Power control method and system of inverter, inverter and storage medium

Abstract

This application discloses a power control method, system, inverter, and storage medium for an inverter, relating to the field of inverter technology. The method includes: collecting operating condition parameters of the inverter and determining the inverter's power limit value; when the operating condition parameters indicate an abnormal operating condition, adjusting the inverter's power change slope from the normal operating condition slope to a corrected power change slope based on the deviation between the operating condition parameters and the normal operating condition parameter threshold; adjusting the inverter's actual output power towards the power limit value based on the corrected power change slope, and limiting the actual output power based on the power limit value. This application enables the inverter to safely and smoothly enter a power-limited operating state under abnormal operating conditions, achieving the dual effect of maintaining rapid response and output efficiency under normal operating conditions, and smoothly limiting power under abnormal operating conditions to avoid protective shutdown.

Description

Technical Field

[0001] This application relates to the field of inverter technology, and in particular to a power control method, system, inverter, and storage medium for an inverter. Background Technology

[0002] As the core power conversion device in an energy storage system, the inverter's power control strategy directly affects the system's stability and safety. During inverter operation, changes in operating conditions such as grid voltage fluctuations, frequency deviations, and device temperature rise trigger power limiting requirements to prevent equipment overload or overheating. Currently, mainstream inverters generally employ a strategy of preset fixed power limits. Specifically, manufacturers pre-set a fixed power upper limit based on the inverter's rated parameters or specific operating conditions, ensuring that the inverter's output power is limited within this fixed value during operation.

[0003] However, the aforementioned fixed-limit control strategy has significant drawbacks in practical applications. Setting the power limit too high, while ensuring the inverter's output capacity under normal operating conditions, can lead to overcurrent, overtemperature, or overvoltage problems under extreme conditions such as sudden voltage spikes in the grid, abnormal frequency, or increased equipment temperature. This can trigger protection shutdowns, affecting the continuity of power supply to the load and extending the equipment's lifespan. Conversely, setting the power limit too low, while improving safety under extreme conditions, artificially suppresses the inverter's output capacity under normal operating conditions, preventing it from fully utilizing its performance and resulting in resource waste. Summary of the Invention

[0004] The main objective of this application is to provide a power control method, system, inverter, and storage medium for an inverter, aiming to solve the technical problem that current fixed power limits cannot simultaneously ensure output efficiency under normal operating conditions and operational safety under extreme operating conditions.

[0005] To achieve the above objectives, this application proposes a power control method for an inverter, the power control method for the inverter comprising: Collect the operating condition parameters of the inverter and determine the power limit value of the inverter; When the operating condition parameters indicate that the inverter is in an abnormal operating condition, the power change slope of the inverter is adjusted from the normal operating condition slope to a corrected power change slope based on the deviation between the operating condition parameters and the preset normal operating condition parameter threshold, wherein the corrected power change slope is less than the normal operating condition slope. The actual output power of the inverter is adjusted toward the power limit value based on the corrected power change slope, and the actual output power is limited based on the power limit value.

[0006] In one embodiment, the step of determining the power limit value of the inverter includes: The inverter is provided with multiple preset power limit values, including a voltage limit power value, a current limit power value, a frequency limit power value, and a temperature limit power value. The voltage limit power value is the power limit value of the inverter under overvoltage derating conditions. The current limit power value is determined based on the rated output current of the inverter. The frequency limit power value is the power limit value of the inverter under overfrequency derating conditions. The temperature limit power value is the power limit value of the inverter under overtemperature derating conditions. Determine the minimum limiting power value among the voltage limiting power value, the current limiting power value, the frequency limiting power value, and the temperature limiting power value; The minimum power limit value is used as the power limit value.

[0007] In one embodiment, after determining the minimum limiting power value among the voltage limiting power value, the current limiting power value, the frequency limiting power value, and the temperature limiting power value, the method further includes: The minimum power limit value is input to a low-pass filter to obtain the filtered minimum power limit, and the step of using the minimum power limit value as the power limit value is performed based on the filtered minimum power limit.

[0008] In one embodiment, after the step of inputting the minimum power limit value to a low-pass filter to obtain the filtered minimum power limit, the method further includes: Obtain the rated power value of the inverter; Determine the minimum power limit value between the filtered minimum power limit and the rated power value, and update the filtered minimum power limit value according to the minimum power value, so as to perform the step of using the minimum power limit value as the power limit value based on the updated minimum power limit value.

[0009] In one embodiment, after the step of limiting the actual output power based on the power limit value, the method further includes: The actual output power and the power limit value are input to the proportional-integral regulator to obtain the calibration power value; The minimum power limit value is adjusted based on the calibration power value to obtain the adjusted minimum power limit value, and then the step of using the minimum power limit value as the power limit value is returned to be executed based on the adjusted minimum power limit value.

[0010] In one embodiment, after the step of collecting the inverter's operating condition parameters, the method further includes: The operating condition parameters are compared with the normal operating condition parameter thresholds. The operating condition parameters include the grid voltage, grid frequency and device temperature corresponding to the inverter. The normal operating condition parameter thresholds include the overvoltage derating voltage corresponding to the grid voltage, the overfrequency derating frequency corresponding to the grid frequency and the overtemperature derating temperature corresponding to the device temperature. If the grid voltage is greater than the overvoltage derating voltage, and / or the grid frequency is greater than the overfrequency derating frequency, and / or the device temperature is greater than the overtemperature derating temperature, the operating condition parameters are determined to indicate that the inverter is in an abnormal operating condition.

[0011] In one embodiment, the step of adjusting the power change slope of the inverter from the normal operating condition slope to a corrected power change slope based on the deviation between the operating condition parameters and a preset normal operating condition parameter threshold includes: The operating condition parameter that is greater than the corresponding normal operating condition parameter threshold is taken as the target operating condition parameter, and the deviation between the target operating condition parameter and the corresponding normal operating condition parameter threshold is determined. The target operating condition parameter includes at least one of the grid voltage, the grid frequency and the device temperature. The slope of the corrected power change is determined based on the deviation, wherein the deviation is negatively correlated with the slope of the corrected power change. The power change slope is adjusted from the normal operating condition slope to the corrected power change slope.

[0012] In one embodiment, the step of adjusting the actual output power of the inverter to the power limit value based on the corrected power change slope includes: The inverter's drive circuit is driven according to a space vector pulse width modulation strategy, so that the inverter adjusts the actual output power toward the power limit value according to the corrected power change slope.

[0013] Furthermore, to achieve the above objectives, this application also proposes a power control system for an inverter, the system comprising: The parameter acquisition module is used to acquire the operating condition parameters of the inverter and determine the power limit value of the inverter. The slope adjustment module is used to adjust the power change slope of the inverter from the normal operating condition slope to a corrected power change slope based on the deviation between the operating condition parameters and a preset normal operating condition parameter threshold when the inverter is in an abnormal operating condition according to the operating condition parameters. The corrected power change slope is less than the normal operating condition slope. The output control module is used to adjust the actual output power of the inverter toward the power limit value according to the corrected power change slope, and to limit the actual output power based on the power limit value.

[0014] In addition, to achieve the above objectives, this application also proposes an inverter, the device comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, the computer program being configured to implement the steps of the power control method of the inverter as described above.

[0015] In addition, to achieve the above objectives, this application also proposes a storage medium, which is a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, it implements the steps of the power control method for the inverter as described above.

[0016] One or more technical solutions proposed in this application have at least the following technical effects: This application first collects the inverter's operating condition parameters and determines a power limit value, providing a constraint boundary for subsequent power adjustment. Based on this, when the operating condition parameters indicate that the inverter is in an abnormal operating condition, the power change slope of the inverter is adjusted from a normal operating condition slope to a corrected power change slope according to the deviation between the operating condition parameters and the preset normal operating condition parameter threshold. This corrected power change slope is set to be smaller than the normal operating condition slope. Thus, under normal operating conditions, the inverter can use a larger normal operating condition slope to achieve rapid power point tracking and ensure output efficiency. When the operating condition parameters are detected to deviate from the normal threshold and enter an abnormal operating condition, the power change slope automatically switches to a smaller corrected power change slope, allowing the inverter's actual output power to adjust towards the power limit value at a smoother rate. This smooth power change process effectively avoids inrush currents and grid disturbances caused by sudden power command changes, while also providing sufficient response time for the inverter's overcurrent, overtemperature, and overvoltage protection mechanisms, thereby preventing the triggering of sudden protection shutdowns. Ultimately, the actual output power is adjusted towards the power limit value based on the corrected power change slope, and the actual output power is limited based on the power limit value. This allows the inverter to safely and smoothly enter the power-limited operation state under abnormal operating conditions, achieving the dual effect of maintaining fast response and output efficiency under normal operating conditions, and achieving smooth power limiting to avoid protection shutdown under abnormal operating conditions. Attached Figure Description

[0017] 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.

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A flowchart illustrating an embodiment of the power control method for the inverter in this application; Figure 2 A flowchart illustrating Embodiment 2 of the power control method for the inverter in this application; Figure 3 A simplified schematic diagram of the power control method for the inverter provided in Embodiment 2 of this application; Figure 4 A simplified flowchart illustrating the power control method for the inverter provided in Embodiment 2 of this application; Figure 5 This is a schematic diagram of the module structure of the power control system of the inverter in an embodiment of this application; Figure 6 This is a schematic diagram of the hardware operating environment involved in the power control method of the inverter in the embodiments of this application.

[0020] The purpose, features, and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0021] It should be understood that the specific embodiments described herein are merely illustrative of the technical solutions of this application and are not intended to limit this application.

[0022] To better understand the technical solution of this application, a detailed description will be provided below in conjunction with the accompanying drawings and specific implementation methods.

