Position Error Correction Method for Sensorless Control of PMLSM Under Variable Speed Conditions

To enhance the accuracy of position and speed estimation obtained through sensorless methods, this paper presents strategies for improving voltage and current quality, along with the design of a feed-forward phase-locked loop (FPLL). Sensorless control methods typically utilize the PLL for position and speed estimation, however, conventional PLL exhibit significant tracking errors during variable-speed operations. Additionally, DC offsets or phase deviations in voltage and current can lead to estimation errors. This paper analyzes the mechanisms by which non-ideal voltage and current affect estimated position and speed, proposing compensation strategies accordingly. Furthermore, an FPLL with amplitude normalization is designed to enhance system order and achieve high estimation accuracy across a wide speed range. Finally, simulations validate the effectiveness of the proposed methods.