Inverter control method and device, medium, product and power supply system

Abstract

The embodiment of the invention provides an inverter control method and device, a medium, a product and a power supply system. The method is applied to a power supply system, the power supply system comprises a load, a power grid and an inverter, the load and the power grid are used for achieving energy transfer through the inverter, and the method comprises the steps of obtaining a first voltage signal of the power grid and a second voltage signal of the output side of the inverter; generating a plurality of groups of feed-forward signals based on the first voltage signal; based on the change rate of the first voltage signal and the harmonic distortion rate of the second voltage signal, under the condition that the change rate of the first voltage signal reaches a preset change rate threshold value, the first voltage signal is adopted to perform parameter control of the inverter; and under the condition that the change rate of the first voltage signal does not reach a preset change rate threshold value, based on the harmonic distortion rate of the second voltage signal and a preset distortion rate threshold value, performing parameter control on the inverter by adopting the fundamental component signal or the hybrid filtering signal. The control strategy is switched in real time, and harmonic waves are suppressed while power grid fluctuation is quickly responded.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electronic power control, and in particular to a control method and device of an inverter, a medium, a product and a power supply system. BACKGROUND

[0002] The global energy transformation promotes large-scale grid connection of wind power, photovoltaic and other new energy. The intermittency and randomness of the output of the new energy increase the equivalent impedance of the power grid and reduce the short-circuit ratio, forming a weak power grid. Superimposed with the influence of instantaneous load switching, the voltage fluctuation and harmonic distortion of the power grid are aggravated. As the core grid-connected equipment, the inverter faces the challenge of complex power grid operation environment.

[0003] The traditional inverter adopts fixed parameter control based on ideal strong grid preset, which is difficult to adapt to the dynamic time-varying characteristics of the weak power grid and is easy to cause impedance mismatch and system resonance. Although the existing improvement scheme attempts to solve the problem through harmonic compensation or impedance reshaping, it often relies on additional hardware or complex algorithms, resulting in high cost, long debugging period and serious lack of engineering practicability.

[0004] In addition, the existing technology adopts a single feedforward signal and lacks real-time sensing and dynamic switching mechanism, which cannot balance system stability and dynamic response speed, and often falls into the performance contradiction of "trade-off". In the face of poor adaptability to weak power grid, dynamic response lag and difficulty in engineering landing, a new control method is needed to adaptively adjust the strategy without hardware modification. SUMMARY

[0005] The embodiments of the present application provide a control method, device, medium, product and power supply system of an inverter to realize real-time switching of control strategies, effectively suppress harmonics while responding to power grid fluctuations, solve the contradiction between stability and response speed, and improve the robustness of the system under weak power grid.

[0006] In a first aspect, the embodiments of the present application provide a control method of an inverter, applied to a power supply system, the power supply system comprising a load, a power grid and the inverter, the load and the power grid being used to realize energy transmission through the inverter, comprising:

[0007] obtaining a first voltage signal of the power grid and a second voltage signal of an output side of the inverter;

[0008] generating a plurality of feedforward signals based on the first voltage signal, the feedforward signals comprising at least the first voltage signal, a hybrid filter signal obtained by filtering based on the first voltage signal, and a fundamental component signal obtained by extracting based on the first voltage signal;

[0009] based on a change rate of the first voltage signal and a harmonic distortion rate of the second voltage signal,

[0010] When the rate of change of the first voltage signal reaches a preset rate of change threshold, the first voltage signal is used to control the parameters of the inverter.

[0011] If the rate of change of the first voltage signal does not reach the preset rate of change threshold, the inverter parameters are controlled using the fundamental component signal or the hybrid filter signal based on the harmonic distortion rate of the second voltage signal and the preset distortion rate threshold.

[0012] In one possible implementation, generating multiple sets of feedforward signals based on the first voltage signal includes:

[0013] The first voltage signal is subjected to low-pass filtering to generate the hybrid filtered signal;

[0014] Extract the fundamental component of the first voltage signal to generate the fundamental component signal.

[0015] In one possible implementation, the parameter control of the inverter based on the harmonic distortion rate of the second voltage signal and a preset distortion rate threshold, using the fundamental component signal or the hybrid filtered signal, includes:

[0016] When the harmonic distortion rate of the second voltage signal reaches the distortion rate threshold, the fundamental component signal is used to control the parameters of the inverter.

[0017] If the harmonic distortion rate of the second voltage signal does not reach the distortion rate threshold, the hybrid filtered signal is used to control the parameters of the inverter.

[0018] In one possible implementation, the parameter control of the inverter using different feedforward signals further includes:

[0019] The inverter parameters are controlled using the currently employed feedforward signal, at least for the preset duration.

[0020] In one possible implementation, the method further includes:

[0021] The first voltage signal and the second voltage signal are input into a pre-trained prediction model to obtain the first predicted voltage signal and the second predicted voltage signal of the power supply system at the next moment.

[0022] The method further includes:

[0023] Based on the rate of change of the first voltage signal, the harmonic distortion rate of the second voltage signal, the rate of change of the first predicted voltage signal, and the harmonic distortion rate of the second predicted voltage signal, the inverter's parameters are controlled using the first voltage signal, the hybrid filtered signal, or the fundamental component signal.

[0024] Secondly, embodiments of this application provide a control device for an inverter, applied in a power supply system. The power supply system includes a load, a power grid, and the inverter. The load and the power grid are used to transfer energy through the inverter, including:

[0025] The acquisition module is used to acquire the first voltage signal from the power grid and the second voltage signal from the output side of the inverter;

[0026] The generation module is used to generate multiple sets of feedforward signals based on the first voltage signal. The feedforward signals include at least the first voltage signal, a hybrid filtered signal obtained by filtering the first voltage signal, and a fundamental component signal extracted based on the first voltage signal.

