Linear Quadratic Control design for a Buck-Boost Power Converter supplied by a Solar array

Renewable energies have gained the attention of society, governments, and researchers for bringing solutions to the growing need of continuous energy supply for homes and industries. Great efforts are being made to develop and adapt technologies that make possible to harvest inexhaustible energy sources such as wind, solar, waves, etc. There are different stages associated to renewable energy injection: first one is the energy extraction, this can be implemented with solar panels, turbines, etc.; the second stage considers power conversion, and in the final stage, transformers make possible energy transmission to users. This paper focuses in the design of a suitable control strategy for a power converter to inject energy from solar panels, tracking the maximum power point. In this paper, an optimal control strategy is tested in a Buck-Boost power converter which is capable to vary the voltage at the first stage to follow the inputs and extract the maximum amount of power, in spite of bounded variations in irradiance and temperature. Particularly, a Linear Quadratic Regulator (LQR) is combined with a Kalman Filter (KF) to regulate a Buck-Boost output for the rejection of constant disturbances, thus mitigating measurement noise. Obtained results show that the proposed controller achieves an acceptable performance for the target setting.