Investigation on hybrid ratio between PM and current excitation sources for high-speed synchronous generator

This paper presents a novel hybrid excited synchronous generator (HESG) for high-speed and high-power applications. The generator features a surface mounted permanent magnet (PM) rotor wrapped by a carbon fiber bandage, and excitation windings fixed under the tangential magnetized magnets to control air-gap flux density. Based on the theory of elastic mechanics, the stress and deformation in the carbon fiber bandage is calculated analytically, and the relationship between the air gap length and magnet thickness is obtained. To optimize the hybrid ratio between PM and current excitation sources, parametric model is built and computed by 2D finite-element method.