New Designs of a Two-Phase E-Core Switched Reluctance Machine by Optimizing the Magnetic Structure for a Specific Application: Concept, Design, and Analysis

Three new magnetic structures for an E-core switched reluctance machine (SRM) comprising two segmented stator cores or a monolithic stator core are proposed for good manufacturability, mechanically robustness, ease of assembly, and electromagnetic-performance improvement. The E-core stator has four small poles with phase windings and two or four large poles (hereinafter referred to as common poles) in between. The common poles do not have copper windings or permanent magnets. The common poles are shared by both phases for positive-torque generation during the entire operation. The air gap around the common pole has constant and minimum reluctance, irrespective of rotor position, by its unique design, and the two small stator poles experience variable reluctance with respect to rotor position. The segmented stator can be constructed with two independent and physically separate E-shaped cores with L- or I-shaped yokes so that the straight back iron in the stator rather than the curved back iron is suitable for assembly with other parts like end bells or brackets. The monolithic stator also has an L-shaped yoke for the same reason, and the new E-core SRMs are designed by means of pole-arc optimization. The novel E-core SRMs are compared to a conventional two-phase SRM. The comparison includes cost savings, torque, copper and core losses, efficiency, and radial force in order to validate the distinct features of the E-core SRMs. For experimental verification, laboratory testing of a segmented E-core SRM is conducted, and the simulated and measured phase currents and voltages correlate well.