International Journal of Advanced Renewable Energy Research
Volume:1 Issue: 6, 2012

A hybrid PV-FC system for standalone DC load application is digitally simulated and presented in this paper. The proposed hybrid (PV-FC) renewable energy scheme has three key subsystems to supply the DC side electric loads. The first one is the renewable generation sources from photovoltaic PV array and Fuel Cell. The second is the interface converter used to connect the renewable energy generators to a common DC collection bus, where all generated energy is collected. The third subsystem is the novel dynamic controller for the switched-modulated power filter. The dynamic controller main function is to ensure efficient energy utilization and dynamic matching between equivalent DC loads and hybrid renewable energy sources. The dynamic controller is an error driven PID regulator to control the switching of the interface converter. The hybrid renewable energy system with the three key subsystems is digitally simulated using the Matlab/Simulink/Sim-Power Software Environment and fully validated for efficient renewable energy utilization and enhanced DC bus - interface power quality under different operating conditions and load excursions.

Increasing demand for wind power generation forces the installation of wind farms with higher capacities and higher structures. Therefore, the probability of lightning strikes increases and more attentions are needed for lightning protection to reduce damages. Blades are the most probable parts of the wind turbines to get struck by lightning. Usually, receptors protect blades, however close investigation of receptors behaviors is necessary. The effects of these receptors in protection against lightning strikes in investigated in this paper. The transient impedance of a wind turbine blade is obtained by using software on the basis of Finite Element Method (FEM) named COMSOL Multiphysics. Various locations and numbers of receptors are investigated and the voltage and the transient impedance curves at the injection points are obtained by the simulations. the results are compared in order to investigate the effects of receptors. The results show that numbers and locations of receptors are very important for lightning protection. In this study, the blade model of V47 wind turbine made by VESTAS is used.

In this paper the impacts of correlated input variables on small signal stability of a power system consisting of intermittent wind generation is presented. The input variables consist of the wind power, the nodal loads and the generation dispatch. The analysis is conducted using Monte Carlo Simulation via modal analysis on three area network system interconnected by tie lines. The probabilistic models of the input variables are first derived. The damping ratio of the power system with the input variables correlated are calculated and then compared with the uncorrelated one. The coefficient of variation is used as an index to determine the fluctuation in the damping ratio as a result of fluctuation in the input variables for both cases. The results show that the coefficient of variation is higher when the input variables are correlated. This indicates that correlated input variable gives the worst case scenario compared to the uncorrelated input variables.

In this work, a closed top throatless downdraft gasifier has been designed, constructed and an attempt has been made to evaluate its performance using coconut shell. The fuel properties of coconut shells and its gasification feasibility for closed top thoatless fixed-bed downdraft gasifier were investigated. The distinctive feature of the gasifier is that it can operate successfully on coconut shell with a producer gas lower heating value (LHV) of 5.96 MJ/m3 and negligible clinker formation. The gasifier performed best at an equivalence ratio of 0.332 was determined at an air flow rate of 0.00092 m3/s and coconut shell consumption rate of 0.000557 kg/s. From the results obtained, coconut shells were successfully used as feedstock in the gasifier. Satisfactory operation was obtained. Gasification of coconut shells could provide required thermal input, with clean fuel to the rural communities in Nigeria.

Bangladesh is going in front to face the lack of available energy. At present the major energy production in Bangladesh is based on natural gas. Around 33% of the total population is covered by electricity network and 4% are covered under natural gas network. About 82% of total electricity comes from natural gas. Lack of energy is the main hindering force for poverty alleviation. On the other hand the reserves of natural gas are running out. To make the energy system of the country sustainable, searching for alternative sources of energy is mandatory. Here Biogas is one of the promising renewable energy sources in Bangladesh. As an agricultural country Bangladesh has embedded with plenty of biomass which has been used for extracting energy by burning directly or making biogas. This paper investigates prospect, opportunity and potential of biogas energy and technology of Bangladesh and also explores the research, development and dissemination of biogas and its plant towards suitable clean energy source of Bangladesh.

The depletion of world petroleum reserves & the increased environmental concerns have stimulated the search for alternative sources for petroleum based fuel. Biodiesel is an alternative to conventional diesel fuel made from renewable resources, such as non-edible vegetable oils. The oil from seeds (e.g., Jatropha and Pongamia) can be converted to a fuel commonly referred to as "Biodiesel."Biodiesel fuel (fatty Acid methyl ester) from vegetable oil is considered as the best of the applicant for diesel engine made from renewable biological sources. It consists of the monoalkyl esters formed by a catalyzed reaction of the triglycerides in the oil or fat with a simple monohydric alcohol. Diesel engines operated on biodiesel have lower emissions of carbon monoxide, unburned hydrocarbons, particulate matter, and air toxics than when operated on petroleum-based diesel fuel. The objective of this paper is to explain the method production of biodiesel which is safe biodegradable and non-toxic.

