The performance of 2-phase high speed SRM with variable air-gap rotor poles for blower system

This paper presents a performance of an advanced 4/2 SRM(Switched Reluctance Motor) for high speed blower system. For the high speed application, lower electrical frequency and constant torque are very important to reduce core losses and mechanical vibration. The presented 4/2 SRM has asymmetric inductance profile and variable air-gap for torque ripple reduction and continuous torque. In order to extend positive torque region, the rotor pole arc is wider than a conventional one, and the air-gap between rotor pole and stator pole of the presented SRM is not constant, and non-linearly optimized according to rotor position to extend positive torque and reduce torque ripple. The optimized air-gap is calculated by the reiterate optimization technology and FEM. The presented high speed 4/2 SRM is verified by computer simulation and practical experiments.