Multidisciplinary analysis of a 750 kW PMSM for marine propulsion including shock loading response

Abstract

This study presents the electromagnetic, thermal and mechanical analysis of a 750 kW, 1200 rpm, 690 V surface permanent magnet motor aimed at marine propulsion (azimuth thruster). Based on a preliminary machine design, key electromagnetic design aspects including magnet demagnetisation and magnet loss reduction by tangential and axial segmentation are assessed. Then, three different cooling solutions are evaluated via computational fluid dynamics simulations combining the use of a water-jacket surrounding the stator, wafters attached to the rotor structure and the addition of an inner fan. Subsequently, the dynamic design analysis method is applied in order to check the machine's response to shock loadings due to underwater explosions. Finally, a machine prototype is successfully manufactured and tested, showing the proper fulfilment of the design requirements.