Thyristor controlled reactor-based voltage and frequency regulation of a three-phase self-excited induction generator feeding unbalanced load

Abstract

A self-excited induction generator (SEIG) is one of the cost-effective ways for power generation in remote areas. Unlike common wind energy systems, SEIG needs an excitation capacitor bank to meet the reactive power demand. The terminal voltage of the SEIG depends on the reactive power delivered from excitation capacitor bank which complicates the voltage and frequency regulation. This article presents an unbalanced loaded three-phase SEIG system controlled by fixed capacitor and thyristor controlled reactor in order to overcome poor voltage regulation problem. Moreover, the output frequency regulation is maintained thanks to the speed controller adjusting the speed of the generator. This regulation process employs a response surface model (RSM) instead of steady state equation that determines accurately the per-phase triggering angle of TCR and speed of the generator. Therefore, there is no need to utilize the per-phase equivalent circuit parameters which is the major advantage of the proposed method. The feasibility and reliability of the RSM have been proven by carrying out test experiments. Experimental results of three-phase SEIG (5.5 kW) feeding unbalanced loads have been performed to confirm the effectiveness of proposed method. According to experimental results, voltage and frequency regulations of SEIG have been well performed by using RSM within the maximum 3% regulation error.