고정자저항을 고려한 동기전동기의 스칼라제어에 관한 연구

In conventional constant V/f control of a permanent magnet synchronous motor, it is well known that maximum torque at a given frequency remains constant in spite of change of frequency. However, maximum torque at a given frequency does not remain constant as frequency varies since stator resistance is neglected. This paper shows that the maximum torque of conventional constant V/f control decreases as frequency decreases. In the proposed method, a voltage for scalar control of a permanent magnet synchronous motor considering stator resistance is presented and it is shown that maximum torque at a given frequency remains constant in spite of change of frequency. In simulation results, it is shown that speed control under load is not achieved by constant V/f control because of the decrease of torque level as frequency decreases. In addition, it is shown that motor starting is achieved under load and speed is regulated with the change of load torque in the proposed method. Further, it is also seen that speed reversal operation is achieved in the proposed method.