Analysis and Application of Synchronous Motor Running at Adjusted Voltage

Two problems-power factor regulation and out of synchronism protection for synchronous motor need to be further investigated under inverter supply power. Due to the inherent relations among the stator voltage, current, power factor, and power angle, the adjustable stator voltage takes an effect on the variation of these parameters. This paper presents the relationship of the quantities using phase graph under steady state adjustable voltage. It also demonstrates the calculating model and their regular interactions of the aforementioned variables. Finally, the validity of analysis has been verified by the experiment. The results show that the power factor control in certain range and out-of synchronism protection can be effectively implemented by adjusting the stator voltage.