Wide Speed Range Control of PMSM Based on MTPA and Flux-Weakening Control

This work gives a brief analysis of vector control strategy for field weakening (FW) and maximum torque per ampere (MTPA) operation of permanent magnet synchronous motor (PMSM). Features such as higher efficiency, smaller size, faster dynamic response and large torque-to-inertia ratio makes the application of PMSM suitable for the electric vehicle (EV). However, because of permanent magnet on rotor, i.e., constant flux, permanent magnet (PM) motors have small constant power speed range (CPSR). This drawback limits the application of PMSM in EV's where wide speed operation, above base speed, is required. The high-speed operation under constant power zone can be extended either by increasing the output voltage of drive or by using FW control methods. However, the dc bus limits the output voltage of a conventional drive. Initially, in the constant torque zone MTPA control is implemented. Then constant voltage constant power (CVCP) FW strategy is implemented in the constant power zone. The above-mentioned vector control strategies have been simulated on a PMSM drive in MATLAB/SIMULINK.