| 摘要 |
PURPOSE:To enable the detection of a rotor position even at a stopping and a low speed time by employing a power source containing pulsating component in the output waveform of a rectifier, chopper or the like as an excitation power source and detecting the armature coil voltage induced by the pulsating component. CONSTITUTION:When a single-phase full-wave rectifier is used in an excitation power source 10', a pulsating field voltage and a U-phase armature coil induced voltage superposed with the electromotive force of a transformer by the field pulsating with the speed induced voltage are inputted to a transformer electromotive force zero point detector 19 via a filter 18. Signals corresponding to the U-phase-W-phase are outputted from an electromotive force zero point detector 19, and are inputted to a signal selector 20. The selector 20 respectively selects the output of the detector 19 at the stopping and low speed times and the output of a speed electromotive force zero point detector 17 at high speed rotating time with sufficiently large speed induced voltage. A phase shifter 21 will produce a motor side firing signal by the selected output, and the outputs of the speed detector 14, and the current detector 15. |
