TUrBO: The Next 100 000+ RPM Synchronous Reluctance Drives

Abstract

Ultrahigh-speed electric drives operating beyond 100 krpm are attracting increasing interest in compact turbomachinery and electrified auxiliary systems. Although synchronous reluctance machines represent an attractive permanent-magnet (PM)-free solution, their extension to this operating range is simultaneously constrained by rotor mechanical integrity, converter voltage capability, and the strong interaction between electromagnetic design, manufacturing accuracy, and drive operation. This article presents an integrated system-level approach for the development and experimental validation of a 100 krpm-class synchronous reluctance drive based on the coordinated use of two complementary enabling technologies: a multimaterial axially laminated anisotropic rotor manufactured by laser-directed energy deposition and an open-end winding dual-inverter architecture. The complete development process is presented, including additive-manufacturing technology selection, material characterization, rotor fabrication, electromagnetic and mechanical design, converter implementation, and multidisciplinary optimization. Two prototype drives were developed and experimentally investigated. The machine validation comprises flux-linkage mapping, apparent inductance evaluation, maximum torque-per-ampere assessment, load tests, and acoustic measurements, while the comparison between experiments and finite-element analysis highlights the influence of manufacturing-related phenomena, including the diffusion region generated between adjacent deposited materials. The drive validation further assesses the proposed converter architecture under very-high-speed operating conditions. The presented results demonstrate that the coordinated design of the synchronous reluctance machine, additive-manufacturing process, and power converter is the key enabler of next-generation ultrahigh-speed PM-free electric drives.