the bus voltage to drop to a lower level and stabilize for a longer period of time. The exit conditions are also more stringent: the voltage must drop below 780V and remain below it for 500ms before the system can exit.

[0159] When the power imbalance level is the third power imbalance level, the second voltage threshold V2 is set to 770V, and the second duration T is set to... 23 The time limit is 800ms. Severe imbalance has the most serious impact on the system, requiring the bus voltage to drop significantly to a safe low value and remain stable for a long time. The exit condition is the most stringent: the voltage must drop below 770V and remain there for 800ms before the system can exit.

[0160] In practice, the controller continuously collects the actual value of the DC bus voltage during the execution of the target control strategy and compares it with the second voltage threshold. When the voltage value is detected to be lower than the second voltage threshold, the controller starts the timing module and accumulates the duration of the low voltage. Only when the duration reaches the second duration will the controller send a control command to stop executing the first sub-strategy to the upstream boost circuit and a control command to stop executing the second sub-strategy to the downstream inverter circuit, so that the two circuits exit the power imbalance regulation state and switch back to the normal operation mode.

[0161] The second voltage threshold and the second duration can be determined by a mapping table pre-stored in the storage unit. The mapping table establishes threshold groups based on the power imbalance level. The higher the power imbalance level, the smaller the corresponding second voltage threshold and the longer the second duration, so as to ensure that the recovery judgment matches the power imbalance recovery process. In practical applications, this mapping relationship can also be implemented by table lookup, piecewise function or rule engine. This application does not limit this.

[0162] This control method ensures that recovery determination is independent of instantaneous voltage fluctuations. Instead, it triggers a switchback based on a stable condition where the voltage is below a second threshold and remains below that threshold for a second duration. This means that the front-end boost circuit and the back-end inverter circuit only exit the target control strategy after the power imbalance is truly resolved, guaranteeing the smoothness of switching and the continuity of control when the photovoltaic inverter returns to normal operating mode. Since the second voltage threshold and the second duration are linked to the power imbalance level of the photovoltaic inverter, the higher the power imbalance level, the more stringent the recovery conditions. Therefore, it can adapt to different degrees of power imbalance and ensure that control recovery is consistent with the bus voltage drop process.

[0163] The power control method for photovoltaic inverters provided in this application dynamically determines the first voltage threshold and the first current threshold by acquiring the temperature of the heat sink, the actual value of the grid voltage, and the operating temperature of the photovoltaic array. This allows the judgment threshold to change synchronously with grid voltage fluctuations and equipment thermal status, improving the pertinence and stability of power imbalance detection. By collecting the actual values ​​of the DC bus voltage and the actual values ​​of the output current for threshold comparison, no power sampling calculation is required, avoiding the amplification effect of sensor errors in the power calculation process. This enables more accurate identification of power imbalance states and reduces the risk of misjudgment. By implementing differentiated control strategies according to different power imbalance levels, the control intensity is matched with the severity of the imbalance, avoiding over-adjustment or under-adjustment problems caused by a single control strategy, and achieving targeted coordinated adjustment of upstream and downstream circuits. By dynamically determining the exit judgment condition according to the power imbalance level, the exit condition is matched with the severity of the imbalance, avoiding premature exit leading to a second rebound of the bus voltage or premature exit leading to unnecessary control delay, further improving the adaptability and robustness of the system under different imbalance scenarios.

[0164] This application embodiment also provides a photovoltaic inverter, which includes: a DC bus, a DC bus voltage sampling circuit, an output current sampling circuit, a front-stage boost circuit, a rear-stage inverter circuit, and a controller. The input terminal of the front-stage boost circuit is electrically connected to the photovoltaic array, the output terminal of the front-stage boost circuit is electrically connected to the DC bus, the input terminal of the rear-stage inverter circuit is electrically connected to the DC bus, and the output terminal of the rear-stage inverter circuit is electrically connected to the power grid.