This paper presents a novel Electric Vehicle (EV) coordinated control scheme for Fuel Cell Plug-in Hybrid Electric Vehicle (FC-PHEV) based on Particle Swarm Optimization (PSO) and Genetic Algorithm (GA) self adjusting algorithms. The proposed EV drive system comprised a FC, Ni-MH battery as secondary DC energy source, and the induction motor. The use of PSO/GA soft computing search and optimization algorithms ensures optimized online control settings. The AC drive utilized the simple hysteresis current controller with PSO/GA optimal slip driven by the reference speed and current signals. The main features of the control scheme are to track speed reference trajectory with minimum over-current, enhanced energy utilization, EV-drive loss reduction and dynamic drive response for parameters variation and stabilization of the common DC-link bus voltage. The integrated DC-AC drive-scheme is fully stabilized using a novel FACTS Green Plug Filter Compensator (GPFC) scheme that ensures stabilized dc bus voltage, minimal inrush current and DC-bus transient conditions. Simulation and experimental results indicate that the strategy can ensure the stabilization of the DC-common bus and the efficient utilization of the FC-Battery DC sources.

This paper describes a novel design concept concerning optimal utilization of the inverter interfaced distributed generator (DG) system working in micro-grids (MG). Some DG systems, e.g., the wind turbine generator (WTG) and the PV solar system conventionally generate real power based on natural conditions thus the average utilization rate of the entire asset is normally low. To eliminate this shortcoming, the proposed control scheme termed multifunctional DG inverter (MDGI) aims to use the DG inverter unit optimally. In the proposed control scheme, besides the regulation of real power the DG inverter can be operated as an active power filter (APF) for current harmonics compensation and as a STATCOM for voltage regulation and power factor compensation. The MDGI is designed to fully utilize the DG inverter capacity that remaining after real power generation for accomplishing various control functionalities required by the system operator. In this paper, the mathematical model of MDGI and its related controllers designed in two-axis stationary reference frame are firstly addressed. Simulation studies on a simple MG network are carried out and followed by a set of experimental tests on dSPACE1104. Typical results are presented with brief discussions to demonstrate the feasibility and effectiveness of the proposed control scheme.

The paper presents the analysis of wind speed data for five windy sites and appropriate wind turbine design for electricity generation in Bangladesh. The data has been collected from the Wind Energy Resource Mapping (WERM) project for Bangladesh. The wind speed data has been measured at 20 m height from ground level. The data have been shorted in the appropriate frequency like monthly, hourly mean wind speed. The frequency distributions of wind speed, velocity duration curve and velocity profile have been drown for getting more clear ideas about the selected site. Then Kuakata Sea belt has got better windy site which has been selected for electricity generation and design a horizontal axis wind turbine for this purpose. Wind turbine design algorithm has been followed to determine different design parameters like design lift coefficient, angle of attack, design tip speed ratio, number of blades, design power coefficient and diameter of the blade for the wind turbine. Then linearized the blade chord and twist angle of the designed wind turbine. Analyses of solidity for different number of blades have been carried out and select the local materials to manufacture of the designated wind turbine.

The thermal decomposition of biomass waste in the form of Mahogany seed waste to produce bio-fuel as well as activated carbon by fixed bed pyrolysis reactor has been taken into consideration in this study. The mahogany seed in particle form is pyrolyzed in an enormously heated fixed bed reactor with nitrogen as the carrier gas. The reactor is heated from 3000C to 5000C using a external heater in which rice husk and charcoal are used as the heater biomass fuel. Reactor bed temperature, running time and feed particle size have been varied to get the optimum operating conditions of the system. The parameters are found to influence the product yields to a large extent. A maximum liquid and solid char yield are 46 wt. % and 31 wt. % respectively obtained at a reactor bed temperature 4500C when the running time is 90 minutes. Acquired pyrolyzed oil at these optimal process conditions were analyzed for some of their properties as an alternative fuel. The oil possesses comparable flame temperature, favorable flash point and reasonable viscosity along with somewhat higher density. The distillation temperature of the pyrolytic oil is comparable with other biomass derived oil and somewhat lower than conventional diesel fuel. The physical properties (porosity, particle and aggregate size, surface area), chemical properties (elemental analysis, ash content and composition) and aqueous adsorption properties (for phenols, tea water, waste water and methyl blue) of the pyrolytic char were examined. The activated carbon was characterized in the same manner as the char. Results revealed that the char must be postcarbonized (600�C) to remove unwanted odor and trace oils. The resulting carbonized char has moderate adsorption capacity for phenol and excellent adsorption capacity of the prepared activated carbon in case of methyl blue, tea water and waste water was also revealed.

The growth in environmental concerns, and the rapid increase on the electric power demand, increased the interest in renewable energy. Wind energy source has the ability to provide electric power in rural or isolated areas. The variation of output power with the variation of wind speed can cause significant power quality issues, especially in the case of a standalone generation system. The paper presents a number of novel self adjusting wind energy utilization schemes using the modified single phase operation of the three phase induction generator supplemented by novel voltage stabilization switched filter compensation scheme. The family of series-parallel switched capacitor filter schemes is controlled by a dynamic Particle Swarm Optimization PSO and Genetic Algorithm GA search techniques error driven self adjusting controller to ensure voltage stabilization, minimum impact of the electric load excursions and wind variations on terminal voltage. A prototype of the GP-EM-EE device has been built and tested in the laboratory. Some selected experimental results are provided for the validation of the system. Based on extensive simulation results using MATLAB/SIMULINK and the prototype laboratory scheme, it has been established that the performance of the controllers both in transient as well as in steady state is quite satisfactory and it can also stabilize the network voltage. The proposed switched smart filter using Green Plug/Energy Management/Energy Economizer GPEM- EE devices for small single phase induction motors can be used in residential motor drives for water pumping, ventilation, air conditioning, compressors, refrigeration applications.