Backstepping control of a capacitance-less photovoltaic power converter with maximum power point tracking

Solar energy offers great potential as a source of energy. The conversion of solar energy to electricity is performed by solar cells. There exists an operating point associated with solar cells at which the power generated is maximized at any given point in time. A maximum power point tracker (MPPT) is required to track this maximum power operating point (MPOP) for varying atmospheric conditions. Maximizing the power extracted from a single PV cell, utilizing the intrinsic capacitance within the cell is the objective of this work. With this approach, the problematic electrolytic capacitors common to power converters for PV systems can be removed. This solution can serve as a building block which can facilitate a system architecture that has increased system-level flexibility and performance due to control of each cell individually. Such a system could outperform today´s when it comes to problems such as shading (with all of its variants), cell to cell mismatch, and cell failure which dramatically reduce the performance of today´s PV system. In a different application, a PV cell level conversion system can be used for energy harvesting in miniaturized systems. In this paper, a novel backstepping control scheme is developed. A Lyapunov based stability analysis is presented to verify that the developed control scheme does not create instability in the closed-loop system, and that the primary control objective is achieved. An instantaneous circuit level simulation is competed to verify the results.