Advanced Materials Research Vols. 1070-1072

Abstract: Closely related to the actual output power and the light intensity, the temperature of the photovoltaic cell panel and the load of the PV array or the like. In the case of the external environment is stable and load conditions change, the output power of the PV modules exist Maximum Power Point, in order to improve the self-tracking PV system energy conversion efficiency, maximum power point tracking method may ensure the system running at maximum power points. Photovoltaic power generation system, optimize allocation method of PV array are also discussed in this paper.

Abstract: Maximum power point tracking (MPPT) algorithm directly affect the conversion efficiency of photovoltaic power generation system independent of energy, the thesis of common strengths and weaknesses of the MPPT algorithm to summarize, the traditional method of perturbation and observation maximum power point tracking algorithm is improved and build a simulation model, the simulation model are direct and network controllers and input grid and grid-independent photovoltaic power generation system model of network simulation, and network time from both the grid conditions, and the impact of current network waveforms and grid voltage waveform analyzed. Simulation results observed with the conventional perturbation method were compared and analyzed to verify the effectiveness of the improved method.

Abstract: The demand on resource is increasing when human beings have entered the 21st century, as the one-time fossil fuels get mined-out, such as coal, natural gas and petroleum the energy crisis has become a central issue. Because the solar energy density is small and the solar orientation changes over time, it’s difficult to collect, transmit and store the solar energy. Therefore, the utilization of solar energy is improved by using the technology of high-power condenser and automatic tracking, and the scope of solar energy application is also expanded. Tracking photovoltaic system be made of sun sensor, automatic tracking control system, the tracking actuator, solar panel, battery. With the guidance of the sensor, the control system can accurately track the position of the sun, so that the solar panel is always vertical to sunlight, to maximize use of eventually reaching solar efficiency. Data show that the utilization efficiency of solar energy can be improved about 10%.

Abstract: Digital control possesses evident advantages and has become a mainstream control of photovoltaic grid connected inverter.The mathematical model and parameter setting of the single phase photovoltaic grid connected inverter with L filter was introduced in the paper.It was analysed on the effect on system stability of digital process from the two aspects which were the zero-order-hold and one-step-delay control. The bode diagram was verified the theoretical analysis on system stability.The conclusions were made that the introduction of digital control reduces the critical stable gain of photovoltaic grid connected inverter system,system stability is varied with sample time, the parameters of L can affect the system stability range,zero-order-hold reduces the stability range and limits the performance improved of digital control system,one-step-delay control on photovoltaic grid connected inverter reduces again the stability range on the basis of the zero-order-hold control.

Abstract: Due to the natural environment, geographic location, the technical conditions and restrictions of many factors, centralized parallel operation of power grid the west extension and popularization in our country with high difficulty and feasibility. The distributed photovoltaic power generation possesses the following advantages: less investment, flexibility and compatibility. The joint operation of DG with power grid brings tremendous variation in control and operation for modern power system, ultimately the stability of power supply is enhanced and the life quality of residents is improved in western region of China. This paper explores the operation mode of distributed photovoltaic power generation in remote areas, and introduces the concrete operation mode of the project, analyzes the adaptability of distributed photovoltaic mode. Finally, the feasibility of the application of the distributed photovoltaic power generation in the western region of China is analyzed in this paper.

Abstract: The generated photovoltaic located at load center has a significant impact on feeders' voltage profile. Firstly, considering the reactive power and the line reactance, after theoretical calculation and simulation, it is proved that the influence on voltage profile of generated PV access to distribution network has a great relationship with its access position and access capacity; when there are multiple PV access to distribution network, the influence on voltage profile is different when combined capacity and location is different. Then the maximum alternative capacity at each node is calculated. Al last, it is illustrated through simulation that shunt reactor at PV node and inverter controlling can solve the voltage violation problem.

Abstract: Thermal gravimetric analysis is an important method in the study of biomass. In this paper, using this method on elmwood, through pyrolysis experimental analysis at different heating rates (10,30,50,80 °C / min), get the TG-DTG curves to investigate the pyrolysis characteristics of elmwood. The results show that the pyrolysis process of Elmwood are divided into three stages; With the increasing of heating rate, the major pyrolysis temperature range expansion, the temperature corresponding maximum weight loss rate rose; while taking advantage of Lyon integration algorithm for solving the activation energy of 78.47-271.58kj/mol. indicating Arrhenius first-order single-step reaction with biomass pyrolysis reaction has good linearity.

Abstract: In this paper, the conversion of biomass-derived glycolide to ethylene glycol over Cu was investigated. As a result, Cu showed significant catalytic role for the conversion of glycolide into ethylene glycol compared to other catalysts, such as Ni and Mo. A 24.3% yield of ethylene glycol was achieved in the process. The possible formation pathway of ethylene glycol from glycolide over Cu under hydrothermal conditions was proposed.

Abstract: The straw-based power generation, as a mature new energy utilization method, has been widely used in different countries. In this paper, we review the development of the straw-based power generation in China and divide it into three stages, namely, research and experimental stage, rapid developing stage and mature stage. Based on the analysis, it is found out that the straw-based power generation in China is now faced with profit loss. The underlying reasons include the high price of straw fuel, high operation and maintenance cost, large investment, low capacity utilization rate and high rate of power consumption in the production. We also propose the managerial suggestions to address the problems.

Abstract: In this paper, the influence of catalyst on the formation of ethyl lactate from glucose and ethanol was investigated. Among the catalysts tested, Co and Cu₂O shows the catalytic activity for the ethyl lactate production and obtained the same 7.2% yield of ethyl lactate. The stability of Co before and after the reaction was suitable for the transformation. The effect of reaction time was also studied over Co.