[0023] The main solution of this application embodiment is: to collect the operating condition parameters of the inverter and determine the power limit value of the inverter; when the operating condition parameters indicate that the inverter is in an abnormal operating condition, based on the deviation between the operating condition parameters and a preset normal operating condition parameter threshold, to adjust the power change slope of the inverter from the normal operating condition slope to a corrected power change slope, wherein the corrected power change slope is less than the normal operating condition slope; to adjust the actual output power of the inverter towards the power limit value based on the corrected power change slope, and to limit the actual output power based on the power limit value.

[0024] Fixed-limit control strategies have significant drawbacks in practical applications. Setting the power limit too high, while ensuring the inverter's output capacity under normal operating conditions, can lead to overcurrent, overtemperature, or overvoltage issues under extreme conditions such as sudden voltage spikes, frequency anomalies, or elevated equipment temperatures. This can trigger protection shutdowns, affecting the continuity of power supply to the load and extending equipment lifespan. Conversely, setting the power limit too low, while improving safety under extreme conditions, artificially suppresses the inverter's output capacity under normal operating conditions, preventing it from fully utilizing its performance and resulting in resource waste.

[0025] This application provides a solution that first collects the inverter's operating condition parameters and determines a power limit value, providing a constraint boundary for subsequent power adjustments. Based on this, when the operating condition parameters indicate that the inverter is in an abnormal operating condition, the power change slope of the inverter is adjusted from a normal operating condition slope to a corrected power change slope according to the deviation between the operating condition parameters and a preset normal operating condition threshold. This corrected power change slope is set to be smaller than the normal operating condition slope. Thus, under normal operating conditions, the inverter can use a larger normal operating condition slope to achieve rapid power point tracking and ensure output efficiency. When the operating condition parameters are detected to deviate from the normal threshold and enter an abnormal operating condition, the power change slope automatically switches to a smaller corrected power change slope, allowing the inverter's actual output power to adjust towards the power limit value at a smoother rate. This smooth power change process effectively avoids inrush currents and grid disturbances caused by sudden power command changes, while also providing sufficient response time for the inverter's overcurrent, overtemperature, and overvoltage protection mechanisms, thereby preventing the triggering of sudden protection shutdowns. Ultimately, the actual output power is adjusted towards the power limit value based on the corrected power change slope, and the actual output power is limited based on the power limit value. This allows the inverter to safely and smoothly enter the power-limited operation state under abnormal operating conditions, achieving the dual effect of maintaining fast response and output efficiency under normal operating conditions, and achieving smooth power limiting to avoid protection shutdown under abnormal operating conditions.

[0026] It should be noted that the executing entity in this embodiment can be a computing service device with data processing, network communication, and program execution functions, such as a tablet computer, personal computer, or mobile phone, or an inverter capable of performing the above functions. The following description uses an inverter as an example to illustrate this embodiment and the subsequent embodiments.

[0027] Based on this, embodiments of this application provide a power control method for an inverter, referring to... Figure 1 , Figure 1 This is a flowchart illustrating the first embodiment of the power control method for the inverter in this application.

[0028] In this embodiment, the power control method of the inverter includes steps S10 to S40: Step S10: Collect the operating condition parameters of the inverter and determine the power limit value of the inverter; It should be noted that operating condition parameters refer to a set of physical quantities that reflect the current real-time operating status of the inverter. These parameters are acquired from the inverter's operating environment through a signal acquisition unit, and specifically include, but are not limited to, the grid voltage, grid frequency, inverter output current, real-time active power, temperature of power devices and heat sinks, and inverter protection status signals (such as software signals for overcurrent, overtemperature, and islanding protection). The core function of operating condition parameters is to provide a basis for subsequent power limit value determination and abnormal operating condition identification: on the one hand, the values ​​of grid voltage, current, frequency, and temperature in the operating condition parameters can be directly used in the calculation of power limit values; on the other hand, these parameters need to be compared with preset normal operating condition parameter thresholds to determine whether the inverter is currently in an abnormal operating condition.

[0029] The power limit value is the maximum power that the inverter is allowed to output at the current operating moment. This value is not a fixed rated power, but a target value that is dynamically determined based on real-time collected operating condition parameters. Specifically, the determination of the power limit value comprehensively considers multiple constraints, such as the voltage limit power value obtained based on the grid voltage limit, the current limit power value obtained based on the inverter's rated output current, the frequency limit power value obtained based on the grid frequency limit, and the temperature limit power value obtained based on the temperature limit. The minimum value among these candidate values ​​is selected as the final power limit value. This power limit value is used for two subsequent key control actions: first, under abnormal operating conditions, the actual output power of the inverter will be adjusted towards this power limit value according to the corrected power change slope; second, regardless of the power change slope used, the actual output power will ultimately be limited within this power limit value, thereby preventing the inverter from experiencing overcurrent, overtemperature, or overvoltage faults due to power exceeding the limit.

[0030] Step S20: When the operating condition parameters indicate that the inverter is in an abnormal operating condition, the power change slope of the inverter is adjusted from the normal operating condition slope to a corrected power change slope based on the deviation between the operating condition parameters and the preset normal operating condition parameter threshold, wherein the corrected power change slope is less than the normal operating condition slope. It should be noted that abnormal operating conditions refer to an abnormal operating state in which the inverter's operating parameters deviate from the preset normal operating range, potentially threatening equipment safety or grid stability. The determination of abnormal operating conditions can be based on comparing the collected operating parameters with preset normal operating parameter thresholds. For example, if the grid voltage exceeds the overvoltage derating voltage threshold, the grid frequency exceeds the overfrequency derating frequency threshold, or the device temperature exceeds the overtemperature derating temperature threshold, the inverter is considered to be in an abnormal operating state if one or more of these conditions are met. Under abnormal operating conditions, the inverter can no longer continue to perform rapid power regulation according to the high power change slope under normal operating conditions; otherwise, it is prone to inrush current, increased temperature rise, or triggering protection shutdown. Therefore, after detecting an abnormal operating condition, by actively adjusting the power change slope from the normal operating condition slope to a smaller corrected power change slope, smooth and safe power adjustment can be achieved.

[0031] The normal operating slope refers to the rate at which the inverter adjusts its actual output power towards the power limit when all operating parameters are within the preset normal range (i.e., no abnormal conditions such as overvoltage, overfrequency, or overtemperature are triggered). The normal operating slope is relatively large, for example, it can be set to 5% to 10% of the rated power per millisecond. Its purpose is to ensure that the inverter can quickly track changes in the power reference value under normal grid environment and temperature conditions, thereby maximizing the inverter's output capacity and dynamic response speed. Since there is no imminent risk of overcurrent, overtemperature, or overvoltage under normal operating conditions, using a larger power change slope will not cause safety issues; on the contrary, it helps improve the system's response efficiency to load demands or dispatch commands. Maintaining a larger normal operating slope under normal operating conditions distinguishes it from a scheme that uses a fixed low slope throughout.

[0032] The corrected power change slope refers to a smaller power change rate obtained by adjusting the power change slope from the normal operating slope after determining that the inverter is in an abnormal operating condition, based on the deviation between the operating parameters and the preset normal operating parameter thresholds. The specific value of the corrected power change slope is usually negatively correlated with the deviation; that is, the greater the deviation of the operating parameters from the normal threshold, the smaller the corrected power change slope, resulting in a smoother power adjustment process. For example, when the temperature is too high or the voltage rise is severe, the corrected power change slope can be as low as 1% to 4% of the rated power per millisecond. The purpose of using the corrected power change slope is to force the inverter to slowly and smoothly reduce or adjust the actual output power towards the power limit value under abnormal operating conditions, thereby avoiding inrush currents, grid disturbances, or further aggravation of device temperature rise caused by sudden power command changes, effectively preventing shutdowns caused by triggering overcurrent, overtemperature, or overvoltage protection. Furthermore, since the corrected power change slope is dynamically adjusted based on real-time deviations, it can adapt to abnormal operating conditions of varying severity, achieving adaptive safety control where the larger the deviation, the slower the change.

[0033] Step S30: Adjust the actual output power of the inverter toward the power limit value according to the corrected power change slope, and limit the actual output power based on the power limit value.

[0034] Understandably, existing inverter power control methods employ fixed power limits or fixed power change slopes, which cannot simultaneously balance output efficiency under normal operating conditions and operational safety under extreme conditions. This can easily trigger overcurrent, overtemperature, or overvoltage protection, leading to shutdowns, in situations such as sudden grid voltage spikes, abnormal frequencies, or excessively high temperatures. Alternatively, artificially suppressing the inverter's output capacity under normal operating conditions can result in resource waste. Therefore, this embodiment collects the inverter's operating condition parameters and determines the power limit value. When the operating condition parameters indicate that the inverter is in an abnormal operating condition, the power change slope is adjusted based on the deviation between the operating condition parameters and the preset normal operating condition parameter thresholds. The slope under normal operating conditions is adjusted to a corrected power change slope that is less than the normal operating condition slope. Then, based on this corrected power change slope, the actual output power of the inverter is adjusted towards the power limit value, and the actual output power is limited based on the power limit value. This avoids the problems of inrush current, grid disturbance, and overcurrent, overtemperature, and overvoltage-triggered protection shutdown caused by sudden power command changes. At the same time, it avoids the problem of the inverter's output capacity being artificially suppressed under normal operating conditions due to a fixed low slope or low limit value. Ultimately, it achieves fast response and high-efficiency output under normal operating conditions, and smooth power transition and safe adaptive limiting under abnormal operating conditions, taking into account both system operating efficiency and safety stability.

