Gearing as a part of an Electric Machine Functionally - Study and optimization of a partitioned stator switched flux permanent magnet machine

Abstract

The idea to couple a gear magnetically has been around for some time, and has gained increased interest in recent years. By manipulating air gap field harmonics, magnetic gearing has been shown to have comparative, or even better performance than its mechanical counterpart, while circumventing typical mechanical disadvantages. Recently, magnetic gearing has been integrated into Permanent Magnet motors to obtain "pseudo" direct-drives that result in efficient high-torque density at low speed electrical machines. This thesis investigates such a promising machine topology, using the Finite Element Analysis tool COMSOL Multiphysics. The general magnetically geared Partitioned Stator Switched Flux Permanent Magnet machine was found to be able to meet the requested specifications of 200kNm and 4.2MW, with challenges being low power factor and high cogging torque. This machine is a very interesting concept that may be used for low-speed high-torque application when lower power factor can be managed(i.e. power electronics).