Preliminary investigation of electromagnetic and thermal performance of closed stator switched reluctance machines

Abstract

This paper presents the preliminary investigation results of a novel closed stator slot structure in Switched Reluctance Machines (SRM) to form direct cooling channels inside the stator slots in electromagnetic and thermal aspects. The investigation starts by identifying the current challenges faced by various cooling arrangements for electric machines. Two sets of baseline SRMs, with and without the closed slot structure, are then obtained via the combined optimization process based on FEA and Genetic Algorithm (GA). Coupled simulation between Matlab/Simulink and FEA is conducted to obtain the transient electromagnetic characteristics of the target SRM under Average Torque Control (ATC) scheme. The incurred iron and copper loss are then fed to Lumped Parameter Circuit (LPC) for thermal investigations. The results show that in spite of the increased leakage flux due to the added flux bridges, the proposed closed stator slot structure can improve the thermal performance of SRM and allow for higher stator current densities without exceeding the winding insulation limits. As a result, the power level and power density of the studied SRM is still increased.