Dynamic adjustment method for wide voltage input of adaptive inverter of high-power photovoltaic module

Abstract

The invention discloses a dynamic adjustment method for wide voltage input of an adaptive inverter of a high-power photovoltaic module, and relates to the technical field of photovoltaic inverter control, and the method comprises the steps: carrying out the dynamic MPPT calculation of an original data packet through analyzing historical I-V curve data, recognizing the attenuation trend of the open-circuit voltage of the photovoltaic module, and generating an MPPT control signal; the microcontroller analyzes the MPPT control signal to determine a target step-up ratio, monitors a voltage and wide voltage input change rate, predicts a voltage trend and generates a dynamic step-up control instruction; physical topology switching is carried out on the switch inductance networks L1 and L2 through a dynamic boost control instruction, meanwhile, a main switch tube and an auxiliary switch tube carry out switching actions through PWM parameters in the dynamic boost control instruction, and direct-current bus voltage is output; and the photovoltaic energy conversion efficiency and the grid-connected electric energy quality are improved.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic inverter control technology, and in particular to a dynamic adjustment method for wide-voltage input of high-power photovoltaic module-adaptive inverters. Background Technology

[0002] As the global energy structure shifts towards cleaner and lower-carbon energy, photovoltaic (PV) power generation is widely used due to its renewable and environmentally friendly nature. As the core device connecting PV modules to the power grid, the performance of the PV inverter directly affects the overall energy conversion efficiency of PV. Existing PV inverters generally employ constant voltage or maximum power point tracking (MPPT) algorithms based on perturbation-observation or incremental conductance methods to regulate the power of the PV array.

[0003] In the field of dynamic regulation of high-power photovoltaic module-adaptive inverters with wide input voltage ranges, traditional inverter control methods mainly rely on fixed topologies and static control strategies based on voltage feedback, such as dual-inductor boost, boost topology, and MPPT algorithms like the disturbance observation method and incremental conductance method. While these methods can achieve basic power point tracking and voltage regulation, the boost control parameters are fixed, lacking the ability to predict the rate of change and future trends of photovoltaic module output voltage, making it difficult to achieve rapid dynamic response under wide input voltage ranges and complex operating conditions. Furthermore, existing methods often rely on single real-time data in the boost ratio calculation and adjustment stages, without incorporating historical operating characteristics and module aging trends for adaptive correction. This easily leads to problems such as power point tracking delay, voltage fluctuations, and decreased output stability during sudden changes in illumination. Summary of the Invention

[0004] In view of the aforementioned existing problems, the present invention is proposed.

[0005] Therefore, this invention provides a dynamic adjustment method for wide-voltage input of high-power photovoltaic module-adaptive inverters to solve the problem of difficulty in achieving fast response and stable voltage control over a wide voltage range in the prior art.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0007] This invention provides a dynamic adjustment method for a wide-voltage input of a high-power photovoltaic module-adaptive inverter, which includes: acquiring raw voltage and current data, converting them into digital signals, and generating raw data packets;

[0008] By analyzing historical IV curve data, the decay trend of open-circuit voltage of photovoltaic modules is identified, dynamic MPPT calculation is performed on the original data packets, and MPPT control signals are generated.

[0009] The microcontroller parses the MPPT control signal to determine the target boost ratio, while monitoring the voltage and wide-range input change rate, predicting the voltage trend, and generating dynamic boost control commands.

[0010] The physical topology of the switching inductor network L1 and L2 is switched by dynamic boost control command. At the same time, the main switch and the auxiliary switch perform switching actions through the PWM parameters in the dynamic boost control command to output DC bus voltage.

[0011] The DC bus voltage is transmitted to the H5 inverter bridge, which converts the DC power into AC power through bipolar modulation according to the sequence of switching transistors, generating a power frequency AC waveform, which is then input to an LC filter for smoothing to obtain clean AC power before it is connected to the power grid.

[0012] As a preferred embodiment of the dynamic adjustment method for wide-voltage input of the high-power photovoltaic module-adaptive inverter described in this invention, the specific steps for acquiring raw voltage and current data, converting it into digital signals, and generating raw data packets are as follows.

[0013] Raw voltage and current data are acquired and converted into digital signals using the resolution and reference range of the ADC.

[0014] A bandpass filter is used to preprocess the digital signal to generate the original data packet.

[0015] As a preferred embodiment of the dynamic adjustment method for wide-voltage input of the high-power photovoltaic module-adaptive inverter described in this invention, the attenuation trend of the open-circuit voltage of the photovoltaic module is obtained by extracting the open-circuit voltage data when the current is zero from the historical IV curve data and identifying the open-circuit voltage data as a time series.

