Design and Evaluation of a Magnetically Geared PM Machine

This paper presents the design and evaluation of a magnetically geared permanent magnet (PM) machine with an inner stator. A brief overview of relevant operating principles is given first. A simplified design and simulation methodology, which can ensure that the magnetic gear and the stator are well matched, is then devised. The method is applied to the design optimization of a small machine resulting in a design with a maximum torque density of 115 kN · m/m³ per active volume. To validate the design, a working prototype has been built and experimentally evaluated. It shows that this computationally efficient design methodology is well suited for the optimization of magnetically geared PM machines. Finally, a method of analyzing the operating points of the machine is described. Relevant conclusions are drawn and recommendations for future work are given.