Switch for the optimization of module power by reconfiguration of all strings (SOMBRA): An insulated integrated switch for a reconfigurable solar panel

Abstract

The energy yield of a solar panel can be severely impacted by partial shading. Shade caused by nearby static objects can hardly be avoided in installations such as building-applied or building-integrated photovoltaics. Smart reconfigurable photovoltaics (PV) panels are able to change their intra-module configuration to reduce this impact: Small substrings can be rewired to be connected in a more optimal configuration. To achieve this, a reconfiguration switch needs to be designed. In this paper a switch for the optimization of module power by reconfiguration of all strings (SOMBRA), a smart switch, is presented. SOMBRA is a fully integrated, low-ohmic switch, designed for currents up to 10 A. It is fully floating up to 50 V,while still being able to communicatewith a central unit as an inter-integrated circuit (I2C) slave. Two versions were realized, SOMBRA-LV10 for low voltages (LV) and a load current of 10 A, and SOMBRA-HV05 for high voltages (HV) and a load current of 5 A. Measurements proved these devices to be functional, measuring an on-resistance of 1.3 mW for SOMBRA-LV10 and 7.3 mW for SOMBRA-HV05. This paper will elaborate on the operation, design, and implementation of SOMRBA, as well as the first tests with a small reconfigurable PV module.