Impact of Bifacial Modules on the Inverter Clipping in Distributed Generation Photovoltaic Systems in Brazil

Abstract

Distributed generation (DG) solar photovoltaic (PV) power plants in Brazil are limited to 5 MW, considering the inverter output power, according to the normative resolution 687/2015. This limitation creates the challenge of trying to work at maximum power for as long as possible to maximize the profit and reduce the payback time. One of the solutions for this is to increase the plant DC/AC ratio (PV array oversizing). Nevertheless, increasing the DC/AC ratio also generates losses on power production when the total power of the PV modules cannot be handled by the inverters. Power clipping by the PV inverter limiting the power of PV modules is a cause of losses in oversized PV arrays, and this fact can have a higher impact when bifacial modules are used. This paper analyzes the level of clipping and the benefits of PV array oversizing in distributed generation PV power plants with different DC/AC ratios with monofacial and bifacial modules. The System Advisor Model (SAM) is used for simulations with a scenario in Minas Gerais-Brazil. The results show that bifacial modules have a higher influence on clipping losses in comparison with monofacial ones. However, bifacial modules provide more energy production. Therefore, this analysis is important for finding the best DC/AC ratio for bifacial PV arrays.