JPS5743600A - Phase control device - Google Patents

Abstract

PURPOSE:To obtain a phase control range which is sufficient even for variation of number of revolutions of a synchronous generator, by providing frequency compensation on a phase control circuit of gate pulse of thyrister. CONSTITUTION:When a synchronous signal 14 is positive, output of an amplifier 16 becomes negative, field effect transistors 42 and 45 become OFF, and a capacitor 40 is charged by bias voltage to be determined by resistors 37 and 38 and also by voltage which is proportional to a signal of number of revolutions sent out from a converter 8. When a total of output of amplifier 41 and a control input signal Ei exceeds a bias voltage Vd to be determined by the resistors 24 and 25, output of an amplifier 28 reverses toward negative direction and generates a gate pulse. When synchronous signal 14 becomes negative, the capacitor 40 discharges even at the time when the field effect transistors 42 and 45 are ON. It is possible, by doing so to obtain a phase control region which is sufficient even for variation of number of revolutions.