A new topology for dual rotor/stator BLDC motors applied to marine thrusters

The aim of this study is to present a new topology for dual-rotor contra-rotating brushless direct current (BLDC) motors specially designed for remotely controlled unmanned underwater vehicles, in the form of “BLDC thrusters”. Once presenting the applied typical design by using sizing procedure, the main results obtained are given via simulation principles applying parametric analysis and performance characteristics of a dual-rotor BLDC thruster. Both external and internal rotor radial-field design in the same structure utilize modular concentrated winding, optimized slot-opening and pole/slot ratio, outer and inner diameter for both stator and rotor and stack length parameters for the machine. The output parameters such as flux linkage, armature current, rated torque, rated power, and cogging torque of each motor for different rotor positions are calculated and evaluated. Moreover, the analytical and numerical studies based on finite element methods are performed and compared. In addition, a coupled-circuit analysis is employed to prove the effectiveness of the achieved design to assess the maximum power and torque capability.