Overview and analysis of PM starter/generator for aircraft electrical power systems

More Electrical Aircraft (MEA) which replaces the hydraulic and pneumatic power by electrical power leads to reducing emissions and fuel consumption. The MEA concept has led to a growing use of the starter/generator (S/G) system. Permanent magnet (PM) machines have been gaining interests for aircraft S/G system application over the last few years. This is mainly due to the several advantages, including high power density, high efficiency and high speed ability. The shortcoming of the PM machines is the de-excitation problem in case of a failure, which is a main issue for the aircraft application. However, by using a PM machine with high reactance or multiphase configuration, the fault-tolerant ability can be improved. In terms of the aircraft S/G system, this paper is going to present a comprehensive analysis of PM machines. Firstly, the state-of-the-art of PM starter/generator (PMS/G) is summarized and the basic structure of PMS/G system is analyzed. Next, key technologies of the PMS/G system are summarized and analyzed. Finally, a flux weakening fault protection strategy that is used to suppress the turn-to-turn short circuit (SC) current is studied, simulated and verified. With the breakthrough of key technologies based on the development of high temperature electromagnetic material and high temperature power electronics, the PMS/G will be a potential candidate for aircraft S/G system including the embedded power generation system.