Parametric dynamic phasor modeling of synchronous machine-rectifier systems for integrated ac-dc microgrids

This paper focuses on the modeling of synchronous machine-rectifier systems, which are widely used as backup generation for supporting medium-to long-term interruptions in integrated ac-dc microgrids. The dynamic phasors (DPs) have been shown to effectively model such ac-dc systems and their components including harmonics. However, most of the existing DP models of line-commutated rectifiers are analytically derived, which have limited accuracy due to: 1) predetermined waveform of voltage/current switch functions that are relying on a single mode of operation; and 2) reduced-order representation of harmonic dynamics. To overcome these challenges, this paper extends the recently developed parametric DP (PDP) modeling approach by including the dynamics of harmonics through a set of numerically-constructed explicit algebraic functions. The proposed PDP model is validated with detailed simulations, and is shown to be very accurate in predicting the system harmonics for various operating modes and large-signal transients.