Torque enhanced Flux-Switching PM machine for aerospace applications

During the past decade Flux-Switching Permanent Magnet (FSPM) machines have been the object of increasing investigation due to its inherent advantages regarding torque density and fault tolerance. Due to these facts they are greatly attractive for aerospace applications where low-weight and limited installation spaces play an all-important role and where safety is a critical factor. In the search for alternative topologies that comply with these criteria, so that they can be deployed in a More-Electric Aircraft (MEA) for the purposes of propulsion or power generation, recent publications have given attention to a machine variant from the conventional FSPM machine called the C-Core FSPM machine. The C-Core FSPM machine offers roughly 40% greater electromagnetic torque than conventional FSPM machines, while using half of the magnet mass. This paper identifies measures to increase the electromagnetic torque by a further 20% to 30% while maintaining the machine volume and phase current constant and using no more magnet material than a conventional FSPM machine. An approach to exploit this advantage is proposed and developed for use in all FSPM machines. The greatest potential is identified to be in C-Core and E-Core FSPM machines.