The Development of Initial Position End-of-Line Test System for PMSM

The resolver is widely used in the production applications due to the robust mounting and high accuracy at full range. However, the mounting accuracy of such sensors will significantly limit the torque accuracy and performance if the initial positions are not calibrated at the end-of-line (EOL) test. An initial position EOL test system is designed base on the production requirements. A simple initial position measurement method is introduced and applied to the PMSM motor, which measures the back EMF and the North mark (NM) signal of the resolver. The time difference between the back EMF zero crossing point and NM signal is divided by the back EMF period and then the initial position is calculated. The method is validated on the target bench and experiments prove the EOL test system is suit for the mass production.