[0027] The control module is used to control the parameters of the inverter based on the rate of change of the first voltage signal and the harmonic distortion rate of the second voltage signal, when the rate of change of the first voltage signal reaches a preset rate of change threshold.

[0028] The control module is used to control the parameters of the inverter based on the harmonic distortion rate of the second voltage signal and the preset distortion rate threshold when the rate of change of the first voltage signal does not reach the preset rate of change threshold. The control module uses the fundamental component signal or the hybrid filter signal to control the parameters of the inverter.

[0029] In one possible implementation, the generation module is further configured to perform low-pass filtering on the first voltage signal to generate the mixed filtered signal;

[0030] The generation module is also used to extract the fundamental component of the first voltage signal and generate the fundamental component signal.

[0031] In one possible implementation, the control module is further configured to use the fundamental component signal to perform parameter control of the inverter when the harmonic distortion rate of the second voltage signal reaches the distortion rate threshold.

[0032] The control module is also used to perform parameter control of the inverter using the hybrid filtered signal when the harmonic distortion rate of the second voltage signal does not reach the distortion rate threshold.

[0033] In one possible implementation, the control module is further configured to perform parameter control of the inverter using the currently employed feedforward signal, at least for a preset duration.

[0034] In one possible implementation, the acquisition module is further configured to input the first voltage signal and the second voltage signal into a pre-trained prediction model to acquire the first predicted voltage signal and the second predicted voltage signal of the power supply system at the next moment.

[0035] The control module is further configured to perform parameter control of the inverter using the first voltage signal, the hybrid filtered signal, or the fundamental component signal based on the rate of change of the first voltage signal, the harmonic distortion rate of the second voltage signal, the rate of change of the first predicted voltage signal, and the harmonic distortion rate of the second predicted voltage signal.

[0036] Thirdly, a power supply system includes a load, a power grid, and the inverter, wherein the load and the power grid are used to transfer energy through the inverter.

[0037] The power supply system is configured to acquire a first voltage signal from the power grid and a second voltage signal from the output side of the inverter using the method described in the first aspect and / or any of the various possible implementations of the first aspect; generate multiple sets of feedforward signals based on the first voltage signal; and, based on the rate of change of the first voltage signal and the harmonic distortion rate of the second voltage signal, perform parameter control of the inverter using the first voltage signal when the rate of change of the first voltage signal reaches a preset rate of change threshold; and, when the rate of change of the first voltage signal does not reach the preset rate of change threshold, perform parameter control of the inverter using the fundamental component signal or the hybrid filtered signal based on the harmonic distortion rate of the second voltage signal and a preset distortion rate threshold.

[0038] Fourthly, embodiments of this application provide a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement the first aspect and / or various possible implementations of the first aspect.

[0039] Fifthly, embodiments of this application provide a computer program product, including a computer program that, when executed by a processor, implements the first aspect and / or various possible implementations of the first aspect.

[0040] The inverter control method, apparatus, medium, product, and power supply system provided in this application are applied to a power supply system, which includes a load, a power grid, and an inverter. The load and the power grid are used to transfer energy through the inverter. The method involves acquiring a first voltage signal from the power grid and a second voltage signal from the inverter output side; generating multiple sets of feedforward signals based on the first voltage signal; and using the first voltage signal for inverter parameter control when the first voltage signal's rate of change reaches a preset rate of change threshold, based on the rate of change of the first voltage signal and the harmonic distortion rate of the second voltage signal. When the first voltage signal's rate of change does not reach the preset rate of change threshold, the fundamental component signal or a hybrid filtered signal is used for inverter parameter control based on the harmonic distortion rate of the second voltage signal and a preset distortion rate threshold. This method achieves a real-time switching control strategy, effectively suppressing harmonics while rapidly responding to grid fluctuations, resolving the contradiction between stability and response speed, and improving system robustness under weak grid conditions. Attached Figure Description

[0041] 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.

[0042] Figure 1 Flowchart of the control method for the inverter provided in this application Figure One ;

[0043] Figure 2 Flowchart of the control method for the inverter provided in this application Figure Two ;

[0044] Figure 3 A schematic diagram of the control device for the inverter provided in this application;

[0045] Figure 4 A schematic diagram of the structure of the electronic device provided in this application.

[0046] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0047] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0048] Figure 1 Flowchart of the control method for the inverter provided in this application Figure One .like Figure 1 As shown in the embodiments of this application, the inverter control method is applied to a power supply system, which includes a load, a power grid, and an inverter. The load and the power grid are used to transfer energy through the inverter. The method includes:

[0049] S101. Obtain the first voltage signal from the power grid and the second voltage signal from the inverter output side.

[0050] The first voltage signal from the grid can be used to indicate the grid voltage signal at the inverter's grid connection point, and can include the amplitude, frequency, phase, and dynamic characteristics of the grid voltage such as fluctuations and distortions. The second voltage signal from the inverter output side can be used to indicate the real-time voltage signal across the filter capacitor on the inverter output side, and can be used to reflect the harmonic distribution at the inverter output to calculate the total harmonic distortion (THD) and evaluate the system's operational stability.

[0051] It is understood that the loads in the power supply system provided in this application embodiment can be resistive loads (such as electric heaters), inductive loads (such as motors), capacitive loads (such as capacitor banks), and various nonlinear loads (such as rectifiers and frequency converters); the power grid can be an energy production and consumption system composed of power generation, transmission, transformation, distribution, and consumption links, which can provide the required power for the loads. Correspondingly, the load side connected to the power grid is also equipped with self-generating equipment (such as photovoltaics, energy storage, small generator sets, etc.). These devices can generate power independently, which can be directly supplied to various loads on the side. When the power generation exceeds the power consumption of the load, it can also send power back to the power grid through an inverter; the inverter can convert DC power (such as from solar panels or energy storage batteries) into AC power to meet the needs of the load and the power grid.

