Two-Phase Switched Reluctance Motors: Optimal Magnet Placement and Drive System for Torque Density

Abstract

This paper focuses on designing new motors with high torque density, which is crucial for applications ranging from electric vehicles to robotics. We propose a double-teeth C-core switched reluctance motor with hybrid excitation, integrating permanent magnets and a novel drive technique to enhance motor torque density. We explore three magnet placement configurations to maximize torque. A common challenge with most self-starting methods used in two-phase SRMs is the generation of negative torque, which reduces the motor's torque density. Our adopted self-starting method minimizes negative torque, and we introduce a new drive strategy to control the switching on and off, effectively eliminating negative torque. Additionally, magnetic equivalent circuits are developed for the analytical design and theoretical analysis of all configurations. The SRMs under study are prototyped and tested, and their performances are evaluated in terms of torque-angle characteristics, current, and voltage. Both experimental and simulation results validate the effectiveness of the PM-assisted SRMs in enhancing torque density and efficiency.