[0165] A DC bus voltage sampling circuit is connected in parallel to the DC bus to collect the actual value of the DC bus voltage.

[0166] The output current sampling circuit is connected in series between the output terminal of the subsequent inverter circuit and the power grid to collect the actual value of the output current of the photovoltaic inverter.

[0167] The controller is electrically connected to the DC bus voltage sampling circuit and the output current sampling circuit, respectively. The controller is used to determine the power imbalance level of the photovoltaic inverter based on the actual values ​​of the DC bus voltage and the actual value of the output current when the actual value of the DC bus voltage is greater than or equal to a first voltage threshold and the actual value of the output current is greater than or equal to a first current threshold and the duration reaches a first duration. According to the power imbalance level of the photovoltaic inverter, the controller determines the target control strategy from multiple preset control strategies. The target control strategy includes a first sub-strategy corresponding to the front-end boost circuit and a second sub-strategy corresponding to the back-end inverter circuit. The controller executes the first sub-strategy and the second sub-strategy.

[0168] By using DC bus voltage and output current as joint criteria and adding a duration condition, misjudgments caused by instantaneous fluctuations can be avoided, thus more accurately identifying persistent power imbalance states during normal operation. The controller matches different target control strategies according to the power imbalance level, enabling coordinated adjustment between the front-end boost circuit and the back-end inverter circuit, thereby achieving targeted balancing of photovoltaic input capacity and grid-connected output capacity. Therefore, it can intervene in time before the bus voltage rises further, improving the reliability and stability of DC bus voltage control, reducing the risk of overvoltage shutdown, and helping to protect the safety and lifespan of bus capacitors and power devices.

[0169] Based on the above embodiments, this application also provides a power control device for a photovoltaic inverter.

[0170] Figure 3 This is a schematic diagram of the power control device for the photovoltaic inverter provided in this application, as shown below. Figure 3 As shown, the photovoltaic inverter includes a front-end boost circuit and a rear-end inverter circuit. The input terminal of the front-end boost circuit is electrically connected to the photovoltaic array, and the output terminal of the rear-end inverter circuit is electrically connected to the power grid. The power control device 300 of the photovoltaic inverter provided in this embodiment includes:

[0171] The data acquisition module 301 is used to acquire the actual value of the DC bus voltage and the actual value of the output current of the photovoltaic inverter.

[0172] Processing module 302 is used to determine the power imbalance level of the photovoltaic inverter based on the actual value of the DC bus voltage and the actual value of the output current when the actual value of the DC bus voltage is greater than or equal to a first voltage threshold, the actual value of the output current is greater than or equal to a first current threshold, and the duration reaches a first duration.

[0173] The processing module 302 is also used to determine a target control strategy from multiple preset control strategies based on the power imbalance level of the photovoltaic inverter. The target control strategy includes a first sub-strategy corresponding to the front-end boost circuit and a second sub-strategy corresponding to the rear-end inverter circuit.

[0174] Control module 303 is used to execute the first sub-policy and the second sub-policy.

[0175] Optionally, the subsequent inverter circuit also includes a heat sink, and the device also includes an acquisition module 304;

[0176] The acquisition module 304 is used to acquire the temperature of the heat sink, the actual value of the grid voltage, and the operating temperature of the photovoltaic array.

[0177] The processing module 302 is also used to determine a first voltage threshold and a first current threshold based on the temperature of the heat sink, the actual value of the grid voltage, and the operating temperature of the photovoltaic array.

[0178] Optionally, the processing module 302 is further configured to determine a first correction value corresponding to the first voltage threshold based on the difference between the actual grid voltage and the rated grid voltage.

[0179] The processing module 302 is also used to determine a second correction value corresponding to the first voltage threshold based on the difference between the operating temperature of the photovoltaic array and the preset operating temperature threshold.

[0180] The processing module 302 is further configured to determine the first voltage threshold based on the first correction value, the second correction value, and the base voltage threshold;

[0181] The processing module 302 is also used to determine a third correction value corresponding to the first current threshold based on the difference between the temperature of the radiator and the preset radiator temperature threshold.

