Analysis and Development of Novel Three-Phase Hybrid Magnetic Paths Switched Reluctance Motors Using Modular and Segmental Structures for EV Applications

Abstract

The classical switched reluctance motors (SRMs) often suffer from drawbacks such as low power and torque densities, high torque ripple, mutual coupling, etc., which limit their industrial applications. This paper presents the analysis and development of two novel three-phase SRMs with hybrid magnetic paths comprising six E-shaped modular stators and three segmental common rotors, termed as the modular SRMs (MSRMs), for electric vehicle applications. The machine topologies with different winding arrangements are described. The voltage and output power equations are analytically derived, and some design particularities and parameters are discussed. The field distributions and static magnetic characteristics of an MSRM with double coil are analyzed by using 3-D finite-element method. After that, two MSRMs with different winding arrangements, namely a double-coil MSRM and single-coil MSRM, are analyzed and compared to evaluate the distinct features of this novel MSRM, accompanied with a classical three-phase 6/4 SRM. The comparison includes static magnetic characteristics, mass of iron core, normal dynamic, and fault-tolerant performances. It is shown that the double-coil MSRM appears to have better characteristics such as higher torque production capability, lower torque ripple and cost, higher torque and output power densities, and higher reliability and fault tolerance. For experimental verification, laboratory testing of a double-coil MSRM is developed, and the simulated and measured static inductance characteristics and dynamic performances correlate well.