An SVPWM control system and method driven by an active power filter

Abstract

The present invention discloses an SVPWM control system and method driven by an active power filter, which relates to the technical field of motor drive. The present invention includes: calculating the switching control states of the inverter controller at different moments in the future period according to the rated voltage waveform of the power supply, the effective value of the rated voltage, and the target voltages at different moments in the future period for the driving power supply of each phase; separating the disturbance states of each harmonic interference source of the power supply according to the historical record of the voltage of the power supply regarding the acquisition moment; predicting the voltages of each harmonic interference source at different moments in the future period according to the disturbance states of each harmonic interference source of the power supply; generating a reverse voltage for canceling each harmonic interference source according to the voltages of each harmonic interference source at different moments in the future period, so as to obtain the reverse voltages at different moments in the future period. The present invention improves the accuracy of motor SVPWM control and also reduces the adverse effects of harmonics on the motor.

Description

Technical Field

[0001] The present invention belongs to the technical field of electric machine drive, and particularly relates to an SVPWM control system and method driven by an active power filter. Background Art

[0002] In recent years, with the development and continuous expansion of the application scope of power electronics technology, power quality problems have become increasingly prominent, especially the harmonic pollution problem. Harmonics are currents or voltages with frequencies that are multiples of the fundamental frequency generated in the power grid when nonlinear loads, such as rectifiers, inverters, speed control systems, and power electronic devices, are connected to the power grid. These harmonics will have a serious impact on the normal operation of the power grid, such as causing equipment overheating, malfunction, increased energy loss, and other problems. Summary of the Invention

[0003] The purpose of the present invention is to provide an SVPWM control system and method driven by an active power filter, which filters the harmonics of the power supply of the driving electrode through the active power filter, improves the accuracy of the SVPWM control of the motor, and at the same time reduces the adverse effects of harmonics on the motor.

[0004] To solve the above technical problems, the present invention is realized through the following technical solutions:

[0005] The present invention provides an SVPWM control method driven by an active power filter, including:

[0006] Obtaining the rated voltage waveform of the power supply and the effective value of the rated voltage;

[0007] Obtaining the target operating state of the motor in the future time period;

[0008] Calculating the target voltages at different moments in the future time period of the driving power supply for each phase according to the target operating state of the motor in the future time period;

[0009] Calculating the switching control states at different moments in the future time period of the inverter controller according to the rated voltage waveform of the power supply, the effective value of the rated voltage, and the target voltages at different moments in the future time period of the driving power supply for each phase;

[0010] Obtaining the historical record of the voltage of the power supply with respect to the acquisition moment;

[0011] Separating the disturbance states of each harmonic interference source of the power supply according to the historical record of the voltage of the power supply with respect to the acquisition moment;

[0012] Predicting the voltages of each harmonic interference source at different moments in the future time period according to the disturbance states of each harmonic interference source of the power supply;

[0013] Generate a reverse voltage that cancels each of the harmonic interference sources based on the voltages of each of the harmonic interference sources at different times in a future period, obtaining the reverse voltages at different times in the future period.

[0014] The present invention also discloses an SVPWM control method driven by an active power filter, including,

[0015] Receiving the reverse voltages at different times in a future period;

[0016] Generate reverse voltages at different times in a future period and connect them to the power supply to supply power to the inverter controller.

[0017] The present invention also discloses an SVPWM control method driven by an active power filter, including,

[0018] Receiving the reverse voltages at different times in a future period;

[0019] Display the reverse voltages at different times in a future period.

[0020] The present invention also discloses an SVPWM control system driven by an active power filter, including,

[0021] Motor;

[0022] Inverter controller;

[0023] A motor drive calculation unit for obtaining the rated voltage waveform of the power supply and the effective value of the rated voltage;

[0024] Obtain the target operating state of the motor in a future period;

[0025] Based on the target operating state of the motor in a future period, calculate the target voltages at different times in the future period for the drive power supply of each phase;

[0026] Based on the rated voltage waveform of the power supply, the effective value of the rated voltage, and the target voltages at different times in the future period for the drive power supply of each phase, calculate the switching control state of the inverter controller at different times in the future period;

[0027] A filtering control unit for obtaining the historical record of the voltage of the power supply regarding the acquisition time;

[0028] Based on the historical record of the voltage of the power supply regarding the acquisition time, separate the disturbance states of each harmonic interference source of the power supply;

[0029] Based on the disturbance states of each harmonic interference source of the power supply, predict the voltages of each harmonic interference source at different times in a future period;

[0030] Generate a reverse voltage to cancel each of the harmonic interference sources based on the voltage of each harmonic interference source at different times in the future period, and obtain the reverse voltage at different times in the future period;

[0031] An active power filter for receiving the reverse voltage at different times in the future period;

[0032] Generate a reverse voltage at different times in the future period and connect it to the power supply to supply power to the inverter controller;

[0033] A display unit for receiving the reverse voltage at different times in the future period;

[0034] Display the reverse voltage at different times in the future period.

[0035] In the present invention, the filtering control unit collects and analyzes the state of harmonics in the power supply, and predicts the reverse voltage at different times in the future period based on this. Then, an active power filter generates a reverse voltage to cancel and filter out the harmonics in the power supply, thereby improving the accuracy of the driving power supply for each phase output by the inverter controller, and thus realizing the improvement of the accuracy of the motor SVPWM control. Moreover, since the harmonics in the power supply are filtered out, the adverse effects of harmonics on the motor can also be avoided.

