Power quality enhancement in off-grid hybrid renewable energy systems using type-2 fuzzy control of shunt active filter

Abstract

Maintaining a clean, reliable and efficient electric power system has become more challenging than ever due to the widespread use of solid-state power electronic controlled equipment in industrial, commercial and domestic applications. Non-linear loads draw non-sinusoidal current and reactive power from the source causing voltage and current distortion, increased losses in the power lines and deterioration of the overall power quality of the distribution grid. Devices such as tuned passive filters are among the oldest and most widely used techniques to remove power line harmonics. Other solutions include active power filters which operate as a controllable current source injecting a current that is equal but with opposite phase to cancel the harmonic current. This chapter deals with the design of fuzzy control strategies for a three-phase shunt active power filter to enhance the power quality in a hybrid wind-diesel power system operating in standalone mode. The proposed control scheme is based on Interval Type 2 fuzzy logic controller and is applied to the regulation of the DC bus voltage to compensate for real power unbalances during variable load conditions. A simulation study is performed under Matlab/Simulink to evaluate the performance and robustness of the system under different wind speed conditions.