A Modified Bypass Circuit for Improved Reliability of PV Module Validated With Real-Time Data

Abstract

Solar Power is a promising way of electricity generation but it comes with a drawback of low conversion efficiency which is caused by several factors, the most prominent being partial shading. Partial shading leads to mismatch of PV cells, resulting in formation of hot spot. This leads to power dissipation and physical damage to PV cells. Consequently, panel’s credibility is called into question. A bypass diode reduces the amount of power dissipated by a shaded cell, but it doesn’t entirely prevent hot spot formation. Moreover, bypass diode doesn’t bypass every small shade as it has a shaded area threshold at and above which it begins to bypass the shaded module. Whereas, the rise in temperature may also be triggered even by a small shaded area, like the area of falling leaves, which further creates reliability issues. A few hot spot mitigation strategies have been devised; however, it still has room for improvement. This paper presents a modified bypass circuit arrangement for reliability enhancement of PV systems and it is evaluated for a 3×1 PV string. A comparative analysis with bypass diode is carried out in an experimental study. The efficacy of the proposed methodology is verified based on four performance metrics, namely reverse voltage, power loss under partial shading, the sensitivity of the bypass circuit, and the temperature of the hot spotted module. The proposed technique ensures sensitivity enhancement of the bypass circuit towards shade effect; thus, enhancing the reliability of PV system.