Sensorless operation of a PWM rectifier for en-gen set as a distributed generation

In this paper an engine generator (en-gen) set is used as a distributed generation system. This paper presents the interface and control strategies for the en-gen set using a PWM rectifier without any ac reactors and voltage sensors. A scheme to estimate the generator´s EMF voltage from the measurement of ac line currents, a method to get a synchronous angle from the estimated EMF voltages and techniques of obtaining the integrators´ initial values in the estimator are proposed. The feasibility of the overall algorithms has been verified throughout experiments using a 35 hp commercial en-gen set.