Characterization of the InGaP/InGaAs/Ge triple-junction solar cell with a two-stage dish-style concentration system

• A mathematical model of triple-junction solar cell is established.
• The calculated results compare well with outdoor experimental data.
• A high efficiency heat pipe exchanger is specially designed to cool the cell.
• The effect of the homogenizer is more significant at small direct solar radiation.
• The impact of solar radiation on the experimental error is researched.

Research on automatic tracking solar concentrator photovoltaic systems has gained increasing focus recently in order to develop high efficient solar PV technologies. A paraboloidal concentrator with a secondary optical system (with a concentration ratio in the range of 100–200×) and a sun tracking system was developed in this work. The performance of a heat-pipe cooled triple-junction GaInP/GalnAs/Ge solar cell was characterized. The experiments showed that the system achieved an average output power of 1.52 W/cm2 and an average efficiency of 29.3% when average direct solar radiation is 450 W/m2, while keeping the maximum cell temperature below 64.9 °C, which were 23.3% and 9.1% higher than those of single stage concentrating system respectively. Moreover, the experimental error is increases with the solar radiation. The experimental results for Voc and Isc compared reasonable well with the predictions from a mathematical model, and the calculated values were out of the measured error, which suggested that the model can be used to analyze the influence of relevant parameters on the performance of high concentration photovoltaic systems.