[0016] As a preferred embodiment of the dynamic adjustment method for wide-voltage input of the high-power photovoltaic module-adaptive inverter described in this invention, the specific steps for performing dynamic MPPT calculation on the original data packet to generate the MPPT control signal are as follows:

[0017] Based on the open-circuit voltage decay trend of photovoltaic modules, the voltage and current data at the current moment are extracted from the original data packet to calculate the current photovoltaic voltage power.

[0018] By comparing the current photovoltaic voltage power with the maximum power point, the future maximum power point is predicted using the least squares method and historical IV curve data, and an MPPT control signal is generated.

[0019] As a preferred embodiment of the dynamic adjustment method for wide-voltage input of the high-power photovoltaic module-adaptive inverter described in this invention, the microcontroller analyzes the MPPT control signal to determine the target boost ratio, and simultaneously monitors the voltage and the rate of change of the wide-voltage input. The specific steps are as follows.

[0020] The MPPT control signal is digitally decoded and filtered to extract the target voltage;

[0021] The target boost ratio is calculated using a microcontroller based on the target voltage, while the microcontroller continuously monitors the rate of change of voltage and the rate of change of wide-range input voltage.

[0022] As a preferred embodiment of the dynamic adjustment method for wide-voltage input of the high-power photovoltaic module-adaptive inverter described in this invention, the specific steps for predicting the voltage trend and generating dynamic boost control commands are as follows:

[0023] Based on the voltage change rate and the wide voltage input change rate, a smooth change rate is obtained by using the moving average method, and a historical data sequence is constructed.

[0024] A quadratic polynomial fit is performed on the historical data sequence to generate a predicted trend of voltage changes.

[0025] Based on the voltage change rate and voltage change prediction trend, voltage change is determined by the voltage change rate stability threshold.

[0026] The target boost ratio is dynamically adjusted according to voltage changes, and the boost control stage is entered. A boost control signal is generated through PWM modulation and output to the boost converter to precisely adjust the output voltage and obtain dynamic boost control commands.

[0027] As a preferred embodiment of the dynamic adjustment method for the wide-voltage input of the high-power photovoltaic module-adaptive inverter described in this invention, the method involves: physically switching the switching inductor networks L1 and L2 using a dynamic boost control command; simultaneously, the main switch and auxiliary switch operate according to the PWM parameters in the dynamic boost control command, outputting the DC bus voltage. The specific steps are as follows:

[0028] It receives dynamic boost control commands, parses the target boost ratio signal, voltage change signal, and wide voltage input change signal, and performs filtering and limiting processing to obtain a smoothed boost control quantity.

[0029] Based on the smoothed boost control quantity, the current optimal topology command is determined using a topology mapping algorithm, and the switching elements are controlled to perform physical topology switching on the inductor connection L1 and inductor connection L2 of the switching inductor network.

[0030] Based on different inductor connection methods, the required PWM frequency and duty cycle are calculated using the target boost ratio, and PWM parameters are extracted from the dynamic boost control command to generate a PWM signal.

[0031] The PWM signal controls the switching action of the main switch and auxiliary switch, monitors the working status of the inductor network, adjusts the PWM duty cycle, and outputs the DC bus voltage.

[0032] As a preferred embodiment of the dynamic adjustment method for wide-voltage input of the high-power photovoltaic module-adaptive inverter described in this invention, the following steps are taken: The DC bus voltage is supplied to the H5 inverter bridge, and the DC power is converted into AC power according to the sequence of switching transistors using bipolar modulation to generate a power frequency AC waveform.

[0033] The DC bus voltage is transmitted to the H5 inverter bridge, and the microcontroller calculates the frequency and voltage amplitude of the target power frequency output.

[0034] Based on frequency and voltage amplitude, a bipolar modulation method is used to generate a PWM modulation signal, which controls the switching sequence of each switch in the H5 inverter bridge, converting DC power into AC power and outputting a power frequency AC waveform.

[0035] As a preferred embodiment of the dynamic adjustment method for wide-voltage input of the high-power photovoltaic module-adaptive inverter described in this invention, the input to the LC filter is smoothed to obtain clean AC power, which is then connected to the power grid. The specific steps are as follows:

[0036] The power frequency AC waveform output from the H5 inverter bridge is input to the LC filter to effectively suppress high-frequency noise and high-order harmonic components in the power frequency AC waveform and output pure AC power.

[0037] The PWM duty cycle and phase of the H5 inverter bridge are adjusted based on the synchronous control algorithm to ensure that the amplitude and frequency of the pure AC power are consistent with those of the power grid before being connected to the grid.

[0038] As a preferred embodiment of the dynamic adjustment method for wide-voltage input of the high-power photovoltaic module-adaptive inverter described in this invention, the voltage change rate stability threshold is obtained by statistical analysis and feature extraction processing based on the dynamic response characteristics of the photovoltaic module and historical operating voltage, current, power output and corresponding voltage change rate data.

