Title:  Design and Control of Ultra-high Speed Switched Reluctance Machines over 1 Million RPM

Committee: 

Dr. Habetler, Advisor   

Dr. Graber, Chair

Dr. Mayor

Abstract:

The objective of the proposed research is to design, control and implement an ultra-high speed switched reluctance machine (UHSSRM) for applications over 1 million rpm, which is the current world speed record of any electric machine. First, a literature survey is conducted to investigate the ultra-high speed electric machines and their applications. Then a novel rotor design is proposed for ultra-high speed SRMs over 1 million rpm. The rotor stack has a unique smooth shape without any holes in the middle. A shaft that has the same outer diameter contains the rotor stack in the middle, with the rotor poles facing directly to the stator poles across the air gap without going through any additional sleeves. Compared with the conventional design, the proposed design has many advantages such as high strength, high power density, high efficiency and high reliability. The new geometry is validated with 3D finite element analysis (FEA). After the rotor mechanical design, a detailed electromagnetic design of the whole UHSSRM is proposed, which includes pole pair number selection, air gap design, dimension calculation, material selection, winding selection and windage torque calculation. The final design is a 4/2 SRM which has an outer diameter of 30 mm. It has 50 turns of gauge 42/24 Litz-wire in each stator pole. The air gap is 0.3 mm. Both of the stator and rotor are made from 0.006’’ Hiperco 50 laminations. The machine is able to produce a maximum torque of 0.7 mN∙m and 1 mN∙m at 1 million and 1.2 million rpm, respectively in order to overcome the high windage torque. The design is validated by a detailed 2D FEA.