Power quality improvement in three-phase four-wire distribution systems by DSTATCOM and using adaptive hysteresis band current controller

In this paper, synchronous reference frame theory controlling strategy is presented to generate reference current utilizing four-leg three-phase four-wire Distribution Static Compensator (DSTATCOM). An adaptive hysteresis band current controller is proposed to control the hysteresis bandwidth according to the modulation frequency, supply voltage, DC capacitor voltage and slope of the reference compensator current wave. DSTATCOM is used to compensate reactive power, neutral current, harmonic elimination and balancing load currents. The performance of these methods is investigated using Matlab/Simulink software under various load conditions considering IEEE standard 519-1992 recommendations for three-phase four-wire distribution systems. The results show appropriate compensation performance under linear and balance load as well as unbalanced and non-linear load conditions for proposed strategies.