[0039] The beneficial effects of this invention are as follows: By calculating the dynamic MPPT based on the open-circuit voltage decay trend, predictive tracking of the maximum power point of photovoltaic modules is achieved, enabling power regulation to have forward-looking and rapid response capabilities; at the same time, by generating dynamic boost control commands through joint prediction of voltage change rate and wide-voltage input change rate, adaptive correction of boost ratio and precise control of output voltage are achieved, thereby maintaining the high-efficiency and stable operation of the inverter under wide-voltage input and complex operating conditions, ultimately improving the energy conversion efficiency of photovoltaics and the grid-connected power quality. Attached Figure Description

[0040] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 A flowchart of a dynamic adjustment method for wide-voltage input inverters adapted to high-power photovoltaic modules.

[0042] Figure 2 This is a flowchart of the raw data acquisition and digital signal generation process.

[0043] Figure 3 This is a flowchart for dynamic MPPT calculation.

[0044] Figure 4 This is a flowchart of the AC conversion process of the H5 inverter bridge. Detailed Implementation

[0045] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0046] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0047] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0048] Reference Figures 1-4 As one embodiment of the present invention, this embodiment provides a dynamic adjustment method for a wide-voltage input of a high-power photovoltaic module-adaptive inverter, comprising the following steps:

[0049] S1. Collect raw voltage and current data, convert them into digital signals, and generate raw data packets.

[0050] S1.1 Acquire raw voltage and current data, and convert them into digital signals using the resolution and reference range of the ADC.

[0051] Furthermore, the outputs from the voltage and current sensors are synchronously sampled at a set sampling frequency by a sample-and-hold circuit. The signals pass through an anti-aliasing filter and a gain / bias adjustment circuit to adjust the amplitude to within the allowable input range of the analog-to-digital converter (ADC). The ADC quantizes the adjusted analog voltage and current signals point by point with a preset quantization resolution (bits) and a reference voltage / range, and applies zero-point and gain calibration coefficients to correct conversion errors, generating calibrated digital samples.

[0052] S1.2. Use a bandpass filter to preprocess the digital signal and generate the original data packet.

[0053] Furthermore, the digital voltage and current signals output from the analog-to-digital converter (ADC) are input into a digital signal processing structure. A bandpass filter algorithm is called to preprocess the signals, filtering out DC bias and high-frequency noise components, retaining only the effective signal components within the photovoltaic output characteristic frequency band. After filtering, the filtered voltage and current data are recombined and aligned according to channel number and timestamp, and the processing results are written into the original data packet buffer in a fixed data structure to generate the final original data packet.

[0054] S2. By analyzing historical IV curve data, identify the attenuation trend of the open-circuit voltage of the photovoltaic module, perform dynamic MPPT calculation on the original data packet, and generate MPPT control signal.

[0055] S2.1 The decay trend of the open-circuit voltage of photovoltaic modules is obtained by extracting the open-circuit voltage data when the current is zero from the historical IV curve data and constructing the open-circuit voltage data into a time series for identification.

[0056] Furthermore, sampling points with zero current values ​​are selected point by point from the historical IV curve dataset. All sampling records are traversed in chronological order, and for each record, it is determined whether the current channel data is less than a set threshold (such as a tiny current close to zero). If the condition is met, the voltage value and timestamp corresponding to the sampling point are extracted and stored in the candidate set, ultimately forming an open-circuit voltage time series. Then, time series analysis is used to smooth the open-circuit voltage time series and perform linear regression fitting to calculate the slope of the open-circuit voltage change and the fitting residual. Finally, the downward trend of the open-circuit voltage over time is determined based on the slope of change, and the identification result is used as the parameter of the open-circuit voltage decay trend.

[0057] S2.2 Based on the open-circuit voltage decay trend of photovoltaic modules, extract the voltage and current data at the current moment from the original data packet and calculate the current photovoltaic voltage power.

[0058] Furthermore, the most recent time point is located from the original data packet using a unified timestamp field, and corresponding samples are extracted based on the voltage channel identifier and current channel identifier. If the sampling times are not completely consistent, nearest neighbor interpolation or linear interpolation is used to align the missing samples. The aligned digital samples are corrected using zero-point calibration coefficients and gain calibration coefficients, and converted to physical units of volts and amperes based on the analog-to-digital converter (ADC) reference voltage / reference range and sensor turns ratio, according to the formula... Calculate the current photovoltaic voltage power, where, This is the current photovoltaic voltage and power. This is the actual voltage value of the photovoltaic module at the current moment after calibration and conversion. It is the actual current value of the photovoltaic module at the current moment after calibration and conversion.

[0059] It should be noted that the open-circuit voltage decay trend of photovoltaic modules refers to the phenomenon that the open-circuit voltage (i.e., the voltage when the current is zero) of photovoltaic modules gradually decreases over time due to factors such as material aging, temperature influence, irradiance changes and internal losses during long-term operation.