[0036] Of course, it is not necessary for any product implementing the present invention to achieve all the above-mentioned advantages simultaneously. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for describing the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0038] Figure 1 It is a schematic diagram of an SVPWM control system driven by an active power filter according to an embodiment of the present invention;

[0039] Figure 2 It is a schematic diagram of the step flow of the motor drive calculation unit and the filtering control unit according to an embodiment of the present invention;

[0040] Figure 3 It is a schematic diagram of the step flow of the active power filter according to an embodiment of the present invention;

[0041] Figure 4 It is a schematic diagram of the step flow of the display unit according to an embodiment of the present invention;

[0042] Figure 5Schematic diagram of the steps of step S6 in an embodiment of the present invention;

[0043] Figure 6 Schematic diagram of the steps of step S64 in an embodiment of the present invention Figure 1 ;

[0044] Figure 7 Schematic diagram of the steps of step S64 in an embodiment of the present invention Figure 2 ;

[0045] Figure 8 Schematic diagram of the steps of step S64 in an embodiment of the present invention Figure 3 ;

[0046] Figure 9 Schematic diagram of the steps of step S7 in an embodiment of the present invention;

[0047] Figure 10 Schematic diagram of the steps of step S72 in an embodiment of the present invention;

[0048] In the drawings, the list of components represented by each reference numeral is as follows:

[0049] 1 - motor, 2 - inverter controller, 3 - motor drive calculation unit, 4 - filter control unit, 5 - active power filter, 6 - active power filter, 7 - display unit. Detailed implementation manners

[0050] To make the objectives, technical solutions and advantages of the present application clearer, the following will further describe the embodiments of the present application in detail with reference to the drawings.

[0051] It should be noted that the terms "first", "second", etc. in the present application are used to distinguish similar objects and do not necessarily need to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances so that the embodiments of the present application described here can be implemented in an order different from those illustrated or described here. The implementation manners described in the following exemplary embodiments do not represent all implementation manners consistent with the present application. On the contrary, they are only examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0052] SVPWM (Space Vector Pulse Width Modulation) is a control technique used for AC power electronic devices (such as three-phase inverters) to generate high-quality output voltage waveforms. It plays an important role especially in motor drive control. SVPWM control achieves precise control of the output voltage by performing timely switching operations on the switching devices of the inverter. This control technique utilizes the concept of space vectors to convert three-phase voltages into a space vector, making it move on two positive half-axes and one negative half-axis.

[0053] During the SVPWM control process, first, the required output voltage vector is determined. This is usually generated by the control system according to the required motor output requirements. Next, the required output voltage vector is converted into the corresponding duty cycle and phase angle. This can be achieved through the mathematical model and transformation formula of the inverter. Then, based on the obtained duty cycle and phase angle, the switching state of the inverter is determined. Specifically, according to the position of the required output voltage vector, it is determined which switching devices in the inverter should be in the on state and which should be in the off state. The switching devices of the inverter controller perform switching operations according to the pre-determined switching state to achieve the required output voltage vector.

[0054] The SVPWM control technique has many advantages, including high voltage utilization, low harmonic distortion, low current ripple, and high dynamic response, etc. It is widely used in the control of AC power electronic devices, especially in AC motor drive systems to achieve efficient and precise motor control. However, there are harmonics in the power supply for the motor. Harmonics refer to the components in a periodic waveform that have frequencies that are integer multiples of the fundamental frequency.

[0055] In the power system, harmonics are introduced by non-linear load devices. These devices, such as electronic devices, frequency converters, arc furnaces, etc., cause non-linear loads to the power grid, resulting in distortion of the current and voltage waveforms. These distorted waveforms contain frequency components that are integer multiples of the fundamental frequency, i.e., harmonic components.

[0056] Harmonics may have some adverse effects on SVPWM (Space Vector Pulse Width Modulation) control. For example, first, the control accuracy decreases. Harmonic components may cause distortion of the voltage waveform, making the SVPWM control unable to accurately generate the required output voltage vector. The distorted waveform may cause the control algorithm to be unable to accurately calculate the switching state and duty cycle, thus reducing the accuracy and performance of the SVPWM control.

[0057] Current distortion caused by harmonic components may lead to additional ripples in the inverter output current. These ripples may increase the losses, vibrations, and noise of the motor, and may also have a negative impact on the performance and lifespan of the motor. Current distortion and voltage distortion caused by harmonic components may result in additional power losses in the inverter and motor system. These additional losses increase the energy consumption of the system and may cause equipment overheating and efficiency degradation. Harmonic components may cause resonance problems in the inverter and motor system. When the harmonic frequency is close to or equal to the natural frequency of the system, it may cause oscillation and instability phenomena, affecting the stability and reliability of SVPWM control.

[0058] To suppress and filter out harmonics in the power supply, the present invention provides the following solutions.

