Analyzing Harmonic Effects on Synchronous Generator Supplying Parallel PWM Rectifier in Hybrid Train Systems

Hybrid trains for transportation now days is increase in popularity due to many benefits than diesel trains. Hybrid trains discussed in this paper contain two generators and one battery as electrical power sources. Generator is connected in series with PWM rectifier and the output rectifier is connected in parallel with the battery. Unbalance PWM signal that controls an insulated gate bipolar transistor (IGBT) creates an unbalanced load to generator that generate harmonics distortion to AC power. This paper is written to analyze harmonic effects on synchronous generator supplying parallel PWM rectifier in hybrid train systems. The analysis uses two cases the first case is using two generator and one battery as power source, and the second case is using one generator and one battery as power source. Research result shows that if the load is higher, the THD will be lower. The results from first case simulation shows load 10% gets 4.08% harmonics distortion in first and second generator, load 20% get 3.66% and 3.397% for first and second generator, load 30% get 3.65% and 3.64% for first and second generator, load 40% get 3.62% and 3.61% for first and second generator. The results from second case simulation shows load 10% get 3.86%, load 20% get 3.68, load 30% get 3.67%, load 40% get 3.60% harmonics distortion for first generator. For load 60 until 70%, the result of total harmonic distortion in first and second case is the same which is load 60% get 3.55% and 3.57% for first and second generator, load 70% get 3.61% and 3.48% for first and second generator, load 80% get 3.60% and 3.46% for first and second generator, load 90% get 3.46% and 3.50% for first and second generator, load 100% get 3.48% and 3.44% for first and second generator.