[0060] The open-circuit voltage decay trend of photovoltaic modules is determined by selecting sampling points with zero current values ​​from the historical IV curve dataset, extracting the corresponding open-circuit voltage values, and establishing an open-circuit voltage time series in chronological order. Through smoothing and linear regression fitting, the slope of the open-circuit voltage change over time is calculated. When the slope is negative, it represents the open-circuit voltage decay trend and is used to describe the degree of performance degradation of the module.

[0061] S2.3 By comparing the current photovoltaic voltage power with the maximum power point, the future maximum power point is predicted using the least squares method and historical IV curve data, and an MPPT control signal is generated.

[0062] Furthermore, several recent voltage and current sampling points are extracted from the historical IV curve dataset. The least squares method is used to fit the model on a quadratic polynomial to obtain a continuous function of power changing with voltage. Based on the quadratic polynomial function of power changing with voltage, the first derivative of the function is calculated and set to zero to obtain the voltage extrema. The extrema voltage is substituted into the original polynomial function to obtain the corresponding power value. The sign of the second derivative of the extrema point is used to determine whether it is the maximum power point. If it is negative, the voltage and power are determined to be the predicted future maximum power point voltage and power value. The current photovoltaic voltage and power are then compared with the predicted maximum power point power to calculate the power deviation and the target voltage deviation. Based on the deviation and dynamic response constraints, a new target operating voltage is determined. Finally, the target operating voltage, adjustment step size, and confidence parameters are encapsulated into an MPPT control signal.

[0063] S3. The microcontroller parses the MPPT control signal to determine the target boost ratio, while monitoring the voltage and wide-range input change rate, predicting the voltage trend, and generating dynamic boost control commands.

[0064] S3.1 Perform digital decoding and filtering on the MPPT control signal to extract the target voltage.

[0065] Furthermore, the microcontroller reads the MPPT control signal frame to be processed from the control signal buffer. First, it performs frame synchronization and cyclic redundancy check (CRC) to verify data integrity and remove erroneous frames. Then, it parses the control signal frame using a predefined field format, decodes the target operating voltage field (e.g., fixed-point representation or IEEE 754 floating-point representation) by byte offset, and converts the original value into internal engineering units. The decoded target operating voltage value is then denoised and smoothed by a digital filter (optionally a finite impulse response (FIR) filter or an infinite impulse response (IIR) filter), followed by range checking and limiting, and written to the microcontroller's target voltage register for subsequent boost ratio calculation, and the target voltage is extracted.

[0066] It should be noted that the predefined field format is determined by specifying the total length of each frame and the positions of the frame header, data area, and check area; then, the byte offset and length of each parameter are allocated sequentially in the data area, for example, the target operating voltage occupies 4 bytes, the adjustment step size occupies 2 bytes, and the confidence level occupies 1 byte; subsequently, the numerical representation method of each field (such as IEEE 754 floating-point or fixed-point Q format), byte order (big-endian or little-endian), and unit conversion ratio are specified; finally, an identifier and version number are added to the frame header so that the content of each field can be accurately located and parsed during reading.

[0067] S3.2 Calculate the target boost ratio using a microcontroller based on the target voltage, and continuously monitor the voltage change rate and wide-range input change rate using the microcontroller.

[0068] Furthermore, the decoded and filtered target operating voltage is read from the microcontroller's target voltage register. Simultaneously, real-time input voltage samples are synchronously acquired from the DC bus voltage channel and the wide-voltage input channel at a unified time. The voltage change rate and the wide-voltage input change rate are calculated, and a stable change rate value is obtained by smoothing using the moving average method. Based on the boost converter transfer function, the microcontroller calculates the initial target boost ratio and compares the result with the upper and lower limits of the boost ratio and the boost step size constraint for amplitude and rate limiting. The final target boost ratio after amplitude and rate constraint is written to the boost ratio register, and at the same time, the microcontroller converts the boost ratio into the corresponding PWM frequency and duty cycle parameters and writes them to the PWM parameter register for subsequent execution by the boost controller.

[0069] It should be noted that the boost converter transfer function describes the dynamic relationship between the input voltage, duty cycle, and output voltage; it can be understood as a mathematical expression for energy transfer during the boost process. It reflects the impact of changes in input voltage and duty cycle on the output voltage. Based on this relationship, the microcontroller calculates the boost ratio required to achieve the target given the input voltage and the target output voltage, which is then used to determine subsequent PWM control parameters.

[0070] The boost ratio upper and lower limits refer to the minimum and maximum allowable boost ratio range in boost control, used to prevent equipment malfunctions caused by excessively low or high output voltage.

[0071] The upper and lower limits of the boost ratio are obtained through statistical analysis and experimental verification of the rated input and output voltage range of the boost circuit, the withstand voltage capability of key components, and historical stable operating data.

