Design of High-Performance Three-Phase Switched Reluctance Motor for Hybrid Electric Vehicle Application

Abstract

Permanent magnet synchronous motors (PMSM) have been a favourite to electric vehicle (EV) application due to their high power density, simple structure, compact size, lightweight, and capability to operate at a wide range of speeds without the requirement of any gear mechanism, in addition to having very high efficiency and producing high torque at low speed. However, they have several drawbacks, such as magnet high costs, limited availability and mechanical strength, flux weakening issues, demagnetisation, complication of extraction and recycling issue, and iron losses that make the whole system unstable at high speeds. This paper presents the design structure of a switched reluctance motor (SRM) and investigates its suitability as an alternative to induction and PMSMs for EV application. While SRMs can provide similar power output and density as PMSMs, their main disadvantages are high torque ripple and, hence, high acoustic noise. The analytical and numerical models here presented address these research gaps by designing a three-phase SMR with improved structure and drive system. Several design criteria are tested to minimise the torque ripple and power losses, including a set of geometrical parameters, different combinations of stator and rotor poles-since the most popular structures present more stator poles than rotor poles and three different topologies: 12/8, 18/12 and 24/16. The design procedure considers the design specifications of Tesla induction motors and takes the following steps: dimensioning of the design parameters, primary drawing using AutoCAD software, structural analysis applying the finite element method using Info-logic Design's Motor-Solve software, performance analysis for the different configurations, and harmonic analysis based on coil voltage data using MATLAB software. The results compare the performance of the newly designed SRM with and equivalent PMSM in terms of efficiency, reliability, stability, cost, and noise level, and provide recommendations for the upcoming of an advanced electric motor drive for electric vehicles.