[0052] Between the load and the grid, an inverter can use high-frequency switching control of power switching devices to convert DC energy (from photovoltaic modules, energy storage batteries, etc.) into AC power synchronized with the grid and inject it into the grid, or in a specific mode, draw power from the grid and rectify it into DC power to supply the load / energy storage, thereby realizing bidirectional or unidirectional energy flow.

[0053] Specifically, voltage transformers, Hall effect voltage sensors, or resistor divider networks can be physically connected to the grid side and the inverter output side, respectively, to linearly convert the high-voltage signal into a low-voltage analog signal. Subsequently, high-frequency switching noise is filtered out by a filtering circuit (such as a low-pass filter), and the signal is amplified or level-shifted by an operational amplifier to match the input range of the analog-to-digital converter (ADC). The ADC module inside the inverter's digital controller samples the analog signal in real time, converting it into a discrete digital sequence, which serves as the basic input data for subsequent control algorithms.

[0054] S102. Based on the first voltage signal, generate multiple sets of feedforward signals.

[0055] The feedforward signal includes at least a first voltage signal, a hybrid filtered signal obtained by filtering the first voltage signal, and a fundamental component signal extracted from the first voltage signal.

[0056] Hybrid filtered signals can be generated based on the first voltage signal after processing by specific filtering algorithms (such as a combination of bandpass filtering, notch filtering, or multi-order low-pass filtering) to filter out high-frequency switching noise or low-frequency oscillation components in specific frequency bands, while retaining the main dynamic change trends. This is used to achieve a balance between noise suppression and maintaining dynamic response, and is suitable for environments where the power grid has specific frequency interference. The fundamental component signal is the power frequency fundamental component extracted from the first voltage signal through algorithms such as phase-locked loop, Second Order Generalized Integrator (SOGI), Fourier transform, or synchronous rotating coordinate system transformation. This signal only contains the fundamental amplitude and phase information of the grid voltage, completely filtering out harmonic distortion and high-frequency noise. It can be used in steady-state control scenarios with strict power quality requirements, needing to achieve zero steady-state error tracking, and avoiding harmonic amplification.

[0057] Understandably, by generating these three sets of feedforward signals, the inverter control system can flexibly select the appropriate feedforward signal as the control input according to different grid conditions and load requirements, thereby achieving more accurate and efficient power conversion and transmission.

[0058] Specifically, for example, the grid voltage signal at the inverter's grid connection point, i.e., the first voltage signal, can be denoted as... The first feedforward signal in the feedforward signal can directly use the original grid voltage, i.e., the first voltage signal. The second feedforward signal, i.e., the hybrid filtered signal generated based on the first voltage signal, can be denoted as... By the first voltage signal The result is obtained through hybrid filtering, and the formula can be expressed as follows: (in, These are the filter coefficients, and typically... The third feedforward signal, namely the fundamental component signal generated based on the first voltage signal, can be denoted as... The first voltage signal can be filtered using an SOGI fundamental frequency filter. It is obtained through processing.

[0059] S103. Based on the rate of change of the first voltage signal and the harmonic distortion rate of the second voltage signal, when the rate of change of the first voltage signal reaches a preset rate of change threshold, the first voltage signal is used to control the parameters of the inverter.

[0060] S104. If the rate of change of the first voltage signal does not reach the preset rate of change threshold, the inverter parameter control is performed using the fundamental component signal or the mixed filter signal based on the harmonic distortion rate of the second voltage signal and the preset distortion rate threshold.

[0061] Specifically, the first voltage signal (grid side) can be differentiated or differentially calculated in real time to characterize the severity of transient voltage fluctuations (such as voltage spikes or drops caused by sudden load switching). Simultaneously, the second voltage signal (inverter output side) can be subjected to spectral analysis or specific harmonic extraction algorithms to calculate its harmonic distortion rate (Total Harmonic Distortion, THD, or specific harmonic content) in real time, characterizing the current system's power quality and resonance risk. Based on these two key state indicators, the control system can dynamically select the optimal set of feedforward signals from multiple sets as the current feedforward input, according to preset threshold logic or fuzzy control rules, thereby adjusting the inverter's modulation wave or control parameters.

[0062] Understandably, the rate of change of the first voltage signal can be obtained by calculating the ratio of the amplitude difference of the first voltage signal within adjacent sampling periods to the sampling time, reflecting the instantaneous fluctuation of the grid voltage. A preset rate of change threshold (e.g., 10V / s) is used as the critical value for judging grid fluctuations. The total harmonic distortion (THD) of the second voltage signal can be obtained by decomposing the fundamental wave and each harmonic component of the second voltage signal using Fourier transform, and calculating the percentage of the total effective value of the harmonic components to the effective value of the fundamental wave, reflecting the degree of harmonic interference on the inverter output side. A preset distortion threshold (e.g., 5%) is used as the critical value for judging system instability.

[0063] If the rate of change of the first voltage signal is greater than or equal to the preset rate of change threshold, it is determined that the power grid has experienced a sudden large fluctuation (such as a sudden voltage rise / fall or a sudden load switching), and the feedforward signal is immediately switched to the original first voltage signal to control the inverter parameters.

[0064] If the rate of change of the first voltage signal is not greater than a preset rate of change threshold, the power grid is considered to be operating stably. In this case, the harmonic distortion rate of the second voltage signal is used as the core indicator to further select the feedforward signal. This can be divided into two sub-scenarios: if the THD of the second voltage signal is greater than the preset distortion rate threshold, the system is considered to have harmonic interference and resonance risk, and the feedforward signal is switched to the fundamental component signal. The inverter is parameter-controlled; if the THD of the second voltage signal is not greater than the preset distortion rate threshold, the system is determined to be stable and without significant harmonic interference, and the feedforward signal is maintained or switched to a hybrid filtered signal. Parameter control of the inverter (this is the default control strategy for normal inverter operation).