[0072] The boost step size constraint refers to the maximum amplitude of the single boost ratio change during continuous regulation, which is used to limit the regulation rate and avoid instability caused by voltage sudden changes.

[0073] The boost step size constraint is obtained through testing and optimization calculations of dynamic response characteristics, output voltage fluctuation amplitude, and steady-state recovery time.

[0074] S3.3 Based on the voltage change rate and the wide voltage input change rate, a smooth change rate is obtained by using the moving average method, and a historical data sequence is constructed.

[0075] Furthermore, the microcontroller reads the latest calculated rate of change samples from the voltage rate of change register and the wide-voltage input rate of change register, writes them into the sliding window buffer according to a uniform timestamp, and sets a fixed window length (e.g., the most recent 10 or 20 sampling periods) to ensure smooth response time. During each update, the arithmetic mean of all rate of change samples within the window is calculated to generate the smoothed voltage rate of change and the smoothed wide-voltage input rate of change. Subsequently, the data record appends the smoothed voltage rate of change, the smoothed wide-voltage input rate of change, and the corresponding timestamp to the historical data sequence buffer in ascending order of time.

[0076] S3.4 Perform quadratic polynomial fitting on the historical data sequence to generate a predicted trend of voltage change.

[0077] Furthermore, the smoothed voltage change rate and corresponding timestamp within the specified fitting window are read from the historical data sequence buffer. The timestamps are shifted to the latest time point to form a normalized time vector and outliers are removed to prepare the fitting data matrix. A design matrix containing constant, linear, and quadratic terms is constructed, and the coefficients of the quadratic polynomial are calculated using the least squares method. The fitting prediction curve is generated based on the quadratic polynomial coefficients, and then the first derivative of the fitting prediction curve is calculated to obtain the voltage change prediction trend.

[0078] It should be noted that "coefficient generation and fitting curve" refers to constructing a mathematical function describing the voltage change trend using the coefficients of a quadratic polynomial calculated by the least squares method. Specifically, during the fitting process, the coefficients of the quadratic, linear, and constant terms are obtained by minimizing the error between the predicted value and the actual smoothed voltage change rate; subsequently, these coefficients are used as parameters and substituted into the quadratic polynomial expression. ,in, Indicates time The corresponding predicted voltage change rate is the output value of the fitted curve; This is a normalized time variable used to represent the relative time of each sampling point within the fitting window; The coefficient of the quadratic term reflects the acceleration or curvature characteristics of the voltage change rate. The coefficient of the first term represents the linear trend of the voltage change rate; This is a constant term, corresponding to the reference time point (i.e. The initial rate of change is when (=0). The function value is calculated point by point on the normalized time vector to generate a continuous fitted curve to reflect the smooth trend of the voltage change rate.

[0079] S3.5. Based on the voltage change rate and voltage change prediction trend, the voltage change is determined by the voltage change rate stability threshold.

[0080] Furthermore, the microcontroller reads the current smoothed voltage change rate from the smoothed voltage change rate register, and reads the first derivative of the quadratic polynomial fitting from the voltage change prediction trend buffer. Simultaneously, it reads the voltage change rate stability threshold from the parameter storage area and calculates the stability metric. If the stability metric is less than or equal to the voltage change rate stability threshold, a "voltage stable" flag is written to the stability flag register, and a smaller allowable operating voltage adjustment step size is calculated. Otherwise, a "voltage unstable" flag is written, and the allowable operating voltage adjustment step size is limited, and a conservative boost control method is switched. Finally, the stability results, confidence index, and corresponding adjustment step size or control method parameters are written to the boost ratio limit register and the boost control method register for use in the subsequent generation of dynamic boost control instructions. It is noted that the voltage change rate stability threshold is obtained through statistical analysis and feature extraction of the dynamic response characteristics of the photovoltaic module and historical operating voltage, current, power output, and corresponding voltage change rate data.

[0081] It should be noted that the voltage change rate stability threshold is obtained by statistical analysis and feature extraction processing based on the dynamic response characteristics of photovoltaic modules and historical operating voltage, current, power output and corresponding voltage change rate data.

[0082] Based on the dynamic response test results of photovoltaic modules under different irradiance and temperature conditions and the fluctuation characteristics of historical operating data, the distribution range of voltage change rate under stable operation and disturbance conditions is comprehensively analyzed, and the range of voltage change rate stability threshold is set to ±(0.5%~2%) / sampling period.

[0083] S3.6. Dynamically adjust the target boost ratio according to voltage changes and enter the boost control stage. Generate a boost control signal through PWM modulation, output the boost control signal to the boost converter, accurately adjust the output voltage, and obtain dynamic boost control commands.

