High-speed scalability of synchronous reluctance machines considering different lamination materials

This paper considers the design of synchronous reluctance (SyR) machines for high-speed applications with the aid of optimization algorithms and considering both electromagnetic and mechanical performances. The design of small SyR machines with rated speeds from 5krpm to 50krpm is investigated, using two commercial laminations: a cobalt iron alloy and a high-grade non-oriented silicon steel. The integrity of the SyR rotors is guaranteed by the structural ribs and posts connecting the steel segments, so to simplify motor construction, without any retaining sleeves. The silicon steel, despite the lower magnetic performances respect to the cobalt iron, appears a competitive choice in high-speed applications due to its superior mechanical performances. Extensive design optimization, magnetic and structural finite element analysis demonstrate the feasibility of such high-speed SyR machines.