[0065] Specifically, for example, the first voltage signal can be calculated first. With mixed filtered signals The difference between them can be denoted as This allows for the evaluation of the voltage change rate of the first voltage signal; simultaneously, it enables real-time monitoring of the THD of the x-y harmonics of the second voltage signal, which can be denoted as... When the inverter is in normal operating condition, a hybrid filter signal can be used by default. To take control.

[0066] First, we can compare and determine the first voltage signal. With mixed filtered signals The difference between Does it exceed the preset threshold? ;like If the grid voltage fluctuation is large, a rapid response is required, and the system should enter fluctuation response mode; if If the voltage of the power grid is relatively stable, the stability of the system can be assessed.

[0067] Optionally, if power grid fluctuations and harmonic distortion occur simultaneously ( and Following the principle of "prioritizing power grid fluctuations," the original first voltage signal is selected first. Responding to power grid fluctuations, waiting for the power grid fluctuations to subside ( After that, immediately assess. Switch to the fundamental component signal for harmonic suppression.

[0068] In one optional embodiment, the inverter parameter control using different feedforward signals further includes: using the currently used feedforward signal for inverter parameter control for at least a preset duration.

[0069] The preset duration is the shortest time that the inverter must continuously use to control parameters after switching to a certain feedforward signal (denoted as ). This duration can be a fixed value preset in the control unit, or it can be adaptively adjusted according to the power grid conditions. For example, it can be tuned based on the inverter's switching frequency, control loop bandwidth, and the duration of typical power grid disturbances (e.g., set to several power grid frequency cycles, such as 20ms to 100ms). Maintaining the current control strategy for a duration no less than the preset minimum maintenance time can prevent system oscillations caused by frequent switching.

[0070] Understandably, when the control system completes a state assessment based on the rate of change of the first voltage signal and the harmonic distortion rate of the second voltage signal, and determines that it needs to switch from the currently used feedforward signal (e.g., the "fundamental component signal") to another set of feedforward signals (e.g., the "original voltage signal"), the system can start a preset hold timer.

[0071] During the preset maintenance time, the inverter will continue to be locked and use the same set of feedforward signals for parameter control as before the switchover. Even if the grid state indicators briefly fall below the original threshold or experience minor fluctuations during this period, the control system will not change the current feedforward strategy. Only when new grid state characteristics (such as high rate of change or high distortion rate) persist for more than the preset maintenance time will the control system officially execute the switchover action and update the feedforward signals to the newly selected signals.

[0072] Specifically, the minimum maintenance time is preset to 50ms to ensure that the control strategy runs for at least 50ms after switching. For example, if the voltage change rate exceeds the threshold due to instantaneous load switching, the inverter switches to the original first voltage signal and starts a 50ms maintenance timer: at 10ms, the grid fluctuation subsides and the change rate returns to the threshold, so the original signal control is maintained and no switch is made; after 50ms, the index is recalculated, and if the change rate is confirmed to be normal, the inverter can switch back to the hybrid filter signal and resume normal control.

[0073] The inverter control method provided in this application is applied to a power supply system, which includes a load, a power grid, and an inverter. The load and the power grid are used to transfer energy through the inverter. The method acquires a first voltage signal from the power grid and a second voltage signal from the inverter output side. Based on the first voltage signal, multiple sets of feedforward signals are generated. According to the rate of change of the first voltage signal and the harmonic distortion rate of the second voltage signal, different feedforward signals are used to control the inverter parameters. This method achieves a real-time switching control strategy, effectively suppressing harmonics while rapidly responding to power grid fluctuations, resolving the contradiction between stability and response speed, and improving the system robustness under weak power grid conditions.

[0074] Figure 2 Flowchart of the control method for the inverter provided in this application Figure Two .like Figure 2 As shown, this embodiment is... Figure 1 Based on the embodiments, the control method of the inverter is described in detail, which includes:

[0075] S201. Obtain the first voltage signal from the power grid and the second voltage signal from the inverter output side.

[0076] Step S201 is similar to step S101 described above, and will not be repeated here.

[0077] S202. Perform low-pass filtering on the first voltage signal to generate a mixed filtered signal.

[0078] The hybrid filtered signal is generated by performing low-pass filtering on the first voltage signal of the power grid, and it combines dynamic response capability and noise suppression characteristics. This signal serves as a feedforward component in the control strategy, providing a voltage reference that is smoother than the original signal but has a faster response than the pure fundamental signal when there is high-frequency noise or slight disturbance in the power grid.

[0079] The hybrid filtered signal is achieved through cascading processing of a low-pass filter and an SOGI fundamental frequency filter. The low-pass filter preserves the low-frequency dynamic trend of the grid voltage, while the SOGI fundamental frequency filter extracts the 50Hz / 60Hz hybrid filtered signal, balancing dynamic response and stability under normal operating conditions, avoiding response delay or signal distortion caused by a single filtering method. The power frequency fundamental frequency component is also included. This combination suppresses high-frequency noise while preserving the dynamic variation characteristics of the grid voltage, making it suitable for scenarios where the grid experiences minor disturbances but complete harmonic suppression is not required.

[0080] Understandably, a digital low-pass filter can be selected to process the discretized first voltage signal sequence. For example, it can include a first-order or second-order infinite impulse response low-pass filter, a moving average filter, or a combination of notch and low-pass filtering.

[0081] S203. Extract the fundamental component of the first voltage signal and generate the fundamental component signal.

