Space Vector Modulation Based on a Multidimensional Approach for Multiphase Inverters with an Odd Number of Phases

Nowadays, there is an increasing attention towards multiphase drives, especially for medium and high power applications in naval and railway propulsion systems. As known, a multiphase motor drive cannot be analyzed using the space vector representation in a single d-q plane, but it is necessary to introduce multiple d-q planes. So far a general space vector modulation (SVM) is not available due to the inherent difficulty of synthesizing more than one independent space vector simultaneously in different d-q planes. In this paper the problem of the SVM of M-phase inverters with an odd number of phases is solved introducing the new concepts of reciprocal vector and ranking function. The proposed approach, confirmed by experimental tests, allows the full exploitation of the dc input voltage and the simultaneous modulation of voltage space vectors in different d-q planes.