[0059] Please refer to Figures 1 to 4 As shown, the present invention provides an SVPWM control system driven by an active power filter, including a motor 1, an inverter controller 2, a motor drive calculation unit 3, a filtering control unit 4, an active power filter 5, a power supply 6, and a display unit 7. During implementation, first, the motor drive calculation unit 3 executes step S1 to obtain the rated voltage waveform of the power supply 6 and the effective value of the rated voltage. The rated voltage waveform usually refers to the ideal sine waveform of the rated voltage in an AC power system. In an ideal situation, the waveform of the rated voltage is a complete sine wave, with the same frequency as the power grid frequency (for example, 50 Hz or 60 Hz), and a constant and stable amplitude.

[0060] The effective value of the rated voltage (also known as the RMS value, i.e., the root mean square value) refers to the equivalent DC voltage of this sine waveform, which produces the same power effect. The effective value is the square root of the amplitude of the voltage waveform, so it is a measure of the average value of the voltage and is related to the amplitude and frequency of the sine wave. For example, in a 50 Hz power grid with a rated voltage of 220 volts, the waveform of the rated voltage is a sine wave with a frequency of 50 Hz and an amplitude of 220 volts. Its effective value is approximately 156.4 volts (for an ideal sine wave). This means that the equivalent DC voltage of this voltage waveform is 156.4 volts, producing the same power effect. The effective value is a commonly used indicator to describe the magnitude of AC voltage and current because it can accurately reflect its actual ability and power transmission ability, rather than just the magnitude of the amplitude.

[0061] After that, the motor drive calculation unit 3 executes step S2 to obtain the target operating state of the motor in the future time period. Next, step S3 can be executed to calculate the target voltages at different times in the future time period for the drive power supply of each phase based on the target operating state of the motor in the future time period. Next, step S4 can be executed to calculate the switching control states of the inverter controller at different times in the future time period based on the rated voltage waveform of the power supply 6, the effective value of the rated voltage, and the target voltages at different times in the future time period for the drive power supply of each phase. SVPWM (Space Vector Pulse Width Modulation) is a commonly used motor control method for controlling the three-phase drive power supply of the motor. Under SVPWM, the target voltage vector is generated by adjusting the switching state and duty cycle of the inverter to achieve the control of the motor. During the calculation process, according to the target operating state, the required output voltage vector is calculated, which can be obtained by calculating based on the motor model and control algorithm. Then the output voltage vector is converted into the target voltage of each phase. According to the SVPWM algorithm, the output voltage vector is decomposed into the target voltages of three phases. Finally, according to the control period and the required target voltage, the target voltages of each phase at different times are determined. Discretization and interpolation are performed as needed to obtain the target voltage values at different times.

[0062] To specifically achieve the elimination of harmonics in the power supply, first, the wave control unit 4 can execute step S5 to obtain the historical record of the voltage of the power supply regarding the acquisition time. Next, step S6 can be executed to separate the disturbance states of each harmonic interference source of the power supply based on the historical record of the voltage of the power supply 6 regarding the acquisition time. Next, step S7 can be executed to predict the voltages of each harmonic interference source at different times in the future time period based on the disturbance states of each harmonic interference source of the power supply. Finally, step S8 can be executed to generate the reverse voltages that cancel each harmonic interference source based on the voltages of each harmonic interference source at different times in the future time period, thereby obtaining the reverse voltages at different times in the future time period.

[0063] Specifically for the active power filter 5, first, step S011 can be executed to receive the reverse voltages at different times in the future time period. After that, step S012 can be executed to generate the reverse voltages at different times in the future time period and connect them to the power supply to supply power to the inverter controller.

[0064] To visually display the harmonic filtering effect of this system, the display unit 7 can execute step S021 to receive the reverse voltages at different times in the future time period. After that, step S022 can be executed to display the reverse voltages at different times in the future time period. Thus, the harmonic filtering effect of this system is visually displayed.

[0065] Please refer to Figure 5As shown, due to the large number of non-linear electrical equipment in the power grid, the periods and interference amplitudes of the harmonics they generate are different. In order to quantitatively describe the disturbance states of the harmonics generated by different harmonic interference sources, in the specific implementation process of step S6 above, step S61 can be first executed to generate a function of the power supply voltage with respect to the acquisition time according to the historical record of the power supply voltage with respect to the acquisition time. Here, a fitting method using discrete values can be used to generate it. Next, step S62 can be executed to separate the function waveform of the power supply voltage with respect to the acquisition time to obtain the harmonic frequencies where the harmonics are located within the historical period. Next, step S63 can be executed to separate the waveforms of the harmonics, the duration of each occurrence, and the interval duration of each occurrence for each harmonic frequency according to the function waveform of the power supply voltage with respect to the acquisition time.

[0066] To separate the harmonic waveforms at each harmonic frequency from the time-domain waveform of the power supply voltage, methods such as spectral analysis, such as the Fast Fourier Transform (FFT), can be used. First, collect the power supply voltage waveform, that is, use an appropriate sampling rate and sampling time to continuously collect the time-domain waveform of the power supply voltage. Next, preprocess the collected voltage waveform, that is, it can be processed to remove DC components, that is, remove the DC component to better analyze the AC component. Then perform spectral analysis, that is, apply the Fourier transform (usually the Fast Fourier Transform) to the preprocessed voltage waveform to convert the time-domain waveform into a frequency-domain representation. Separate the harmonic components, that is, in the frequency domain, the harmonic components can be determined by viewing the spectrogram or selecting a specific frequency range. Harmonics are usually integer multiples of the fundamental frequency. Extract the harmonic waveforms, that is, for each determined harmonic frequency, it can be restored from the frequency domain to the time domain through the inverse Fourier transform (usually the Fast Inverse Fourier Transform) to obtain the corresponding harmonic waveforms.

