Grid-connected photovoltaic system featuring low-frequency ripple suppression and high voltage conversion ratio

A grid-connected photovoltaic system, based on a sixth-order dc/dc converter with a non-linear compensation technique, is proposed. This solution addresses the main challenges in double-stage photovoltaic systems connected to the grid: increase the dc/dc stage voltage conversion ratio, reduce the photovoltaic voltage ripple, avoid electrolytic capacitances, and mitigate the effect of dc-link voltage oscillations generated by grid-connected inverters. The compensation technique is analytically derived from the voltage conversion ratio of the dc/dc converter, therefore its design does not require a control-oriented model, and the compensator is independent from the system parameters, which simplify its application. Finally, the proposed solution is validated by means of detailed PSIM simulations.