Characteristics of a disc permanent magnet linear synchronous machine with back iron

A disc permanent magnet linear synchronous machine (DPMLSM) with back iron is presented in this paper. The proposed machine is to fulfill the requirements of high efficiency and targe torque for electric vehicle (EV) applications. The bark iron plays an important role to enhance flux linkage and reduce flux leakage so that the designed machine is with the characteristics of high flux and power density to reduce the physical volume of EV. The steady-state, dynamic operating characteristics, and three-dimensional (3-D) finite element analyzes are obtained to demonstrate the performance of the machine. Experimental results show that the proposed machine has a very low line current distortion with just a six-step inverter and a very wide range of operating speed without gear-ratio devices.