Tested Performance of Photovoltaic Array Optimization Technologies

Growth in the solar industry continues as the cost of photovoltaic power is approaching grid parity. Several technologies have been developed that address reductions in power production associated with partial shading of panels, mismatch at the panel and string levels, and multiple array orientations, conditions that often arise in residential installations. In the absence of existing testing standards, a methodology was developed to evaluate performance of power optimization devices under shading conditions. Technologies investigated include buck-boost, parallel voltage boost, and impedance matching. Performance improvements range from negligible to a 44% increase in energy delivered under partial shading. Comparison data is presented along with guidance for selecting among the different technologies currently available on the market.