Amending Algorithm to Measure Motor's Initial Position in PMSM Servo Systems

In the applications of increment photo-electricity pulse encoders, how to measure rotor's initial position accurately was a difficulty for servo systems. Based on principle of initially positioning, function of Z signal and calculation of electromagnetism torque, a rotor's initial position amending algorithm was proposed. Stator current in aimed position was output to detect rotor's actual position and the rotor should return to the initial position in real time. For the recursive function, range of detection reduced gradually. Moreover alveolus clearances in transmission machine could submerge the rotor's libration so as to decrease loads' dithering. Experimental results prove that the algorithm can decrease the rotor's librating amplitude and improve the positioning precision in rotor's initial position measurement.