Novel Scheme For Extracting Maximum Power From Façade Based Building Integrated Photovoltaics

Abstract

Building Integrated Photovoltaics (BIPV) is expected to be a viable option for Near Zero/Zero Energy Buildings (NZEB/ZEB) in urban areas. Facade based BIPV gives an option to the builders/designers to manage human comfort as well as improve aesthetics by including more than one BIPV technology or transparency. However, from the power generation point of view, these PV modules are subjected to non-uniform illumination and partial shading due to the surrounding buildings and structures in most urban scenario. The power output of the modules do not match with the inverter rating as they do not receive direct radiation for most of the day and implementation of vertical orientation minimizes the power generation. Connecting them in series and/or parallel is an option to increase power generation, but it is highly influenced by the shading patterns. In this paper, we propose a scheme of power converters for BIPV in which each module is connected to a dedicated DC-DC power converter and the outputs of several such converters are connected to a grid-tied inverter. This configuration helps to track the maximum global power of the BIPV modules and inject power into the grid even under the partially shaded conditions. The simulation results for a two-module case show that the designed controller can handle sudden changes in radiation level in either or both of the BIPV technologies and stable state MPP(Maximum Power Point) condition is achieved. The impact of the fill factor on the dynamic response of the controller for various BIPV technologies is also highlighted.