A comparative study on pulse sinusoidal high frequency voltage injection and INFORM methods for PMSM position sensorless control

High Frequency (HF) voltage injection methods have been widely used in the low speed drive applications of Permanent Magnet Synchronous Machines (PMSMs). This paper compared two of the HF voltage injection methods, which are HF sinusoidal voltage injection method in the d-q reference frame and Indirect Flux detection by On-line Reactance Measurement (INFORM) method in the α-β reference frame. Implementation methods are deliberated in detail and the position estimation error caused by magnetic field distorsion is also discussed. Experiments using a commercial PMSM are carried out for verifications.