Axial flux circumferential current permanent magnet electric machines

A novel class of permanent magnet machines featured with axial flux and circumferential current, or AFCC, is presented in this thesis. The new drives are based on an innovative AFCC machine topology which consists of a stator with permanent magnets and iron poles, a circumferential current winding and a rotor with salient poles. The stator has embedded flux concentration structures. The winding links all the flux of every pole which offers the potential to obtain higher variation ratio of the winding flux linkage by an increase in the number of poles. The circumferential winding totally eliminates the end-winding portion of the machine, resulting a significant reduction of copper used, and copper loss.; In order to develop the concept of AFCC machines, a general approach is presented to investigate the theory of sizing equations of electric machines. The general purpose sizing equations can be a very desirable tool to investigate a variety of electrical machines. The power densities of several novel electrical machine topologies have been assessed using the traditional induction machines as the reference point.; Based on the above investigations, the guidelines have been summarized for the quest for machine topologies with high power density or high torque capability. The innovative AFCC machine topologies are then introduced.; Sizing equations and the equivalent circuit models of the proposed AFCC machines are derived. Three-dimensional finite element analysis technique is used to predict flux distribution, inductance and torque capability. The design guidelines and optimization suggestions are discussed and time domain simulation results are also included.; The prototype of a single-phase 12-pole AFCC machine, as well as a closed loop drive system based on DSP technology, has been designed, manufactured and tested. The operating principle and torque capability of the AFCC machine has been verified and assessed. It is found that the machine offers higher torque capability in comparison to traditional commercial induction machines and brushless permanent magnet machines.