[0182] The processing module 302 is also used to subtract the sum of the basic current deviation threshold and the third correction value from the maximum allowable output current of the photovoltaic inverter to obtain the first current threshold.

[0183] Optionally, the processing module 302 is also used to determine the rate of change of the actual value of the DC bus voltage based on the difference between the actual value of the DC bus voltage collected at the current moment and the actual value of the DC bus voltage collected at the previous moment, as well as the time interval between the current moment and the previous moment.

[0184] The processing module 302 is also used to determine the power imbalance level of the photovoltaic inverter based on the rate of change of the actual value of the DC bus voltage and the ratio of the actual value of the output current to the maximum allowable output current of the photovoltaic inverter.

[0185] Optionally, the processing module 302 is specifically used to determine the power imbalance level of the photovoltaic inverter as the first power imbalance level when the rate of change of the actual value of the DC bus voltage is less than the first rate of change threshold and the ratio of the actual value of the output current to the maximum allowable output current of the photovoltaic inverter is less than the first ratio threshold.

[0186] The processing module 302 is specifically used to determine the power imbalance level of the photovoltaic inverter as the second power imbalance level when the rate of change of the actual value of the DC bus voltage is greater than or equal to the first rate of change threshold and less than the second rate of change threshold, and the ratio of the actual value of the output current to the maximum allowable output current of the photovoltaic inverter is greater than or equal to the first ratio threshold and less than the second ratio threshold.

[0187] The processing module 302 is specifically used to determine the power imbalance level of the photovoltaic inverter as the third power imbalance level when the rate of change of the actual value of the DC bus voltage is greater than or equal to the second rate of change threshold and the ratio of the actual value of the output current to the maximum allowable output current of the photovoltaic inverter is greater than or equal to the second ratio threshold.

[0188] Among them, the second rate of change threshold is greater than the first rate of change threshold, and the second ratio threshold is greater than the first ratio threshold.

[0189] Optionally, multiple preset control strategies include: a first control strategy, a second control strategy, and a third control strategy;

[0190] The processing module 302 is specifically used to determine the first control strategy as the target control strategy when the power imbalance level is the first power imbalance level; in the first control strategy, the first sub-strategy is used to indicate the adjustment of the duty cycle of the front-stage boost circuit according to the first adjustment range, and the second sub-strategy is used to indicate the adjustment of the output power value of the rear-stage inverter circuit according to the first overload coefficient.

[0191] The processing module 302 is specifically used to determine the second control strategy as the target control strategy when the power imbalance level is the second power imbalance level. In the second control strategy, the first sub-strategy is used to indicate the adjustment of the duty cycle of the front-stage boost circuit according to the second adjustment range, the second adjustment range being greater than the first adjustment range. The second sub-strategy is used to indicate the adjustment of the output power value of the rear-stage inverter circuit according to the second overload coefficient, the second overload coefficient being greater than the first overload coefficient.

[0192] The processing module 302 is specifically used to determine the third control strategy as the target control strategy when the power imbalance level is the third power imbalance level. In the third control strategy, the first sub-strategy is used to indicate the adjustment of the duty cycle of the front-stage boost circuit according to the third adjustment range, where the third adjustment range is greater than the second adjustment range. The second sub-strategy is used to indicate the adjustment of the output power value of the rear-stage inverter circuit according to the third overload coefficient, where the third overload coefficient is greater than the second overload coefficient.

[0193] Optionally, the control module 303 is also used to control the front-end boost circuit to stop executing the first sub-strategy in the target control strategy and control the rear-end inverter circuit to stop executing the second sub-strategy in the target control strategy when the actual value of the DC bus voltage is less than the second voltage threshold and the duration reaches the second duration, so that the photovoltaic inverter can be restored to the normal operation mode.

