| 摘要 |
PURPOSE:To effectively reduce loss in a synchronous motor and an inverter even if the output of the motor varies by providing a phase difference detector, integrating the deviation by an integrator as a voltage correction signal to a voltage reference signal. CONSTITUTION:A phase difference detector 14 detects a phase difference theta on the basis of a current signal (i) from a current detector 13 and a voltage phase signal (v) from a PWM controller 10. Then, a deviation theta between the signal theta and the phase difference reference signal thetaRF of the output of a phase difference reference setter 15 is integrated by an integrator 16 to produce a volage correction signal Vc to raise the voltage when the signal is theta is advanced from the signal thetaFR and to reduce the voltage when the signal theta is delayed from the signal thetaFR. Thus, the armature current (i) can be always operated near the minimum current value, and the losses of the motor and the inverter can be effectively reduced at a light load time. |
