Robust H∞ control design for PFC rectifiers

Power factor correction (PFC) converter circuits are non-linear system due to the contribution of their multiplier. This non-linearity reflects the difficulty of analysis and design. Models that reduce the system to a linear system involve considerable approximation, and produce results that are susceptible to instability problems. Our goal is to design a controller that achieves some performance specifications despite these uncertainties in modeling. This paper addresses a robust H_∞ control problem for switched circuits with parameter uncertainties. The necessary and sufficient conditions for existence of strong robust H_∞ dynamic compensators and static output feedback controllers are established in terms of linear matrix inequality (LMI) approach. It is shown that the dynamics of the voltage loop can be significantly improved using an H_∞ controller.