Standalone Pico-Hydro Battery Integrated Universal Power Active Filter for PQ Improvement

This paper presents a damped ratio adaptive second-order generalized integrator (DRASOGI) control method for power quality (PQ) improvement of standalone three-phase system. This system consists of a governor-less pico-hydro turbine-driven three-phase squirrel-cage induction generator (SCIG) battery energy storage. This microgrid is integrated with a three-phase universal power active filter (UPAF) for improving the voltage profile of the load side network and power quality of the generator output voltages and currents. The system’s efficiency is maintained and reduced the maintenance cost by operating the SCIG at 10 % to 20 % below its rated capacity. The load voltage is maintained at its rated voltage even when the source voltage is below its rated value by injecting a proper voltage by the series active filter of UPAF. Moreover, the reactive power and harmonics are eliminated by the shunt active filter of the UPAF. The voltage magnitudes and the frequency are maintained during any fluctuation in load (increased or decreased) or load unbalancing condition. The total harmonic distortions of the currents and voltages output of the SCIG and load side network are achieved within the limit of IEEE standard 519 and IEC standard 61727.