Nonlinear Controller Based MPPT Using Quadratic Buck Boost Converter

Abstract

Due to the decreasing natural resources and increasing demand of energy by consumers, it becomes necessary to look for the environmental friendly alternatives. Solar energy provides the best alternative to the fossil fuels. However, its output power is not uniform all the time. The energy generated by the photo-voltaic (PV) system changes according to the temperature and irradiance values. The maximum power point tracking (MPPT) algo rithm extracts maximum power from the PV system. The inability of the linear control techniques to cater for the non-linear behaviors of the systems makes it necessary to look towards much complex but more efficient nonlinear control methods. With the advancements of technology, novel dc to dc converters are proposed with time that give much higher voltage gains and hence permit the operation in wider range of positive output. One such example is that of a quadratic buck/boost converter that gives quadratic gain as compared to the normal converters. In this thesis, a non-linear control of the quadratic buck/boost converter is proposed that achieves the required goal of MPPT. Regression plane is used to generate the reference voltages for the desired controller. The thesis first discusses the detailed modeling of the system, then suggests the non-linear controller, proves the asymptotic stability and then finally the results are implemented in Matlab to validate the feasibility of the proposed controller.