Position sensorless control of synchronous reluctance motors at very low speeds region using high-frequency current control system

Synchronous reluctance motors (SynRMs) have attracted studies, because SynRMs have no magnets in the rotors. The position sensorless control at low speeds of SynRMs is now desired, and several methods have been proposed. In this paper, by using the high-frequency current control system, a new position sensorless control method of SynRMs at low speeds by superimposing high-frequency current whose amplitude is small constant value has been proposed. The experiments show that the proposed method is very useful even if the very low speeds region.