[0194] The second voltage threshold and the second duration are determined based on the power imbalance level of the photovoltaic inverter. The higher the power imbalance level, the smaller the second voltage threshold and the longer the second duration. The second voltage threshold is less than the first voltage threshold and the second duration is greater than the first duration.

[0195] The power control device for a photovoltaic inverter provided in this application can execute the power control method for a photovoltaic inverter provided in any of the above embodiments. Its principle and technical effect are similar, and will not be repeated here.

[0196] This application also provides an electronic device.

[0197] Figure 4 A schematic diagram of the structure of the electronic device provided in this application. Figure 4 As shown, this application provides an electronic device 400, which includes a receiver 401, a transmitter 402, a processor 403, and a memory 404.

[0198] Receiver 401 is used to receive instructions and data;

[0199] Transmitter 402 is used to send commands and data;

[0200] Memory 404 is used to store instructions executed by the computer;

[0201] Processor 403 is used to execute computer execution instructions stored in memory 404 to implement the various steps of the power control method for the photovoltaic inverter in the above embodiments. For details, please refer to the relevant descriptions in the foregoing embodiments of the power control method for the photovoltaic inverter.

[0202] Alternatively, the memory 404 can be either standalone or integrated with the processor 403.

[0203] When the memory 404 is set up independently, the electronic device also includes a bus for connecting the memory 404 and the processor 403.

[0204] In the above embodiments, it should be understood that the processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), etc. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the method disclosed in this invention can be directly implemented by a hardware processor, or implemented by a combination of hardware and software modules within the processor.

[0205] The memory may include random access memory (RAM) and may also include non-volatile memory (NVM), such as at least one disk storage device.

[0206] The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be categorized as address buses, data buses, control buses, etc. For ease of illustration, the buses shown in the accompanying drawings are not limited to a single bus or a single type of bus.

[0207] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the power control method for a photovoltaic inverter provided in any of the above embodiments.

[0208] This application also provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the power control method for a photovoltaic inverter provided in any of the above embodiments.

[0209] The aforementioned readable storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk. The readable storage medium can be any available medium accessible to a general-purpose or special-purpose computer.

[0210] An exemplary readable storage medium is coupled to a processor, enabling the processor to read information from and write information to the readable storage medium. Of course, the readable storage medium can also be a component of the processor. The processor and the readable storage medium can reside in an Application Specific Integrated Circuit (ASIC). Alternatively, the processor and the readable storage medium can exist as discrete components in the device.

[0211] The division of units is merely a logical functional division; in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be indirect coupling or communication connection through some interfaces, devices, or units, and may be electrical, mechanical, or other forms.

[0212] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0213] In addition, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0214] If a function is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0215] Those skilled in the art will understand that all or part of the steps of the above-described method embodiments can be implemented by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When executed, the program performs the steps of the above-described method embodiments; and the aforementioned storage medium includes various media capable of storing program code, such as ROM, RAM, magnetic disks, or optical disks.

[0216] Finally, it should be noted that other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein, and is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope.

