Modeling and control of a multi-phase induction machine withstructural unbalance

The multiphase winding structure provides an induction machine with capabilities of starting and running even with one or more of its stator phases open-circuited. However, when operated with such a structurally unbalanced condition, the dynamic properties of the machine will change drastically from its balanced operation condition. For example, field-oriented control strategies developed for a balanced winding structure will no longer function properly and could lead to catastrophic consequences. In this paper, a unified approach to the modeling and field-oriented control of dual three phase induction machine with one phase open is presented. Using the concept of vector space decomposition, the proposed technique is established on the basis of the asymmetrical winding structure directly, and thus provides a precise, physically insightful tool to the modeling and control of induction machines with structural unbalance