| 摘要 |
PURPOSE:To prevent the decrease in the controllability by comparing the power factor calculated during nonintrference control with the actually measured power factor to correct the setting of a magnetic flux, thereby always constantly controlling the variation in the magnetic flux due to the variation in the constant of a motor. CONSTITUTION:A reverse/normal tangent function calculator 11 calculates the phase angle phii of the primary current, and a reverse/normal tangent function calculator 12 calculates the phase angle phiv of the primary voltage. A deviation is obtained from the phase angles phii, phiv by a comparator 13, and the phase difference and hence the set value of the power factor phi* is obtained. The actually measured phase difference of ea* and ia and hence the actually measured power factor phiFB is detected by waveform shapers 14, 15, an inhibit circuit 16, a timer 17 and a divider 18. A comparator 19 buts the set power factor phi* and the actually measured power factor phiFB, and a set current value i1alpha* is obtained by a magnetic flux control amplifier 20 via the deviation. |
