The engine-generator dynamics at a sudden load change (from low load to high load) remains a challenge in case of variable speed diesel generator. The dynamic behavior analysis presented here proves that the introduction of an energy storage element into the EGS with variable-engine-speed concept eliminates this drawback. This paper addresses the identification of the dynamic behaviour of such variable-speed EGS systems and the problems encountered during a sudden increase of load (power and voltage drops).@en

This paper brings some practical results of research devoted to the new generation of mobile electrical power sources, based on the VSCF technology (Variable Speed ¿ Constant Frequency). In this generation of mobile electrical power sources the driving motor and generator speed is optimally controlled in accordance with the load power thus decreasing the fuel consumption. The output voltage and frequency are stabilized by means of power electronics converter. The measurements show that the real drawback of this concept of EGS with variable speed of engine is the engine-generator dynamics at sudden transient from low load to high load. Dynamic behaviour of the driving engine in the case of sudden power output increase requires the time of few seconds to change the speed of engine from low to higher speed. During this time, the power required by the load is not available and diesel engine can by high load at the low speed stop undesirably. Electronic converter can improve the dynamic behaviour of whole EGS system by means of inserting accumulated energy to the DC link of AC/DC/AC converter.@en