A Robust H2 State Feedback Controller Applied To Boost Converters

Abstract

This paper proposes the design and the experimental validation of a robust H2 control technique applied to boost converters. Differently from conventional techniques, the proposed controller has a certificate of stability and performance under arbitrary parameter variations. The design procedure adopts a linearized model with a polytopic structure for the converter affected by time-varying parameters. An optimal H2 state feedback controller (under quadratic stability) is synthesized using convex optimization based on linear matrix inequalities. This framework allows the determination of the control gains in a very fast way, using a finite set of inequalities to obtain a controller that ensures robust stability and performance for the entire set of uncertain parameters. An experimental setup of a boost converter is used to validate the controller designed here. The input voltage, the operating point duty cycle and the load are considered as arbitrarily time-varying uncertain parameters. The synthesized control gains produce good simulated and experimental results when compared to those obtained with a classical strategy based on PI controllers, without introducing additional implementation cost. The experimental validation proves the viability of practical application of this important robust control technique for boost converters.