Adaptive digital notch filter based on online grid impedance estimation for grid-tied LCL filter systems

2019 ◽  
Vol 172 ◽  
pp. 183-192 ◽  
Author(s):  
Jing Yuan ◽  
Ahmed Al Durra ◽  
Ehab El-Saadany
Keyword(s):  
Notch Filter ◽  
Lcl Filter ◽  
Grid Impedance ◽  
Digital Notch Filter

scholarly journals Stability Analysis of Grid-Connected Inverters with an LCL Filter Considering Grid Impedance

2013 ◽  
Vol 13 (5) ◽  
pp. 896-908 ◽  
Author(s):  
Xiao-Qiang Li ◽  
Xiao-Jie Wu ◽  
Yi-Wen Geng ◽  
Qi Zhang
Keyword(s):  
Stability Analysis ◽  
Lcl Filter ◽  
Grid Impedance

Adaptive Notch Filter Based Active Damping Control for Grid-Connected Inverter

2014 ◽  
Vol 986-987 ◽  
pp. 1169-1172
Author(s):  
Ping Wang ◽  
Meng Meng Cai
Keyword(s):  
Notch Filter ◽  
Active Damping ◽  
Band Pass Filter ◽  
Pass Filter ◽  
Adaptive Notch Filter ◽  
Attenuation Characteristic ◽  
Damping Control ◽  
Grid Impedance ◽  
Grid Connected Inverter ◽  
Active Damping Control

The LCL filter is widely applied as interface between grid-connected inverter and grid due to the preferable high frequency attenuation characteristic. Under the condition of weak grid, impedance value of grid model cannot be ignored, the existence of grid impedance results in different LCL resonant frequencies, which will arise challenges of traditional active damping control. Based on the analysis of band pass filter using active damping control strategy, an adaptive active damping control is proposed in this paper by introducing the application of active notch filter, which can adjust the position of negative resonance point adaptively so as to manage sudden grid changes. Theoretical analysis and simulation results presented on the platform of grid-connected PV inverter system indicate the effectiveness and adaptability of this active damping strategy.

scholarly journals An approach of adaptive notch filtering design for electrocardiogram noise cancellation

2021 ◽  
Vol 22 (3) ◽  
pp. 1303
Author(s):  
Rahmad Hidayat ◽  
Ninik Sri Lestari ◽  
Herawati Herawati ◽  
Givy Devira Ramady ◽  
Sudarmanto Sudarmanto ◽  
...  
Keyword(s):  
Notch Filter ◽  
Ecg Signal ◽  
Least Mean Square ◽  
Heart Activity ◽  
Frequency Range ◽  
Biomedical Signal ◽  
Nlms Algorithm ◽  
Digital Notch Filter ◽  
Notch Filtering ◽  
Electrocardiogram Ecg

An electrocardiogram (ECG) is a means of measuring and monitoring important signals from heart activity. One of the major biomedical signal issues such as ECG is the issue of separating the desired signal from noise or interference. Different kinds of digital filters are used to distinguish the signal components from the unwanted frequency range to the ECG signal. To address the question of noise to the ECG signal, in this paper the digital notch filter IIR 47 Hz is designed and simulated to demonstrate the elimination of 47 Hz noise to obtain an accurate ECG signal. The full architecture of the structure and coefficient of the IIR notch filter was carried out using the FDA Tool. Then the model is finished with the help of Simulink and the MATLAB script was to filter out the 47 Hz noise from the signal of ECG. For this purpose, the normalized least mean square (NLMS) algorithm was used. The results indicate that before being filtered and after being filtered it clearly shows the elimination of 47 Hz noise in the signal of the ECG. These results also show the accuracy of the design technique and provide an easy model to filter out noise in the ECG signal.

scholarly journals Research on Adaptive Suppression of LCL Converter Resonance Grid-Connected System

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Junwei Li ◽  
Yafang Tang ◽  
Junke Li
Keyword(s):  
Particle Swarm Optimization ◽  
Particle Swarm ◽  
Stability Margin ◽  
System Stability ◽  
Current Feedback ◽  
Swarm Optimization ◽  
Lcl Filter ◽  
Rbf Network ◽  
Grid Impedance ◽  
Suppression Method

LCL-type converters are widely used in grid-connected systems due to their small size and good filtering performance. However, the resonance suppression problem brought by the LCL filter cannot be ignored. The capacitive current feedback is a commonly used resonance suppression method. In applications, the grid impedance can cause LCL filter resonance. Thus, this paper presents an adaptive resonance suppression method based on the RBF network optimized by particle swarm optimization. This method optimizes the initial parameters of the RBF network through particle swarm optimization, identifies the parameters of the PI controller by RBF neural network’s own identification capability, and updates the active damping coefficient based on constraints such as stability margin, thereby realizing the LCL-type inverter to maintain the system stability when the grid impedance changes. The effectiveness of the method is verified by experiments.

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