AC power generating system

摘要

An electric power generating set which automatically varies its speed to match load variations at any time includes an engine driven generator G which provides a positive, Ga and a negative, Gb AC output voltage each of which is rectified by a respective rectifier Re3a, Re3b. Each rectifier Re3a,Re3b has one terminal connected to a common neutral line N. The DC output voltage of each rectifier Re3a, Re3b is boosted in a respective booster circuit which also has one terminal connected to the neutral line N. The combined output of the two booster circuits, Va+Vb is fed to an Inverter IN which converts it to the AC power output of the generating set. A DC load current between the booster circuits and the inverter IN is monitored and used to provide a speed demand feedback signal Srs to the speed control of the engine EN. The inverter IN is controlled so that the voltage and frequency of the AC power output of the generating set are reduced in response to a fall in the intermediate DC voltage Va+Vb that is fed to the inverter IN and which is monitored by a voltage sensor Vsab.