How Electrical Steel Optimizes Traction Electric Machine Design: A Serviceable Contribution to Electric Vehicles

The development of automotive traction machines has created a new wave of ES developments. Previously, ES development concentrated on industry applications at 50/60 Hz and aeronautic and medical applications at high frequencies. Industry applications were basically 0.35 -1 -mm grades and aeronautic applications were mostly at 0.20 mm. The automotive market has created a need for grades with gauges in the range of 0.20-0.35 mm. Each powertrain design has its own needs in terms of ES losses, polarization/permeability, and mechanical constraints. The PMSM is widely used for vehicle electrification; however, other machines, such as WRSMs, induction machines, switched reluctance machines, synchronous reluctance machines, and axial flux machines, are analyzed and considered for specific needs. Each of these motor topologies, combined with specific vehicle applications, dictates different steel characteristics. This has created a wide range of ES with different property optimizations. These steels are now commercially available from major steel suppliers. Two machine types (a PMSM and a WRSM) were analyzed and their performances calculated with different electrical steel types with different thickness, loss, and polarization. These simulations show the impact of the ES choice on power density and efficiency.