Conference article

In this paper the focus is on a particular type of converters that is the two-level VSC (DC/AC Voltage Source Converter). In this category the averaged model and the switching model of an half-bridge converter are considered. The half-bridge is a building block for multiphase and multilevel converters. The implementation of the two models of half-bridge converter using Modelica language is described with the structure of the package developed in Dymola. Different control strategies are introduced showing different behavior of the models in the simulations. The goals of this paper are several. First of all the modeling choice was to use Modelica for this type of work, that is traditionally carried out with domain specific tools, to show that it is possible to perform implementation and studies in the same field where traditional commercial softwares have been commonly and extensively used, with additional benefits that the language provides. In addition to that, this paper shows that the control design studies for an half-bridge converter, typically performed using averaged value models, can result in a set of control parameters values that are not successfully applicable to switching models of the same power electronic device.

VSC converters, half-bridge, averaged model, switching model, STATCOM, Modelica, Dymola, PI control, lead compensator, lag compensator, resonant control