Analysis of Low Cost Permanent Magnet and Reluctance Electrical Machines with Different Rotor Anisotropy for Variable Speed Drive

Abstract

This thesis deals with the electromagnetic design of low cost Permanent Magnet Synchronous Motor (PMSM) with different rotor anisotropies as well as two types of Synchronous Reluctance (SynR) machines. Six machines have been compared and analysed on the basis of same stator winding and the number of poles. This thesis conducts holistic approach to investigate maximum torque per ampere (MTPA) angle for each topology. The main objective of this work is to investigate some of the key machine performance, in order to investigate the electromechanical characteristics such as, power, efficiency, torque, PM flux linkage, d-q axes synchronous inductances, saliency ratio and current characteristics with all operating speed range and in various loading conditions. This analysis is conducted by means of finite element analysis (FEM) and mathematical formulations. This thesis presents an analytical model for surface mount permanent magnet (SMPM) and results are verified with FEM. In addition, SMPM, Inset permanent magnet (PMs) and Interior PMs machines are optimized by reducing the air gap in order examine performance with their base model. Moreover, an analytical model to estimate the iron loss in PMs machine is developed and included in the designed procedures. However, flux density values in areas corresponding to stator teeth and back iron core were taken from results of FEMM for using in the iron loss model. Finally, this thesis presents the effects of magnet on d-q inductances in PMs machines configuration are studied and their results are compared to each others