[0084] Furthermore, the microcontroller reads the current target boost ratio and voltage stability flag from the boost ratio register, determines whether the target boost ratio needs to be adjusted based on the voltage change rate, predicted trend, and stability flag, and calculates the corrected target boost ratio according to a preset adjustment step size. After amplitude and rate limiting, the target boost ratio is converted into the corresponding PWM duty cycle and PWM frequency parameters to generate a boost control signal. Subsequently, the boost control signal is output by the PWM controller to the main switch and auxiliary switch of the boost converter to realize duty cycle adjustment to precisely control the output voltage, and encapsulates the current boost ratio, PWM parameters, and feedback voltage into a dynamic boost control instruction.

[0085] S4. The physical topology of the switching inductor network L1 and L2 is switched by the dynamic boost control command. At the same time, the main switch and the auxiliary switch perform switching actions by the PWM parameters in the dynamic boost control command, and output DC bus voltage.

[0086] S4.1 Receive dynamic boost control command, and parse the target boost ratio signal, voltage change signal and wide voltage input change signal, and perform filtering and limiting processing to obtain the smoothed boost control quantity.

[0087] Furthermore, the microcontroller or control unit reads the dynamic boost control command frame to be processed from the boost control command buffer. First, it performs frame synchronization and cyclic redundancy check to confirm the integrity of the command. Then, it parses the target boost ratio field, voltage change signal field, and wide-voltage input change signal field by byte offset according to the predefined field format and converts the original values ​​into internal engineering units. Subsequently, the parsed target boost ratio value, voltage change signal, and wide-voltage input change signal are respectively processed by digital filters for noise reduction and smoothing. And each value is subjected to amplitude limiting and rate limiting according to the upper and lower limits and maximum change rate rules. Finally, the smoothed boost control quantity after filtering and amplitude limiting is obtained.

[0088] S4.2 Based on the smoothed boost control quantity, the current optimal topology command is determined using the topology mapping algorithm, and the switching element is controlled to perform physical topology switching on the inductor connection L1 and inductor connection L2 of the switching inductor network.

[0089] Furthermore, the control unit reads the smoothed boost control quantity from the smoothed boost control register and inputs the target boost ratio, input voltage, load conditions, and constraints into the topology mapping algorithm. The algorithm calculates the current optimal topology command and switching sequence under the premise of considering topology switching losses, switch damage limits, and allowed switching paths. After the topology mapping module generates the topology command containing the specific switching element action sequence, gate pulse timing, and necessary dead time, the control unit first checks the protection interlock and the current switching element status. Then, it sends the switch control signal through the gate driver in sequence to perform physical topology switching of the switching inductor network to change the inductor connection method L1 and inductor connection L2. The switching process is monitored in real time by inductor current and switch voltage sensors.

[0090] S4.3. Based on different inductor connection methods, calculate the required PWM frequency and duty cycle through the target boost ratio, and extract PWM parameters from the dynamic boost control command to generate a PWM signal.

[0091] Furthermore, the control unit identifies the boost topology type based on the current inductor connection method and inputs the target boost ratio into the PWM parameter calculation structure; it calculates the required PWM frequency and duty cycle based on the topology characteristic model, and performs amplitude limiting and quantization processing on the calculation results to ensure modulation stability; subsequently, the control unit parses the PWM modulation parameters from the dynamic boost control command and performs synchronous correction to generate a PWM signal containing real-time frequency, duty cycle and phase information.

[0092] S4.4. The switching action of the main switch and auxiliary switch is controlled by the PWM signal, the working status of the inductor network is monitored, the PWM duty cycle is adjusted according to feedback, and the DC bus voltage is output.

[0093] Furthermore, it receives PWM signals and controls the on / off actions of the main switch and auxiliary switch respectively, forming an alternating on and off boost operation state; it monitors the current change and magnetic flux state of the inductor network in real time to determine whether the operating mode is in the continuous or intermittent conduction region; it dynamically adjusts the PWM duty cycle according to the feedback of the inductor operating state and the output voltage deviation to stabilize the DC bus voltage within the target value range and output the DC bus voltage.

[0094] S5 transmits the DC bus voltage to the H5 inverter bridge, which converts the DC power into AC power through bipolar modulation according to the sequence of switching transistors, generates a power frequency AC waveform, and inputs it to an LC filter for smoothing to obtain clean AC power, which is then connected to the power grid.

[0095] S5.1. The DC bus voltage is transmitted to the H5 inverter bridge, and the microcontroller calculates the frequency and voltage amplitude of the target power frequency output.

[0096] Furthermore, the DC bus voltage is transmitted to the input terminal of the H5 inverter bridge via the DC input terminal. The microcontroller calculates the frequency and voltage amplitude of the target power frequency output in real time based on the grid parameters and the set output requirements.

[0097] S5.2 Based on frequency and voltage amplitude, a PWM modulation signal is generated using a bipolar modulation method to control the switching sequence of each switching transistor in the H5 inverter bridge, converting DC power into AC power and outputting a power frequency AC waveform.

