Advanced Materials Research Vols. 724-725

Abstract: Traditional incremental conductance method is one of the most widely used methods of MPPT in solar photovoltaic system. But oscillation and misjudgment also exist, which have a great impact on the efficiency and stability of solar system. This thesis proposes a new MPPT algorithm, that is, to combine power prediction method with incremental conductance method organically; simultaneously to apply variable step theory to reduce oscillation and avoid misjudgment. After the simulation in MATLAB7, it proved to be feasible by comparing with traditional incremental conductance.

Abstract: Z-source inverter is the key part of the new energy equipment. A model of Z-source inverter has been built by using the State Space Average Overall Modeling method. It can achieve the linkage control of the direct zero vector d and modulation factor m. According to the model, a control system adopted MPPT tracking control and voltage & current double loop grid-connected control is designed to realize the coordinated control. SHEPWM modulation strategy is used to ensure that the grid current waveform quality. Z-source photovoltaic grid-connected experimental system has been designed and carried out, and the experimental results verify the validity and correctness of the control system.

Abstract: A novel distributed photovoltaic power generation and commercial power complementary hybrid power supply system was designed and developed, and the proposed system applied to the lighting power supply system used in university classroom energy-saving lighting. Combined with intelligent control technologies, to realize the classroom energy-saving and LED efficient lighting, effectively reduce the lighting energy consumption in university campus. The proposed system can ensure efficient and reliable power supply for classroom lighting applications.The designed and developed experimental system verified the feasibility, reliability and superiority of the proposed system.

Abstract: A new direct illuminated receiver (DIR) for Dish/Stirling system was introduced in this study. The new cavity receiver was designed to help avoid the ruptures of the heater-head result from nonuniformities of temperature distribution. A method was also proposed to optimize the design of DIR. Both the efficiency and the reliability were improved as using this method in the experiment. The power output of the electric generating system was increased by around 300W. The new DIR operates safely at 900°C-1000°C, and cannot be sensitive to a short-lived cloud.

Abstract: This paper proposes an improved LVRT control strategy based on PIR controller for grid-connected photovoltaic system under asymmetric voltage sag fault. First, the PIR current controller is designed in the positive synchronous frame without the need to decompose the positive and negative sequence components and the dynamic adjustment method for the current-reference calculation is given in order to gain a constant active power. And then, the principle how control strategies switching between the one in normal state and the other one in fault state is revealed in detail. Finally, simulations and experiment test on a 500kVA grid-connected photovoltaic inverter verify that this control strategy achieves good dynamic performance and it improves the PV inverters’ capacity of riding through asymmetric voltage sag fault effectively.

Abstract: Taking factors such as astronomy, atmosphere, microgeography and local landscape that comprehensively affect solar radiation into account, we established a direct solar radiation (DSR) model on the accidented topography. Dynamics of DSR on accidented topography in Henan province were also statistically analyzed. Modeling results showed that highest DSR in Henan occurred between May and July, while lowest DSR occurred between December and February of the next year, and the multi-annual mean DSR in Henan province was 2127.7MJ/ m². Impacts of local landscape on DSR on accidented topography in Henan province differs in different seasons. In winter half year, during which solar altitude angle is relatively low, this impact is more significant.

Abstract: In remote areas, the scheme of networking grid complementarily by the large capacity ofPV plants and the hydropower units becomes an important choice. After analyzing the design of ahydroelectric-connected PV plants, this paper presents a detailed requirement of a large capacitybattery charger. The Buck circuit topology is adopted as the topology of the battery charger satisfyingthe demand the high charging efficiency and reliability and a 3 phase phase-shifted interleavingtopology is adopted to resolve the problem of high power application. Finally a double-loop controlstrategy was designed for implementing the batteries three-stage charging control and PV MPPTfunction. A 150kW battery charger is developed and used in PV plant of the Yushu, Qinghai province,China. The experimental data acquired form

Abstract: In the design process of building integration photovoltaic (BIPV), the architectural design, power system design and structure design are very important. Moreover, some kinds of suitable connection are required which should meet the requirements of bearing capacity and deformation. In this paper, the connections between photovoltaic system and buildings were discussed. Then based on the 1MW HIMOER photovoltaic support in Lianyungang technical college, we selected the suitable connection, and designed the space photovoltaic support .This results are useful for the development of the BIPV.

Abstract: In this paper, we investigate an active layer treatment method that is referred to as solvent annealing. Organic solar cell was fabricated and an isopropanol (IPA) solvent annealing process was carried out. The experiment result should that the value of absorbance and the crystallinity is improved by isopropanol solvent annealing of active layer. Moreover, the current density, series resistance and the efficiency improved, leading to enhanced efficiency of 3.22%, whereas a pristine sample showed an efficiency of 3.04%

Abstract: In order to improving the conversion efficiency of polycrystalline silicon solar cells, progressive SiNx thin films were deposited on the surface via Roth&Rau plasma-enhanced chemical vapor deposition method. The effects of progressive SiNx thin films, such as surface passivation, anti-reflection, and electrical performance were systematically investigated. Compared with monolayer films, progressive SiNx thin films have better anti-reflective properties in the wavelength range of 300-500 nm, resulting in improvement of the short wavelength absorption of the crystalline silicon solar cells. Moreover, the bottom of progressive SiNx thin films with high refractive index enhances the surface passivation. Thus, higher open-circuit voltage and fill factor could be obtained by this technique.