Toward a Hot Spot Free PV Module

In the photovoltaic (PV) market, effective strategies regarding operation and maintenance are needed to guarantee the return of investment. Accelerated aging of PV modules and catastrophic failures, leading to undesired plant stops, must be prevented. Significant effort must be paid to avoid the occurrence of localized overheating (hot spot), which may induce, in severe cases, irreversible malfunctioning and even fire. In this paper, an innovative concept of PV module, not affected by hot spots, is presented. The module is equipped with a bypass and disconnection circuit, replacing traditional diodes in the junction box. The behavior of the circuit is described to explain its peculiar bypass mechanism along with the impact on the operation of the PV module under different conditions. Moreover, experimental tests have been conducted to fairly compare, under the worst condition, consisting of a bypass event due to a single malfunctioning cell, the proposed solution with a traditional PV module adopting bypass diodes. IR analysis has been performed to map the temperature distribution on the module. Results show that, in the proposed PV module, the malfunctioning cell operates close to the temperature of the other cells, while in a traditional module significant overtemperature occurs.