[0098] Furthermore, the microcontroller establishes a bipolar SPWM modulation model based on the target frequency and voltage amplitude, and generates a bipolar PWM modulation signal by comparing a sinusoidal reference wave with a triangular carrier wave. The generated PWM modulation signal is used to precisely control the turn-on and turn-off timing of the main switch and auxiliary switch in the H5 inverter bridge, thereby realizing the alternating switching of the polarity of the DC bus voltage and outputting a stable power frequency AC voltage waveform.

[0099] The microcontroller establishes a bipolar SPWM modulation model based on the target frequency and voltage amplitude. Specifically, it generates a standard sine reference wave according to the set target frequency, which serves as the reference for output voltage changes. Then, it internally generates a high-frequency triangular carrier signal with a frequency much higher than the reference wave frequency to control the switching signal. Next, it compares the reference wave and the carrier voltage in each sampling period. When the reference wave is higher than the carrier wave, it outputs a high level; when it is lower than the carrier wave, it outputs a low level, forming an alternating positive and negative polarity PWM waveform. Finally, it adjusts the peak value of the sine reference wave according to the target voltage amplitude so that the output PWM wave satisfies both the target frequency and the required voltage amplitude. Based on this, by applying complementary and opposite polarity PWM signals to the two power switches on the upper and lower arms of the bridge arm, the output voltage alternates between positive and negative polarities, thus establishing a complete bipolar SPWM modulation model.

[0100] S5.3 Input the power frequency AC waveform output from the H5 inverter bridge to the LC filter to effectively suppress high-frequency noise and high-order harmonic components in the power frequency AC waveform and output pure AC power.

[0101] Furthermore, the power frequency AC waveform output from the H5 inverter bridge is input to an LC filter. The inductor stores energy and isolates the high-frequency components, while the capacitor smooths and filters the voltage waveform. Through the synergistic effect of the inductor and capacitor, high-frequency noise and high-order harmonic components are effectively suppressed, thereby outputting a power frequency AC signal with stable amplitude and pure waveform.

[0102] S5.4. Based on the synchronous control algorithm, adjust the PWM duty cycle and phase of the H5 inverter bridge to keep the amplitude and frequency of the pure AC power consistent with the grid and integrate it into the grid.

[0103] Furthermore, based on the synchronous control algorithm, the grid voltage and phase information are detected in real time. The PWM duty cycle and phase angle of the H5 inverter bridge are dynamically adjusted by the microcontroller so that the voltage amplitude and frequency of the output AC power gradually become consistent with the grid. When the amplitude and phase error meet the synchronization conditions, the grid-connected switch is turned on to achieve smooth grid-connected output of pure AC power.

[0104] In summary, this invention achieves predictive tracking of the maximum power point of photovoltaic modules through dynamic MPPT calculation based on the open-circuit voltage decay trend, enabling power regulation to have forward-looking and rapid response capabilities. Simultaneously, by jointly predicting the voltage change rate and the wide-range input change rate to generate dynamic boost control commands, it achieves adaptive correction of the boost ratio and precise control of the output voltage, thereby maintaining the inverter's efficient and stable operation under wide-range input and complex operating conditions, ultimately improving the photovoltaic energy conversion efficiency and grid-connected power quality.

[0105] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A dynamic adjustment method for a wide-voltage input inverter adapted to high-power photovoltaic modules, characterized in that: include, The system collects raw voltage and current data, converts it into digital signals, and generates raw data packets. By analyzing historical IV curve data, the decay trend of open-circuit voltage of photovoltaic modules is identified, dynamic MPPT calculation is performed on the original data packets, and MPPT control signals are generated. The microcontroller parses the MPPT control signal to determine the target boost ratio, while monitoring the voltage and wide-range input change rate, predicting the voltage trend, and generating dynamic boost control commands. The physical topology of the switching inductor network L1 and L2 is switched by dynamic boost control command. At the same time, the main switch and the auxiliary switch perform switching actions through the PWM parameters in the dynamic boost control command to output DC bus voltage. The DC bus voltage is transmitted to the H5 inverter bridge, which converts the DC power into AC power through bipolar modulation according to the sequence of switching transistors, generating a power frequency AC waveform, which is then input to an LC filter for smoothing to obtain clean AC power before it is connected to the power grid.

2. The dynamic adjustment method for a wide-voltage input inverter adapted to high-power photovoltaic modules as described in claim 1, characterized in that: The process of acquiring raw voltage and current data, converting it into digital signals, and generating raw data packets involves the following steps: Raw voltage and current data are acquired and converted into digital signals using the resolution and reference range of the ADC. A bandpass filter is used to preprocess the digital signal to generate the original data packet.

