| 摘要 |
PURPOSE:To detect the malfunction of the reverse blocking voltage of a coupling rectifier by producing a logical product of an inverted signal of an operation command signal for alternately operating in every one period of time and the output signal of a chopper circuit at the operation side. CONSTITUTION:Chopper circuits 4-1, 4-2, are alternately operated based on operation command signals (b), (c) to produce output signals (h), (i). When coupling rectifiers 6-1, 6-2 are normal, the logical product of the inverted signal of the signal (b) or (c) and an output voltage detection signal (h) or (i) is produced, and then the output (j) remains ''0'' level as it is. When the rectifier 6-1 is, for example, abnormal, the output voltage of the chopper circuit 4-1 side is affected by the influence of the chopper circuit 4-2, the output voltage detection signal becomes wave-form (h'). When the logical product of the detection signal and the inverted signal of the signal (b) is then produced, a ''1'' level signal is presented as the waveform (j'), this is inputted to a flip-flop 13-1 to obtain the output (k), thereby separating the switch 9-1. |