[0067] Finally, step S64 can be executed to obtain the waveforms of the harmonics of each harmonic interference source, as well as the numerical distributions of the duration and interval duration as the disturbance states of each harmonic interference source of the power supply according to the waveforms of the harmonics, the duration of each occurrence, and the interval duration of each occurrence for each harmonic frequency.

[0068] To supplement the implementation process of steps S61 to S64 above, the source codes of some functional modules are provided, and corresponding explanations are given in the comment section. To avoid data leakage of trade secrets, some data that do not affect the implementation of the solution are desensitized. The same applies hereinafter.

[0069] #include <iostream>

[0070] #include <vector>

[0071] #include <complex>

[0072] #include <cmath>

[0073] / / Define some constants

[0074] const double PI = 3.14159265358979323846;

[0075] / / Function: Simple Discrete Fourier Transform (DFT)

[0076] std::vector<std::complex <double>> discreteFourierTransform(conststd::vector <double>& signal) {

[0077] size_t N = signal.size();

[0078] std::vector<std::complex <double>> spectrum(N);

[0079] for (size_t k = 0; k < N; ++k) { / / For each frequency component k

[0080] std::complex <double>sum(0.0, 0.0);

[0081] for (size_t n = 0; n < N; ++n) { / / For each point n in the signal

[0082] double angle = 2 * PI * k * n / N;

[0083] sum += std::polar(signal[n], -angle);

[0084] }

[0085] spectrum[k] = sum;

[0086] }

[0087] return spectrum;

[0088] }

[0089] / / Function: Separate harmonics

[0090] std::vector <double>separateHarmonics(const std::vector <double>&voltageHistory) {

[0091] / / Fourier transform the voltage history

[0092] std::vector<std::complex <double>> spectrum =discreteFourierTransform(voltageHistory);

[0093] / / The harmonic frequencies are known and are integer - multiple frequencies

[0094] std::vector <double>harmonics;

[0095] size_t fundamentalFrequencyIndex = 1; / / Index of the fundamental frequency (1 in this example, corresponding to the fundamental wave)

[0096] for (size_t i = fundamentalFrequencyIndex; i < spectrum.size(); i += fundamentalFrequencyIndex) {

[0097] / / Calculate the amplitude of each harmonic

[0098] double amplitude = std::abs(spectrum[i]) / (spectrum.size() / 2);

[0099] harmonics.push_back(amplitude);

[0100] }

[0101] return harmonics;

[0102] }

[0103] int main() {

[0104] / / Voltage history of the power supply

[0105] std::vector <double>voltageHistory = { / *...Fill in voltage data...* / };

[0106] / / Separate harmonics

[0107] std::vector <double>harmonics = separateHarmonics(voltageHistory);

[0108] / / Output the amplitude of each harmonic

[0109] for (size_t i = 0; i < harmonics.size(); ++i) {

[0110] std::cout << "Harmonic " << (i + 1) << " amplitude: " << harmonics[i] << std::endl;

[0111] }

[0112] / / Time series analysis or state machine

[0113] return 0;

[0114] }

[0115] In this code, first a function discreteFourierTransform is defined to calculate the DFT of the signal, that is, the discrete Fourier transform. Then a function separateHarmonics is defined to separate the harmonic components in the signal. The main function main simulates the voltage history of the power supply and calls separateHarmonics to output the amplitude of each harmonic. This code demonstrates how to separate the harmonic interference sources in the voltage history of the power supply and calculate their amplitudes. The fast Fourier transform (FFT) is also used to improve efficiency, and time series analysis is implemented to determine the numerical distribution of the duration and interval of each harmonic.

[0116] Please refer to Figure 6 As shown, since the harmonic interference sources do not continuously generate interference, their activity is usually periodic. In order to analyze the activity periodicity of the harmonic interference sources in combination with the historical records, it is necessary to eliminate some noise data. To achieve the technical effect of eliminating some noise data, in the specific implementation process of step S64 above, step S641 can first be executed to regard the harmonics at each harmonic frequency as the harmonics generated by the same harmonic interference source to obtain the waveforms of the harmonics of each harmonic interference source.

[0117] For each harmonic interference source, first, step S642 can be executed to calculate and obtain the ratio of the duration of each occurrence of the harmonic interference source to the adjacent interval duration within the historical period. Next, step S643 can be executed to sort the ratios of the duration of each occurrence of the harmonic interference source to the adjacent interval duration within the historical period according to the numerical values to obtain a ratio sequence. Next, step S644 can be executed to calculate the average value of the differences between each numerical value in the ratio sequence and the adjacent numerical value as the proportional window value of the ratio sequence. Next, step S645 can be executed to eliminate the duration and interval duration corresponding to the ratios in the ratio sequence whose differences from the adjacent numerical values are greater than the proportional window value. After that, step S646 can be executed to obtain the numerical distribution of the remaining duration and interval duration after elimination. Finally, step S647 can be executed to summarize and obtain the waveform of the harmonics of each harmonic interference source and the numerical distribution of the duration and interval duration.

