Advanced Materials Research Vols. 622-623

Abstract: This paper presents on overview of maximum power point tracking (MPPT) techniques for different types of wind energy conversion systems (WECS). In order to obtain maximum power from the wind turbine (WT), variable speed wind energy conversion systems (VSWECSs) are preferred over constant speed wind energy conversion systems (CSWECSs).In VSWECS, the rotational speed of the turbine is varied by controlling the aerodynamic or electrical parameters of WECS to maintain a constant tip-speed ratio (TSR). This is called maximum power point tracking and different techniques are applied to WECS namely Squirrel Cage Induction Generators (SCIGs) based WECS, Permanent Magnet Synchronous Generators (PMSGs) based WECS.

Abstract: Plant utilization as a part of building envelope has never been introduced in view of the compliance to Building Energy Code or the successful building energy codes or even in view of energy for building labeling. This research tries to find out the approach to utilize the equivalent plant conductivity (k_e) in order to make the plant as a construction material for the building envelope. The k_e is plugged into the formula of the Overall Thermal Transfer Value to see the energy saving for air-condition from having vertical green. By testing on two rooms with air conditioner, one with vertical green and another is without vertical green, the room with vertical green reduced the Overall Thermal Transfer Value from 59.87 W/m² to 49.39 W/m².

Abstract: The Maximum Power Point Tracking (MPPT) is a very important function in a Solar Photovoltaic (SPV) system. While previous research has been focussed on optimizing the performance of the MPPT, there is further scope to improve upon the MPPT efficiency without compromising on the complexity of the MPPT technique in terms of the algorithm and hardware requirements. The research work presented in this paper aims to address this gap. The paper presents two novel MPPT schemes which are the proposed Perturb and Observe (P&O) and proposed Incremental Conductance (IC) methods based on two-step control and direct duty ratio perturbation. The proposed techniques are efficient, computationally less complex and hardware minimal than previous study in this field. For verification, simulation has been performed for extensive irradiation profiles of Standard Test Conditions (STC), rapidly changing and gradually changing insolation conditions which are representative of the boundary cases. Results of the proposed MPPT methods are compared with that of conventional MPPT methods. The results show that proposed MPPT schemes have excellent tracking efficiency and dynamic response with respect to previous research.

Abstract: In this paper, a hybrid topology of FACTS devices has been investigated to improve stability features of static voltage. The primary assumption is a power system which has been located under SVC parallel compensation. HPFC forms a hybrid controller using IPFC series converters as a hybrid with existing parallel and passive compensator (SVC) in power system. Thus, simultaneous and independent control of active power flow can be reached through transmission lines and the exchanged reactive power values towards sending and receiving line. Using a hybrid structure makes the use of convertors to improve performance of the old and existing compensators in the power system possible. In this study, the power injection model (PIM) has been used to model series-parallel parts of hybrid power flow controller in Newton-Raphson load flow, and all have been simulated in M-file environment of MATLAB software. In order to investigate the effect of this controller on stability properties of static voltage, P-V curve of PQ buses of a prototype system has been evaluated in a continuous power flow (CPF) in M-file environment of MATLAB software. In the section of simulation results, SVC parallel compensation and UPFC series-parallel compensation are compared in terms of the amount of losses, active and reactive power, and improvement of the system’s loading limit with the proposed hybrid structure.

Abstract: This paper presents comparative performances of an linear and disk AC MHD power generation with an active power. The configuration of linear and disk consist of the top and bottom stators. the top stator bottom stator winding are connected with a power supply and an electrical load, respectively. The interaction between the metal fluid and traveling magnetic field can be explained by Maxwell’s equations and Ohm’s law based on the method of finite-elements. Power flow and electrical efficiency of an AC MHD power generation have been evaluated by various slip conditions. The optimal operating point of the generator was defined by adjusting slip values. The result confirms that disk AC MHD power generation has high active power more than linear AC MHD power generation at the same slip.

Abstract: This paper is intended to be an evaluation of the use of Wind Power to reduce Carbon Dioxide emissions (C02) in Brazil. In the first part of the paper, the mean aspects of Wind Power Energy and the importance of clean energy in the current world received an introductory description. Next, the mean emission assessment method was described, then, the contribution, in terms of emissions of C02, of several energy sources was depicted in terms of tons per MW produced. It was done a comparative of the integration of Wind Parks in grids with different energy matrices (hydro, coal and etc.), a study comparing the several energy sources both in Brazil and the world. And finally, it was done an approach about the planning and future opportunities for Brazilian energetic panorama, emphasizing the technical feasibility and the stimulus of the public policies.

Abstract: Combined with the thermal system analysis, the mathematical model for selecting the optimal initial pressure of the power unit is established based on the comprehensive consideration of the effect of main steam pressure on governing stage efficiency, steam feed pump consumption and flow passage efficiency. Then the steam pressure with the maximum unit efficiency is searched using variable condition calculation. With quantitative calculations of N600-16.7/537/537-I unit of Pan Shan thermal power plant taken as an example, the optimal initial pressure is obtained by exhaustive method around the 75% load point. The results reveal that the unit power, heat absorption and unit efficiency all increase with the increase of the main steam pressure. However, the increasing velocity of efficiency is less than heat absorption when main steam pressure attains to certain value, which makes the unit efficiency begin to decrease. Therefore, this main steam pressure is the optimal initial point to be searched.

Abstract: We have developed a flexible piezoelectric device (FPED) composed of polyvinylidene fluoride (PVDF) and functional resin to generate electric power from wind energy with wide range in frequency. We made clear electrical characteristics of the FPED generated by wind power and availability of an attached bluff body in uniform wind. Moreover, we also validated electric performance of the FPED which is laminated with a stretching resin and has a roughness surface such as woolen and small hemisphere. We showed that both a force caused by breeze and wind energy with wide range of spectrum could be harvested effectively using the FPED.

Abstract: The ever increasing problems related to air pollution and the difficulties for power lines to reach inaccessible areas are pushing to find new solutions for powering telecommunications equipments (TLC). The renewable energy systems, although relatively expensive, have the required characteristics. The purpose of this work is to find a solution based on a low power wind turbine to serve a real telecommunication site located near Palermo, the main city of Sicily (Italy).

Abstract: Integrating wind turbines in urban areas especially over buildings is a new way of producing electricity which is supported in recent years. Wind turbines sited well above the roof of buildings operate in skewed flow. In this paper, to examine variations in efficiency of wind turbines in this condition, two models of H-Rotor and horizontal axis wind turbine analyzed based on axial momentum theory through computer simulations. Simulations conducted through CFD method and k-ε turbulence model was utilized to analyze flow fluctuations in Navier-Stokes equations. Models show that, for an H-Rotor, the optimal power output in tilted flow can be up to two times the power output of horizontal axis wind turbine (HAWT).