[0082] Specifically, for the digitized first voltage signal, a dedicated fundamental wave extraction technology can completely separate the fundamental wave from harmonic or interference components, retaining only the pure 50 / 60Hz fundamental voltage signal of the power grid (including complete fundamental wave characteristics of amplitude and phase), filtering out all subharmonics, high-frequency interference, and voltage fluctuation spikes, and generating a fundamental wave component signal with extremely strong stability and optimal anti-interference capability. This signal is used for inverter parameter control when the power grid harmonic distortion exceeds the standard and the system has a risk of resonance, isolating the interference of harmonics on the control loop from the signal source level.

[0083] The fundamental component signal is implemented using the SOGI fundamental filter, whose core is a second-order generalized integrator module. The SOGI module synchronizes with the grid fundamental frequency through a phase-locked loop (PLL) and outputs a fundamental component in phase with the input signal. The fundamental component signal completely filters out harmonics and noise, retaining only the fundamental amplitude and phase information of the grid voltage. It is suitable for scenarios with excessive harmonic distortion, effectively suppressing the risk of harmonic amplification and improving system stability. For example, an adaptive filter can be constructed using a second-order generalized integrator (SOGI). The SOGI has bandpass filtering characteristics, and its center frequency is locked to the grid fundamental frequency. When the input voltage signal contains harmonics, the SOGI output directly provides a fundamental component (or quadrature component) in phase with the input signal, while its internal structure naturally suppresses harmonic interference at non-fundamental frequencies.

[0084] Optionally, the SOGI fundamental filter structure includes two parallel second-order generalized integrator modules, used to extract the fundamental orthogonal components (I and Q) of the grid voltage, respectively. Its core processing flow includes: the input grid voltage signal, after low-pass filtering, enters the orthogonal component generation unit of the SOGI module, synchronizing with the grid fundamental frequency (50Hz / 60Hz) via a phase-locked loop (PLL); the SOGI module outputs the fundamental component (I) and orthogonal component (Q) in phase with the input signal, calculates the phase angle using the arctangent function (atan2), and reconstructs the fundamental voltage signal by combining the amplitude; the gain coefficient of the SOGI is dynamically adjusted through a feedback adjustment mechanism to adapt to small shifts in the grid frequency, ensuring the stability of the fundamental extraction.

[0085] S204. When the rate of change of the first voltage signal reaches the preset rate of change threshold, the first voltage signal is used to control the parameters of the inverter.

[0086] Wherein, when the rate of change of the first voltage signal reaches a preset rate of change threshold, i.e. If the voltage fluctuation is large, it indicates that a rapid response is needed, and the system should enter fluctuation response mode.

[0087] Understandably, when the rate of change of the first voltage signal on the grid side exceeds the preset rate of change threshold, it can be determined that the grid is undergoing a severe dynamic disturbance (such as sudden load changes, short-circuit fault clearing, or voltage spikes / drops caused by lightning strikes). At this time, in order to suppress transient overcurrents to the greatest extent and maintain the stability of the DC bus, the system directly selects the unfiltered original first voltage signal as the feedforward quantity to correct the inverter's control parameters (such as modulation duty cycle, current loop reference value, etc.) in real time.

[0088] Specifically, the control strategy can be switched to use... It serves as the sole feedforward input for inverter parameter control, superimposed on the output feedback signal, and acts as the input to the proportional-integral-differential (PID) controller. The regulator adjusts the proportional and integral parameters in real time, changing the on / off duty cycle of the power switching module (IGBT / MOSFET) to quickly match transient changes in the grid voltage.

[0089] It should be noted that during the strategy switching process, a preset minimum maintenance time is simultaneously activated. The timer (e.g., 50ms) enters a forced maintenance phase, during which it remains active regardless of whether the rate of change returns to the threshold. control.

[0090] Optionally, after the maintenance time ends, the rate of change of the first voltage signal can be judged again. If If this is the case, then the power grid fluctuations can be considered to have stabilized, and the control logic under normal operating conditions can be restored. If so, the current parameter control will continue to be maintained to monitor power grid fluctuations.

[0091] S205. If the rate of change of the first voltage signal does not reach the preset rate of change threshold, and if the harmonic distortion rate of the second voltage signal reaches the distortion rate threshold, the fundamental component signal is used for inverter parameter control.

[0092] S206. If the rate of change of the first voltage signal does not reach the preset rate of change threshold, and if the harmonic distortion rate of the second voltage signal does not reach the distortion rate threshold, a hybrid filter signal is used for inverter parameter control.

[0093] If the rate of change of the first voltage signal (grid voltage) does not reach the preset rate of change threshold, it indicates that there is no drastic transient change in the grid. Further comparison can be made between the harmonic distortion rate (THD) of the second voltage signal (inverter output voltage) and the preset distortion rate threshold, dynamically selecting between the fundamental component signal and the mixed filtered signal to achieve the best balance between control accuracy and dynamic response. That is, if... If the voltage of the power grid is relatively stable, the stability of the system can be assessed.

[0094] Understandably, under the premise of stable grid voltage (without significant fluctuations), by calculating the harmonic distortion rate of the second voltage signal on the inverter output side in real time and comparing it with a preset threshold, it is possible to accurately determine whether there is harmonic interference or resonance risk in the system. Based on the determination result, a hybrid filter signal (normal stable operating condition) or a fundamental component signal (harmonic distortion operating condition) is dynamically selected as the control input. This ensures the basic dynamic response capability of the inverter when the grid is stable, and can accurately suppress harmonics and improve system stability when harmonics exceed the standard. This adapts to different system operating states after the grid stabilizes at the signal source level.

[0095] Specifically, In this case, the mixed filtered signal can be... THD value With threshold Make a judgment when If so, the system is determined to be unstable and needs to enter stable control mode; if In this case, the system can be considered stable, the power grid fluctuations are considered to be stable, and the control logic under normal operating conditions can be maintained, that is, the feedforward signal is kept as a hybrid filtered signal. Parameter control of the inverter.

