Improvement of reliability and fault tolerance of traction drives by means of multiphase actuators

The ongoing electrification of road and air traffic leads to an increase of component requirements within the electric vehicle's drive train. Especially the requirements on reliability and fault tolerance are significantly increasing. This contribution depicts the investigation results considering multiphase traction systems using the example of an aircraft application. Thus, the advantages of multiphase systems, the comparison of different phase numbers, and methods for an evaluation at an early stage will be presented. The results allow the conclusion, that a permanent magnet synchronous machine with a minimum of nine phases is the most promising solution regarding reliability and fault tolerance. The contribution's focus is set on the different ways of connecting power electronics and electrical machine. Therefore, three different topologies are discussed: a 3x3-phase system with three star connections, a 1x9-phase system with one star connection, and a system with nine galvanically separated phases. The latter results in being the best option considering fault propagation, cooling, magnetic decoupling, energy storage, etc.