European Journal of Advances in Engineering and Technology

218-229

Authors: M Abdulkadir and AHM Yatim

This paper presents a control method suitable for photovoltaic (PV) systems which ensure that power generated is maximized for various conditions. Due to partial shading conditions in PV, the power-voltage characteristics exhibit multiple local peaks; one such phenomenon is the global peak. These conditions make it very challenging for maximum power point tracking (MPPT) to locate the global maximum power point. Many tracking algorithms have been proposed for this purpose. In this paper, a modified particle swarm optimization (PSO)-based MPPT technique is proposed. Unlike the conventional PSO-based MPPT methods, the proposed method accelerate convergence of the PSO algorithm by consistently decreasing the weighting factor, the cognitive and social parameters thus reducing the steps of iterations and improved the tracking response time. The advantage of the proposed method is that it requires fewer search steps (converges to the desired solution in a reasonable time) compared to other methods. It requires only the idea of series cells; thus, it is system independent. The study is supported by numerical and experimental results.

236-243

Authors: I O Eze and I O Igwe

Comparison of some mechanical properties of injection and extrusion moulded pineapple leaf powder (PALP) filled high density polyethylene (HDPE) was studied. PALP and HDPE composites were prepared using injection and extrusion moulding techniques respectively. The weight percentages (wt.%) of filler contents investigated were varied as 0, 2, 4, 6, 8, 10 wt.%. It was observed from the results of the mechanical properties carried out on the composites that the tensile strength, tensile modulus, abrasion resistance, and hardness of the composites increased with increases in filler content for all the filler contents investigated both for the injection, and extrusion moulded composites while the elongation at break (EB) for HDPE/PALP composites was found to decrease with increases in filler content for all the filler contents investigated both for the injection, and extrusion moulded composites. The results also showed that the extrusion moulded HDPE/PALP composites exhibited better tensile strength, tensile modulus, hardness, abrasion resistance and flexural strength than the injection moulded HDPE/PALP composites for all the filler contents investigated while the elongation at break (EB) of the extrusion moulded HDPE/PALP composites exhibited lower elongation at break (EB) values than the injection moulded composites for all the filler contents investigated. From the present study, it has been proved that PALP can be used as reinforcing filler in polymer composites and that the use of extrusion moulding technique produced HDPE/PALP composites of slightly better mechanical properties than those produced using injection moulding technique. This has shown that the quality of moulded products depends on the selection of correct processing techniques. Therefore, in processing bio- composites, suitable processing techniques must be carefully selected in order to obtain optimum composite properties.

250-254

Authors: Deepanshu Kaushal and T Shanmuganantham

The improvement in the radiation gain characteristic of a conventional RMPA upon the use of alphabetical slots has been investigated. The RMPA design has been built using a 58mm x 80 mm Flame Retardant-4 Epoxy substrate that is 1.6 mm thick and has a dielectric constant of 4.4. The employed feeding technique is coaxial feed. Simulation has been carried over HFSS-15. An improvement in the radiation characteristic of gain has been ob-served in each design iteration. The final design stage has been fabricated and experimentally verified. The meas-ured results have been found to be in close approximation with the simulated ones.

274-281

Authors: Soumyajit Datta, Arabindo Chandraand Sumana Chowdhuri

The paper describes a new technique for sensorless rotor flux estimation of vector control induction motor at low speed operation. The sensorless rotor flux estimation at low speed region is difficult mainly due to the terminal voltage acquisition problem and parameter variation effect. The estimation technique proposed here, estimates rotor fluxes without the motor terminal voltages signal. Thus, the problems associated with the estimation of rotor fluxes at low-speed due to terminal voltage measurement can be eliminated. To achieve this feature, the rotor flux is estimated during null or zero space vector (state 8 or 7) periods of Space Vector PWM Inverter. The terminal voltages are zero during null or zero space vector period as motor terminals are shorted through the upper or lower switching devices of the inverter. Thus, the rotor position estimation can be performed using the zero vector period stator currents considering terminal voltages are zero. Theoretically the proposed estimator can estimate the position signal just after the first sampling period of the inverter. The method is simple and easy for implemen-tation. Extensive computer Simulation results are presented in this work to validate the performance of the pro-posed estimator scheme.

288-295

Authors: Shruti Singhroy and PL Zade

Cognitive Radio (CR) is an adjusting of quick, ready intelligence radio and network technology that can automatically discover ready narrow ways in a radio band and change sending parameters making able to more making connections to run taking place together and also get well radio operating behaviour. CR uses a number of technologies including adjusting radio and software formed radio (SDR) where old and wise hardware parts including mixers, modulators and makes greater have been put in place of quick, ready intelligence software. Wi-Fi based wireless terminal structure block that can be used to design cognitive radio network (CRN). In this paper the design procedure of cognitive radio network using IEEE 802.11 wireless standards is given. Also new reactive routing protocol namely Improved Ad-hoc On-demand Multipath Distance Vector (IMAOMDV) which is extension of Adhoc On-demand Multipath Distance Vector (AOMDV) is designed. The performance of Wi-Fi based CRN is evaluated by its performance parameterslike average throughput, average end to end delay and packet delivery ratio. Finally designed routing protocol’s performance is compared with various reactive and proactive routing protocols.