Claims

1. A power control method for a photovoltaic inverter, characterized in that, The photovoltaic inverter includes a front-end boost circuit and a back-end inverter circuit. The input terminal of the front-end boost circuit is electrically connected to the photovoltaic array, and the output terminal of the back-end inverter circuit is electrically connected to the power grid. The method includes: The actual values ​​of the DC bus voltage and output current of the photovoltaic inverter are collected. If the actual value of the DC bus voltage is greater than or equal to a first voltage threshold and the actual value of the output current is greater than or equal to a first current threshold and the duration reaches a first duration, the power imbalance level of the photovoltaic inverter is determined based on the actual value of the DC bus voltage and the actual value of the output current. Based on the power imbalance level of the photovoltaic inverter, a target control strategy is determined from multiple preset control strategies. The target control strategy includes a first sub-strategy corresponding to the front-end boost circuit and a second sub-strategy corresponding to the back-end inverter circuit. Execute the first sub-policy and the second sub-policy; The determination of the power imbalance level of the photovoltaic inverter based on the actual value of the DC bus voltage and the actual value of the output current includes: The rate of change of the actual DC bus voltage is determined based on the difference between the actual DC bus voltage value collected at the current moment and the actual DC bus voltage value collected at the previous moment, as well as the time interval between the current moment and the previous moment. If the rate of change of the actual value of the DC bus voltage is less than a first rate of change threshold, and the ratio of the actual value of the output current to the maximum allowable output current of the photovoltaic inverter is less than a first ratio threshold, the power imbalance level of the photovoltaic inverter is determined to be the first power imbalance level. If the rate of change of the actual value of the DC bus voltage is greater than or equal to the first rate of change threshold and less than the second rate of change threshold, and the ratio of the actual value of the output current to the maximum allowable output current of the photovoltaic inverter is greater than or equal to the first ratio threshold and less than the second ratio threshold, the power imbalance level of the photovoltaic inverter is determined to be the second power imbalance level. If the rate of change of the actual value of the DC bus voltage is greater than or equal to the second rate of change threshold, and the ratio of the actual value of the output current to the maximum allowable output current of the photovoltaic inverter is greater than or equal to the second ratio threshold, the power imbalance level of the photovoltaic inverter is determined to be the third power imbalance level. Wherein, the second rate of change threshold is greater than the first rate of change threshold, and the second ratio threshold is greater than the first ratio threshold.

2. The method according to claim 1, characterized in that, The subsequent inverter circuit also includes a heat sink. Before acquiring the actual values ​​of the DC bus voltage and output current of the photovoltaic inverter, the method further includes: The temperature of the heat sink, the actual value of the grid voltage, and the operating temperature of the photovoltaic array are obtained. The first voltage threshold and the first current threshold are determined based on the temperature of the heat sink, the actual value of the grid voltage, and the operating temperature of the photovoltaic array.

3. The method according to claim 2, characterized in that, Determining the first voltage threshold and the first current threshold based on the temperature of the heat sink, the actual value of the grid voltage, and the operating temperature of the photovoltaic array includes: Based on the difference between the actual grid voltage and the rated grid voltage, a first correction value corresponding to the first voltage threshold is determined; Based on the difference between the operating temperature of the photovoltaic array and the preset operating temperature threshold, a second correction value corresponding to the first voltage threshold is determined; The first voltage threshold is determined based on the first correction value, the second correction value, and the base voltage threshold; Based on the difference between the temperature of the radiator and the preset radiator temperature threshold, a third correction value corresponding to the first current threshold is determined. The first current threshold is obtained by subtracting the sum of the base current deviation threshold and the third correction value from the maximum allowable output current of the photovoltaic inverter.

4. The method according to claim 1, characterized in that, The plurality of preset control strategies include: a first control strategy, a second control strategy, and a third control strategy; The step of determining a target control strategy from multiple preset control strategies based on the power imbalance level of the photovoltaic inverter includes: When the power imbalance level is the first power imbalance level, the first control strategy is determined as the target control strategy; in the first control strategy, the first sub-strategy is used to indicate the adjustment of the duty cycle of the front-stage boost circuit according to the first adjustment range, and the second sub-strategy is used to indicate the adjustment of the output power value of the rear-stage inverter circuit according to the first overload factor. When the power imbalance level is the second power imbalance level, the second control strategy is determined as the target control strategy; in the second control strategy, the first sub-strategy is used to indicate the adjustment of the duty cycle of the front-stage boost circuit according to the second adjustment range, the second adjustment range being greater than the first adjustment range, and the second sub-strategy is used to indicate the adjustment of the output power value of the rear-stage inverter circuit according to the second overload coefficient, the second overload coefficient being greater than the first overload coefficient. When the power imbalance level is the third power imbalance level, the third control strategy is determined as the target control strategy; in the third control strategy, the first sub-strategy is used to instruct the adjustment of the duty cycle of the front-stage boost circuit according to a third adjustment range, the third adjustment range being greater than the second adjustment range, and the second sub-strategy is used to instruct the adjustment of the output power value of the rear-stage inverter circuit according to a third overload factor, the third overload factor being greater than the second overload factor.