[0118] To supplement the implementation process of the above steps S641 to S647, the source code of some functional modules is provided, and corresponding explanations are given in the comment section.

[0119] #include <iostream>

[0120] #include <vector>

[0121] #include <algorithm>

[0122] #include <numeric>

[0123] / / There is a structure to store the information of each harmonic interference source

[0124] struct HarmonicDisturbance {

[0125] std::vector <double>waveform; / / Waveform of the harmonic

[0126] std::vector <double>durations; / / Duration per time

[0127] std::vector <double>intervals; / / Duration of each interval

[0128] };

[0129] / / Function: Calculate the ratio sequence

[0130] std::vector <double>calculateRatios(const std::vector <double>&durations, const std::vector <double>& intervals) {

[0131] std::vector <double>ratios;

[0132] size_t count = std::min(durations.size(), intervals.size());

[0133] for (size_t i = 0; i < count; ++i) {

[0134] if (intervals[i] != 0) { / / Avoid division by zero

[0135] ratios.push_back(durations[i] / intervals[i]);

[0136] }

[0137] }

[0138] return ratios;

[0139] }

[0140] / / Function: Calculate the average of differences

[0141] double calculateMeanDifference(const std::vector <double>&sortedValues) {

[0142] double totalDiff = 0;

[0143] for (size_t i = 1; i < sortedValues.size(); ++i) {

[0144] totalDiff += std::abs(sortedValues[i] - sortedValues[i - 1]);

[0145] }

[0146] return sortedValues.size() > 1? totalDiff / (sortedValues.size() - 1) : 0;

[0147] }

[0148] / / Function: Remove outlier ratios

[0149] void removeOutliers(std::vector <double>& durations, std::vector <double>& intervals, double windowValue) {

[0150] std::vector <double>ratios = calculateRatios(durations,intervals);

[0151] std::vector <double>sortedRatios = ratios;

[0152] std::sort(sortedRatios.begin(), sortedRatios.end());

[0153] double meanDiff = calculateMeanDifference(sortedRatios);

[0154] double threshold = meanDiff * windowValue;

[0155] / / Determine the threshold for outliers

[0156] for (size_t i = 0; i < ratios.size(); ++i) {

[0157] / / Compare and remove in the original ratio array

[0158] if (std::abs(ratios[i] - sortedRatios[i]) > threshold) {

[0159] durations[i] = -1; / / Mark as -1 indicating this is an outlier

[0160] intervals[i] = -1;

[0161] }

[0162] }

[0163] / / Remove all values marked as outliers

[0164] durations.erase(std::remove_if(durations.begin(), durations.end(), [](double value) { return value == -1;}), durations.end());

[0165] intervals.erase(std::remove_if(intervals.begin(), intervals.end(), [](double value) { return value == -1;}), intervals.end());

[0166] }

[0167] int main() {

[0168] / / harmonicsDisturbances contains data for all harmonic disturbance sources

[0169] std::vector <harmonicdisturbance>harmonicsDisturbances;

[0170] / / For each harmonic disturbance source, analyze the numerical distributions of its duration and interval duration

[0171] for (auto& disturbance : harmonicsDisturbances) {

[0172] removeOutliers(disturbance.durations, disturbance.intervals, 1.5); / / Here, 1.5 is used as the ratio window value

[0173] }

[0174] / / After this, each element in harmonicsDisturbances will only contain non-outlier duration and interval duration

[0175] / / Output the results

[0176] for (const auto& disturbance : harmonicsDisturbances) {

[0177] std::cout << "Harmonic waveform size: " << disturbance.waveform.size() << std::endl;

[0178] std::cout << "Non-outlier durations size: " << disturbance.durations.size() << std::endl;

[0179] std::cout << "Non-outlier intervals size: " << disturbance.intervals.size() << std::endl;

[0180] }

[0181] return 0;

[0182] }

[0183] This code defines a `HarmonicDisturbance` structure to store data of harmonic disturbance sources. Then several auxiliary functions are defined to calculate the average of ratios and differences and remove outliers. Note that in the `main` function, the `removeOutliers` function in the above code actually does not correctly remove outliers because the ratios are directly compared with the sorted ratios during the removal process without considering the original order. The correct approach should be to determine the outlier threshold based on the calculated average of the differences and compare and remove in the original ratio array.

[0184] Please refer to Figures 7 to 8 As shown, to achieve the technical effect of removing some noise data, during the process of removing the above values, step S6421 can also be synchronously executed to sort the duration of each harmonic disturbance source in each historical period according to the numerical size to obtain a duration sequence. Next, step S6422 can be executed to calculate the average of the differences between each value and its adjacent value in the duration sequence as the duration window value of the duration sequence. Finally, step S6423 can be executed to remove the durations in the duration sequence whose differences from adjacent values are greater than the duration window value. This can also achieve the removal of abnormal values in the duration.

[0185] Based on the same principle, to achieve the removal of abnormal values in the interval duration, step S6431 can also be synchronously executed to sort the interval duration of each harmonic disturbance source in each historical period according to the numerical size to obtain an interval duration sequence. Next, step S6432 can be executed to calculate the average of the differences between each value and its adjacent value in the interval duration sequence as the interval window value of the interval duration sequence. Finally, step S6433 can be executed to remove the interval durations in the interval duration sequence whose differences from adjacent values are greater than the interval window value. These two outlier removal steps are both based on the principle that the values of outliers are too separated from normal values.