[0035] For example, the inverter's signal acquisition unit first collects operating condition parameters in real time, such as the temperature of the power devices. Simultaneously, a power limit value is pre-determined based on the inverter's rated parameters; this power limit value is the maximum power the inverter is allowed to output under safe operating conditions. The collected temperature is then compared with a preset normal operating condition parameter threshold (e.g., the upper limit of normal operating temperature). If the current temperature does not exceed this threshold, the inverter is determined to be in normal operating condition, and a relatively large normal operating condition slope (e.g., 8% of rated power per millisecond) is maintained for power adjustment. If the current temperature exceeds this threshold, the inverter is determined to be in abnormal operating condition. The deviation between the temperature and the threshold is calculated (e.g., exceeding 10°C). Based on this deviation, the power change slope is adjusted from the normal operating condition slope to a smaller corrected power change slope, with a larger deviation resulting in a smaller corrected power change slope (e.g., 2% of rated power per millisecond when exceeding 10°C). Finally, based on the corrected power change slope, the inverter reduces the actual output power to the power limit value in a slow and smooth manner, and always keeps the actual output power within the power limit value, thereby avoiding further temperature rise or over-temperature shutdown due to rapid power changes when the temperature is abnormal.

[0036] For example, the inverter first collects the grid voltage in real time as an operating condition parameter through a voltage sampling circuit. Simultaneously, based on the product of the inverter's rated output current and the current grid voltage, combined with the power factor, a power limit value is dynamically calculated. This power limit value represents the maximum safe output power allowed by the inverter under the current grid voltage conditions. Then, the collected grid voltage is compared with a preset normal operating condition parameter threshold (i.e., an overvoltage derating threshold). If the grid voltage is lower than this threshold, the inverter is determined to be in normal operating condition, and the output power is adjusted at a relatively fast rate while maintaining the normal operating condition slope (e.g., 8% of rated power per millisecond). If the grid voltage is higher than this threshold, the inverter is determined to be in abnormal operating condition. In this case, the deviation of the grid voltage from the threshold is calculated (e.g., exceeding the rated voltage by 5%), and the power change slope is adjusted from the normal operating condition slope to a smaller corrected power change slope based on this deviation. The larger the deviation, the smaller the corrected power change slope (e.g., 2% of rated power per millisecond when exceeding 5%, and 1% of rated power per millisecond when exceeding 10%). Finally, based on the corrected power change slope, the inverter gradually reduces the actual output power from the current value to the power limit value in a step-by-step manner, and keeps the actual output power within the power limit value throughout the entire operation. This allows for a smooth reduction in power when the grid voltage rises abnormally, avoiding inrush current or overvoltage protection shutdown caused by power surges.

[0037] This embodiment provides a power control method for an inverter. First, by collecting the inverter's operating condition parameters and determining a power limit value, a constraint boundary is provided for subsequent power adjustments. Based on this, when the operating condition parameters indicate that the inverter is in an abnormal operating condition, the power change slope is adjusted from a normal operating condition slope to a corrected power change slope according to the deviation between the operating condition parameters and a preset normal operating condition threshold. This corrected power change slope is set to be smaller than the normal operating condition slope. Thus, under normal operating conditions, the inverter can use a larger normal operating condition slope to achieve rapid power point tracking, ensuring output efficiency. When the operating condition parameters deviate from the normal threshold and enter an abnormal operating condition, the power change slope automatically switches to a smaller corrected power change slope, allowing the inverter's actual output power to adjust towards the power limit value at a smoother rate. This smooth power change process effectively avoids inrush currents and grid disturbances caused by sudden power command changes, while also providing sufficient response time for the inverter's overcurrent, overtemperature, and overvoltage protection mechanisms, thereby preventing sudden protection shutdowns. Ultimately, the actual output power is adjusted towards the power limit value based on the corrected power change slope, and the actual output power is limited based on the power limit value. This allows the inverter to safely and smoothly enter the power-limited operation state under abnormal operating conditions, achieving the dual effect of maintaining fast response and output efficiency under normal operating conditions, and achieving smooth power limiting to avoid protection shutdown under abnormal operating conditions.

[0038] In one feasible implementation, the step of determining the power limit value of the inverter in step S10 may include steps S11 to S13: Step S11: Obtain multiple preset power limit values ​​for the inverter, wherein the preset power limit values ​​include voltage limit power value, current limit power value, frequency limit power value, and temperature limit power value. The voltage limit power value is the power limit value of the inverter under overvoltage derating conditions. The current limit power value is determined based on the rated output current of the inverter. The frequency limit power value is the power limit value of the inverter under overfrequency derating conditions. The temperature limit power value is the power limit value of the inverter under overtemperature derating conditions. It's important to note that the voltage-limited power value is the maximum power output allowed by the inverter under overvoltage derating conditions. Specifically, when the inverter detects that the grid voltage exceeds a preset overvoltage derating threshold, it activates the overvoltage derating function, reducing the output power proportionally to the degree to which the grid voltage exceeds the threshold. The calculated power limit is the voltage-limited power value. For example, if the grid voltage exceeds the rated voltage by 5%, the inverter drates by 20%, and the voltage-limited power value is equal to 80% of the rated power. This value will continue to decrease as the grid voltage rises further until it returns to the normal range. The purpose of the voltage-limited power value is to prevent the inverter from continuously outputting high power when the grid voltage is too high, which could lead to overvoltage damage to the equipment or adverse effects on the grid.

[0039] Overvoltage derating is an abnormal operating condition where the grid voltage connected to the inverter exceeds the preset upper limit of the normal operating voltage, triggering the inverter to actively reduce its output power. When the AC grid voltage collected by the inverter reaches or exceeds the preset overvoltage derating voltage threshold, for example, when the grid voltage exceeds the rated value by 5%, the inverter determines that it is in overvoltage derating condition and performs corresponding power reduction operations according to the magnitude of the voltage exceedance, such as derating by 20% or 30%, etc. The derating range can be set through the host computer. Overvoltage derating is a specific manifestation of abnormal operating conditions, and its core characteristic is that the grid voltage is too high. If normal power output is continued under these conditions, it may lead to excessive voltage stress inside the inverter or cause an impact on the grid, thus requiring active power limiting.

[0040] The current-limited power value is a power limit determined based on the inverter's rated output current. Specifically, it can be determined by multiplying the inverter's rated output current by the current grid voltage, and then multiplying by the power factor: Current-limited power value = Grid voltage × Rated output current × Power factor. The rated output current is determined by the inverter model; for example, a 7.6kW model has a different rated output current than a 3.6kW model. Alternatively, the current-limited power value can be used directly as the upper limit of the inverter's current loop without converting to power factor. This limit reflects the constraint of the inverter's own hardware capacity on the output power. It is a fixed, basic limit based on the equipment's rated parameters and does not change dynamically with abnormal operating conditions. Its main purpose is to ensure that the inverter's output current does not exceed its design safety threshold.

[0041] The frequency-limited power value is the maximum power output allowed by the inverter under over-frequency derating conditions. When the inverter detects that the grid frequency exceeds the preset over-frequency derating frequency threshold, it activates the over-frequency derating function, reducing the output power proportionally based on the degree to which the grid frequency exceeds the threshold. The calculated power limit value is the frequency-limited power value. For example, when the grid frequency exceeds the rated frequency by 2%, the inverter drates by 10%, and the frequency-limited power value equals 90% of the rated power. If the frequency increases further, the derating percentage increases accordingly. The purpose of this limit is to actively reduce the inverter's output power to suppress further frequency increases when the grid frequency is too high, thereby assisting the grid in restoring frequency stability and preventing the inverter from triggering protection shutdown due to frequency anomalies.

[0042] Over-frequency derating is an abnormal operating condition where the frequency of the grid connected to the inverter exceeds the preset upper limit of the normal operating frequency, triggering the inverter to actively reduce its output power. When the grid frequency collected by the inverter reaches or exceeds the preset over-frequency derating frequency threshold, for example, when the grid frequency exceeds the rated frequency of 50Hz by 2% (i.e., 51Hz), the inverter determines that it is in over-frequency derating condition and performs corresponding power reduction operations according to the magnitude of the frequency exceedance, such as derating by 10% or 20%. The derating range can also be set through the host computer. Over-frequency derating is another specific manifestation of abnormal operating conditions. Its purpose is to suppress further frequency increases by reducing the power injected by the inverter into the grid, participate in grid frequency regulation, and prevent the inverter from triggering islanding protection or over-frequency shutdown due to excessive frequency.

[0043] The temperature-limited power rating is the maximum power output allowed by the inverter under over-temperature derating conditions. When the temperature of critical components (such as power switches) or heat sinks inside the inverter reaches a preset over-temperature derating threshold, the inverter will activate the over-temperature derating function, reducing the output power proportionally based on the degree to which the current temperature exceeds the threshold. The power limit calculated in this way is the temperature-limited power rating. For example, when the ambient temperature or component temperature reaches 65°C, derating begins at 20%, and thereafter increases by 20% for every 10°C increase. The purpose of the temperature-limited power rating is to prevent the inverter from operating at high power for extended periods, causing the component temperature to rise continuously and ultimately triggering over-temperature protection shutdown or shortening the equipment's lifespan. By dynamically reducing power, the temperature is maintained within a safe range.

[0044] Over-temperature derating refers to an abnormal operating state in which the temperature of internal components of the inverter (such as power switches, heat sinks, or ambient temperature) exceeds the preset safe operating temperature limit, triggering the inverter to actively reduce its output power. When the temperature collected by the inverter reaches or exceeds the preset over-temperature derating temperature threshold (e.g., ambient temperature reaches 65°C), the inverter determines that it is in over-temperature derating condition and performs corresponding power reduction operations according to the degree to which the temperature exceeds the threshold, such as derating by 20%, and the derating value increases by another 20% for every 10°C increase in temperature. Over-temperature derating is another specific manifestation of abnormal operating conditions. Its core purpose is to reduce heat generation by actively reducing output power, allowing the component temperature to fall back to a safe range, thereby avoiding triggering over-temperature protection and causing the inverter to suddenly shut down, ensuring the long-term reliability and lifespan of the equipment.

