Optimal Design of a Novel Doubly Salient Permanent Magnet Motors for High Power Ship Propulsion

In this paper, an optimal design of unconventional electrical motor called Multiphase Doubly Salient Permanent Magnet Motors is performed in order to fulfil the specifications of a high power naval propulsion motor. The design aims to maximize torque to mass ratio. Particle swarm optimization method is used for the design of this kind of doubly salient permanent magnet machines with 3, 4 and 5 phases. All the studied machines have the same volume and use the same active part material characteristics (magnets, iron and copper). The electromagnetic performances and geometrical main data of the studied machines are analyzed and compared with those of a reference 3-phase conventional permanent magnet synchronous machine designed for ship propulsion. For the same constraints, the proposed machines exhibit a 90% lower permanent magnet volume and are colder than the compared machine. So, the proposed machines appear suitable for this kind of application.