Design and Analysis of Mutually Coupled SRMs for Low Torque Ripple Applications Using Standard Voltage Source Inverters

Mutually coupled switched reluctance motors (MC-SRMs) are alternatives in the family of reluctance motors that can overcome switched reluctance motor's (SRM) system level integration and control challenges by utilizing standard three-phase voltage source inverters (VSIs). The objective of this work is to investigate MCSRM torque ripple minimization from the machine design aspects in order to reduce the burden on current controllers. In this work, two different topologies of 12/8 MCSRMs, full pitched and concentrated wound, are designed and analyzed for high-performance applications with stringent torque ripple requirements, such as the electric power steering (EPS). The design targets and constraints, initial sizing process, along with the design guidelines are illustrated. Optimization analysis is performed based on Genetic Algorithm (GA) with the objective of minimal torque ripple design. The torque ripple is limited to 17% without any current profiling or torque sharing functions. Design guidelines are discussed to select turn numbers for low voltage and low ripple applications. The considered topologies are then compared based on torque ripple, torque density, efficiency, etc. Designed models are analyzed with finite element (FE) simulation tools and the parameters affecting the torque ripple for both the topologies are discussed.