scholarly journals An Improved ip − iq Harmonic Detection Method Based on Time-Varying Integral Duration

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Jifang Li ◽  
Jidong Wang ◽  
Kunlin Song ◽  
Zhen Feng
Keyword(s):  
Detection Method ◽  
Integration Time ◽  
Detection Accuracy ◽  
Harmonic Suppression ◽  
Harmonic Detection ◽  
Response Delay ◽  
Harmonic Current ◽  
Harmonic Compensation ◽  
Pass Filter ◽  
Low Pass Filter

By analyzing harmonic related to instantaneous active current and instantaneous reactive current, we propose an improved harmonic detection method to remedy long response delay and low detection accuracy corresponding to harmonic of power system. This method introduces a series connection scheme composed of Low-Pass Filter (LPF) and a current average module firstly. Then, detection accuracy of harmonic current is enhanced by adaptive tuning cut-off frequency of LPF and integration time which was obtained by proposed algorithm of the current average module. Moreover, feedback loop is introduced to compensated delay caused by LPF. Simulations including uncontrollable rectifier and three-phase voltage type inverter show proposed method has many advantages such as high detection accuracy, low response delay and good generality. Our method provides reliable harmonic current detection for later harmonic suppression and harmonic compensation.

scholarly journals Improved harmonic detection method based on ip-iq theory

2021 ◽  
Vol 261 ◽  
pp. 01028
Author(s):  
Zhisen Yao ◽  
Guige Gao
Keyword(s):  
Detection Method ◽  
Phase Error ◽  
Response Speed ◽  
Detection Accuracy ◽  
Harmonic Detection ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass ◽  
In Series ◽  
Filtering Effect

Based on the traditional ip-iq harmonic detection theory, the accuracy of harmonic detection is easily affected by the phase-locked loop (PLL) output phase error, and the single low-pass filter (LPF) detection accuracy and filtering effect cannot be simultaneously. In this paper, an improved harmonic detection method based on the second-order generalized integrator-frequency locked loop (SOGI-FLL) technique is proposed to generate sine and cosine signals with the same frequency as the grid voltage; The traditional low-pass filter and average filter are used in series to improve the response speed and accuracy. Through theoretical analysis of the improved harmonic detection method and simulation in MATLAB environment, the theory and simulation results prove the effectiveness of the improved method.

Based on Delay Compensation System for Shunt Active Power Filter Research

2013 ◽  
Vol 860-863 ◽  
pp. 2050-2053
Author(s):  
Xin Yao ◽  
Zai Lin Yao ◽  
Xin Ying Teng
Keyword(s):  
Compensation System ◽  
Matlab Simulation ◽  
Harmonic Detection ◽  
Delay Compensation ◽  
Harmonic Current ◽  
Shunt Active Power Filter ◽  
Harmonic Compensation ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass

APF harmonic detection is the study of the most important parts of the core , quickly and accurately detect the harmonic current is able to quickly output harmonic compensation circuit current of the premise. Delay compensation system is based on the increase in the method specified time compensation angle , which can accurately detect the harmonic current at the same time , the low-pass filter to minimize the time delay generated by MATLAB simulation, the use of delay compensation system active Filter harmonic Detection and Compensation excellent performance, while ensuring high precision detection and compensation while ensuring at the same time , and fully complete filter real-time functionality .

Based on System Delay Time to Compensate for Harmonic Current Detection Method Research

2012 ◽  
Vol 614-615 ◽  
pp. 953-956
Author(s):  
Xin Yao ◽  
Zai Lin Yao ◽  
Xin Ying Teng
Keyword(s):  
Reactive Power ◽  
Detection Method ◽  
Matlab Simulation ◽  
System Delay ◽  
Harmonic Current ◽  
Harmonic Compensation ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass ◽  
Pros And Cons

Harmonic detection is one of the most important core part of Active Power Filter,which can quickly and accurately detect the harmonic current that is the premise of circuit to quickly output harmonic compensation current,therefore the pros and cons of the detection method,a direct impact on the effect of harmonic compensation.Time compensation method is to add a specific time compensation angle based on the method of instantaneous reactive power compensation,so that it can accurately detect the harmonic currents at the same time,minimize the low-pass filter time delay.By MATLAB simulation,the results show high detection accuracy.And to ensure detection and compensation,while fully to improve the real-time function of the filter.

