Performance of Interior Permanent Magnet Motor Drive over Wide Speed Range

This paper investigates the performance of an interior permanent magnet synchronous motor (IPMSM) drive over wide speed range for high-precision industrial applications. The scheme incorporates the maximum torque per ampere (MTPA) operation in constant torque region and the flux-weakening operation in constant power region in order to expand the operating limits for an IPMSM. Improved mathematical expressions are derived to analyze the performances of the IPMSM. The power ratings of the motor and the inverter are considered. The effects of motor parameters particularly, the saliency ratio (Xq/Xd) on the voltage limit constraint, and the power capability of the inverter are also investigated. The efficacy of the above-mentioned drive system and the improved steady-state analysis are evaluated by both experimental and computer simulation results. The complete drive is implemented in real time using digital signal processor (DSP) controller board DS 1102 on a laboratory 1 hp interior permanent magnet synchronous motor.