Design of several un-skewed radial flux permanent magnet synchronous motors with asymmetric and symmetric AC windings — A comparative study

A detailed comparative study on several un-skewed surface mounted permanent magnet motors including asymmetric and symmetric winding structures are completed in this paper. Motors with integer and “almost integer” slot are designed and compared using 2D FEA. The goal of obtaining low cogging, high quality torque output and sinusoidal back EMF are investigated for various motors without complicating the design with skewing. Some of the designed motor prototypes have been built, tested and compared with experimental data. The results show that obtaining high quality torque output, zero cogging and sinusoidal back-EMF is possible even with no skew for integer (or almost integer) slot PM motors.