A Comprehensive Generalized Theory and Classification of Multiphase Systems for Rotating and Linear Electric Machines

The growing interest in electrical machines equipped with multiphase configurations has directed the research to the conception of new design methods and optimization strategies to maximize the performance and the efficiency of the machine for its specific application. In this context, a noticeable gap persists in the comprehensive generalized theory of multiphase systems applied to electrical machines. Therefore, this article aims to propose a new possible classification of multiphase systems based on the electrical symmetries between the corresponding star of slots phasors, starting from the general law related to the spatial distribution of the air-gap magnetic flux density field. This theory extends beyond symmetrical configurations, encompassing both reduced and normal systems, which can be derived from redundant multiphase configurations. Furthermore, the proposed generalization applies to all possible $m$-phase configurations, including the structures with slight asymmetries or unbalances. The article provides illustrative examples to reinforce these theoretical concepts to establish a systematic and unified theory and classification that can be adopted for any possible topology of a multiphase system.