High-Speed Synchronous Reluctance Motor for Electric-Spindle Application

In last years, high speed integral motor spindles are obtaining attentions due to their compact frame. The actual choice for raw plastic and wood materials processing are the induction motor and the interior permanent magnet machine. In particular, permanent magnet motors are suitable for wide constant power-speed range; they show high power density and high power factor. However, the increasing cost of rare-earth magnets leads the designer to investigate other solutions. For this sake, this paper deals with the design procedure of a high-speed free rare-earth motor for a electric-spindle applications. Hereafter, the synchronous reluctance machine is investigated. Such a machine represents a valid alternative thanks to the absence of rare-earth magnets and, consequently, the reduced cost. The goal of this study is to show the feasibility of such a high-speed motor. For this aim, a SI{4.5}{kilowatt} motor at the maximum rotation speed of SI{20000}{rpm} is designed. A multi-objective optimization process is proved to be an useful tool for this sake. The best individual is capable to deliver the rated power at both base speed and maximum speed. Synchronous reluctance machine proves to be a good free rare-earth candidate for high speed integral motor spindle applications.