Basic experiments for high-torque, low-speed permanent magnet synchronous motor and a technique for reducing cogging torque

Fully integrated electric propulsion systems are gaining popularity in both commercial and military sectors. Propulsion motor manufacturers are investigating new direct drive solutions for use in electric ships. These applications require motors with high torque output at low speeds. Such requirements were the motivation for the design of a new PMSM with a novel topology. Firstly, this paper describes an efficient model of a motor used for high thrust at low speed. Secondly, the authors analyze the theory for motor´s behavior. To compare the theoretical result, characteristics of the proposed motor have been tested. The cogging torque has been a serious problem. Therefore, an analytical model of the cogging torque has been derived for calculating and reducing it. An appropriate skew angle can be designed based on the model.