[0186] Please refer to Figure 9 As shown, to achieve the prediction of the harmonic voltage of each harmonic disturbance source, in the specific implementation of step S7 above, step S71 can first be executed to obtain the current duration or current interval duration of each harmonic disturbance source at each harmonic frequency at the current moment. Next, step S72 can be executed to obtain the activity period distribution of different harmonic disturbance sources in the future period based on the current duration or current interval duration of each harmonic disturbance source at the current moment and the numerical distribution of the duration and interval duration of each harmonic disturbance source. Finally, step S73 can be executed to superimpose the waveforms of the harmonics of each harmonic disturbance source according to the activity period distribution of different harmonic disturbance sources in the future period to obtain the voltage of each harmonic disturbance source at different moments in the future period.

[0187] Please refer to Figure 10 As shown, in order to estimate the active period distribution of different harmonic interference sources, for each harmonic interference source, in the specific implementation process of step S72 above, step S721 can be first executed to determine whether the harmonic interference source generates harmonics at the current moment.

[0188] If so, then step S722 can be executed next to select a duration greater than the current duration of the harmonic interference source at the current moment according to the numerical distribution of the duration of the harmonic interference source. Next, step S723 can be executed to calculate and obtain the average value of the durations greater than the current duration of the harmonic interference source at the current moment as the expected duration of the harmonic interference source generating harmonics in the future period. If not, then step S724 can be executed next to select an interval duration greater than the current interval duration of the harmonic interference source at the current moment according to the numerical distribution of the interval duration of the harmonic interference source. Next, step S725 can be executed to calculate and obtain the average value of the interval durations greater than the current interval duration of the harmonic interference source at the current moment as the expected interval duration of the harmonic interference source generating harmonics in the future period. Next, step S726 can be executed to obtain the active period distribution of the harmonic interference source in the future period according to the current duration or current interval duration of the harmonic interference source at the current moment, and the expected duration and expected interval duration of the harmonic interference source generating harmonics in the future period. Finally, step S727 can be executed to summarize the active period distributions of different harmonic interference sources in the future period.

[0189] To supplement the implementation process of steps S721 to S727 above, the source code of some functional modules is provided, and corresponding explanations are given in the comment section.

[0190] #include <iostream>

[0191] #include <vector>

[0192] #include <algorithm>

[0193] / / Definition of the harmonic interference source structure

[0194] struct HarmonicDisturbance {

[0195] bool is_active; / / Whether harmonic is being generated

[0196] double current_duration; / / Current duration

[0197] double current_interval; / / Current interval duration

[0198] std::vector <double>duration_distribution; / / Numerical distribution of the duration

[0199] std::vector <double>interval_distribution; / / Numerical distribution of interval duration

[0200] double expected_duration; / / Expected duration

[0201] double expected_interval; / / Expected interval duration

[0202] };

[0203] / / Function to calculate the mean value of the values in the distribution that are greater than the current value

[0204] double calculateExpectedValue(const std::vector <double>&distribution, double currentValue) {

[0205] / / Use lambda expression to filter values greater than the current value

[0206] auto it = std::upper_bound(distribution.begin(), distribution.end(), currentValue);

[0207] / / Calculate the mean value

[0208] if (it != distribution.end()) {

[0209] double sum = std::accumulate(it, distribution.end(), 0.0);

[0210] return sum / std::distance(it, distribution.end());

[0211] } else {

[0212] / / If there is no larger value, return the current value, indicating no new data

[0213] return currentValue;

[0214] }

[0215] }

[0216] / / Function to predict the active period distribution of harmonic interference sources in the future time period

[0217] void predictActivityDistribution(std::vector <harmonicdisturbance>&disturbances) {

[0218] for (auto& disturbance : disturbances) {

[0219] if (disturbance.is_active) {

[0220] / / If harmonic is currently being generated, calculate the expected duration

[0221] disturbance.expected_duration = calculateExpectedValue(disturbance.duration_distribution, disturbance.current_duration);

[0222] } else {

[0223] / / If harmonic is not currently being generated, calculate the expected interval

[0224] disturbance.expected_interval = calculateExpectedValue(disturbance.interval_distribution, disturbance.current_interval);

[0225] }

[0226] }

[0227] }

[0228] int main() {

[0229] / / Example: Create a list of harmonic disturbance sources

[0230] std::vector <harmonicdisturbance>disturbances = {

[0231] {true, 5.0, 0.0, {4.0, 5.0, 6.0, 7.0}, {10.0, 11.0, 12.0}},

[0232] {false, 0.0, 8.0, {3.0, 4.0, 5.0}, {8.0, 9.0, 10.0, 11.0}}

[0233] };

[0234] / / Predict the activity period distribution of different harmonic disturbance sources in the future time period

[0235] predictActivityDistribution(disturbances);

[0236] / / Output the prediction results

[0237] for (const auto& disturbance : disturbances) {

[0238] std::cout << "Harmonic disturbance source " << (disturbance.is_active? "is generating harmonics." : "is not generating harmonics.")