[0096] Optional, in In this case, the fundamental component signal can be selected. As a feedforward input, the inverter's control parameters are corrected in real time to improve system stability. Simultaneously, during the stabilization control process, [further adjustments are made]. Perform threshold judgment: If again In this case, priority will be given to handling power grid fluctuations, and the appropriate method will be switched to... This is the feedforward input for inverter parameter control; if If the threshold requirement is met, then the fundamental component signal will be maintained. As feedforward input, until the minimum sustaining time After completion, re-evaluate whether the condition is met. At this time, if If the power grid fluctuations are deemed stable, the control logic under normal operating conditions is restored, i.e., the feedforward signal is switched to a hybrid filtered signal. Perform parameter control on the inverter; such as Then the fundamental component signal will continue to be maintained. As a feedforward input, it improves system stability and enables continuous stability control.

[0097] In some optional embodiments, the method further includes: inputting the first voltage signal and the second voltage signal into a pre-trained prediction model to obtain the first predicted voltage signal and the second predicted voltage signal of the power supply system at the next moment;

[0098] The method further includes: using the first voltage signal, the hybrid filtered signal, or the fundamental component signal to perform parameter control of the inverter based on the rate of change of the first voltage signal, the harmonic distortion rate of the second voltage signal, the rate of change of the first predicted voltage signal, and the harmonic distortion rate of the second predicted voltage signal.

[0099] Specifically, the first voltage signal (grid side) and the second voltage signal (inverter output side) at the current and historical moments can be used as time series data and input into a pre-trained prediction model. This model can be a state-space model based on physical mechanisms or a data-driven deep learning model, specifically designed to capture the dynamic trends and harmonic evolution of grid voltage. The model can output the power supply system's performance at the next moment. Even the predicted grid voltage waveform of the first predicted voltage signal at multiple future moments and the predicted inverter output voltage waveform of the second predicted voltage signal.

[0100] Understandably, introducing machine learning models (such as LSTM time series prediction networks) and combining historical grid voltage fluctuation data, filter capacitor voltage data, and real-time grid status data allows for the training of prediction models to forecast grid fluctuation trends and harmonic distortion changes in the near future. By using machine learning models to predict grid status trends, potential changes in grid fluctuations and harmonic distortion can be anticipated in advance, allowing for proactive adjustments to control strategies during operation and reducing system response delays.

[0101] The ensemble of prediction models can take the current grid voltage signal (first voltage signal) and the inverter output voltage signal (second voltage signal) as inputs, and output the predicted value for the next time step through an LSTM time series prediction network; the output of the prediction model includes the predicted rate of change of grid voltage (…). ) and predicted harmonic distortion rate ( The parameters are weighted and fused with the real-time calculated grid voltage change rate and THD value (the weights are dynamically adjusted by historical error data); the fused parameters are used to trigger control strategy switching in advance, such as when... Exceed In such cases, the system can switch back to the original voltage signal in advance to cope with upcoming power grid fluctuations.

[0102] For example, when a sudden change in grid voltage is predicted, the system can be switched to power in advance. To enhance response speed; in predicting When the temperature is about to rise, you can switch to [the appropriate setting] in advance. This approach aims to suppress harmonic interference. By introducing a predictive mechanism, the scheme significantly improves the foresight and dynamic adaptability of the control strategy, while reducing the risk of system instability caused by real-time judgment lag.

[0103] Specifically, the first and second voltage signals at the current and historical moments are input into a pre-trained voltage prediction model to obtain the first and second predicted voltage signals for the next moment of the power supply system. During the inverter parameter control process, not only is the feedforward signal selected based on the rate of change of the current first voltage signal and the harmonic distortion rate of the second voltage signal, but also a comprehensive judgment condition is formed by combining the rate of change of the first predicted voltage signal and the harmonic distortion rate of the second predicted voltage signal. Based on the real-time state and the predicted state, the optimal feedforward signal is jointly decided to achieve advanced adaptive control of the inverter and improve the dynamic response speed and operational stability of the system under complex power grid conditions.

[0104] In one possible implementation scenario, taking the industrial park's new energy grid-connected power supply system (a typical application scenario of load-side self-generation connected to the grid) as an example, the park can build distributed photovoltaic power generation equipment and small wind power generation equipment as self-generation units on the load side, and combine them with energy storage battery packs and 50kW hybrid inverters to form a core energy conversion system; the park's loads include production resistive loads (industrial electric heaters, electric heating furnaces), inductive loads (three-phase asynchronous motors, fans and pumps), nonlinear loads (industrial frequency converters, rectifiers) and office and civil loads, all of which are connected to the park's low-voltage weak power grid. Due to the fluctuation of new energy output and the instantaneous switching of park loads, the power grid has obvious voltage fluctuations and harmonic distortion problems.

[0105] Specifically, the inverters in the park can use a hybrid filtered signal for parameter control by default. When the rate of change of the first voltage signal is detected to be greater than 10V / s (such as a sudden increase in wind power output in the park or instantaneous switching of high-power loads causing grid fluctuations), it immediately switches to the original first voltage signal to achieve millisecond-level rapid response to grid fluctuations. When the grid voltage is stable (rate of change is less than 10V / s), if the harmonic distortion rate of the second voltage signal is detected to be greater than 5% (such as harmonic exceedance caused by concentrated operation of nonlinear loads in the park), it switches to the fundamental component signal to suppress harmonics and avoid system resonance. All signal switches are forcibly maintained for 50ms to prevent transient disturbances from causing frequent switching and system oscillations. At the same time, the predicted values ​​of voltage signal change rate and harmonic distortion rate output by the prediction model are integrated to achieve advance adjustment of the control strategy and respond to changes in the state of the grid and system in advance.

