PVG输送带覆盖胶性能的研究

用粉末丁腈P83来改性PVC研制PVG输送带覆盖胶,研究了P83对覆盖胶的拉伸强度、撕裂强度、表面电阻、热空气加速老化性能和阻燃性能的影响。实验结果表明,P83与PVC共混的性能较好,可达到性能互补的效果。综合考察,P83用量在30份时,PVG输送带覆盖胶的综合性能较佳。     

Implementation of photovoltaic water pumping system with MPPT controls

To increase the output efficiency of a photovoltaic (PV) system, it is important to apply an efficient maximum power point tracking (MPPT) technique. This paper describes the analysis, the design and the experimental implementation of the tracking methods for a stand-alone PV system, using two approaches. The first one is the constant voltage (CV) MPPT method based on the optimum voltage, which was deduced experimentally, and considered as a reference value to extract the optimum power. The second one is the increment conductance (Inc-Cond) MPPT method based on the calculation of the power derivative extracted by the installation. The output controller can adjust the duty ratio to the optimum value. This optimum duty ratio is the input of a DC/DC boost converter which feeds a set of Moto-pump via a DC/AC inverter. This paper presents the details of the two approaches implemented, based on the system performance characteristics. Contributions are made in several aspects of the system, including converter design, system simulation, controller programming, and experimental setup. The MPPT control algorithms implemented extract the maximum power point (MPP), with satisfactory performance and without steady-state oscillation. MATLAB/Simulink and dSpace DS1104 are used to conduct studies and implement algorithms. The two proposed methods have been validated by implementing the performance of the PV pumping systems installed on the roof of the research laboratory in INSAT Tunisia. Experimental results verify the feasibility and the improved functionality of the system.     

Fuzzy energy management of hybrid renewable power system with the aim to extend component lifetime

In this paper, a fuzzy energy management algorithm for a hybrid renewable power system based on lifetime extending is presented. When the system contains two storage elements or more, the selection of the suitable element to be charged or discharged becomes of paramount importance. When the storage elements are of different types, the decision will be difficult. Conventional algorithms that make series of tests to select the storage element choose always the first available element. This way of testing affects badly the most used element and may affect the other storage elements too as they rarely operate under hard load scenarios. In this study, and in order to solve this problem, two fuzzy controllers have been used to manage the energy flow for a hybrid renewable power system. It is composed of: a photovoltaic generator as a main source, a fuel cell and batteries as a storage elements. The controllers operate as master and slave. The master controller gives orders to all the system power converters and to the slave controller as well. The latter is activated only when the storage elements are at the same state of charge. It is charged, instead of the master's, to select the suitable element to be charged or discharged. Its orders are given based on lifetime functions for each element. To examine the proposed algorithm, simulations have been performed under Matlab /Simulink (The MathWorks, Inc., Massachusetts, USA). Comparison and statistics have been carried out to give the percentage of the worked hours for each element in each operating mode. The obtained results show the high performance of the proposed algorithm. Copyright © 2017 John Wiley & Sons, Ltd.     

Modeling and control of photovoltaic energy conversion connected to the grid

This paper presents modeling and control of a photovoltaic generator (PVG) connected to the grid. The parameters of the PVG have been identified in previous work (series and parallel resistance, reverse saturation current and thermal voltage) using Newton-Raphston and the gradient algorithm. The electrical energy from a PVG is transferred to the grid via two static converters (DC/DC and DC/AC). The objective of the proposed control strategy is to maximize energy captured from the PVG. The adapted control law for extracting maximum power from the PVG is based on the incremental conductance algorithm. The developed algorithm has the capability of searching the maximum photovoltaic power under variable irradiation and temperature. To control the DC/AC inverter, an intelligent system based on two structures is constructed: a current source control structure and a voltage source control structure. The system has been validated by numerical simulation using data obtained from the PVG installed in the laboratory research (INSAT, Tunisia).     

