Self tunning filter for three levels four legs shunt active power filter with fuzzy logic controller

The low harmonic distortion and reduced switching losses are the advantages of using the multilevel inverter. For this purpose, the three-level inverter is used in this paper as a three-phase four-leg shunt active power filter (SAPF). The SAPF is used to eliminate the harmonic current to compensate the reactive power current, and to balance the load currents under an unbalanced non-linear load. A fuzzy logic controller and self-tuning filters (STF) are used to control the active power filter (APF) and generate the reference current. To demonstrate the validity of the proposed control strategy, we compared it with a conventional p − q theory, under distortion voltage conditions and unbalanced non-linear load. The Matlab-Simulink toolbox is used to implement the algorithm of Fuzzy logic control. The performance of the SAPF controller is found very effective and adequate as compared with the p − q theory

Simulation and Experimental Realization of Adaptive Controllers for Shunt Active Power Filter to improve Power Quality

As of late, the demand for electric power is increasing, which has developed a greater demand to maintain a higher level of power quality and continuity of power supply at the consumer end. But increased use of power electronic devices has imperatively degraded the overall power quality of the power system. Due to the non-linear nature of the power electronic devices various current and voltage harmonics are generated, causing harmonic distortion. These harmonics cause various undesirable effects such as equipment heating, nuisance tripping, overheating transformer, data losses, etc. Shunt Active Power Filters are a viable solution to mitigate these harmonics and thus improve the power quality. In this thesis work, various control strategies of shunt active power filter based on voltage and current controller has been presented to mitigate the current harmonics. To extract the three phase reference source current we have developed control algorithm based on Synchronous reference frame theory (id-iq) and Self Tuning Filter. For regulating the DC capacitor bus voltage various voltage controllers such as PI, PID, Fuzzy and Adaptive Fuzzy PID controllers has been developed. While to generate the gate signal of SAPF multiple current controllers such as Hysteresis band current controller, adaptive hysteresis band current controller, weighted adaptive hysteresis band current controller and Lyapunov function based stable current controller has been developed. To analyze their performance, simulation models of these controllers have been developed using Matlab/Simulink for different operating conditions. A complete hardware setup of the three phase shunt active power filter has been developed using dSPACE 1104 to verify the credibility of the proposed controllers

Fuzzy Logic Controller of Five Levels Active Power Filter

AbstractThis paper presents five-level inverter as a shunt active power filter (SAPF) to compensate reactive power and suppresses harmonics drawn from a diode rectifier supplying RL load under distorted voltage conditions. The harmonic current extraction is based on the use of self tuning filter (STF) and fuzzy logic controller employed to control harmonic current and inverter DC voltage. The aim of the present work is to obtain a perfect compensation by extracting accurate harmonic currents to improve the performances of the five-levels active power filters.The proposed scheme is validated by computer simulation using MATLAB Fuzzy Logic Toolbox in order to show the effectiveness and ability of this method. The results have demonstrated that the proposed shunt active power filter with STF and Fuzzy Logic Controller (FLC) have produced a sinusoidal supply current with low harmonic distortion and in phase with the line voltage

Modelling, Simulation and Fuzzy Self-Tuning Control of D-STATCOM in a Single Machine Infinite Bus Power System

© 2019 Bentham Science Publishers. This is the accepted manuscript version of an article which has been published in final form at https://doi.org/10.2174/2352096511666180314141205In recent years, demand for electricity has increased considerably, while the expansion of generation and transmission has been very slow due to limited investment in resources and environmental restrictions. Methods: As a result, the power system becomes vulnerable to disturbances and instability. FACTS (Flexible AC Transmission Systems) technology has now been accepted as a potential solution to this problem. This paper deals with the modelling, simulation and fuzzy self-tuning control of a D-STATCOM to enhance the stability and improve the critical fault clearing time(CCT) in a single machine infinite bus (SMIB).A detailed modelling of the D-STATCOM and comprehensive derivation of the fuzzy logic self-tuning control is presented. Results: The dynamic performance of the power system with the proposed control scheme is validated through in a simulation study carried out under Matlab/Simulink and SimPowerSystems toolbox. Conclusion: The results demonstrate a significant enhancement of the power system stability under the simulated fault conditions considered.Peer reviewe

Control of the Shunt Active Power Filter under Non-ideal Grid Voltage and Unbalanced Load Conditions

In this study a new method is proposed in order to improve the harmonic suppression efficiency of Active Power Filter for the problems caused by the distorted and unbalanced voltages with unbalanced load currents in control strategy. The proposed control method gives an adequate compensating current reference even for non ideal voltage and unbalanced current conditions. The results of simulation study are presented to verify the effectiveness of the proposed control technique in this study

Improved harmonic suppression efficiency of single-phase APFs in distorted distribution systems

In this study, a control method is proposed to improve the harmonic suppression efficiency of the single phase active power filter in a distorted power system to suppress current harmonics and reactive power. The proposed method uses the self-tuning filter (STF) algorithm to process single phase grid voltage in order to provide a uniform reference grid current, which increases the efficiency of the system. The results of the simulation study are presented to verify the effectiveness of the proposed control technique in this study

Active Filter Modelling To Mitigate Harmonics Generated By Electric Vehicle Chargers

The Automotive industry is going through a rapid transformation to adopt electrified technology. A major share of the electrified vehicles is going to be in the Battery electric vehicles (BEVs) and plug in hybrids segments that need to connect to the grid to recharge the batteries. For customer convenience, the time required for fully charging the battery need to be brought down significantly. EV charging stations are getting installed that could bring down the charging time to less than 30 minutes. However this pose a unique issue to the power quality of the utility grid. During charging, the EV charging unit injects harmonics to the grid. When a large number of EVs are getting charge simultaneously, which is a likely scenario in the future, the degradation in the power quality of the grid would be significant. This thesis discuss the modelling of an active filter to reduce the Total harmonic distortion (THD) generated by electric vehicle (EV) chargers. The main objective of this thesis is to determine the percentage of harmonic current injected by the EV chargers to the power grid and to model an active filter to mitigate the harmonic distortion generated by these chargers. The active filter is modelled as bidirectional three-phase pulse width modulation (PWM) rectifier. The EV in this proposed model is represented as an injected current harmonic source. Positive sequence synchronous reference frame controller (SRFC) is used to generate the reference current. The hysteresis controller is used to compare the load current and injected current, and its output is used to generate the switching pulses for Metal oxide semiconductor field effect transistor (MOSFET). The DC link voltage control is achieved by using conventional Proportional and integral controller (PI) and fuzzy logic control PI. MATLAB/Simulink simulation result shows that the proposed filter can be used to mitigate the THD of EV chargers without violating the limit set by IEEE Std. 519 - 1992