Optimal switching-flux motor design and its cogging effect reduction

This paper presents an optimal switching-flux motor design in terms of cheap cost, simple manufacturing process, and easy maintenance. The high cogging effect and its impact on the performance of the machine is studied by measuring the following electromechanical characteristics of the machine in both generating and motoring regimes: cogging torque, electromagnetic torque and induced voltage. The results showed that high cogging torque negatively affect the performance of the machine. The goal of the research was to reduce the cogging torque of the motor without changing the shapes of permanent magnets and magnetic poles, and to avoid any implementation of the magnetic shunts or magnetic bars into the machine. Parametric analysis of the outer rotor configuration with different air-gap diameters showed the optimal machine design which offered: five times lower cogging torque, 8 percent increase in electromagnetic torque, 24 percent decrease in volume, and 33 percent decrease in copper mass compared to initial design of the machine. Additional recommendations on the motor improvements based on Finite Element Analysis (FEA) are also provided.