Torque control method for permanent magnet synchronous motor operating in field weakening region at middle speed range

Abstract

In this paper, a torque control method for permanent magnet synchronous motors (PMSMs) functioning in the middle speed range of the field weakening control region is proposed. The current resonance due to d axis and q axis coupling cannot be neglected. The current resonance is depressed by the appropriate design of PID controller for the q-axis current. The proposed controller designing method is verified both numerically and experimentally. The influence of parameter changes is also examined to reveal that the Lq change affect the torque performance more than Lq and Rm does.