Variable Speed Engine Generator with Super-Capacitor; Isolated Power Generation System and Fuel Efficiency

A variable speed engine generator set for an isolated power system is investigated to reduce fuel consumption and emission than conventional fixed speed engine generator. However, the power quality of the variable speed engine generator set would be degraded to the sudden load power surge, and the power required by the load would not be available because of the lowered operating speed condition and the sluggish dynamics of the engine in this variable speed engine generator system. A super-capacitor bank incorporated with the variable speed engine generator set can improve dynamic characteristics under such a sudden load change, and power quality, fuel consumption, and emission of pollutants can be improved remarkably. And the superiority of three phase four leg inverter to an unbalanced load is verified by the computer simulation and experimental results In this paper, the feasibility of the system has been verified based on a 26 kw commercial diesel engine generator system.