Design using simple modeling and experimental study on direct-drive disk-type motor with dense stator configuration

Electric propulsion system in marine application has been given high attention due to energy saving and low maintenance requirements. A transverse flux-type machine (TFM) with permanent magnets (PMs) has been developed as a direct-drive propulsion motor without gearbox called for high torque at low speed and high reliability simultaneously. This manuscript describes design procedure of the TFM using simple modeling focused on magnetic-circuit structure of the motor. The electrical design of the motor is based on electrical and magnetic theory. The minimalist design is shown to be advantageous for effective use in three-dimensional numerical analysis. The validity of the proposed method and the fulfillment of design requirements, torque density defined as torque to total volume ratio of more than 10kNm/m³ and power factor (PF) of more than 0.80, are verified through the numerical computation and experimental result on a prototype machine. High torque density and high PF contributes to compactness of whole motor-drive system including motor and power converter system.