| As the third generation of photovoltaic technology, concentrating photovoltaic(CPV) owns lots of incomparable advantages by comparing with conventional photovoltaic technology, such as high efficiency, low-cost, low power dissipation and etc, which is expected to be the dominant technology in the future. Although multi-junction solar cell’s photoelectric conversion efficiency has exceeded 44.7%, the whole conversion efficiency of the concentrated photovoltaic power generation system still has great space to improve. This article mainly focuses on the key to improve the technologies of the whole conversion efficiency optimization on the concentrated photovoltaic power generation system. Combined with the mechanical structural characteristic, organic integrated the related theory of semiconductor materials, non-imaging optic theory, automatic control theory and thermodynamic with the working principle of high efficiency CPV, which effectively solves the existing crucial technical matters of CPV and provides a new direction for their application development.The main contents of this paper include the following aspects,Using the theory of semiconductor optoelectronics and connecting with the material and structural characteristics of actual photovoltaic device establish the equivalent circuit model of a monolithic Ga In P/Ga In As/Ge triple-junction cell and concentrated module with dual-diode model. Utilizing MATLAB software fits the triple-junction cell and subcell’s I-V curve which is measured under the given condition, combining the hidden constraints of two major temperature coefficient iterates to calculate 11 parameters to be determined. Meanwhile proposes an effective extraction of the equivalent parallel resistance of every subcell through the new fitting iteration, and analyses the influence of related parameters quantization on the performances of solar cell.Based on analysis of primary and secondary optical structure, and utilizing the principle of non-imaging optics, concentrated optical system based on refraction and reflection to form the primary optical unit and then combined with secondary optical unit is proposed. CPV system by using optical simulation software is studied, and optimizes the design of optical structure. Satisfying the high transmission, total reflection intensity of a primary concentrator unit, achieves uniform distribution of a light spot on the surface of the solar cell through the secondary optical structure simultaneously, to which the solar cell is in optimum condition of high photoelectric conversion efficiency.Characteristics of mechanical structure based on two-dimensional polar-axis linkage, the high accuracy tracking sensor and the hardware controlling system is designed. The related experments taken by own has verified the tracking system’s reliability and stability in operation. What’s more, the new tracking control scheme based on combining tolerance and timing is proposed, ±0.35° tolerances can still get 90% maximum output power of CPV when to guarantee the accuracy of tracking system. Cutting down the operating costs of the control system is realized.For the temperature-dependent properties of photovoltaic devices under high concentration, adopt active or passive heat-dissipating method to simulate the heat effect of photovoltaic device. Then, a new heat-dissipating method to reusing the heat and improving the synthetical efficiency of the solar energy simultaneously is achieved. Meanwhile the heat-dissipating realizes maintain its high output characteristics of photovoltaic devices, reaching on secondary use of solar thermal energy, to achieve the purpose of improving the comprehensive efficiency of solar energy utilization.Based on what mentioned above four aspects, Micro-improvements in production processes, by increasing the equivalent parallel resistance value to improve output characteristics of concentrator solar cell. Using concentrated optical system with two optical processing achieves the beam intensity distribution and adopting mechanical structure using a two-dimensional polar axis to meet the tracking accuracy of PV system structurally. Combining with tolerance and timing optimization programme meet the large tolerance range in terms of control, while reducing their operation costs. Comprehensive parts advantages, trying to maximize the conversion efficiency and reliability of photovoltaic devices and systems. Then, the CPV’s photoelectric conversion efficiency will be greater than 30%, which occupied area also will be less 30 percent than the flat crystalline silicon systems under the same power output. |
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