A Novel Hot Spot Mitigation Circuit for Improved Reliability of PV Module

Generation of hot spot in photovoltaic (PV) cells, under mismatch condition, is a reliability and safety issue associated with PV systems since its very early applications in satellites. Some of the solutions to this long-standing problem, proposed by the researchers in the past, were though effective in reducing the hot spot temperature, but were not accepted widely in commercial scale, because of design complexity and significant cost implications. The main aim of this paper is to present a novel hot spot mitigation circuit (HSMC), which effectively reduces temperature of the cells under mismatch conditions through a modified bypass arrangement, and thereby increase the reliability of the complete PV system. Special attention is paid to ensure that the proposed solution does not increase complexity of the bypass circuit to restrict its impact on the project cost and system reliability. Experimental investigation is carried out to quantify the comparative performance of the proposed HSMC vis-à-vis standard bypass circuit (SBC). Thermographic images revealed that temperature of the cells, under mismatch condition, reduced by up to 10.3 °C when protected by the proposed HSMC, while the temperature increased by 6 °C under protection of the SBC under same ambient and operating conditions.