Analysis of the performance of a permanent- magnet A.C. machine

The work presented in this thesis is mainly involved with predicting and evaluating the performance of a hybrid permanent-magnet reluctance synchronous motor. Both computational and experimental results are presentedThe analysis of permanent-magnet machines is very complex due to the presence of both hard and soft magnetic materials, saturation, etc. Conventional methods of analysis are therefore not very suitable. A complete field solution method based on a finite element technique has been used for studying the machine performance. Various aspects of the finite element method as applied to the analysis of permanent-magnet machine fields are also discussed. In order to avoid difficulties of convergence in numerical solutions, iuse has been made of an apparent permeability in re-formulating the field equations. When the magnetic field perpendicular to the initial polarisation is large there is uncertainty about the field components in those directions. Two models for this vector representation have been suggested and tried in solving the fields of several kinds of permanent magnets. A computer program capable of solving many types of field problems has vii been developed. It has also been used in studying several important aspects of design of hybrid motors. A method of analysis, based on field solution, has been suggested for predicting the steady state performance of a hybrid permanent-magnet motor. A system for the accurate measurements of the dynamic performance of motors has been developed and described in this thesis. An analysis of the results of dynamic measurements such as currents, accelerating torques, pull-in and pull-out torques, etc. has also been presented.