[0045] Step S12: Determine the minimum limiting power value among the voltage limiting power value, the current limiting power value, the frequency limiting power value, and the temperature limiting power value; It should be noted that the minimum power limit value refers to the power value obtained by taking the minimum value among multiple preset power limit values ​​(i.e., voltage limit power value, current limit power value, frequency limit power value, and temperature limit power value). Specifically, the inverter can calculate the above four power limit values ​​in each control cycle, and then select the smallest value through a comparison module. This minimum value is the minimum power limit value and is directly used as the power limit value. The purpose of using the minimum power limit value is to ensure that the inverter's output power simultaneously meets the safety constraints of four dimensions: voltage, current, frequency, and temperature. The most stringent constraint (i.e., the smallest power limit value) determines the maximum power that the inverter is actually allowed to output at the current moment, thereby ensuring that the inverter will not exceed any of the safety limits under any operating conditions.

[0046] Step S13: Use the minimum power limit value as the power limit value.

[0047] It is understandable that if the power limit value is determined based on only a single constraint (such as only voltage or only temperature), the inverter may still exceed the limit under other unconsidered constraints (such as excessive current or abnormal frequency), leading to overcurrent, overfrequency, or overtemperature protection shutdown. Therefore, this embodiment further obtains four preset power limit values: voltage limit power value, current limit power value, frequency limit power value, and temperature limit power value, and determines the minimum limit power value among them as the power limit value. This avoids the defect that other safety constraints are broken due to only considering a single constraint. It realizes the comprehensive selection of the most stringent constraints from the four dimensions of voltage, current, frequency, and temperature to limit the inverter output power, ensuring that the power limit value meets all safety boundaries at the same time, and significantly improving the inverter's comprehensive safety protection capability under multiple operating conditions.

[0048] For example, the inverter first calculates four preset power limit values ​​based on the currently collected operating condition parameters. For the voltage limit power value, when the grid voltage exceeds the overvoltage derating threshold (e.g., 105% of the rated voltage), a power limit is calculated according to a preset derating curve (e.g., derating by 5% for every 1% increase in voltage). For the current limit power value, the current limit power value is calculated as 220V × 32A × 0.9 = 6336W, calculated by multiplying the inverter's rated output current (e.g., 32A for a 7.6kW model) by the current grid voltage (e.g., 220V) and power factor (e.g., 0.9). For the frequency limit power value, when the grid frequency exceeds the overfrequency derating threshold (e.g., 51Hz), the frequency limit power value is calculated according to a 2% derating rule for every 0.1Hz increase. For the temperature limit power value, when the power device temperature exceeds the overtemperature derating threshold (e.g., 65℃), the temperature limit power value is calculated according to a 5% derating rule for every 1℃ increase. The inverter then compares these four calculated power limit values: for example, a voltage power limit of 5000W, a current power limit of 6336W, a frequency power limit of 5500W, and a temperature power limit of 4800W. The minimum value of 4800W is then taken as the minimum power limit. Finally, this minimum power limit is directly used as the power limit for subsequent power adjustment and limiting control, ensuring that the inverter's output power at the current moment simultaneously meets the most stringent safety constraints across the four dimensions of voltage, current, frequency, and temperature.

[0049] In the specific implementation process, step A121 may also be included after step S12: Step A121: Input the minimum power limit value into a low-pass filter to obtain the filtered minimum power limit, and then perform the step of using the minimum power limit value as the power limit value based on the filtered minimum power limit.

[0050] Understandably, when there is instantaneous sampling noise or high-frequency fluctuations in operating parameters such as grid voltage, frequency, or temperature, the minimum power limit value may change rapidly, causing frequent fluctuations in the power limit value. This leads to oscillations in the actual output power of the inverter and inrush current. Therefore, by further inputting the minimum power limit value into a low-pass filter to obtain the filtered minimum power limit value, and then executing the step as the power limit value based on the filtered minimum power limit value, the power command jitter, output oscillation, and disturbance impact on the grid caused by sudden changes in the power limit value are avoided. This achieves a smooth transition of the power limit value, enabling the inverter to output a stable, oscillating power command even when there is noise or slight fluctuations in operating parameters, thus improving the system's anti-interference capability and operational stability.

[0051] For example, the minimum value among the voltage-limited power value, current-limited power value, frequency-limited power value, and temperature-limited power value is selected to obtain the minimum power limit value, for example, 4800W. This 4800W value is then input into a first-order low-pass filter with a preset cutoff frequency (e.g., 10Hz) to filter out high-frequency components caused by sampling noise or minor grid fluctuations. When the minimum power limit value jumps from 4800W to 4900W and then back to 4800W due to transient interference, the low-pass filter does not immediately follow the jump. Instead, it outputs a smoothly transitioned, filtered minimum power limit value, for example, slowly rising from 4800W to 4810W and then slowly decreasing back to 4800W. The inverter uses this filtered minimum power limit value as the final power limit value for subsequent power adjustment and limiting control, thereby ensuring that the power limit value does not change abruptly due to transient noise and achieving a smooth output of the power limit value.

[0052] In the specific implementation process, after step A121, steps A122 to A123 may also be included: Step A122: Obtain the rated power value of the inverter; It should be noted that the rated power value refers to the maximum active power that the inverter is designed to continuously output under rated operating conditions (i.e., rated grid voltage, rated grid frequency, rated ambient temperature, and rated power factor). It is a fixed factory parameter of the inverter. For example, a 7.6kW inverter has a rated power value of 7600W, while a 3.6kW inverter has a rated power value of 3600W. The rated power value represents the maximum power capability that the inverter's main circuit (including power switches, transformers, inductors, etc.) can continuously and safely operate without triggering overcurrent or overtemperature protection. This rated power value is used as an absolute upper limit constraint. Even if the minimum power limit calculated after filtering is greater than the rated power value, the actual allowable output power of the inverter should not exceed the rated power value, because operating beyond the rated power value may exceed the safety design margin of the equipment, leading to a decrease in long-term reliability or triggering overcurrent protection.

[0053] Step A123: Determine the minimum power limit after filtering and the minimum power value among the rated power values, and update the minimum power limit after filtering according to the minimum power value, so as to perform the step of using the minimum power limit value as the power limit value based on the updated minimum power limit value.

[0054] It's important to note that the minimum power value refers to the smaller of the filtered minimum power limit and the rated power value. Specifically, after obtaining the filtered minimum power limit (e.g., the power limit value smoothed by a low-pass filter), the inverter obtains its inherent rated power value and then determines the minimum of the two through comparison. This minimum value is the minimum power value. For example, if the filtered minimum power limit is 5000W and the rated power is 7600W, then the minimum power value is 5000W; conversely, if the filtered minimum power limit is 8000W and the rated power is 7600W, then the minimum power value is 7600W. This minimum power value is then used to update the filtered minimum power limit, replacing the original filtered minimum power limit. This ensures that the final power limit value will not exceed the inverter's rated power, achieving a dual limiting effect between the absolute safety boundary of the rated power and the dynamically calculated value based on multiple constraints.

[0055] Understandably, since the minimum power limit after filtering may still exceed the inverter's rated power due to an abnormally high calculated value of one of the voltage, frequency, or temperature power limits, directly using this minimum power limit after filtering as the power limit would instruct the inverter to output power exceeding its hardware design capacity, causing overcurrent, overtemperature, or even equipment damage. Therefore, by further obtaining the inverter's rated power, determining the minimum power limit after filtering and the minimum power value among the rated power, and updating the minimum power limit after filtering based on this minimum power value, the power limit is used as the updated minimum power limit. This avoids the risk of overload operation caused by the power limit exceeding the inverter's rated power, and achieves secondary limiting by introducing the rated power as an absolute safety upper limit on the basis of filtering smoothing. This ensures that the final power limit meets the requirements of multi-constraint dynamic adjustment without exceeding the inverter's own hardware safety limits.

[0056] For example, the inverter first inputs the minimum power limit value to a first-order low-pass filter to obtain the filtered minimum power limit, assuming it is 4780W. Then, the inverter obtains its stored rated power value; for example, for a 7.6kW model, the rated power value is 7600W. Next, the inverter compares the filtered minimum power limit of 4780W with the rated power value of 7600W, determining that the minimum power is 4780W. Then, the inverter updates the filtered minimum power limit based on this 4780W value, replacing the original filtered minimum power limit with 4780W, resulting in an updated minimum power limit of 4780W. Finally, the inverter uses this updated minimum power limit as the power limit value for subsequent power adjustment and limiting control. In another scenario, if the minimum power limit after filtering is 8000W and the rated power is 7600W, then the minimum power value is 7600W. In this case, the inverter will update the minimum power limit after filtering from 8000W to 7600W, thereby ensuring that the value of the power limit will not exceed the inverter's inherent rated power value and preventing the command output from exceeding the hardware safety capacity.

[0057] In one feasible implementation, steps S40 to S50 may be included after step S30: Step S40: Input the actual output power and the power limit value into the proportional-integral regulator to obtain the calibration power value; It's important to note that the calibration power value refers to the power correction output by the proportional-integral (PI) regulator, which calculates the difference between the actual output power and the power limit by performing proportional and integral operations. Specifically, the PPI regulator compares the actual output power with the power limit in real time, calculates the difference, and then applies proportional and integral coefficients to this difference to obtain the calibration power value. This calibration power value quantifies the degree of deviation of the current actual output power from the target power limit and the accumulated error, allowing for subsequent feedback adjustments to the minimum power limit. For example, when the actual output power is lower than the power limit, the calibration power value is positive, used to adjust the minimum power limit upwards; when the actual output power is higher than the power limit, the calibration power value is negative, used to adjust the minimum power limit downwards; and when the actual output power equals the power limit, the calibration power value is zero, requiring no adjustment. In this way, the calibration power value achieves closed-loop dynamic optimization of power control accuracy.

