Robust Electromagnetic Design of Double-Canned IM for Submergible Rim Driven Thrusters to Reduce Losses and Vibration

Due to their harsh operational environment, losses and vibrations are vital performances in the design stage of double-canned induction motors (IM) for the submergible rim-driven thruster (SRDT) applications. However, the traditional design approaches cannot be directly applied to that family of IMs as more influential factors (i.e., the flat structure, large diameters, eddy current losses in the cans, and the local saturation effect) should be attentively considered. This study presents a robust electromagnetic design procedure for double-canned IM, combining the traditional magnetic circuit method (MCM) and the finite element method (FEM). Firstly, the improved MCM is adopted to determine the size of the machine, including the stator outer and inner diameters, the core length, etc. Moreover, the reasonable ranges of the critical parameters are obtained. Afterward, considering the losses and electromagnetic forces, time-stepping FEM is used to perform an excellent analysis of the essential parameters of design, and the thermal and stress analyses are coupled to evaluate the optimal design schemes. A design example of a 3 kW double-canned IM is presented, and the prototype is manufactured. Loss and noise experiments are performed to verify the effectiveness of the given procedure.