An optimal direct thrust force control for interior Permanent Magnet Linear Synchronous Motors incorporating field weakening

Abstract

This paper presents an optimum direct thrust force control for interior permanent magnet linear synchronous motor (PMLSM) over wide velocity range in which the maximum thrust force per ampere (MTPA) strategy is used below the base velocity and field weakening strategy is used above the base velocity. Using MTPA strategy, copper losses is minimized in constant force region, and using field weakening strategy, maximum capacity of motor is utilized in constant power region. The proposed scheme incorporates all the optimal strategies and operates the drive within the voltage and current limits of the motor/inverter. Simulation results for a prototype interior permanent magnet linear synchronous motor demonstrate that the MTPA and field weakening strategies can be successfully implemented for direct thrust force controlled PMLSM drives.