Improved control techniques for IPM motor drives on vehicle application

The interior permanent magnet (IPM) motor has been popular in both hybrid and fuel cell electric vehicles due to its high efficiency, high torque density and low phase current. Automobiles require both a wide speed range and low power consumption. Peak torque per ampere, regenerative braking and constant power range are critical to maximizing overall vehicle efficiency. Improved control techniques show better performance for vehicle application (limited power source, rapid response of speed and torque). During flux-weakening, a bottom line of maximum torque current is set and controlled. For smooth torque control, flux current is regulated by torque current rather than torque.