High-speed permanent-magnet generator with controlled magnetic flux for aerospace application

This paper presents the design of a 150-kVA 24,000-rpm high-speed permanent-magnet generator with controlled magnetic flux for an auxiliary power unit in more electric aircrafts. Electromagnetic, mechanical, thermal, and hydraulic calculations have been carried out. The generator is designed in order to operate without high-performance inverters in the framework of aviation standards. The additional toroidal winding, fed by a simple regulator with a direct current, is implemented in order to perform a variety of additional functions such as short-circuit protection, providing a starter launch by using the increased voltage of the main aircraft engine’s starter-generators, and adjusting the voltage of the auxiliary power unit in a given range. Based on the multi-physics design calculations, a full-size experimental SG prototype with an additional winding located on the stator back has been manufactured and tested. The experimental results are in good agreement with the computer simulation data, demonstrating the proposed technology and the additional functionalities within a power-to-mass ratio of 4 kW/kg.