Fast Dynamical Model in View of Simulation of a Synchronous Generator with Diode Rectifier

Abstract

This paper deals with a dynamical modeling methodology of a synchronous generator diode rectifier set in order to reduce the computation time for the simulation of large multi machines and multi converters systems. With the classical approach, the synchronous generator is described by a five order state model in the dq frame. Several state equations are determined to take into account the variation of topology introduced by the diode rectifier. This simulator will be the benchmark. It switches between those equations to reproduce the behavior of the system. As its state matrix depends on the converter topology and the generator electrical angle, the all state matrices must be computed at each simulation step. The order of the model must be reduced without losing precision to optimize the simulation time. The proposed approach allows describing the synchronous generator and the diode rectifier with a one dimensional state space model. A preliminary study emphasizes the importance of the dampers currents, which represent a high dynamic state variable, on the system behavior: they cannot be neglected. So, a method is proposed to analytically solve those fast states variables. Then, a simplified one dimensional state model is developed. Finally simulations and experimental results are compared in dynamic and steady states to validate the proposed approach.