A starting strategy for a robust position sensorless technique in non-salient PM AC motor drives

This paper discusses the starting strategy of the position sensorless technique for PM motors without rotor saliency. The technique relies on the rotor position increment calculation, which can form an internal closed loop. Using a PLL algorithm, the internal closed loop can correct position from random initial value. Therefore, the technique can start the motor drive from standstill directly without the help of any special stalling strategy. The results provided in this paper demonstrate that the technique can directly start a PM motor drive smoothly and has relatively higher dynamic performance.