Insulation Design of a High Frequency Electrical Machine for More Electric Aircraft Propulsion

High-frequency electric machines have been developed to provide propulsion in the electric aircraft system. However, the partial discharge (PD) issue has been paid significant attention to electric machine's insulation design due to the high temperature and low pressure operating environment, which poses threatens to the reliable operation of electric machine. This study proposes an insulation design procedure to avoid PD for air-core form-wound stator windings of high frequency permanent magnet synchronous machines. The effect of air pressure and temperature on partial discharge inception voltage (PDIV) is investigated by experiments. A three-dimensional stator model is built by the finite element method and used to simultaneously obtain thermal the electric field distribution in the insulation. Besides, a design margin is also provided by considering delamination due to manufacturing process or insulation degradation. The proposed procedure may provide useful references for electric machine insulation design for more electric aircraft propulsion.