scholarly journals A rapid harmonic detection method for grid-connected photovoltaic when three-phase voltage is unbalanced

2021 ◽  
Author(s):  
Tiezhou Wu ◽  
An Wang ◽  
Yawen Xu
Keyword(s):  
Phase Angle ◽  
Detection Method ◽  
Positive Sequence ◽  
Harmonic Detection ◽  
Phase Voltage ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Negative Sequence ◽  
Three Phase ◽  
Low Pass

Abstract By using power electronic devices, photovoltaic grid-connected power generation may inject harmonics into the power system. As the photovoltaic grid-connected inverter has the same basic structure as the active power filter, so the unified control of the photovoltaic grid and active filtering can be achieved. When the current unified control system compensates harmonics of the grid side, it mainly uses ip-iq harmonic detection method, which is based on instantaneous reactive power theory. When the three-phase voltage is unbalanced, the method has a large voltage phase angle detection error and the signal of the low-pass filter tracking system is long, detection time delay and even failure occur. This paper proposes an improved fast harmonic detection method. When phase deviation or amplitude change occurs to the three-phase voltage, the positive and negative-sequence voltages are simultaneously park transformed. The negative-sequence component is filtered by the current average module to obtain the fundamental amount of the voltage, then the phase angle of the positive-sequence voltage is accurately calculated to improve the harmonic current detection accuracy. Through the study of the integral method, it is found that the least common multiple of each harmonic period can be used as the integral interval, and the integral value is also zero, so the detection delay time is reduced by replacing the low-pass filter with an integration module. The simulation results show that the proposed harmonic detection algorithm can accurately detect harmonics when the three-phase voltage is unbalanced, and about 0.057 s improve the harmonic detection speed compared with the commonly used ip-iq method.

scholarly journals Study of Harmonic Detection Methods under Non-Ideal Conditions in Ship Power Network

2015 ◽  
Vol 22 (3) ◽  
pp. 82-89
Author(s):  
Xiao-Yan Xu ◽  
Janusz Mindykowski ◽  
Tomasz Tarasiuk ◽  
Chen Cheng
Keyword(s):  
Phase Lock Loop ◽  
Mean Value ◽  
Detection Methods ◽  
Harmonic Detection ◽  
Phase Voltage ◽  
Rapid Variation ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Three Phase ◽  
In Series

Abstract An improved harmonic detection method based on average arithmetic is proposed. According to the research results, the designed solution uses an LPF (low-pass-filter) and a mean value module connected in series instead of the conventional mean value module, and simultaneously, a three-phase voltage phase-locked module instead of commonly used PLL (phase lock loop) module is applied in order to reduce the influence caused by three-phase distorted voltage and rapid variation of load. The experimental results show that the application of this solution leads to increase in the accuracy of harmonics detection for distorted three-phase voltage and rapid variation of load.

scholarly journals CSI-HC: A WiFi-Based Indoor Complex Human Motion Recognition Method

2020 ◽  
Vol 2020 ◽  
pp. 1-20
Author(s):  
Zhanjun Hao ◽  
Yu Duan ◽  
Xiaochao Dang ◽  
Tong Zhang
Keyword(s):  
Real Time ◽  
Human Motion ◽  
Detection Accuracy ◽  
Behavior Recognition ◽  
Motion Recognition ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Motion Data ◽  
Indoor Scenes ◽  
Human Motion Recognition

WiFi indoor personnel behavior recognition has become the core technology of wireless network perception. However, the existing human behavior recognition methods have great challenges in terms of detection accuracy, intrusion, and complexity of operations. In this paper, we firstly analyze and summarize the existing human motion recognition schemes, and due to the existence of the problems in them, we propose a noninvasive, highly robust complex human motion recognition scheme based on Channel State Information (CSI), that is, CSI-HC, and the traditional Chinese martial art XingYiQuan is verified as a complex motion background. CSI-HC is divided into two phases: offline and online. In the offline phase, the human motion data are collected on the commercial Atheros NIC and a powerful denoising method is constructed by using the Butterworth low-pass filter and wavelet function to filter the outliers in the motion data. Then, through Restricted Boltzmann Machine (RBM) training and classification, we establish offline fingerprint information. In the online phase, SoftMax regression is used to correct the RBM classification to process the motion data collected in real time and the processed real-time data are matched with the offline fingerprint information. On this basis, the recognition of a complex human motion is realized. Finally, through repeated experiments in three classical indoor scenes, the parameter setting and user diversity affecting the accuracy of motion recognition are analyzed and the robustness of CSI-HC is detected. In addition, the performance of the proposed method is compared with that of the existing motion recognition methods. The experimental results show that the average motion recognition rate of CSI-HC in three classic indoor scenes reaches 85.4%, in terms of motion complexity and indoor recognition accuracy. Compared with other algorithms, it has higher stability and robustness.

