Dynamic Models for Electrically Excited Synchronous Machines based on Flux-to-Current and Current-to-Inductance Maps

The electrically excited synchronous machine represents a suitable permanent magnet-free alternative for transportation applications. The regulation of the excitation flux, enabled by the presence of the rotor winding, allows high efficiency and power factor operations in a wide speed range. However, the mathematical modeling of these machines becomes non-trivial due to the additional degree of freedom introduced by the rotor current, particularly when considering the magnetic saturation nonlinearities. In such context, this paper presents a dynamic modeling approach for electrically excited synchronous machines for numerical simulations, taking into account the magnetic saturation. An innovative method to obtain the flux-to-current maps is developed for providing the machine model with enhanced simulation capabilities. Dynamic simulations are performed by means of the presented approach and compared to the state-of-the-art models, using the data of a 100 kW sample of the Renault ZOE motor.