The electrical property of space solar array under partial shading conditions and its in-orbit influence

In the present work, the electrical property of space solar array under partial shading condition and its in-orbit influence on Chang'e-4 Relay Satellite is analyzed. I-V and P-V characteristics of triple-junction InGaP2/InGaAs/Ge solar module under different shading proportions and the different number of shading cells are illustrated considering the opening of the bypass diode. Two obvious steps occur in I-V curves and the decrease of the photovoltaic current mainly depends on the shading proportion of the shaded cell. Meanwhile, two peaks occurred in P-V curves when the solar module is partially shaded, and shading loss and misleading loss are figured out. According to the working mode of the shaded cell, the I-V curve of the shaded module can be divided into three portions: forward bias, reverse bias and bypass diode opening with the scanning voltage decreasing. As for P-V characterization, execution ration is introduced to demonstrate the shading loss quantitatively. The energy conversion efficiency and execution ratio both decrease at the beginning and then stabilize as the shading proportion and number of shading cells increase. Eventually, the in-orbit influence of partial shading on Chang'e-4 Relay Satellite is studied. A two-step decrease of photovoltaic current is observed when the relay antenna outspreads. The present work will be helpful to deepen the understanding of the electrical property of space solar array under partial shading as well as providing reference to the solar array design existing partial shading condition.