3. The dynamic adjustment method for a wide-voltage input inverter adapted to high-power photovoltaic modules as described in claim 1, characterized in that: The decay trend of the open-circuit voltage of the photovoltaic module is obtained by extracting the open-circuit voltage data when the current is zero from the historical IV curve data and constructing the open-circuit voltage data into a time series for identification.

4. The dynamic adjustment method for a wide-voltage input inverter adapted to high-power photovoltaic modules as described in claim 3, characterized in that: The specific steps for performing dynamic MPPT calculation on the original data packet to generate MPPT control signals are as follows. Based on the open-circuit voltage decay trend of photovoltaic modules, the voltage and current data at the current moment are extracted from the original data packet to calculate the current photovoltaic voltage power. By comparing the current photovoltaic voltage power with the maximum power point, the future maximum power point is predicted using the least squares method and historical IV curve data, and an MPPT control signal is generated.

5. The dynamic adjustment method for a wide-voltage input inverter adapted to high-power photovoltaic modules as described in claim 4, characterized in that: The microcontroller analyzes the MPPT control signal to determine the target boost ratio, while simultaneously monitoring the voltage and the rate of change of a wide-range input voltage. The specific steps are as follows. The MPPT control signal is digitally decoded and filtered to extract the target voltage; The target boost ratio is calculated using a microcontroller based on the target voltage, while the microcontroller continuously monitors the rate of change of voltage and the rate of change of wide-range input voltage.

6. The dynamic adjustment method for a wide-voltage input inverter adapted to high-power photovoltaic modules as described in claim 5, characterized in that: The predicted voltage trend generates dynamic boost control commands, and the specific steps are as follows: Based on the voltage change rate and the wide voltage input change rate, a smooth change rate is obtained by using the moving average method, and a historical data sequence is constructed. A quadratic polynomial fit is performed on the historical data sequence to generate a predicted trend of voltage changes. Based on the voltage change rate and voltage change prediction trend, voltage change is determined by the voltage change rate stability threshold. The target boost ratio is dynamically adjusted according to voltage changes, and the boost control stage is entered. A boost control signal is generated through PWM modulation and output to the boost converter to precisely adjust the output voltage and obtain dynamic boost control commands.

7. The dynamic adjustment method for a wide-voltage input inverter adapted to high-power photovoltaic modules as described in claim 6, characterized in that: The process involves physically switching the switching inductor networks L1 and L2 using dynamic boost control commands. Simultaneously, the main and auxiliary switches operate according to the PWM parameters in the dynamic boost control commands, outputting the DC bus voltage. The specific steps are as follows: It receives dynamic boost control commands, parses the target boost ratio signal, voltage change signal, and wide voltage input change signal, and performs filtering and limiting processing to obtain a smoothed boost control quantity. Based on the smoothed boost control quantity, the current optimal topology command is determined using a topology mapping algorithm, and the switching elements are controlled to perform physical topology switching on the inductor connection L1 and inductor connection L2 of the switching inductor network. Based on different inductor connection methods, the required PWM frequency and duty cycle are calculated using the target boost ratio, and PWM parameters are extracted from the dynamic boost control command to generate a PWM signal. The PWM signal controls the switching action of the main switch and auxiliary switch, monitors the working status of the inductor network, adjusts the PWM duty cycle, and outputs the DC bus voltage.

8. The dynamic adjustment method for a wide-voltage input inverter adapted to high-power photovoltaic modules as described in claim 7, characterized in that: The process of transmitting the DC bus voltage to the H5 inverter bridge, converting the DC power into AC power through bipolar modulation and following the sequence of switching transistors to generate a power frequency AC waveform, is detailed below. The DC bus voltage is transmitted to the H5 inverter bridge, and the microcontroller calculates the frequency and voltage amplitude of the target power frequency output. Based on frequency and voltage amplitude, a bipolar modulation method is used to generate a PWM modulation signal, which controls the switching sequence of each switch in the H5 inverter bridge, converting DC power into AC power and outputting a power frequency AC waveform.

9. The dynamic adjustment method for a wide-voltage input inverter adapted to high-power photovoltaic modules as described in claim 8, characterized in that: The input is smoothed by an LC filter to obtain clean alternating current, which is then fed into the power grid. The specific steps are as follows: The power frequency AC waveform output from the H5 inverter bridge is input to the LC filter to effectively suppress high-frequency noise and high-order harmonic components in the power frequency AC waveform and output pure AC power. The PWM duty cycle and phase of the H5 inverter bridge are adjusted based on the synchronous control algorithm to ensure that the amplitude and frequency of the pure AC power are consistent with those of the power grid before being connected to the grid.

10. The dynamic adjustment method for a wide-voltage input inverter adapted to high-power photovoltaic modules as described in claim 6, characterized in that: The voltage change rate stability threshold is obtained by statistical analysis and feature extraction processing based on the dynamic response characteristics of the photovoltaic module and historical operating voltage, current, power output and corresponding voltage change rate data.

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