Universal switched state-space representation for model predictive control of power converters

Abstract

In order to enable interoperability of Renewable Energy Sources (RES) with smart grids, power converters together with high speed and high accuracy controllers are needed. The use of power converters and of their associated enhanced control techniques both ensures the interface of intermittent energy sources with the grid and supports the grid with ancillary services, while also improving the power quality and stability during different grid disturbances. Therefore, to address all these important issues, the controllers applied to power converters are more and more complex, and rely on precise models. This paper focuses on formalizing a universal method to generate accurate state-space models for any controlled power converter, down to the level of its power switches. This model representation is particularly useful for direct power controllers, as they bypass the conventional modulation techniques to increase reliability and efficiency of power converters. The accuracy of the proposed method is demonstrated on a 4 Leg 3 Level Flying Capacitor (4L-3L FC) topology associated with a LCL filter through several simulation results.