Back-EMF synthesis for sinusoidal and trapezoidal tooth-wound interior permanent magnet synchronous machines without skewing

The paper presents back-EMF synthesis (design) techniques for both -sinusoidal and trapezoidal -permanent magnet synchronous machines (PMSM) technologies. One of the major original contributions is the fact that the introduced synthesis methods are taking into account the simultaneous cogging torque minimization. In comparison with the known machines with surface permanent magnets (PM), distributed windings and skewing, the present paper considers only machines with interior PM, concentrated windings (tooth-wound machines) and without skewing, as robust, low-cost solutions for the industrial practice. Several machine topologies are presented in comparison for the sinusoidal and trapezoidal technologies. The synthesis process involves exclusively nonlinear finite elements (FE) calculations of the back-EMF shape and cogging torque. For each machine technology design solutions with optimal back-EMF and low cogging torque are offered. Experimental (measurements) results for the built prototypes are presented in detail.