Model and its applications of nonlinear coupled system with discrete-sample and modulation

The coupling effects of two nonlinearities for power electronics and motor drives present some difficulties to system analysis. They can cause oscillations or vibrations to the system, such as the vibrations of mechanical plant or civil building structure. In this paper, a method of establishing the model for this system is proposed, that is, the method of logic-switching function. The logic-switching model of AC and DC power systems coupled by thyristor converter is also established. Consisting of two eigenequations, this model is characterized by systematics, completeness, compactness and comprehensiveness. This model can be used in the dynamic simulation, harmonic analysis, steady-state and stability studies for AC and DC power systems. Some application results of this model in dynamic modeling and vibration analysis are given.