Current limiter circuit to avoid photovoltaic mismatch conditions including hot-spots and shading

Abstract

Photovoltaic (PV) hot-spots are considered as one of the main reliability issues for PV modules. Although PV modules are capable to tolerate over-temperature, the hot-spots can lead to accelerated aging and, sometimes, to sudden failure with possible risk to fire. The common-practise for mitigating this phenomenon is the adoption of the conventional bypass diode circuit, yet, this method does not guarantee a decrease in the temperature of hot-spotted solar cell. Therefore, in this paper, we present the development of a new current limiter circuit that is capable of mitigating the current flow of PV modules affected by mismatch conditions including partial shading and hot-spotting phenomenon. The foundation of the proposed circuit is fundamentally based on an input buffer which allows high impedance input voltages, and an operational amplifier circuit which controls the current flow of an integrated MOSFETs. Hence, to allow the control of the amount of current passing though mismatched PV sub-strings, and therefore, increase the output power generation. Detailed circuit simulations and multiple experiments are presented to evidence the capability of the circuit. In contrast, the average dissipated power of the circuit is limited to 0.53 W.