A method to identify the equivalent loss resistance of voltage source converters for current control design

Optimization of the current control loop in voltage source converters (VSCs) requires an accurate modeling. The VSC behavior can be significantly influenced by its working conditions. To consider such effect, converter losses should be included in the model, which can be done by means of an equivalent series resistance. This paper proposes a method to identify the VSC equivalent loss resistance for current control optimization. It is based on analysis of the closed-loop transient response provided by a synchronous proportional-integral current controller, according to the internal model principle. The developed identification procedure has been tested in the laboratory at different specifications of power rating and switching frequency.