[0106] Alternatively, the park's self-generated power equipment can achieve local consumption of electricity and reverse power transmission to the grid through inverters. In a weak grid environment, the inverter's response time to grid voltage fluctuations is shortened to within 20ms, and the harmonic distortion rate on the output side of the park inverter is controlled below 5%. This can solve the impedance mismatch and system resonance problems under traditional fixed parameter control, so as to ensure stable power supply for various loads in the park.

[0107] Correspondingly, in industrial park scenarios, different load types can affect control strategies. For example, resistive loads (such as electric heaters) are sensitive to grid voltage fluctuations and require the use of the original voltage signal for a fast response. Inductive loads (such as three-phase asynchronous motors) are prone to voltage drops during startup and require dynamic adjustment of the control strategy in conjunction with the THD threshold. Nonlinear loads (such as rectifiers) have significant harmonic injection and require the use of the SOGI fundamental signal to suppress harmonic interference.

[0108] The inverter control method provided in this application acquires a first voltage signal from the power grid and a second voltage signal from the inverter output side. The first voltage signal is then low-pass filtered and SOGI fundamental frequency extracted to generate a hybrid filtered signal and a fundamental frequency component signal, which together with the original first voltage signal form three sets of feedforward signals. The method then first determines the rate of change of the first voltage signal. If the rate exceeds a threshold, the original signal is used for rapid response to power grid fluctuations. If the rate does not exceed the threshold, the fundamental frequency component signal is used for stabilization when harmonic distortion exceeds the limit, and the hybrid filtered signal is used to balance stability and response when harmonic distortion is normal. The entire process is coupled with a preset hold-time mechanism to avoid frequent switching. Through hierarchical judgment of fluctuations followed by harmonic distortion and dynamic switching of multiple feedforward signals, the inverter achieves rapid response to power grid fluctuations and effective suppression of harmonic distortion under weak power grid conditions, while also considering the real-time performance, stability, and robustness of the system control.

[0109] It should be understood that although the steps in the flowcharts of the above embodiments are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the above embodiments may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0110] Based on the same inventive concept, this application also provides a control device for an inverter to implement the control method of the inverter described above. The solution provided by this inverter control device is similar to the solution described in the inverter control method above. Therefore, the specific limitations of one or more device embodiments provided below can be found in the limitations of the inverter control method above, and will not be repeated here.

[0111] In one embodiment, such as Figure 3As shown, a control device 300 for an inverter is provided, applied in a power supply system. The power supply system includes a load, a power grid, and an inverter. The load and the power grid are used to transfer energy through the inverter, including:

[0112] The acquisition module 301 is used to acquire the first voltage signal of the power grid and the second voltage signal of the inverter output side;

[0113] The generation module 302 is used to generate multiple sets of feedforward signals based on the first voltage signal. The feedforward signals include at least the first voltage signal, a mixed filtered signal obtained by filtering the first voltage signal, and a fundamental component signal extracted based on the first voltage signal.

[0114] Control module 303 is used to control the parameters of the inverter based on the rate of change of the first voltage signal and the harmonic distortion rate of the second voltage signal, when the rate of change of the first voltage signal reaches a preset rate of change threshold.

[0115] The control module 303 is used to control the inverter parameters using the fundamental component signal or a hybrid filtered signal based on the harmonic distortion rate of the second voltage signal and the preset distortion rate threshold when the rate of change of the first voltage signal does not reach the preset rate of change threshold.

[0116] In one possible implementation, the generation module 302 is further configured to perform low-pass filtering on the first voltage signal to generate a mixed filtered signal;

[0117] The generation module 302 is also used to extract the fundamental component of the first voltage signal and generate the fundamental component signal.

[0118] In one possible implementation, the control module 303 is further configured to use the fundamental component signal for inverter parameter control when the harmonic distortion rate of the second voltage signal reaches the distortion rate threshold.

[0119] The control module 303 is also used to perform inverter parameter control using a hybrid filtered signal when the harmonic distortion rate of the second voltage signal does not reach the distortion rate threshold.

[0120] In one possible implementation, the control module 303 is also configured to perform inverter parameter control using the currently employed feedforward signal for at least a preset duration.

[0121] In one possible implementation, the acquisition module 301 is further configured to input the first voltage signal and the second voltage signal into a pre-trained prediction model to acquire the first predicted voltage signal and the second predicted voltage signal of the power supply system at the next moment.

[0122] The control module 303 is also used to perform parameter control of the inverter using the first voltage signal, the mixed filter signal, or the fundamental component signal based on the rate of change of the first voltage signal, the harmonic distortion rate of the second voltage signal, the rate of change of the first predicted voltage signal, and the harmonic distortion rate of the second predicted voltage signal.

[0123] Each module in the above-mentioned device can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in the processor of a computer device in hardware form or independent of it, or stored in the memory of a computer device in software form, so that the processor can call and execute the operations corresponding to each module.

[0124] Figure 4 A schematic diagram of the structure of the electronic device provided in this application. Figure 4 As shown, the electronic device 400 provided in this embodiment includes at least one processor 401 and a memory 402. Optionally, the device 400 further includes a communication component 403. The processor 401, memory 402, and communication component 403 are connected via a bus 404.

[0125] In a specific implementation, at least one processor 401 executes computer execution instructions stored in memory 402, causing at least one processor 401 to perform the above-described method.

[0126] The specific implementation process of processor 401 can be found in the above method embodiments, and its implementation principle and technical effect are similar. It will not be repeated here.

[0127] In the above embodiments, it should be understood that the processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), etc. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the method disclosed in this invention can be directly implemented by a hardware processor, or implemented by a combination of hardware and software modules within the processor.

