Variable speed constant frequency diesel power conversion system using doubly fed induction generator (DFIG)

Most of the diesel generators (DG) set used in remote areas runs at constant speed to produce ac output power with constant voltage and constant frequency. In remote areas the peak demand typically occurs only for a few hours in the evening. Therefore the DG set has to be heavily over-sized in relation to the prevalent load conditions. However prolonged light load operation results in poor fuel efficiency and excessive maintenance problems. In this paper, a variable speed diesel power generation system using a DFIG is presented. The control strategy for the diesel engine enables it to operate below and above the synchronous speed according to load demand. Simulation results of the dynamic system and preliminary experimental results based on a 15 kW prototype are included.