A Novel Computationally Efficient Finite Position Set-Phase Locked Loop for Low-Speed Sensorless IPMSM Control

This letter proposes a novel computationally efficient finite position set-phase locked loop (FPS-PLL) for lowspeed sensorless interior permanent magnet synchronous motor (IPMSM) control. A novel equivalent position error is designed based on the complex operation of current responses, enabling the derivation of an improved Newton iteration formula. The iteration formula is convergent in the whole computational domain, so that the iterative operations about cost function for appropriate iterative initial value can be avoided. Only two iterations are required to obtain the finest rotor position, which is less than existing FPS-PLL schemes. The parameter tuning is avoided in the iterative search process for rotor position and the fast dynamic response is achieved. Moreover, a tracking differentiator-based speed observer (TDSO) is designed to extract the rotor speed without introducing the differentiator. Finally, the effectiveness of proposed scheme is verified by experimental results.