Design and experimental verification of high power density interior permanent magnet motors for underwater propulsions

This paper presents the design details for IPMs developed for underwater propulsion with a peak power to weight ratio of 4.09 kW/kg. The technical aspects of the increase in power density and the reduction of losses are discussed. Load characteristics and motor design requirements are analyzed. Optimization procedure is presented and comparisons are made between different designs in order to examine the effect of critical design parameters and materials. The electromagnetic, thermal and stress fields are computed with the finite-element method (FEM). Special attentions are paid to the electromagnetic and thermal designs in order to extend the duration of operation at short-time duty. Practical IPMs are designed and manufactured. Finite element analysis (FEA) and experimental results show that the designs fulfill the applications effectively.