[0058] Step S50: Adjust the minimum power limit value based on the calibration power value to obtain the adjusted minimum power limit value, and then return to the step of using the minimum power limit value as the power limit value based on the adjusted minimum power limit value.

[0059] Understandably, steady-state deviations may exist between the actual output power and the power limit value. These deviations can be caused by factors such as sampling errors, nonlinearity of the actuator, or inaccurate power tracking due to load disturbances. Over time, these accumulated deviations can prevent the inverter's actual output power from accurately reaching the power limit value, affecting the accuracy and safety of control. Therefore, by further inputting the actual output power and the power limit value into the proportional-integral regulator to obtain a calibration power value, and then adjusting the minimum power limit value based on the calibration power value, the process returns to the step of using the adjusted minimum power limit value as the power limit value. This avoids the steady-state tracking error problem that exists under open-loop control and achieves dynamic calibration of the power limit value through closed-loop feedback. This allows the actual output power to accurately converge to the power limit value, significantly improving the steady-state accuracy and dynamic adaptive capability of the inverter's power control.

[0060] For example, the inverter first determines a minimum power limit value (e.g., 4800W) and uses it as the power limit value, then performs limiting control on the actual output power based on this power limit value. After the limiting control is executed, the inverter simultaneously inputs the actual output power (e.g., the current actual output is 4750W) and the power limit value (e.g., 4800W) into a proportional-integral (PI) regulator. This PPI regulator first calculates the deviation between the actual output power and the power limit value, i.e., 4800W minus 4750W equals 50W, then performs proportional calculations (e.g., multiplying by a proportional coefficient of 0.1 to obtain 5W) and integral calculations (e.g., multiplying the accumulated deviation by an integral coefficient of 0.05 to obtain 2W) on this deviation, and adds the proportional output and integral output to obtain a calibrated power value of 7W. Next, the inverter performs feedback adjustments on the original minimum power limit value of 4800W based on this calibrated power value, for example, using an additive adjustment: 4800W plus 7W equals 4807W, which is used as the adjusted minimum power limit value. Finally, the inverter returns to the step of using the adjusted minimum power limit value of 4807W as the new power limit value, thereby gradually bringing the actual output power closer to and stabilizing near the power limit value through closed-loop feedback, eliminating steady-state tracking error. If the actual output power is higher than the power limit value, the calibration power value is negative, and the minimum power limit value is adjusted downward accordingly, achieving bidirectional accurate calibration.

[0061] In one feasible implementation, the step of adjusting the actual output power of the inverter to the power limit value according to the corrected power change slope in step S30 may include step S31: Step S31: Drive the inverter's drive circuit according to the space vector pulse width modulation strategy, so that the inverter adjusts the actual output power to the power limit value according to the corrected power change slope.

[0062] It should be noted that space vector pulse width modulation (SVM) is a modulation technique used to control the output voltage and current of an inverter. Its basic principle is to map the eight switching states of the inverter onto a complex plane, forming six effective voltage space vectors and two zero vectors. By precisely calculating and allocating the duration of adjacent effective and zero vectors within a switching cycle, the synthesized output voltage vector can approximate any desired voltage amplitude and phase, thereby achieving pulse width modulation control of the inverter's output AC voltage. Compared to traditional sinusoidal pulse width modulation, this modulation strategy offers higher DC bus voltage utilization and lower output harmonic content.

[0063] The drive circuit receives the space vector pulse width modulation signal generated by the control unit, and after electrical isolation, level conversion and power amplification, it is directly connected to the gate or base of the power switching devices (such as IGBTs or MOSFETs) in the main circuit of the inverter. It is used to control the switching devices to turn on and off according to the modulation signal timing. Its core function is to convert the low-voltage control signal into a gate drive voltage and current sufficient to drive the high-voltage and high-current power switches. At the same time, it provides auxiliary functions such as overcurrent protection and fault feedback to ensure that the main circuit of the inverter can accurately execute the power adjustment command.

[0064] It is understandable that using conventional modulation strategies (such as sinusoidal pulse width modulation) may result in high harmonic content in the inverter's output voltage and current or low DC bus voltage utilization, leading to poor tracking accuracy, waveform distortion, or inrush current during power adjustment. Therefore, this embodiment drives the inverter's drive circuit based on a space vector pulse width modulation strategy, enabling the inverter to adjust the actual output power toward the power limit value according to the corrected power change slope. This avoids low power adjustment accuracy, high output harmonics, and poor dynamic response caused by improper modulation methods. Under the constraint of the corrected power change slope, the high DC bus voltage utilization and low harmonic characteristics of the space vector pulse width modulation strategy enable the inverter to execute power adjustment commands accurately, smoothly, and efficiently, ensuring that the actual output power strictly follows the corrected power change slope to transition toward the power limit value.

[0065] For example, the inverter adjusts the power change slope from the normal operating slope to a corrected power change slope (e.g., from 8% per millisecond of rated power to 2% per millisecond) based on the deviation between the operating condition parameters and the preset normal operating condition parameter thresholds, and determines a power limit value (e.g., 4800W). Subsequently, when performing the step of "adjusting the actual output power to the power limit value according to the corrected power change slope," the control unit inside the inverter generates a voltage command signal corresponding to the corrected power change slope. This signal is processed using a space vector pulse width modulation strategy. Specifically, the control unit can synthesize a reference voltage vector on the complex plane based on the current DC bus voltage, the desired output AC voltage amplitude and frequency, and calculate the duration of the two adjacent effective voltage vectors and the zero vector in the sector where the vector is located, generating a corresponding pulse width modulation waveform. This modulated waveform is output to the inverter's drive circuit, which isolates and amplifies it before directly controlling the six power switches (e.g., IGBTs) in the inverter's main circuit to alternately turn on and off according to the modulation sequence, thereby converting DC power into AC power output. Because the space vector pulse width modulation strategy has the characteristics of high DC bus voltage utilization, low output harmonics and fast dynamic response, the inverter can accurately and smoothly reduce the actual output power from the current value (e.g., 5000W) to the power limit value (4800W) according to the corrected power change slope (2%Pn / ms). Moreover, the output voltage and current waveform distortion is small and there is no inrush current during the entire adjustment process, realizing accurate tracking and smooth transition of power command.

[0066] Based on the first embodiment of this application, in the second embodiment of this application, the content that is the same as or similar to that in Embodiment 1 above can be referred to the above description, and will not be repeated hereafter. Based on this, please refer to... Figure 2 After step S10, which involves collecting the inverter's operating parameters, the system may further include steps S01-S02: Step S01: Compare the operating condition parameters with the normal operating condition parameter thresholds. The operating condition parameters include the grid voltage, grid frequency and device temperature corresponding to the inverter. The normal operating condition parameter thresholds include the overvoltage derating voltage corresponding to the grid voltage, the overfrequency derating frequency corresponding to the grid frequency, and the overtemperature derating temperature corresponding to the device temperature. It should be noted that grid voltage refers to the instantaneous or effective value of the voltage of the public or local power grid connected to the AC side of the inverter, which can be measured in volts, but is not limited to that measured in volts. The inverter acquires the voltage waveform between the live and neutral wires on the AC side in real time through a voltage sampling circuit (such as a resistive voltage divider network or voltage transformer), and obtains the grid voltage value used for control after analog-to-digital conversion and software filtering. Grid voltage is one of the core parameters for determining whether the inverter is in an overvoltage abnormal operating condition. When the grid voltage rises due to load changes, grid faults, or other reasons and exceeds the overvoltage derating voltage, the inverter will determine that it is in an abnormal operating condition and initiate corresponding power limiting control.

[0067] The grid frequency refers to the periodic frequency of the AC voltage waveform of the public or local power grid to which the inverter's AC side is connected, changing over time. Standard values ​​can be, but are not limited to, 50Hz or 60Hz, measured in Hertz. The inverter obtains the grid frequency value in real time by detecting the zero-crossing moment of the grid voltage or by using phase-locked loop (PLL) technology. The grid frequency is one of the core parameters for determining whether the inverter is in an abnormal over-frequency operating condition. When the grid frequency rises due to factors such as power generation and consumption imbalance and exceeds the over-frequency derating frequency, the inverter will determine that it is in an abnormal operating condition and initiate corresponding power limiting control to suppress further frequency increases.

[0068] Device temperature refers to the measured temperature value of key power devices (such as insulated-gate bipolar transistors and metal-oxide-semiconductor field-effect transistors) or heat sinks (such as aluminum heat sinks) inside the inverter, which can be, but is not limited to, measured in degrees Celsius. The inverter collects this temperature data in real time using temperature sensors such as negative temperature coefficient thermistors or thermocouples mounted on the surface of the power devices or heat sinks, and obtains the device temperature value after analog-to-digital conversion. Device temperature is one of the core parameters for determining whether the inverter is in an abnormal over-temperature operating condition. When the device temperature rises due to prolonged high power output or excessively high ambient temperature and exceeds the over-temperature derating temperature, the inverter will determine that it is in an abnormal operating condition and initiate corresponding power limiting control to reduce heat generation and protect the devices from overheating damage.

[0069] Overvoltage derating voltage refers to a preset grid voltage threshold for the inverter, used to determine whether to activate the overvoltage derating function. It can be expressed as a percentage of the rated voltage (e.g., 105% of the rated voltage) or a specific voltage value (e.g., 253V corresponds to 115% of the 220V rated voltage). When the collected grid voltage exceeds this overvoltage derating voltage, the inverter determines it is in an abnormal overvoltage state and begins to reduce its output power according to the magnitude of the voltage exceedance. The overvoltage derating voltage is one of the normal operating condition parameter thresholds, and its value can be set or adjusted via a host computer to adapt to different grid standards and grid connection requirements.