[0239] << " Expected duration: " << disturbance.expected_duration

[0240] << ", Expected interval: " << disturbance.expected_interval << std::endl;

[0241] }

[0242] return 0;

[0243] }

[0244] This code first defines a HarmonicDisturbance structure to store relevant information for each harmonic disturbance source. It includes whether harmonic is being generated currently, the current duration and interval duration, the numerical distributions of the duration and interval duration, and the expected duration and interval duration. Through the calculateExpectedValue function, the mean value of the numerical values greater than the current value in the numerical distribution can be calculated. The predictActivityDistribution function uses this calculation to predict the expected duration and expected interval duration of harmonic generation for each harmonic disturbance source in the future time period. Finally, in the main function, a list of example harmonic disturbance sources is created, and the predictActivityDistribution function is called to predict and output the activity period distribution of each source.

[0245] The flowcharts and block diagrams in the accompanying drawings illustrate the possible architectures, functions, and operations of devices, systems, methods, and computer program products according to various embodiments of the present application. In this regard, each block in the flowchart or block diagram may represent a module, a segment of a program, or a part of an instruction, which contains one or more executable instructions for implementing the specified logical function. In some alternative implementations, the functions marked in the blocks may occur in a different order than that marked in the accompanying drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in the reverse order, depending on the functions involved.

[0246] It should also be noted that each block in the block diagram and / or flowchart, and the combination of blocks in the block diagram and / or flowchart, can be implemented by hardware that performs the corresponding functions or actions, such as a circuit or an ASIC (Application Specific Integrated Circuit), or can be implemented by a combination of hardware and software, such as firmware, etc.

[0247] Although the present invention has been described in conjunction with the various embodiments herein, however, during the implementation of the claimed invention, those skilled in the art can understand and realize other variations of the disclosed embodiments by viewing the accompanying drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude a plurality. A single processor or other unit may implement several functions recited in the claims. Certain measures are recited in mutually different dependent claims, but this does not mean that these measures cannot be combined to produce good results.

[0248] The embodiments of the present application have been described above. The above description is exemplary and not exhaustive, and is also not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope of the described embodiments. The choice of terms used herein is intended to best explain the principles of the embodiments, the practical application, or the improvement of the technology in the market, or to enable other ordinary skilled persons in the art to understand the embodiments disclosed herein.< / harmonicdisturbance> < / harmonicdisturbance> < / double> < / double> < / double> < / algorithm> < / vector> < / iostream> < / harmonicdisturbance> < / double> < / double> < / double> < / double> < / double> < / double> < / double> < / double> < / double> < / double> < / double> < / double> < / numeric> < / algorithm> < / vector> < / iostream> < / double> < / double> < / double> < / double> < / double> < / double> < / double> < / double> < / double> < / double> < / cmath> < / complex> < / vector> < / iostream>

Claims

1. A SVPWM control method driven by an active power filter, including: Obtain the rated voltage waveform of the power supply and the effective value of the rated voltage; Obtain the target operating state of the motor in the future time period; Calculate the target voltage at different moments within the future time period for the drive power supply of each phase according to the target operating state of the motor in the future time period; Calculate the switching control state of the inverter controller at different moments within the future time period according to the rated voltage waveform of the power supply, the effective value of the rated voltage, and the target voltage at different moments within the future time period for the drive power supply of each phase; It is characterized in that, Obtain the historical record of the voltage of the power supply with respect to the acquisition time; Separate the disturbance state of each harmonic interference source of the power supply according to the historical record of the voltage of the power supply with respect to the acquisition time; Predict the voltage of each harmonic interference source at different moments within the future time period according to the disturbance state of each harmonic interference source of the power supply; Generate a reverse voltage to cancel each harmonic interference source according to the voltage of each harmonic interference source at different moments within the future time period, and obtain the reverse voltage at different moments within the future time period; The step of separating the disturbance state of each harmonic interference source of the power supply according to the historical record of the voltage of the power supply with respect to the acquisition time includes, Generate a function of the voltage of the power supply with respect to the acquisition time according to the historical record of the voltage of the power supply with respect to the acquisition time; Separate the harmonic frequencies where the harmonics are located within the historical time period from the function waveform of the voltage of the power supply with respect to the acquisition time; Separate the waveform, the duration of each occurrence, and the interval duration of the harmonics at each harmonic frequency from the function waveform of the voltage of the power supply with respect to the acquisition time; Obtain the waveform of the harmonics of each harmonic interference source, as well as the numerical distribution of the duration and interval duration as the disturbance state of each harmonic interference source of the power supply according to the waveform, the duration of each occurrence, and the interval duration of the harmonics at each harmonic frequency; The step of obtaining the waveform of the harmonics of each harmonic interference source, as well as the numerical distribution of the duration and interval duration as the disturbance state of each harmonic interference source of the power supply according to the waveform, the duration of each occurrence, and the interval duration of the harmonics at each harmonic frequency includes, Regard the harmonics at each harmonic frequency as the harmonics generated by the same harmonic interference source to obtain the waveform of the harmonics of each harmonic interference source; For each harmonic interference source, Calculate and obtain the ratio of the duration of each occurrence of the harmonic interference source to the adjacent interval duration within the historical time period; Sort the ratio of the duration of each occurrence of the harmonic interference source to the adjacent interval duration within the historical time period according to the numerical magnitude to obtain a ratio sequence; Calculate the average value of the difference between each value and the adjacent value in the ratio sequence as the proportional window value of the ratio sequence; Eliminate the duration and interval duration corresponding to the ratio whose difference from the adjacent value in the ratio sequence is greater than the proportional window value; Obtain the numerical distribution of the remaining duration and interval duration after elimination; Summarize to obtain the waveform of the harmonics of each harmonic interference source, as well as the numerical distribution of the duration and interval duration; The step of predicting the voltage of each harmonic interference source at different moments within the future time period according to the disturbance state of each harmonic interference source of the power supply includes, Obtain the current duration or current interval duration of each harmonic interference source at each harmonic frequency at the current moment; Obtain the active period distribution of different harmonic interference sources in the future period according to the current duration or current interval duration of each harmonic interference source at the current moment and the numerical distribution of the duration and interval duration of each said harmonic interference source; Superimpose the waveforms of the harmonics of each said harmonic interference source according to the active period distribution of different harmonic interference sources in the future period to obtain the voltage of each said harmonic interference source at different moments in the future period; The step of obtaining the active period distribution of different harmonic interference sources in the future period according to the current duration or current interval duration of each harmonic interference source at the current moment and the numerical distribution of the duration and interval duration of each said harmonic interference source includes, For each said harmonic interference source, Judge whether the harmonic interference source generates harmonics at the current moment, If so, according to the numerical distribution of the duration of the harmonic interference source, select a duration greater than the current duration of the harmonic interference source at the current moment, Calculate and obtain the average value of the durations greater than the current duration of the harmonic interference source at the current moment as the expected duration for the harmonic interference source to generate harmonics in the future period, If not, according to the numerical distribution of the interval duration of the harmonic interference source, select an interval duration greater than the current interval duration of the harmonic interference source at the current moment, Calculate and obtain the average value of the interval durations greater than the current interval duration of the harmonic interference source at the current moment as the expected interval duration for the harmonic interference source to generate harmonics in the future period, Obtain the active period distribution of the harmonic interference source in the future period according to the current duration or current interval duration of the harmonic interference source at the current moment, and the expected duration and expected interval duration for the harmonic interference source to generate harmonics in the future period; Summarize to obtain the active period distribution of different harmonic interference sources in the future period.

