MODELING AND ANALYSIS OF A GRID CONNECTED INDUCTION GENERATOR USING AC VOLTAGE CONTROLLER

Abstract

In this thesis, the performance of a three phase grid-connected induction generator has been studied using a solid state converter as an interface between the grid and the generator terminals. Three types of AC voltage controllers have been used. The first one is the naturally commutated AC voltage controller, the second one is the transistorized AC voltage controller under different control strategy, and the third one is the AC chopper control strategy. The performance analysis has been carried out through modeling the system by a novel equivalent circuit in a pseudo-stationary abc-dq reference frame. Based on the circuit model, a comprehensive mathematical model has been developed. The model is capable of dealing with nonlinearities introduced by the used solid state converters. The performance characteristics of the grid-connected induction generator have been computed for a wide range of operation conditions and different switching strategies, through a simulation computer program. The performance using AC chopper control strategy has been assessed by comparing it with the performance when using AC voltage controller employing natural and forced commutation control strategies. The comparison highlights the advantages and disadvantages of using AC chopper as an interface between the network and the induction generator.