Split-Winding Switched Reluctance Machine to Minimize Torque Ripple

Abstract

Switched reluctance machines (SRM) are recommended for electric vehicle applications due to their merit points over other rotating electrical machines like robust structure, high efficiency at a lower speed, higher fault tolerance capability, and permanent magnet-less feature. However, in conventional SRM, the torque ripple is high, which causes vibration issues. The torque ripple will be further amplified in proportion to the power rating of the machine. In this paper, a split-winding switched reluctance machine (SW -SRM) is presented with a split-winding concept. The actual phase winding of one phase is distributed over the two adjacent poles of SRM. The split winding helps to maintain the torque in an aligned as well as unaligned position of the rotor and stator poles and reduce the torque ripple produced by the SRM with a proper excitation scheme. To validate the proposed split winding concept, a 50kW SW-SRM has been modeled and simulated with the help of FEA (Finite Element Analysis) tools. From these studies, the magnetic characteristics like flux density, inductance, and torque for various rotor positions and stator currents are captured and used as a lookup table. These look-up tables are utilized for modeling the SW-SRM in MATLAB. A comparison study on torque ripple produced by 50kW SRM and SW-SRM is performed based on the MATLAB simulation results.