The Analysis and Design of Three-Phase Static Inverter Deadband Effect and Harmonic Suppression

2013 ◽  
Vol 575-576 ◽  
pp. 293-296
Author(s):  
Qun Min Yan
Keyword(s):  
Control Method ◽  
Design Method ◽  
Harmonic Suppression ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Analysis And Design ◽  
Three Phase ◽  
Low Pass ◽  
Harmonic Components ◽  
Simulated Analysis

in order to solve the problem of three-phase static inverter output waveform distortion, detailed analyzed of the voltage distortion caused by the deadband effect and the resulting harmonic components. The control method is proposed to set the deadband time combining with the voltage compensation, while in order to improve the inverter output, the converter output to design a trap filter and a low pass filter cascaded filtering circuit. Simulated analysis the entire system though Saber, using the digital chip TMS320F2812 to achieve appropriate compensation strategies, simulation results and experimental results have all proved the effectiveness of the design method.

A Survey on Detecting Methods for Harmonic of Power System

2012 ◽  
Vol 614-615 ◽  
pp. 907-910
Author(s):  
Xue Song Zhou ◽  
Guang Zhu Chen ◽  
You Jie Ma
Keyword(s):  
Power System ◽  
Reactive Power ◽  
Detection Method ◽  
Response Speed ◽  
Development Trend ◽  
Detection Methods ◽  
Detection Accuracy ◽  
Harmonic Detection ◽  
Advantages And Disadvantages ◽  
Power System Harmonics

This paper describes Detecting Methods for Harmonics of power system has been considered one of the serious harms for power system. The research of harmonics has obtained high attention among people. The researches of harmonics detection have many methods, such as Based on Fryze theory of harmonic power detection, Instantaneous reactive power theory detection method, Fourier Transformation harmonic detection method, wavelet transform detection method, neural networks harmonic detection method etc. Aiming at harmonic detection, the different detection methods of power system harmonics are summarized and compared. This paper reviews the existing harmonic detection methods, and discuss their advantages and disadvantages in terms of detection accuracy and response speed, and finally summarizes the development trend of the harmonic detection method.

Broadband temporal stimuli decrease the integration time of neurons in cat striate cortex

1992 ◽  
Vol 9 (1) ◽  
pp. 39-45 ◽  
Author(s):  
R.C. Reid ◽  
J.D. Victor ◽  
R.M. Shapley
Keyword(s):  
Cortical Neurons ◽  
Time Course ◽  
Striate Cortex ◽  
Ganglion Cells ◽  
Temporal Frequency ◽  
Integration Time ◽  
Systematic Change ◽  
Response Dynamics ◽  
Pass Filter ◽  
Low Pass Filter

AbstractWe have studied the responses of striate cortical neurons to stimuli whose contrast is modulated in time by either a single sinusoid or by the sum of eight sinusoids. The sum-of-sinusoids stimulus resembles white noise and has been used to study the linear and nonlinear dynamics of retinal ganglion cells (Victor et al., 1977). In cortical neurons, we have found different linear and second-order responses to single-sinusoid and sum-of-sinusoids inputs. Specifically, while the responsivity near the optimal temporal frequency is lower for the sum-of-sinusoids stimulus, the responsivity at higher temporal frequencies is relatively greater. Along with this change in the response amplitudes, there is a systematic change in the time course of responses. For complex cells, the integration time, the effective delay due to a combination of actual delays and low-pass filter stages, changes from a median of 85 ms with single sinusoids to 57 ms with a sum of sinusoids. For simple cells, the integration times for single sinusoids range from 44–100 ms, but cluster tightly around 40 ms for the sum-of-sinusoids stimulus. The change in time constant would argue that the increased sensitivity to high frequencies cannot be explained by a static threshold, but must be caused by a fundamental alteration in the response dynamics. These effects are not seen in the retina (Shapley & Victor, 1981) and are most likely cortical in origin.

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