Quasi-Dynamic Domain Modeling and Simulation of Voltage Source Converters

The voltage source converter (VSC) has become the dominant inverter technology for modern power systems and various VSC models have been developed for many different applications. Most models are in time domain that are time consuming. Also averaging models have been developed which are faster but exhibit variable accuracy performance. In general, the converter loss is not usually considered in these models. This paper presents a quasi-dynamic domain VSC model. This model has been developed to alleviate computational burden while maintaining accuracy. The model is integrated with other high-fidelity models of the electric power system, enabling system-level study. The model is based on dynamic phasors and express the relationship between the AC and DC side states to represent the conversion physics by the switching functions. The quasi-dynamic domain VSC model in this paper incorporates the converter loss by adding a quadratic loss function. The model improves simulation speed with little deterioration of accuracy as compared to time domain models.