| 摘要 |
PURPOSE:To enable to monitor the speed even when the speed signal from a tachometer generator is interrupted by monitoring the rotating speed by the logic sum of the output of a pulse width modulator and an interphase energizing timing signal obtained from a phase current signal. CONSTITUTION:A DC/3-phase converter 19 outputs 3-phase AC signals IU-IW by a deviation IS between a speed command voltage VCMD and the actual speed voltage TSA from a tachometer generator 16 and a signal from a pulse coder 15. A pulse width modulator 26 outputs pulse width modulation signals S1-S6 to an inverter 13 in response to a deviation between the signals IU-IW and a phase current. An interphase energizing timing circuit 27 outputs an interphase energizing timing signal by the signals S1-S6 and the phase current, and the timing signal becomes a rotating speed signal through an OR gate 28 and a filter 29. |
