Performance Analysis of Type-1 and Type-2 FLC based Shunt Active Filter Control Strategies for Power Quality Improvement

摘要

In recent years electrical power quality has been an important and growing problemudbecause of the proliferation of nonlinear loads such as power electronic converters in typicaludpower distribution systems. Particularly, voltage harmonics and power distribution equipmentudproblems result from current harmonics produced by nonlinear loads. The electronicudequipments like; computers, battery chargers, electronic ballasts, variable frequency drives,udand switch mode power supplies, generate perilous harmonics and cause enormous economicudloss every year. Problems caused by power quality have great adverse economic impact onudthe utilities and customers. Due to that both power suppliers and power consumers areudconcerned about the power quality problems and compensation techniques.udIssue of harmonics are of a greater concern to engineers and building designers becauseudharmonics can do more than distort voltage waveforms, they can overheat the buildingudwiring, causes nuisance tripping, overheat transformer units, and cause random end-userudequipment failures. Thus power quality (PQ) has become more and more serious with eachudpassing day. As a result active power filter (APF) gains much more attention due to excellentudharmonic and reactive power compensation in two-wire (single phase), three-wire (threephaseudwithout neutral), and four-wire (three-phase with neutral) ac power networks withudnonlinear loads. The APF technology has been under research and development for providingudcompensation for harmonics, reactive power, and/or neutral current in ac networks. Currentudharmonics are one of the most common power quality problems and are usually resolved byudthe use of shunt active filters.udIn this research work, the performance of the shunt active filter control strategies has beenudevaluated in terms of harmonic mitigation and DC link voltage regulation. Three-phaseudreference current waveforms generated by proposed scheme are tracked by the three-phaseudvoltage source converter in a hysteresis band control scheme. This research presents differentudtopologies and controllers with enhanced performance of shunt active filter for power qualityudimprovement by mitigating the harmonics and maintaining dc link voltage constant.udFor extracting the three-phase reference currents for shunt active power filters, we haveuddeveloped shunt active filter Instantaneous active and reactive power “p-q” andudInstantaneous active and reactive current “Id-Iq” control strategies. For regulating andudmaintaining the DC link capacitor voltage constant, the active power flowing into the activeudfilter needs to be controlled. In order to maintain DC link voltage constant and to generate theudcompensating reference currents, we have developed PI Controller, Type-1 and Type-2 Fuzzyudlogic controller with different Fuzzy MFs (Trapezoidal, Triangular and Gaussian). Theudproposed APF is verified through MATLAB/SIMULINK. The detailed real-time results usingudReal-time digital simulator are presented to support the feasibility of proposed controludstrategy.