[0070] Over-frequency derating frequency refers to a preset grid frequency threshold for the inverter, used to determine whether to activate the over-frequency derating function. It can be, but is not limited to, expressed as the rated frequency (e.g., 50Hz) plus an offset (e.g., 51Hz, exceeding the rated frequency by 2%). When the collected grid frequency exceeds this over-frequency derating frequency, the inverter determines it is in an abnormal over-frequency state and begins to reduce its output power according to the magnitude of the exceedance. The over-frequency derating frequency is one of the normal operating condition parameter thresholds, and its value can be set via a host computer to support grid frequency regulation.

[0071] Over-temperature derating temperature refers to a preset device temperature threshold for the inverter, used to determine whether to activate the over-temperature derating function. It can be expressed as a specific temperature value (e.g., 65°C). When the collected device temperature exceeds this over-temperature derating temperature, the inverter determines it is in an abnormal over-temperature state and begins to reduce output power according to the magnitude of the temperature increase. The over-temperature derating temperature is one of the normal operating condition parameter thresholds. Its value can be preset according to the inverter's heat dissipation design, power device specifications, and environmental adaptability requirements, or adjusted via a host computer. Its purpose is to proactively reduce power before the temperature reaches a level that could damage devices or trigger hard protection.

[0072] Step S02: If the grid voltage is greater than the overvoltage derating voltage, and / or the grid frequency is greater than the overfrequency derating frequency, and / or the device temperature is greater than the overtemperature derating temperature, the operating condition parameters are determined to indicate that the inverter is in an abnormal operating condition.

[0073] Understandably, in practical applications, ambiguity in the judgment criteria may lead to the misjudgment of minor normal fluctuations in grid voltage, frequency, or temperature as abnormal operating conditions, resulting in unnecessary switching to a smaller corrected power change slope and excessive suppression of output efficiency. Alternatively, it may result in untimely or missed responses to genuine overvoltage, overfrequency, or overtemperature anomalies, leading to protection lag. Therefore, this embodiment further compares the grid voltage, grid frequency, and device temperature in the operating condition parameters with the overvoltage derating voltage, overfrequency derating frequency, and overtemperature derating temperature, respectively. When the grid voltage is greater than the overvoltage derating voltage, and / or the grid frequency is greater than the overfrequency derating frequency, and / or the device temperature is greater than the overtemperature derating temperature, the inverter is determined to be in an abnormal operating condition. This avoids the misjudgment and missed judgment problems caused by ambiguity in the judgment criteria, and achieves clear, rapid, and comprehensive identification of the three typical abnormal operating conditions of overvoltage, overfrequency, and overtemperature. This ensures that the inverter only switches to the corrected power change slope when safety constraints are truly required, without sacrificing output efficiency under normal operating conditions or omitting any single-dimensional abnormal protection needs.

[0074] For example, after the inverter completes the step of collecting operating condition parameters, it first compares the collected grid voltage value with the preset overvoltage derating voltage. For example, the overvoltage derating voltage is set to 253V (corresponding to 115% of the 220V rated voltage). If the current grid voltage is 258V, then the condition of being greater than is met. At the same time, it compares the collected grid frequency with the preset overfrequency derating frequency. For example, the overfrequency derating frequency is set to 51Hz (corresponding to 102% of the 50Hz rated frequency). If the current grid frequency is 50.2Hz, then the condition of being greater than is not met. Then, it compares the collected power device temperature with the preset overtemperature derating temperature. For example, the overtemperature derating temperature is set to 65℃. If the current device temperature is 68℃, then the condition of being greater than is met. Since both the grid voltage (258V > 253V) and the device temperature (68℃ > 65℃) are greater than their respective thresholds, satisfying at least one condition in the "AND / OR" logic, the inverter determines that the current operating parameters indicate an abnormal operating condition, thus triggering the subsequent power change slope adjustment step. Conversely, if the grid voltage, grid frequency, and device temperature are all less than or equal to their respective thresholds, the inverter is determined to be in a normal operating condition, maintaining the normal operating slope unchanged.

[0075] In this embodiment, the grid voltage, grid frequency, and device temperature in the operating condition parameters are compared with preset overvoltage derating voltage, overfrequency derating frequency, and overtemperature derating temperature, respectively. When the grid voltage is greater than the overvoltage derating voltage, and / or the grid frequency is greater than the overfrequency derating frequency, and / or the device temperature is greater than the overtemperature derating temperature, the inverter is determined to be in an abnormal operating condition. This avoids misjudgment (i.e., normal fluctuations are judged as abnormal) or missed judgment (i.e., failure to identify the real overvoltage, overfrequency, and overtemperature in time). It achieves clear, quantitative, and rapid identification of the three typical abnormal operating conditions of overvoltage, overfrequency, and overtemperature, ensuring that the inverter only triggers subsequent slope adjustment and power limiting control when it is truly facing a safety risk. This improves the reliability of abnormal judgment and avoids unnecessary performance suppression under normal operating conditions.

[0076] In one feasible implementation, step S20 may include steps S21 to S23: Step S21: Take the operating condition parameter that is greater than the corresponding normal operating condition parameter threshold as the target operating condition parameter, and determine the deviation between the target operating condition parameter and the corresponding normal operating condition parameter threshold, wherein the target operating condition parameter includes at least one of the grid voltage, the grid frequency and the device temperature. It should be noted that target operating condition parameters refer to those parameters selected from the collected operating condition parameters (including grid voltage, grid frequency, and device temperature) whose values ​​exceed the corresponding normal operating condition parameter thresholds. Specifically, when the grid voltage exceeds the overvoltage derating voltage, the grid voltage is identified as a target operating condition parameter; when the grid frequency exceeds the overfrequency derating frequency, the grid frequency is identified as a target operating condition parameter; and when the device temperature exceeds the overtemperature derating temperature, the device temperature is identified as a target operating condition parameter. Target operating condition parameters can be any one, two, or all three of the above three parameters, depending on whether the actual collected values ​​exceed the thresholds. The core function of target operating condition parameters is that they serve as the basis for subsequent deviation calculations. Only parameters exceeding the normal range are included in determining the corrected power change slope, while parameters within the normal range are not considered target operating condition parameters. This ensures that the power slope adjustment only targets the actual abnormal dimensions that exceed limits.

[0077] Deviation refers to the absolute value or relative magnitude of the difference between the target operating condition parameter and its corresponding normal operating condition threshold, used to quantify the severity of abnormal operating conditions. For example, for the target operating condition parameter of grid voltage, if the overvoltage derating voltage is 253V and the actual collected grid voltage is 258V, the deviation can be an absolute difference of 5V or a relative difference (e.g., 5V / 253V≈1.98%). For device temperature, if the overtemperature derating temperature is 65℃ and the actual temperature is 72℃, the deviation is 7℃. For grid frequency, if the overfrequency derating frequency is 51Hz and the actual frequency is 52Hz, the deviation is 1Hz. This deviation is negatively correlated with the slope of the corrected power change; that is, the larger the deviation, the smaller the slope of the corrected power change, meaning that the more severe the anomaly, the smoother the power change. The smaller the deviation, the closer the slope of the corrected power change is to the slope of the normal operating condition, thus achieving adaptive adjustment.

[0078] Step S22: Determine the slope of the corrected power change based on the deviation, wherein the deviation is negatively correlated with the slope of the corrected power change; Step S23: Adjust the power change slope from the normal operating condition slope to the corrected power change slope.

[0079] It is understandable that if a uniform correction power change slope is used, using an excessively small slope in the case of minor anomalies (such as the grid voltage only slightly exceeding the overvoltage derating voltage) will cause unnecessary power response delay and efficiency loss. On the other hand, using an insufficiently small slope in the case of severe anomalies (such as voltage exceeding the limit significantly) may lead to over-adjustment of power, inrush current, or protection shutdown. Therefore, this implementation further uses the operating condition parameter that is greater than the corresponding normal operating condition parameter threshold as the target operating condition parameter, determines the deviation between the target operating condition parameter and the corresponding threshold, and determines the correction power change slope based on the deviation. The deviation and the correction power change slope are negatively correlated, thereby avoiding the inability of a fixed correction slope to adapt to different anomaly severity. Thus, the smoothness of power change can be adaptively adjusted according to the magnitude of the deviation. When the deviation is small, the correction power change slope is close to the normal operating condition slope to take into account the response speed. When the deviation is large, the correction power change slope is further reduced to ensure the stability and safety of power adjustment.

[0080] For example, the inverter first determines abnormal operating conditions. Assume the current measured grid voltage is 258V, while the overvoltage derating voltage is 253V, therefore the grid voltage exceeds the threshold. Simultaneously, the measured grid frequency is 50.1Hz (overfrequency derating frequency is 51Hz, not exceeded), and the device temperature is 60℃ (overtemperature derating temperature is 65℃, not exceeded). Therefore, only the grid voltage, the operating condition parameter, exceeds the corresponding normal operating condition parameter threshold. The inverter uses the grid voltage as the target operating condition parameter and calculates the deviation: Deviation = Grid Voltage - Overvoltage Derating Voltage = 258V - 253V = 5V. Subsequently, based on this deviation, a corrected power change slope is determined, and the deviation and the corrected power change slope are negatively correlated. For example, the preset rule is: for every 1V increase in deviation, the corrected power change slope decreases by 0.5% per millisecond from the normal operating slope (set as 8% of rated power per millisecond). Therefore, the corrected power change slope corresponding to a 5V deviation is 8% - 5 × 0.5% = 5.5% per millisecond. Ultimately, the inverter adjusts the power change slope from the normal operating slope to this corrected power change slope of 5.5% per millisecond for subsequent power adjustments.

