Optical,thermal And Electric Performances Of The Dense-array Concentrator Photovoltaic (DA-CPV) System Under Non-uniform Illuminations And Temperatures

In recent years,many investigators concentrated on the development of Dense-array concentrator photovoltaic(DA-CPV)system due to its high conversion efficiency.The DA-CPV system is facing large mismatch losses due to the highly concentrated non-uniform radiation.In this paper,the multi-physics model based on optical model,electrical model and thermal model is eatablished and then the simulated model is set up based on the Simulink software.Based on the investigations of non-uniform irradiation and characteristics of solar cells,a novel rotational symmetry(RS)connection approach with two examples,including the dichotomic rotational symmetry(DRS)and quartered rotational symmetry(QRS)connections,is proposed to reduce the mismatch losses.The output performances of the two RS connections are compared with that of four conventional connections by using a two-stage simulation method.The results indicate that under different illumination distributions and CPV cell's series resistances,the RS connection approach can dramatically reduce power losses.The DRS and QRS connections can significantly improve the output characteristics of DA-CPV modules.Compared with the conventional series-parallel(SP)connections,the DRS and QRS connections can improve the conversion efficiency by at most 48%and 64.3%,respectively.Meanwhile,the QRS connection exhibits smoother I-V and P-V curves,reducing the difficulty of system's maximum power point tracking(MPPT)and improving the stability of output performance with varying Gaussian illuminations.When considering the Joule heat losses generated from the series resistance of CPV cells,the RS connections can also achieve much higher conversion efficiencies than other conventional configurations.The multi-physics effects on the performance of dense array concentrator photovoltaic(DA-CPV)system are also investigated in detail by considering CPV module connections,non-uniform illumination,and temperature distribution.It is observed that the optimized module configuration can significantly reduce the overall cells temperature.We also analyze the effect of temperature uniformity on the output performance.When the illumination,configuration and mean temperature are certain,the temperature distribution can affect the output performance of the DA-CPV system.In the case of non-uniform illumination,the maximum power of the module will be achieved with an inverse Gaussian temperature distribution.