| 摘要 |
PURPOSE:To detect a synchronizing signal having an insensitive band stable even if the waveform of an AC power source is deformed by connecting a filter with a synchronizing signal source, and correcting the voltage waveform distortion. CONSTITUTION:Filters 4F, 5F, 6F are, for example, formed of filters made of resistors and capacitors, thereby correcting the waveform distortions of the phase voltages. In this case, even if the crossing points of the phases 1, 2, 3 are displaced by the influence of the time constant of the filters 4F, 5F, 6F, the suitably divided voltage and the phase voltages are combined and inputted to a comparator 7, and the time points of leading or delaying by the electric angle determined by the voltage dividing ratio of voltage dividers 4R, 5R, 6R with respect to the time point of switching the amplitude relationship of power source voltages can be detected. When the delay or lead electric angle is used as a base for the control signal, a synchronizing signal having stable insensitive band can be obtained. |
