Three-port isolated DC-DC converter with LQG/LTRI robust control applied to photovoltaic systems with energy storage

This work proposes to use a centralized multi-variable control strategy for an isolated three-port DC-DC converter, which interfaces a photovoltaic panel, a battery, and a DC bus. The proposed control consists of a Linear Quadratic Gaussian (LQG) approach with Loop Transfer Recovery (LTR) and integral action (LQG/LTRI) applied in a multivariable state-space model. It is designed to maintain stabilization and voltage tracking performance in the presence of step-type disturbances typical of abrupt variations in the solar incidence and load levels. Finally, simulation and experimental results are presented and discussed to validate the performance of the proposed approach.