Distributed MPPT scheme for grid connected operation of photovoltaic system using cascaded H-bridge multilevel converter under partial shading

This paper proposes a strategy to mitigate the effects of partial shading in grid-connected photovoltaic systems. In order to reach this goal, a cascaded H-bridge multilevel (CHB-ML) converter was selected and the energy balance was obtained based on phase-shifted pulse width modulation, which allows individual power tracking of each level. Many constraints have been noted as the research has been evolving. That's why an extensive literature review was done aiming to find solutions to select better ways to compensate shading effects in more severe situations. It was noticed that there is a relation between the photovoltaic strings voltages and the capability of energy transmission, since the output voltage of each level must be summed to obtain the appropriate grid voltage level. Simulation results were obtained through Simulink/MatLab. The results were collected considering three different scenarios of solar irradiance and the limits of operation were addressed in order to evaluate the restrictions of the proposed solution.