| 摘要 |
PROBLEM TO BE SOLVED: To provide a power failure detection circuit for an auxiliary power supply unit for a PWM (pulse width modulation) converter system capable of conducting positive stringing power failure detection with a structure consisting of a small number of electronic parts. SOLUTION: In this power failure detection circuit used in the auxiliary power supply unit for the PWM converter system including an AC reactor and a PWM converter in a main-circuit input, the power failure circuit measures step-out amount of a phase-comparator 23a output of a PLL (phase-locked loop) circuit 23 for PWM converter control, sets power failure when it is beyond a prescribed level, and is provided to detect power failure on power supply side connected with a main circuit. COPYRIGHT: (C)2004,JPO |
