Optimal MPPT and Inverter Control of Grid Connected Photovoltaic System

Arpita Jain and Monika Vardia,JECET; June 2017- August 2017; Sec. C; Vol.6. No.3, 326-344.,[DOI: 10.24214/jecet.C.6.3.32644]

Abstract

In recent years, the average rate of world primary power consumption has increased to about 16000GW. The amount of traditional energy such as petroleum and coal has been gradually becoming insufficient to meet these demands. Hence, renewable energies are playing a vital role in supplying the world’s current power demands. The photovoltaic power generation system using solar energy is growing to produce promising energy source. However solar power is not effectively utilized to replace the fossil fuels due to its intermittence nature. Due to temperature, radiation and load variations, the efficiency of the solar module reduces. Thus, to track the maximum power from the solar array, the converter must operate in the maximum power point tracking (MPPT). In this paper a P&O method of MPPT is discussed for maximum extraction of power from the PV system. Here the boost converter is working as a MPPT and a three phase voltage source inverter (VSI) are connected to the grid. Space vector pulse width modulation (SVPWM) is proposed for generation of gating pulses for voltage source inverter.

Investigation of Conductor Pipes in Offshore Fixed Platforms

Memardoost M.JECET; June 2017- August 2017; Sec. C; Vol.6. No.3, 314-325,[DOI: 10.24214/jecet.C.6.3.31425.]

Abstract

Conductor pipes are used in offshore platforms for oil and gas extraction. The pipes are continued from the deck to the lower surface of the soil. The pipes are used as conductive drilling. The task of conductor pipes is protecting the drilling equipment during drilling and protecting the pipes in the production phase. In industry, the length of buried pipe conductor is not modelled so conductor pipe and soil interaction is not considered. In this study, exact modeling is done by considering the interaction of soil and conductor pipe. In this paper, the conductor pipe from the deck to the sea bed is modeled and along of the pipe is modeled in the soil. The conductor pipe and soil interaction is done by friction vertical non-linear and tip vertical springs. After modeling the conductor pipe using SACS software, situ analysis and analysis of earthquakes are done. The situ analysis results show that stresses on the exact model are less than the simple model in most cases. Also in earthquake analysis is shown that stresses on the exact model are less than the simple model in most cases. According to the results obtained in this study it can be concluded that fixed offshore platform used in this study using exact modeling instead of simple modeling is appropriate to optimize some of the members section.

Nonlinear Least Squares Parameter Estimation Problem Using Levenberg-Marquardt Method

Wei Ching Kaw, Sie Long Kek, Sy Yi Sim,JECET; June 2017- August 2017; Sec. C; Vol.6. No.3, 303-313.,[DOI: 10.24214/jecet.C.6.3.30313]

Abstract

Least squares method, which is a statistical method with minimum sum squares of errors (SSE), is used for curve fitting and parameter estimation. In general, the Gauss-Newton (GN) and the Levenberg-Marquardt (LM) methods are the popular least squares method. In this paper, a nonlinear least squares problem and the LM method are discussed. In our study, the derivation of the LM algorithm is briefly described and the relevant necessary condition is satisfied. During the calculation procedure, the optimal solution, which is the optimal parameter estimate, is obtained once the convergence is achieved. For illustration, the related models for an exponential distribution with two unknown parameters, and for the average monthly high temperature with four unknown parameters are constructed. Their respective unknown parameters are estimated by applying the LM method. Besides, the best model selection is suggested to represent the dataset of the concentration of a blood sample. Moreover, a numerical comparison between the methods of LM and GN is carried out. By virtue of these examples studied, the results show the applicability of the LM method in solving the nonlinear least squares problem. In conclusion, the efficiency of the LM method is highly presented

Modeling and Simulation Analysis of Proton-Exchange Membrane based Fuel Cell System Using MATLAB/Simulink

Nishita Mishra and Monika Vardia,JECET; June 2017- August 2017; Sec. C; Vol.6. No.3, 286-302.;[DOI: 10.24214/jecet.C.6.3.28602]

Abstract

Modeling of fuel cells is getting more and more important as powerful fuel cell stacks are getting available and have to be integrated into power systems. Proton exchange membrane fuel cells (PEMFCs) have aroused great interest in recent years, in particular for transportation applications. The simulation of proton-exchange membrane fuel cells (PEMFC) may work as a powerful tool in the development and widespread testing of alternative energy sources. In order to obtain an adequate PEMFC model, (which could be used in the analysis of FC generation systems), it is necessary to define the values for a specific group of modeling parameters. The simulation results are strongly affected by the choice of such modeling parameters. In order to investigate the output characteristic of a proton exchange membrane fuel cell (PEMFC) based on the electrical empirical model, a novel dynamic model of the PEMFC has been developed with MATLAB/ Simulink, which is distinct from the models that have been published previously. In this paper, the governing equations of the transient behavior of a proton exchange membrane fuel cell are presented. They show the influence of the operating conditions and the current density on internal parameters, especially the ohmic resistance. By using a fuel cell test system of the Fuel Cell Application Centre (FAC) at Temasek Polytechnic, the transient electrical responses of PEMFC were conducted and analyzed under various operating conditions. A good match is found between simulation results and experimental data. The comprehensive results of simulation manifested that the model is effective and operational. This model will be very useful to optimize the structure design, improve the operation performance, and develop the real-time control system of PEMFC.

Ultrasonic Ride Height Monitoring of Automobile by Cross-correlation

Md. Manjurul Gani, Jitu Prakash Dhar, Dr. Md. Saiful Islam,JECET; June 2017- August 2017; Sec. C; Vol.6. No.3, 275-285.[DOI: 10.24214/jecet.C.6.3.27585]

Abstract

Ground clearance or ride height (distance between the lowest part of the vehicle and ground) is an important parameter for automobile. It varies with respect to load on the vehicle as well as road which could be rough and bumpy. Therefore scratching of vehicle with the ground or road is a common scenario. To avoid this scratching we need to monitor ground clearance. To do so we design and simulate an ultrasonic ground clearance monitoring system. Here an ultrasonic sensor is used to transmit and receive the signal (reflected pulse). Then an adaptive filter is used to de-noise the received signal. After that using cross-correlation the time of flight is determined to measure the ride height. When the ground clearance reaches the safety margin it will activate an indicator or alarm. It helps to avoid the scratching of vehicles which will reduce the maintenance and repairing cost/time.