Design interventions to reduce embodied emissions and in-use energy losses of radial switched reluctance motors for electric vehicles

The transport sector is rapidly electrifying, so the emissions of vehicles in-use will reduce in line with the grid. The embodied emissions of motor manufacture are therefore gaining more attention. This work investigates design interventions for an automotive switched reluctance motor (SRM), with the aim of improving its environmental performance compared to permanent magnet (PM) machines. The components investigated are the coils, stator, case, and rotor components (magnetic pole pieces, frame and shaft), considering the materials, manufacturing processes, and scrap waste. The effect of design choices on embodied emissions and in-use energy losses over a vehicle lifetime are determined from a representative duty cycle. In both categories significant savings are identified. Individual changes may reduce embodied emissions by 33% and in-use losses by 26%, while combining interventions can at best lead to savings of 80% and 55% respectively.