Development of dynamic thermal input models for simulation of photovoltaic generators

ABSTRACT

Development of dynamic thermal input models for simulation of photovoltaic generators (PVG) is the main concern of this work. The dynamic thermal input models consist of insolation and temperature models. The model development involves acquisition of meteorological input data for Kampala at latitude (0.3476^oN) and longitude (32.5825^oE), measurement of physical conditions in which PVG is operating, carrying out thermal balance around PVG and application of solar analytic equations. The emerging models are simple simulated dynamic insolation and temperature models. These models were superimposed with quadruple sinusoidal waves to obtain superimposed simulated dynamic models. Furthermore, the superimposed insolation models were validated with the superimposed sky model and meteorological data while the corresponding temperature model was validated with the experimental data. The developed models become universal by substituting localised input parameters. Moreover, these models are useful for operation, installation, design and dynamic performance analysis of PVG.     

PVG带全橡胶覆盖胶加工性能与带芯粘合质量关系的研究

通过ＰＶＧ整芯输送带所用的丁腈橡胶覆盖胶胶料的粘度，焦烧性能和硫化速度与带芯粘合质量关系试验指出，设计具有良好加工性能的覆盖胶胶料和控制在适宜温度范围进行硫化是确保粘合质量稳定的重要条件     

超支化膨胀型阻燃剂的合成及其在PVG输送带中的应用研究

将超支化结构引入膨胀型阻燃剂中,合成了一种超支化膨胀型阻燃剂,研究了不同代数及添加量的超支化膨胀型阻燃剂对丁腈橡胶/聚氯乙烯糊树脂(PVG)输送带覆盖胶阻燃性能和力学性能的影响。研究结果表明,超支化膨胀型阻燃剂在对带体力学性能影响较小的情况下能较大提升橡胶输送带覆盖胶层的氧指数,在阻燃剂添加量为30.0%(质量分数)时,氧指数可达到31%,具有较好的阻燃性能。     

采用四联压延机贴橡塑复盖胶

介绍了采用四联压延机贴椽塑复盖胶的技术改造和研发过程。通过反复论证、实验,对原有工艺路线和设备做了大胆改造,成功实现了压延机贴橡塑复盖胶。     

Pore Size Distribution and Chord Length Distribution of Porous VYCOR Glass (PVG)

A porous VYCOR-glass of porosity c 30% was analyzed by use of nitrogen adsorption (NA), mercury intrusion (MI) and small-angle scattering (SAS). The distribution density of the pore diameter was determined from the SAS experiment, based on the stereological information for a fixed order range L = 40 nm.A pore can be described by use of two random variables, which depend on each other: The pore diameter d and the chord length l. In a first step, an assumption free data evaluation method yields the second derivative of the SAS correlation function (r). Then, based on the intimate connection between (r) with random chord lengths, an interpretation of the first two mean peaks was performed. These peaks reflect the chord length distributions of pore and wall. The problem of the allocation of the peaks has been solved based on the information of the NA and MI experiments. The transformation of the distribution densities of the pore diameters V _M(d) (obtained by MI a experiment) and V _N(d) (obtained by a MI experiment) into chord length distribution densities A _M(l) and A _N(l) have allowed the clear interpretation of (r). It was possible to separate the chord distributions of the pores from those of the walls. The first (r) peak reflects the chord length distribution density (l) of the pores (first moment l¯ = 10.6 nm) and the second one that of the walls f(m) (first moment m¯ = 21 nm). It follows c 30%. The average mean chord length is d¯ _lm 15 nm. The second moment of (l) is 108 nm².Finally, from the separated function (l), the diameter distribution density of the pores V _SAS(d) has been obtained. V _SAS(d) was calculated, neither assuming a defined mathematical function type of the distribution nor a certain shape or dimension of the pore. The first and second moments of V _SAS(d) are 7 nm and 74 nm². From comparing the three distribution densities V _SAS(d), V _M(d) and V _N(d) it can be concluded that the assumption of cylindrical pores is fulfilled.While the chord length distribution density of the walls is a highly symmetrical function, which can be approximated by a Gauss term, the pores have an unsymmetrical chord distribution density with the PVG.