Design Optimization of Cylindrical-Rotor Synchronous-Induction Motors

The study of large three-phase synchronous-induction motors that are started as induction motors and synchronized with the grid-supply to operate as synchronous motors, is an important topic from an electrical energy efficiency point of view, with limited publication studies. Since no critical account of the optimum design of these motors is yet available, in this paper, the optimum design of the cylindrical-rotor synchronous-induction motor at synchronous speed considering different rotor excitations, is studied. The motor is modeled using both analytical equivalent circuit and finite element methods for performance prediction. Based on the modeling methods, full non-dominated sorting genetic algorithm optimization with Pareto fronts are demonstrated. The algorithm showed the selected objective performance behavior of the motor on a given feasible solution which led to the discussion conclusions of this paper. It is shown that the concentrated flux pole winding of different geometry at a given efficiency results in higher power output when compared to the distributed flux pole winding.