[0081] For example, assume the inverter collects a grid voltage of 260V (exceeding the overvoltage derating voltage of 253V), a grid frequency of 52Hz (exceeding the overfrequency derating frequency of 51Hz), and a device temperature of 72℃ (exceeding the overtemperature derating temperature of 65℃). All three operating parameters exceed their respective normal operating condition thresholds. The inverter uses the grid voltage, grid frequency, and device temperature as target operating parameters and calculates their respective deviations: voltage deviation = 260V - 253V = 7V; frequency deviation = 52Hz - 51Hz = 1Hz; temperature deviation = 72℃ - 65℃ = 7℃. Due to these three deviations, the inverter needs to comprehensively determine a corrected power change slope based on these deviations. One feasible approach is to take the maximum value (or the maximum relative percentage value) of the three deviations as the dominant deviation, or to calculate the corresponding candidate slope value for each deviation and then take the minimum value. For example, the preset mapping relationship is as follows: for every 1V voltage deviation, the slope decreases by 0.6% per millisecond; for every 0.2Hz frequency deviation, the slope decreases by 0.5% per millisecond; and for every 1℃ temperature deviation, the slope decreases by 0.4% per millisecond. Furthermore, the deviation and the corrected power change slope are negatively correlated. Calculations are performed separately: a 7V voltage deviation corresponds to a 4.2% slope decrease per millisecond; a 1Hz frequency deviation corresponds to a 2.5% slope decrease per millisecond; and a 7℃ temperature deviation corresponds to a 2.8% slope decrease per millisecond. The largest decrease (4.2% per millisecond) is taken as the corrected power change slope. If the normal operating slope is 8% per millisecond, then the corrected power change slope is 8% - 4.2% = 3.8% per millisecond. The inverter adjusts the power change slope from the normal operating slope to 3.8% per millisecond, thus achieving the smoothest safe power adjustment under the most severe abnormality.

[0082] For example, to help understand the implementation flow of the inverter power control method obtained in this embodiment combined with the above embodiment one, please refer to... Figure 3 , Figure 3 A simplified framework diagram of a power control method for an inverter is provided, specifically: First, the signal acquisition unit acquires real-time operating parameters such as grid voltage, grid frequency, device temperature, inverter output current, and inverter protection status signals. Then, the multi-constraint limit calculation unit retrieves multiple preset power limit values ​​pre-generated or stored by the inverter, including voltage limit power values, current limit power values, frequency limit power values, and temperature limit power values. These preset limit values ​​are pre-generated by the inverter based on its rated parameters and derating strategy. The multi-constraint limit calculation unit compares these preset power limit values ​​and selects the minimum value as the power limit value. The maximum output power generation unit receives this power limit value and dynamically updates it in conjunction with the calibration value provided by the subsequent closed-loop feedback correction unit. Next, the variable slope smoothing filter unit detects abnormal operating conditions (such as grid voltage exceeding the overvoltage derating voltage, grid frequency exceeding the overfrequency derating frequency, or device...). When the temperature exceeds the over-temperature derating temperature, the power change slope is adjusted from the normal operating slope to a smaller corrected power change slope based on the deviation between the operating parameters and the normal operating parameter thresholds. At the same time, the power command is low-pass filtered to achieve a smooth transition. The power limiting output unit further compares the filtered power command with the inverter's rated power value and takes the minimum of the two as the final upper limit of the output power. The execution unit drives the inverter main circuit according to the space vector pulse width modulation strategy, so that the actual output power is adjusted towards the power limit value according to the corrected power change slope and is always limited within the power limit value. The closed-loop feedback correction unit inputs the actual output power and the power limit value into the proportional-integral regulator to obtain the calibrated power value and sends it back to the maximum output power generation unit to form a closed-loop dynamic optimization, thereby ensuring the accuracy and stability of power control.

[0083] Further, please refer to Figure 4First, operating parameters, including grid voltage, grid frequency, and device temperature, are collected in real time. Simultaneously, a minimum power limit is determined from multiple preset power limits of the inverter (such as voltage limit, current limit, frequency limit, and temperature limit). This minimum power limit is then combined with a calibration power value generated by subsequent closed-loop feedback to determine the final power limit. In the abnormal operating condition determination phase, the collected operating parameters are compared with normal operating condition thresholds. If none exceed the threshold, the normal operating condition slope is maintained. If any parameter exceeds the corresponding threshold (e.g., grid voltage exceeds the overvoltage derating voltage, grid frequency exceeds the overfrequency derating frequency, or device temperature exceeds the overtemperature derating temperature), this parameter is designated as the target operating condition parameter, and the deviation is calculated. Based on the negative correlation between the deviation and the corrected power change slope, a corrected power change slope is determined, and the power command is adjusted accordingly. Subsequently, the determined power limit is further limited using the rated power value to ensure that the power limit does not exceed the inverter's hardware safety capacity. Subsequently, a space vector pulse width modulation strategy is used to drive the inverter main circuit, so that the actual output power is smoothly adjusted towards the power limit value according to the set slope and is always limited within that value. Finally, a calibration power value is generated based on the actual output power value and the power limit value, and fed back to the power limit value determination stage to form a closed-loop dynamic correction, thereby achieving accurate, smooth, and safe adaptive control of the inverter output power.

[0084] It should be noted that the above examples are only for understanding this application and do not constitute a limitation on the power control method of the inverter in this application. Any simple modifications based on this technical concept are within the protection scope of this application.

[0085] This application also provides a power control system for an inverter; please refer to [reference needed]. Figure 5 The system includes: The parameter acquisition module 10 is used to acquire the operating condition parameters of the inverter and determine the power limit value of the inverter. The slope adjustment module 20 is used to adjust the power change slope of the inverter from the normal operating condition slope to a corrected power change slope based on the deviation between the operating condition parameters and the preset normal operating condition parameter threshold when the inverter is in an abnormal operating condition according to the operating condition parameters. The corrected power change slope is less than the normal operating condition slope. The output control module 30 is used to adjust the actual output power of the inverter toward the power limit value according to the corrected power change slope, and to limit the actual output power based on the power limit value.

[0086] Optionally, the parameter acquisition module 10 is further configured to: The inverter is provided with multiple preset power limit values, including a voltage limit power value, a current limit power value, a frequency limit power value, and a temperature limit power value. The voltage limit power value is the power limit value of the inverter under overvoltage derating conditions. The current limit power value is determined based on the rated output current of the inverter. The frequency limit power value is the power limit value of the inverter under overfrequency derating conditions. The temperature limit power value is the power limit value of the inverter under overtemperature derating conditions. Determine the minimum limiting power value among the voltage limiting power value, the current limiting power value, the frequency limiting power value, and the temperature limiting power value; The minimum power limit value is used as the power limit value.

[0087] Optionally, the parameter acquisition module 10 is further configured to: The minimum power limit value is input to a low-pass filter to obtain the filtered minimum power limit, and the step of using the minimum power limit value as the power limit value is performed based on the filtered minimum power limit.

[0088] Optionally, the parameter acquisition module 10 is further configured to: Obtain the rated power value of the inverter; Determine the minimum power limit value between the filtered minimum power limit and the rated power value, and update the filtered minimum power limit value according to the minimum power value, so as to perform the step of using the minimum power limit value as the power limit value based on the updated minimum power limit value.

[0089] Optionally, the parameter acquisition module 10 is further configured to: The actual output power and the power limit value are input to the proportional-integral regulator to obtain the calibration power value; The minimum power limit value is adjusted based on the calibration power value to obtain the adjusted minimum power limit value, and then the step of using the minimum power limit value as the power limit value is returned to be executed based on the adjusted minimum power limit value.

[0090] Optionally, the slope adjustment module 20 is further configured to: The operating condition parameters are compared with the normal operating condition parameter thresholds. The operating condition parameters include the grid voltage, grid frequency and device temperature corresponding to the inverter. The normal operating condition parameter thresholds include the overvoltage derating voltage corresponding to the grid voltage, the overfrequency derating frequency corresponding to the grid frequency and the overtemperature derating temperature corresponding to the device temperature. If the grid voltage is greater than the overvoltage derating voltage, and / or the grid frequency is greater than the overfrequency derating frequency, and / or the device temperature is greater than the overtemperature derating temperature, the operating condition parameters are determined to indicate that the inverter is in an abnormal operating condition.

[0091] Optionally, the slope adjustment module 20 is further configured to: The operating condition parameter that is greater than the corresponding normal operating condition parameter threshold is taken as the target operating condition parameter, and the deviation between the target operating condition parameter and the corresponding normal operating condition parameter threshold is determined. The target operating condition parameter includes at least one of the grid voltage, the grid frequency and the device temperature. The slope of the corrected power change is determined based on the deviation, wherein the deviation is negatively correlated with the slope of the corrected power change. The power change slope is adjusted from the normal operating condition slope to the corrected power change slope.

[0092] Optionally, the output control module 30 is further configured to: The inverter's drive circuit is driven according to a space vector pulse width modulation strategy, so that the inverter adjusts the actual output power toward the power limit value according to the corrected power change slope.

[0093] The inverter power control system provided in this application, employing the inverter power control method described in the above embodiments, can solve the technical problem that current methods using fixed power limits cannot simultaneously achieve both output efficiency under normal operating conditions and operational safety under extreme operating conditions. Compared with the prior art, the beneficial effects of the inverter power control system provided in this application are the same as those of the inverter power control method provided in the above embodiments, and other technical features in the inverter power control system are the same as those disclosed in the methods of the above embodiments, and will not be repeated here.

[0094] This application provides an inverter, which includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, which are executed by the at least one processor to enable the at least one processor to perform the power control method of the inverter in the first embodiment described above.