2. The method according to claim 1, characterized in that, The step of obtaining the waveform of the harmonics of each said harmonic interference source and the numerical distribution of the duration and interval duration as the disturbance state of each harmonic interference source of the power supply according to the waveform of the harmonics at each harmonic frequency and each duration and each interval duration further includes, Sort the durations of each time of the harmonic interference source in the historical period according to the numerical size to obtain a duration sequence; Calculate the average value of the differences between each value in the duration sequence and the adjacent values as the duration window value of the duration sequence; Eliminate the durations in the duration sequence whose differences from the adjacent values are greater than the duration window value.

3. The method according to claim 1, characterized in that, The step of obtaining the waveform of the harmonics of each said harmonic interference source and the numerical distribution of the duration and interval duration as the disturbance state of each harmonic interference source of the power supply according to the waveform of the harmonics at each harmonic frequency and each duration and each interval duration further includes, Sort the interval durations of each time of the harmonic interference source in the historical period according to the numerical size to obtain an interval duration sequence; Calculate the average value of the differences between each value in the sequence of interval durations and its adjacent value as the interval window value of the sequence of interval durations; Eliminate the interval durations in the sequence of interval durations whose differences from adjacent values are greater than the interval window value.

4. An SVPWM control method driven by an active power filter, characterized in that, Including, Receiving the reverse voltages at different moments in the future period in a SVPWM control method driven by an active power filter according to any one of claims 1 to 3; Generating reverse voltages at different moments in the future period and connecting them to the power supply to supply power to the inverter controller.

5. An SVPWM control method driven by an active power filter, characterized in that, Including, Receiving the reverse voltages at different moments in the future period in a SVPWM control method driven by an active power filter according to any one of claims 1 to 3; Displaying the reverse voltages at different moments in the future period.

6. A control system for an SVPWM control method driven by an active power filter according to any one of claims 1 to 5, comprising, a motor; Inverter controller; Motor drive calculation unit, used to obtain the rated voltage waveform of the power supply and the effective value of the rated voltage; Obtain the target operating state of the motor in the future period; Calculate the target voltages at different moments in the future period of the drive power supply for each phase according to the target operating state of the motor in the future period; Calculate the switching control state of the inverter controller at different moments in the future period according to the rated voltage waveform of the power supply, the effective value of the rated voltage, and the target voltages at different moments in the future period of the drive power supply for each phase; Characterized in that, Filter control unit, used to obtain the historical record of the voltage of the power supply regarding the acquisition moment; Separate the disturbance states of each harmonic interference source of the power supply according to the historical record of the voltage of the power supply regarding the acquisition moment; Predict the voltages of each harmonic interference source at different moments in the future period according to the disturbance states of each harmonic interference source of the power supply; Generate reverse voltages to cancel each harmonic interference source according to the voltages of each harmonic interference source at different moments in the future period, and obtain the reverse voltages at different moments in the future period; Active power filter, used to receive the reverse voltages at different moments in the future period; Generate reverse voltages at different moments in the future period and connect them to the power supply to supply power to the inverter controller; Display unit, used to receive the reverse voltages at different moments in the future period; Display the reverse voltages at different moments in the future period.

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