A simulation analysis of photovoltaic AC Module Integrated Converters in parallel, under controlled edge shading conditions

A DC and AC power simulation comparison of: a Photovoltaic (PV) array with a modular, parallel, AC converter configuration; and a series, string configuration with a central AC converter, is presented. The systems are simulated using a comprehensive range of edge shading scenarios and irradiance conditions. Power control and transformation circuitry must be designed for shade and module mismatch tolerance to prevent over-proportional power to shade losses, as average losses from Building Integrated PV (BIPV) systems are approximately 20 to 25%, due to shade, mismatch, differences in orientation and inclination, and temperature effects. 59.4% of the simulations showed gains in AC power by using the parallel modular converter system, with a maximum gain of 10.74%, when compared with the series configuration. Losses up to 6.61% can be experienced when most of the modules are experiencing edge shading of 200 or 400W/m², as i) the converter efficiency is lower in this power range for the modular converter, and ii) this low efficiency conversion occurs n times, where n is the number of modules in the array. Significant power increases are experienced by the parallel modular system when there is a wide distribution of irradiance levels within the shading pattern.