5. The method according to claim 1, characterized in that, The method further includes: When the actual value of the DC bus voltage is less than the second voltage threshold and the duration reaches the second duration, the front-stage boost circuit is controlled to stop executing the first sub-strategy in the target control strategy, and the rear-stage inverter circuit is controlled to stop executing the second sub-strategy in the target control strategy, so that the photovoltaic inverter can be restored to normal operation mode. The second voltage threshold and the second duration are determined based on the power imbalance level of the photovoltaic inverter. The higher the power imbalance level, the lower the second voltage threshold and the longer the second duration. The second voltage threshold is less than the first voltage threshold and the second duration is greater than the first duration.

6. A photovoltaic inverter, characterized in that, The photovoltaic inverter includes: a DC bus, a DC bus voltage sampling circuit, an output current sampling circuit, a front-stage boost circuit, a rear-stage inverter circuit, and a controller. The input terminal of the front-stage boost circuit is electrically connected to the photovoltaic array, the output terminal of the front-stage boost circuit is electrically connected to the DC bus, the input terminal of the rear-stage inverter circuit is electrically connected to the DC bus, and the output terminal of the rear-stage inverter circuit is electrically connected to the power grid. The DC bus voltage sampling circuit is connected in parallel to the DC bus and is used to collect the actual value of the DC bus voltage of the DC bus. The output current sampling circuit is connected in series between the output terminal of the subsequent inverter circuit and the power grid, and is used to collect the actual value of the output current of the photovoltaic inverter. The controller is electrically connected to the DC bus voltage sampling circuit and the output current sampling circuit, respectively. The controller is configured to: determine the rate of change of the actual DC bus voltage based on the difference between the actual DC bus voltage value collected at the current moment and the actual DC bus voltage value collected at the previous moment, and the time interval between the current moment and the previous moment, when the actual DC bus voltage value is greater than or equal to a first voltage threshold, the actual output current value is greater than or equal to a first current threshold, and the duration reaches a first time duration; determine the power imbalance level of the photovoltaic inverter as a first power imbalance level when the rate of change of the actual DC bus voltage value is less than a first rate of change threshold, and the ratio of the actual output current value to the maximum allowable output current of the photovoltaic inverter is less than a first ratio threshold; and determine the power imbalance level of the photovoltaic inverter as a first power imbalance level when the rate of change of the actual DC bus voltage value is greater than or equal to the first rate of change threshold and less than a second rate of change threshold. If the ratio of the actual output current to the maximum allowable output current of the photovoltaic inverter is greater than or equal to the first ratio threshold and less than the second ratio threshold, the power imbalance level of the photovoltaic inverter is determined to be the second power imbalance level. If the rate of change of the actual DC bus voltage is greater than or equal to the second rate of change threshold and the ratio of the actual output current to the maximum allowable output current of the photovoltaic inverter is greater than or equal to the second ratio threshold, the power imbalance level of the photovoltaic inverter is determined to be the third power imbalance level. Based on the power imbalance level of the photovoltaic inverter, a target control strategy is determined from multiple preset control strategies. The target control strategy includes a first sub-strategy corresponding to the front-end boost circuit and a second sub-strategy corresponding to the rear-end inverter circuit. The first sub-strategy and the second sub-strategy are executed.

7. A control device, characterized in that, include: Memory, processor; The memory stores computer-executed instructions; The processor executes computer execution instructions stored in the memory, causing the processor to perform the power control method for a photovoltaic inverter as described in any one of claims 1-5.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions, which, when executed by a processor, are used to implement the power control method for a photovoltaic inverter as described in any one of claims 1-5.

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