AC electrical architecture propelling systems for aeronautics

This paper describes the study of an original ("power electronic-less") AC electrical architecture for propulsive purposes in aeronautics. This architecture is composed of two or more Permanent Magnets Synchronous Machines (PMSM) directly linked to each other by an AC bus, one in generator mode driven by a gas turbine and all the other PMSM in motor mode, each one driving a propeller. The simple architecture with only two PMSM-one generator and one motor-will be mainly developed here. Although this architecture may seem too rigid to be implemented, the absence of power electronic offers potential savings in mass and costs, which justifies its study to determine whether this architecture could be implemented and used for propelling systems or not. This paper focuses on the development of an analytical model enabling to fully describe the dynamic and permanent behaviour of such an architecture. Once this model is set, the stability of the architecture is analysed: a classical approach, with the linearization of the analytical model and the use of root locus analysis, is considered.