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Ding K.,Hohai University | Ding K.,Changzhou Key Laboratory of Photovoltaic System Integration and Production Equipment Technology | Qin S.,Hohai University | Feng L.,Hohai University | And 4 more authors.
IET Power Electronics | Year: 2016

A new outdoor photovoltaic (PV) module test platform was introduced to measure I-V characteristic curve of PV module in this study. The proposed test platform was designed centring on the programmable electronic load (E-load) which used the transfer characteristics of metal-oxide-semiconductor field-effect transistor (MOSFET) and controlled PV module output current by controlling the drain current ID of MOSFET indirectly. Ultimately, controlling the PV module work on any operating point of the I-V curve. This test platform can automatically shift operation mode contraposing the I-V curve of PV module. It can continuously measure I-V curves and ambient data in the outdoors including the total irradiance, temperature of PV module back sheet and ambient temperature. The test results show the proposed test platform's accuracy meets the user's requirements, and more details of I-V curve can be obtained than by using traditional measurement mode. © 2016, The Institution of Engineering and Technology.

Ding K.,Hohai University | Feng L.,Hohai University | Qin S.-Y.,Hohai University | Mao J.,State Key Laboratory of PV Science and Technology | And 4 more authors.
Journal of Power Electronics | Year: 2016

Usually, the output characteristics of a photovoltaic (PV) array are significantly affected by non-uniform irradiance which is caused by ambient obstacles, clouds, orientations, tilts, etc. Some local maximum power points (LMPP) in the current-voltage (I-V) curves of a PV array can result in power losses of the array. However, the output power at the global maximum power point (GMPP) is different in different interconnection schemes in a PV array. Therefore, based on the theoretical analysis and mathematical derivation of different topological structures of a PV array, this paper investigated the output characteristics of dual series PV arrays with different interconnections. The proposed mathematical models were also validated by experimental results. Finally, this paper also concluded that in terms of performance, the total cross tied (TCT) interconnection was not always the optimal structure, especially in a dual series PV array. When one of the PV modules was severely mismatched, the TCT worked worse than the series parallel (SP) structure. This research can provide guidance for switching the interconnection to gain the greatest energy yield in a changeable- structure PV system. © 2016 KIPE.

Ding K.,Hohai University | Feng L.,Hohai University | Wang X.,Hohai University | Qin S.,Hohai University | Mao J.,State Key Laboratory of PV Science and Technology
ICCAIS 2015 - 4th International Conference on Control, Automation and Information Sciences | Year: 2015

With the increase of the capacity of photovoltaic (PV) systems, how to alleviate the problem caused by the random output power of PV system becomes significant. This paper uses Markov model to correct prediction results of power generation for grid-connected PV system based on gray neural network model. Using the hourly data of PV system output power under similar climate conditions, gray model of the output power is established in real-time. Then, the output of the gray model, the temperature, irradiance and measured values are used to build the prediction model with neural network, and the residual is corrected by Markov chain. The accuracy of model is researched under three typical weather conditions. The results show that this model gains the high precision, and the efficiency is comparatively better in sunny and cloudy condition than low irradiance. The proposed method reflects the actual trend of the PV generations, which can be successfully applied to engineering and scientific research. © 2015 IEEE.

Xu G.,State Key Laboratory of PV Science and Technology | Yang Y.,State Key Laboratory of PV Science and Technology | Zhang K.,State Key Laboratory of PV Science and Technology | Liu W.,State Key Laboratory of PV Science and Technology | And 3 more authors.
Conference Record of the IEEE Photovoltaic Specialists Conference | Year: 2013

The combination of light reflectance, light trapping and absorption plays an important role in the conversion efficiency of solar cells. An accurate modeling of these parameters is paramount for optimizing solar cells through simulation. In the past, optical simulations have suffered from lack of accuracy. In particular, quality of texturization, non-specular reflection on the back surface and free carrier absorption (FCA) has been difficult to simulate. An improved optical simulation method is introduced in this paper. Based on the image of the textured front surface, obtained from scanning electron microscope (SEM), a three-dimensional model is automatically generated for Sentaurus TCAD simulator. The roughness of the rear side of the cell creates non-specular reflection of infra-red light, which is simulated by combining a three-dimensional pyramid structure and Phong's model. Free carrier absorption is introduced after measurement of the doping profiles. A good fit between measured and simulated reflectivity data over a wide range of wavelengths is demonstrated, resulting in a reliable optical generation profile for the subsequent semiconductor device simulation. © 2013 IEEE.

Wang W.,State Key Laboratory of PV Science and Technology | Sheng J.,State Key Laboratory of PV Science and Technology | Yuan S.,State Key Laboratory of PV Science and Technology | Sheng Y.,State Key Laboratory of PV Science and Technology | And 5 more authors.
IEEE Journal of Photovoltaics | Year: 2015

Screen-printed high-efficiency industrial n-type rear-junction silicon solar cells were fabricated on 5-in commercial grade Cz wafers. A furnace-diffused boron emitter and a laser-doped phosphorous front-surface field were applied to produce n-type rear-junction cells with PECVD SiNx on the front and PECVD AlO x/SiNx on the back for surface passivation. All contacts were screen printed. An average efficiency of 20.33% was achieved, while the best efficiency was 20.65%. The initial results indicate that the potential for a higher FF can be achieved by improving the front pattern and optimizing the condition for metallization, enabling an even higher efficiency. © 2011-2012 IEEE.

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