Initial position estimation of small SPMSM for position sensorless control

Much attention has been paid to the initial position estimation of permanent magnet synchronous motors (PMSMs), the most of which are effective to only interior permanent magnet synchronous motors (IPMSMs) with the rotor magnetic saliency. This paper aims at the position sensorless control of small surface permanent magnet synchronous motors (SPMSMs) designed for high speed operation, so that the saliency-dependent position estimation approaches are no longer effective to this type of the motor with no saliency. This paper proposes a method for the initial position estimation of SPMSMs based on inherent characteristics of the test motor, that means the position-dependent line-voltage waveforms.