A Parallel Differential Power Processing Scheme with Mismatching Detection

Partial shading faults or mismatching faults in photovoltaic (PV) modules can lead to significant power loss, hot spots, and a reduction in the system's operational lifespan. Although bypass diodes can mitigate the effects of shaded modules, the maximum output power remains substantially lower than under ideal conditions. In this paper, a differential power processing scheme with a shadow fault detection method is proposed for two parallel-connected PV strings. The mismatching faults can be detected by the estimating the irradiance from the measured short circuit currents and the current at maximum power point (MPP). When the shadow fault is detected, the proposed voltage equalizer is activated to compensate for the unbalanced voltage and power , thereby improving the peak output power. The voltage equalizer utilizes the series resonant voltage multiplier (SRVM) to achieve the stated objectives.