Modeling of Multi Terminal VSC-HVDC links using port-Hamiltonian Systems

Abstract

In recent years, different strategies have been used to model HVDC systems. A usual strategy is to look for the models simplification (or linearization) to do a small-signal analysis. However, VSC-HVDC multiterminal links have intrinsically non-linear characteristics that need to be considered. Port-Hamiltonian (pH) systems provide a modeling methodology that allows incorporating the elements of the HVDC system in a modular way while explicitly providing the energy function, internal interconnection, and dissipation, which is helpful for analysis and control. This paper presents the modeling of a multiterminal HVDC network commonly used in the Electrical Power Systems literature from the pH perspective. It aims to use the pH structure to incorporate elements into the system while preserving its properties. Numerical simulations are carried out to show a comparison between the common model and the pH representation and it is shown that the latter reproduces the same dynamics of the former without loss of information but gaining in simplicity and structure.