抄録
This paper presents the phase control characteristics for the vector control of a wound-field synchronous motor at a fixed modulation ratio. In the general vector control method, current control is based on two-axis or three-axis control by estimation of the flux direction. In this case, the amplitude of the current control result is generally neglected. However, because several current controllers are work independently, the synthetic amplitude of the voltage must be less than the maximum value of the inverter voltage. This amplitude of the inverter voltage is due to the error in flux estimation. This implies that the utilization efficiency based on inverter voltage modulation reduces. In this paper, the method of phase control using fixed modulation ratio is proposed. With this method, the rating voltage of the inverter and the margin can be easily set. The phase control method assumes a fixed modulation ratio, and hence, it is more efficient than the conventional M-T axis method, which involves current control. Continuous crossover gain change is applied to this control in order to combine the conventional M-T axis current control and the proposed phase control. The characteristics of this control are confirmed by experimental results.
