Magnetic Equivalent Circuit Model of a Dual Three-Phase PMSM with Winding Short Circuit

Multi-phase electric machines are frequently used in applications where a high system reliability is required. An accurate but computationally simple mathematical model of these electric machines is essential for the development of model-based control and fault detection strategies. Typically, fundamental wave models (dq0-models) are utilized for this task. They, however, exhibit a low accuracy for motor designs or in operating ranges where magnetic saturation or non-fundamental wave characteristics is relevant. In this article, magnetic equivalent circuit (MEC) modeling is utilized to derive a highly accurate model for a dual three-phase permanent magnet synchronous motor (PMSM). Thereby, graph theory is applied to both the electric and magnetic system to systematically derive a mathematical model of minimum order. The proposed approach allows for an accurate prediction of the system behavior in the entire operating range, including the case of a winding short circuit. The feasibility and high accuracy of the proposed model is proven by a comparison of the model with measurement results.