[0128] The memory may include random access memory (RAM) and may also include non-volatile memory (NVM), such as at least one disk storage device.

[0129] The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be categorized as address buses, data buses, control buses, etc. For ease of illustration, the buses shown in the accompanying drawings are not limited to a single bus or a single type of bus.

[0130] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the above-described method.

[0131] This application also provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the above-described method.

[0132] The aforementioned readable storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk. The readable storage medium can be any available medium accessible to a general-purpose or special-purpose computer.

[0133] An exemplary readable storage medium is coupled to a processor, enabling the processor to read information from and write information to the readable storage medium. Of course, the readable storage medium can also be a component of the processor. The processor and the readable storage medium can reside in an Application Specific Integrated Circuit (ASIC). Alternatively, the processor and the readable storage medium can exist as discrete components in the device.

[0134] The division of units is merely a logical functional division; in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be indirect coupling or communication connection through some interfaces, devices, or units, and may be electrical, mechanical, or other forms.

[0135] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0136] In addition, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0137] If a function is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0138] Those skilled in the art will understand that all or part of the steps of the above-described method embodiments can be implemented by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When executed, the program performs the steps of the above-described method embodiments; and the aforementioned storage medium includes various media capable of storing program code, such as ROM, RAM, magnetic disks, or optical disks.

[0139] Finally, it should be noted that other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein, and is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. A control method for an inverter, characterized in that, Applied to a power supply system, the power supply system including a load, a power grid, and the inverter, the load and the power grid are used to transfer energy through the inverter, the method includes: Acquire the first voltage signal from the power grid and the second voltage signal from the output side of the inverter; Based on the first voltage signal, multiple sets of feedforward signals are generated. The feedforward signals include at least the first voltage signal, a hybrid filtered signal obtained by filtering the first voltage signal, and a fundamental component signal extracted from the first voltage signal. Based on the rate of change of the first voltage signal and the harmonic distortion rate of the second voltage signal, when the rate of change of the first voltage signal reaches a preset rate of change threshold, the first voltage signal is used to control the parameters of the inverter. If the rate of change of the first voltage signal does not reach the preset rate of change threshold, the inverter parameters are controlled using the fundamental component signal or the hybrid filter signal based on the harmonic distortion rate of the second voltage signal and the preset distortion rate threshold.

2. The method according to claim 1, characterized in that, The generation of multiple sets of feedforward signals based on the first voltage signal includes: The first voltage signal is subjected to low-pass filtering to generate the hybrid filtered signal; Extract the fundamental component of the first voltage signal to generate the fundamental component signal.

3. The method according to claim 1, characterized in that, The parameter control of the inverter based on the harmonic distortion rate of the second voltage signal and a preset distortion rate threshold, using the fundamental component signal or the hybrid filtered signal, includes: When the harmonic distortion rate of the second voltage signal reaches the distortion rate threshold, the fundamental component signal is used to control the parameters of the inverter. If the harmonic distortion rate of the second voltage signal does not reach the distortion rate threshold, the hybrid filtered signal is used to control the parameters of the inverter.

4. The method according to claim 1, characterized in that, The method further includes: The inverter parameters are controlled using the currently employed feedforward signal, at least for the preset duration.

5. The method according to claim 1, characterized in that, The method further includes: The first voltage signal and the second voltage signal are input into a pre-trained prediction model to obtain the first predicted voltage signal and the second predicted voltage signal of the power supply system at the next moment. The method further includes: Based on the rate of change of the first voltage signal, the harmonic distortion rate of the second voltage signal, the rate of change of the first predicted voltage signal, and the harmonic distortion rate of the second predicted voltage signal, the inverter's parameters are controlled using the first voltage signal, the hybrid filtered signal, or the fundamental component signal.

6. A control device for an inverter, characterized in that, The device is applied to a power supply system, which includes a load, a power grid, and the inverter. The load and the power grid are used to transfer energy through the inverter. The device includes: The acquisition module is used to acquire the first voltage signal from the power grid and the second voltage signal from the output side of the inverter; The generation module is used to generate multiple sets of feedforward signals based on the first voltage signal. The feedforward signals include at least the first voltage signal, a hybrid filtered signal obtained by filtering the first voltage signal, and a fundamental component signal extracted based on the first voltage signal. The control module is configured to, based on the rate of change of the first voltage signal and the harmonic distortion rate of the second voltage signal, control the parameters of the inverter using the first voltage signal when the rate of change of the first voltage signal reaches a preset rate of change threshold; and, when the rate of change of the first voltage signal does not reach the preset rate of change threshold, control the parameters of the inverter using the fundamental component signal or the hybrid filtered signal based on the harmonic distortion rate of the second voltage signal and a preset distortion rate threshold.

7. A power supply system, characterized in that, The power supply system includes a load, a power grid, and the inverter, wherein the load and the power grid are used to transfer energy through the inverter. The power supply system is configured to acquire a first voltage signal from the power grid and a second voltage signal from the output side of the inverter using the method described in any one of claims 1 to 5; generate multiple sets of feedforward signals based on the first voltage signal, wherein the feedforward signals include at least the first voltage signal, a hybrid filtered signal obtained by filtering the first voltage signal, and a fundamental component signal extracted from the first voltage signal; and, based on the rate of change of the first voltage signal and the harmonic distortion rate of the second voltage signal, perform parameter control of the inverter using the first voltage signal when the rate of change of the first voltage signal reaches a preset rate of change threshold; and, when the rate of change of the first voltage signal does not reach the preset rate of change threshold, perform parameter control of the inverter using the fundamental component signal or the hybrid filtered signal based on the harmonic distortion rate of the second voltage signal and the preset distortion rate threshold.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 5.

9. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 5.

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