Engine-driven power generating system with over-current protection and

Abstract

An engine-driven power generating system having a bridge circuit section in which low-frequency switching elements are driven alternately by low-frequency drive signals, and high-frequency switching elements driven by high-frequency drive signals during the ON period of the low-frequency switching elements are connected in a bridge network, and an inverter circuit section having a drive signal supply circuit for supplying low-frequency and high-frequency drive signals are each supplied to the low-frequency and high-frequency switching elements that form a pair; the a-c voltage generated by an engine-driven a-c generator is converted into d-c voltage that is in turn converted into a predetermined level of low-frequency a-c voltage; characterized in that an overcurrent detecting circuit for detecting an overcurrent flowing in the bridge circuit section at a level higher than a predetermined level, a drive-signal control circuit that outputs to a drive-signal supply circuit, when the overcurrent detecting circuit detects an overcurrent during a half-cycle of the low-frequency signal in which the low-frequency switching element is turned on, a signal which turns off at least any one of the low-frequency and high-frequency switching elements to be turned on during the half-cycle after the detection of the overcurrent, and a low-pass filter for obtaining a sine-wave waveform on an output end are provided.