Interfacing photovoltaic panels via a capacitive converter

Photovoltaic panels are most often connected to a DC bus via an electronic power converter. This converter either performs a simple power management task or might be used also for maximum power point tracking (MPPT). MPPT circuits couple the output terminals of photovoltaic panels (or arrays) to the electrical load while attempting to provide impedance matching by operating the solar panel at its maximum power point. Operation at the maximum power point is maintained against variations in insulation level, temperature, and solar cells aging. This task is performed by means of a closed loop control scheme, which continuously tunes the DC transfer ratio of the converter. The main property required from the converter is high efficiency; therefore the converter is implemented via a switched mode circuit. In this paper, a novel topology for the switched mode converter is proposed in which the means of incremental energy transfer is a capacitive switching cell rather than the conventional inductive cell. Thus this new type of converter might benefit of reduced volume and weight. A simulation example is provided for a 100 W converter running at a switching frequency of 100 kHz. Than, it is validated by an experimental prototype, which showed efficiency above 90%.