Automatic Formulation of Models for Simulation of the Dynamic Performance of Electronically Commutated DC Machines

This paper presents a numerical analysis model by which one can analyze and predict the sustained steady state dynamic performance of electronically commutated dc machines of the stationary and rotating armature types during normal operation, as well as under sustained fault conditions. The machine models used here are suited for such steady state dynamic performance. The reason these authors refer to the present modeling approach as a "steady state dynamic" analysis method is that electronic switching is continuously taking place throughout the normal operation, hence network modeling must be on an instantaneous basis. Thus time domain models are required as will be described below. An automatic formulation of the state equations, an explicit integration routine, and control logic needed to impose electronic switching and/or fault conditions were used in the dynamic simulation program. The general modeling description and its verification, using as an example a stationary armature electronically commutated dc machine system, are included for verification of the validity of the modeling approach. The modeling techniques of the dynamic simulation program were then applied to an example rotating armature electronically commutated dc machine system of the type used in modern brushless systems for field excitation of large turbine generators.