[0095] The following is for reference. Figure 6 It shows a schematic diagram of an inverter suitable for implementing the embodiments of this application. Figure 6 The inverter shown is merely an example and should not be construed as limiting the functionality and scope of use of the embodiments of this application.

[0096] like Figure 6As shown, the inverter may include a processing unit 1001 (e.g., a central processing unit, a graphics processing unit, etc.), which can perform various appropriate actions and processes according to a program stored in a read-only memory 1002 or a program loaded from a storage device 1003 into a random access memory 1004. The random access memory 1004 also stores various programs and data required for inverter operation. The processing unit 1001, the read-only memory 1002, and the random access memory 1004 are interconnected via a bus 1005. An input / output interface 1006 is also connected to the bus. Typically, the following systems can be connected to the input / output interface 1006: input devices 1007 including, for example, a touchscreen, touchpad, keyboard, mouse, image sensor, microphone, accelerometer, gyroscope, etc.; output devices 1008 including, for example, a liquid crystal display (LCD), speaker, vibrator, etc.; storage devices 1003 including, for example, magnetic tape, hard disk, etc.; and communication devices 1009. The communication device 1009 allows the inverter to communicate wirelessly or wiredly with other devices to exchange data. Although inverters with various systems are shown in the figures, it should be understood that implementation or possession of all the systems shown is not required. More or fewer systems may be implemented alternatively.

[0097] Specifically, according to the embodiments disclosed in this application, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments disclosed in this application include a computer program product comprising a computer program carried on a computer-readable medium, the computer program containing program code for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via a communication device, or installed from storage device 1003, or installed from read-only memory 1002. When the computer program is executed by processing device 1001, it performs the functions defined in the methods of the embodiments disclosed in this application.

[0098] The inverter provided in this application, employing the power control method of the inverter in the above embodiments, can solve the technical problem that current methods using fixed power limits cannot simultaneously achieve both output efficiency under normal operating conditions and operational safety under extreme operating conditions. Compared with the prior art, the beneficial effects of the inverter provided in this application are the same as those of the power control method of the inverter provided in the above embodiments, and other technical features of this inverter are the same as those disclosed in the previous embodiment method, and will not be repeated here.

[0099] It should be understood that the various parts disclosed in this application can be implemented using hardware, software, firmware, or a combination thereof. In the description of the above embodiments, specific features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments or examples.

[0100] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0101] This application provides a computer-readable storage medium having computer-readable program instructions (i.e., a computer program) stored thereon, the computer-readable program instructions being used to execute the power control method of the inverter in the above embodiments.

[0102] The computer-readable storage medium provided in this application may be, for example, a USB flash drive, but is not limited to, electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems or devices, or any combination thereof. More specific examples of computer-readable storage media may include, but are not limited to: electrical connections having one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof. In this embodiment, the computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system or device. The program code contained on the computer-readable storage medium may be transmitted using any suitable medium, including but not limited to: wires, optical cables, RF (Radio Frequency), etc., or any suitable combination thereof.

[0103] The aforementioned computer-readable storage medium may be included in the inverter; or it may exist independently and not be assembled into the inverter.

[0104] The aforementioned computer-readable storage medium carries one or more programs that, when executed by the inverter, cause the inverter to: collect operating condition parameters of the inverter and determine the power limit value of the inverter; when the operating condition parameters indicate that the inverter is in an abnormal operating condition, adjust the power change slope of the inverter from the normal operating condition slope to a corrected power change slope based on the deviation between the operating condition parameters and a preset normal operating condition parameter threshold, wherein the corrected power change slope is less than the normal operating condition slope; adjust the actual output power of the inverter towards the power limit value based on the corrected power change slope, and limit the actual output power based on the power limit value.

[0105] Computer program code for performing the operations of this application can be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, and C++, and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network—including a Local Area Network (LAN) or a Wide Area Network (WAN)—or can be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0106] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0107] The modules described in the embodiments of this application can be implemented in software or hardware. The names of the modules do not necessarily limit the functionality of the unit itself.

[0108] The readable storage medium provided in this application is a computer-readable storage medium that stores computer-readable program instructions (i.e., a computer program) for executing the power control method of the inverter described above. This solves the technical problem that current methods using fixed power limits cannot simultaneously achieve both output efficiency under normal operating conditions and operational safety under extreme conditions. Compared with the prior art, the beneficial effects of the computer-readable storage medium provided in this application are the same as those of the power control method of the inverter provided in the above embodiments, and will not be elaborated upon here.

[0109] The above description is only a part of the embodiments of this application and does not limit the patent scope of this application. All equivalent structural transformations made under the technical concept of this application and using the contents of the specification and drawings of this application, or direct / indirect applications in other related technical fields, are included in the patent protection scope of this application.

Claims

1. A power control method for an inverter, characterized in that, The method includes: Collect the operating condition parameters of the inverter and determine the power limit value of the inverter; When the operating condition parameters indicate that the inverter is in an abnormal operating condition, the power change slope of the inverter is adjusted from the normal operating condition slope to a corrected power change slope based on the deviation between the operating condition parameters and the preset normal operating condition parameter threshold, wherein the corrected power change slope is less than the normal operating condition slope. The actual output power of the inverter is adjusted toward the power limit value based on the corrected power change slope, and the actual output power is limited based on the power limit value.

2. The method as described in claim 1, characterized in that, The step of determining the power limit value of the inverter includes: The inverter is provided with multiple preset power limit values, including a voltage limit power value, a current limit power value, a frequency limit power value, and a temperature limit power value. The voltage limit power value is the power limit value of the inverter under overvoltage derating conditions. The current limit power value is determined based on the rated output current of the inverter. The frequency limit power value is the power limit value of the inverter under overfrequency derating conditions. The temperature limit power value is the power limit value of the inverter under overtemperature derating conditions. Determine the minimum limiting power value among the voltage limiting power value, the current limiting power value, the frequency limiting power value, and the temperature limiting power value; The minimum power limit value is used as the power limit value.

3. The method as described in claim 2, characterized in that, After the step of determining the minimum limiting power value among the voltage limiting power value, the current limiting power value, the frequency limiting power value, and the temperature limiting power value, the method further includes: The minimum power limit value is input to a low-pass filter to obtain the filtered minimum power limit, and the step of using the minimum power limit value as the power limit value is performed based on the filtered minimum power limit.

4. The method as described in claim 3, characterized in that, After the step of inputting the minimum power limit value into a low-pass filter to obtain the filtered minimum power limit, the method further includes: Obtain the rated power value of the inverter; Determine the minimum power limit value between the filtered minimum power limit and the rated power value, and update the filtered minimum power limit value according to the minimum power value, so as to perform the step of using the minimum power limit value as the power limit value based on the updated minimum power limit value.

5. The method as described in claim 2, characterized in that, After the step of limiting the actual output power based on the power limit value, the method further includes: The actual output power and the power limit value are input to the proportional-integral regulator to obtain the calibration power value; The minimum power limit value is adjusted based on the calibration power value to obtain the adjusted minimum power limit value, and then the step of using the minimum power limit value as the power limit value is returned to be executed based on the adjusted minimum power limit value.

6. The method as described in claim 1, characterized in that, Following the step of collecting the inverter's operating condition parameters, the method further includes: The operating condition parameters are compared with the normal operating condition parameter thresholds. The operating condition parameters include the grid voltage, grid frequency and device temperature corresponding to the inverter. The normal operating condition parameter thresholds include the overvoltage derating voltage corresponding to the grid voltage, the overfrequency derating frequency corresponding to the grid frequency and the overtemperature derating temperature corresponding to the device temperature. If the grid voltage is greater than the overvoltage derating voltage, and / or the grid frequency is greater than the overfrequency derating frequency, and / or the device temperature is greater than the overtemperature derating temperature, the operating condition parameters are determined to indicate that the inverter is in an abnormal operating condition.

7. The method as described in claim 6, characterized in that, The step of adjusting the power change slope of the inverter from the normal operating condition slope to a corrected power change slope based on the deviation between the operating condition parameters and the preset normal operating condition parameter threshold includes: The operating condition parameter that is greater than the corresponding normal operating condition parameter threshold is taken as the target operating condition parameter, and the deviation between the target operating condition parameter and the corresponding normal operating condition parameter threshold is determined. The target operating condition parameter includes at least one of the grid voltage, the grid frequency and the device temperature. The slope of the corrected power change is determined based on the deviation, wherein the deviation is negatively correlated with the slope of the corrected power change. The power change slope is adjusted from the normal operating condition slope to the corrected power change slope.

8. The method as described in claim 1, characterized in that, The step of adjusting the actual output power of the inverter to the power limit value based on the corrected power change slope includes: The inverter's drive circuit is driven according to a space vector pulse width modulation strategy, so that the inverter adjusts the actual output power toward the power limit value according to the corrected power change slope.

9. A power control system for an inverter, characterized in that, The system includes: The parameter acquisition module is used to acquire the operating condition parameters of the inverter and determine the power limit value of the inverter. The slope adjustment module is used to adjust the power change slope of the inverter from the normal operating condition slope to a corrected power change slope based on the deviation between the operating condition parameters and a preset normal operating condition parameter threshold when the inverter is in an abnormal operating condition according to the operating condition parameters. The corrected power change slope is less than the normal operating condition slope. The output control module is used to adjust the actual output power of the inverter toward the power limit value according to the corrected power change slope, and to limit the actual output power based on the power limit value.

10. An inverter, characterized in that, The device includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, the computer program being configured to implement the steps of the power control method for the inverter as claimed in any one of claims 1 to 8.

11. A storage medium, characterized in that, The storage medium is a computer-readable storage medium, and a computer program is stored on the storage medium. When the computer program is executed by a processor, it implements the steps of the power control method for the inverter as described in any one of claims 1 to 8.

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