A Parallel-Connection Voltage Equalizer With A Shadow Fault Detection Method

Partial shading faults on photovoltaic (PV) modules can lead to power reduction, hot spots, and life reduction. Although the shaded modules can be bypassed by the bypass diodes, the peak power produced is lower than the ideal values. In this paper, a differential power processing scheme with a shadow fault detection method is proposed for two parallel-connection PV strings. The method utilizes normalized error (DE) of the comparison of the I-V curve in normal operation and under partial shading conditions to define whether PV cells dissipated power. When the shadow fault is detected, the proposed voltage equalizer would operate to eliminate the unbalanced voltage and power and improve the peak output power. The voltage equalizer use the series resonant voltage multiplier (SRVM) to realize the aims.