| 摘要 |
PURPOSE:To perform detection of a flux actual value with a high accuracy little affected by drift or offset by obtaining said flux actual value as a digital quantity. CONSTITUTION:The output line voltage of a PWM inverter 1 is divided into the information on magnitude and polarity by a polarity detection circuit 3. A clock generator circuit 4 outputs a pulse having a frequency proportional to a DC intermediate voltage Edc. From said both outputs, a flux arithmetic circuit 5 switches the directions of counting up and down of a counter according to the information on polarity, conducts an integrating action by counting by means of a clock and obtains flux actual values phiR, phiS, phiT as digital quantities to contrive to improve the detection accuracy. |
