Sensorless control of PM synchronous motors at zero speed

A simple but effective sensorless technique for permanent magnet synchronous motor drives is presented in this paper exploiting the anisotropy of the machine. It properly works at any speed, ranging from zero to the rated value and can be applied to both salient and nonsalient machines. A suitable procedure allows to detect the initial rotor position as required in PM drives. Experimental results on some prototypes with different PMSMs are presented to practically evaluate the consistence of the proposed technique