Hunting Protection of Synchronous Motor by Field Control

계자제어에 의한 동기전동기의 난조방지

To proteting hunting of synchronus motor a new one which has two field windings is designed. One is main field winding excited constantly and the other is control field winding excited only during the load of motor changes. The oscillation of the motor is controlled by increasing or decreasing the control field excitation. To determine the optimal field excitation the Pontryagin's minimum principle is applied. Also this paper gives the optimal trajectories of the motor and it's transition time. This motor has some of better properties than the old motor with damper winding. These phroperties are (1) there is no hunting (2) the transient stability is improved (3) transition time is very short.