Patent ID: 8575772

Claim:
A permanent magnet (PM) machine system, comprising: a PM machine having a q-axis voltage feedback signal and a pullout torque that represents a peak torque that the PM machine generates; a controller in communication with the PM machine, the controller including: at least one control logic for monitoring the q-axis voltage feedback signal of the PM machine to determine a machine flux; at least one control logic for calculating a torque producing current limit based on at least the determined machine flux, the torque producing current limit representing the peak torque producing current the PM machine operates at before surpassing the pullout torque value; at least one control logic for limiting a q-axis current command using the torque producing current limit such that the q-axis current command does not substantially exceed the torque producing current limit; and a q-axis current regulator that receives the limited q-axis current command to produce a commanded q-axis voltage that is supplied to the PM machine.