Asmarashid Ponniran

A design of single axis sun tracking system

Solar power generation had been used as a renewable energy since years ago. Residential that uses solar power as their alternative power supply will bring benefits to them. The main objective of this project is to develop an automatic solar tracking system which will keep the solar panels aligned with the Sun in order to maximize in harvesting solar power. The system tracks the maximum intensity of light. When the intensity of light is decreasing, this system automatically changes its direction to get maximum intensity of light. LDR light detector is used to trace the coordinate of the Sun. While to rotate the appropriate position of the panel, a DC geared motor is used. The system is controlled by two relays as a driver and a microcontroller as a main processor. This project is covered for a single axis and is designed for residential usage. Finally, the project is able to track and follow the Sun intensity in order to get maximum power at the output regardless motor speed.

Study on the performance of underground XLPE cables in service based on tan delta and capacitance measurements

Performance of underground XLPE cables in service is critical because of ageing mechanisms influences. One of the techniques to evaluate performance of aged and unaged underground XLPE cables is based on tan delta and capacitance measurements of the cable insulations. This study focuses on underground XLPE cables which rated at 11 kV and 22 kV for both 1-core and 3-core types. Tan delta and capacitance data of underground XLPE cables are obtained using a Schering bridge instrument. Tan delta and capacitance measurements are performed at ambient temperature (about 27degC) and 50 Hz power frequency. The analysis of data show that tan delta values increased in proportion to the aging time of the cables. Meanwhile the data analysis of the capacitance measurement shows that the values of capacitance inconsistent. Nevertheless, tan delta measurement is more accurate and appropriate parameter for evaluating performance of underground XLPE cables as compared to capacitance parameter. Therefore, the finding of this study shows that aging mechanisms contributes the deteriorations of underground XLPE cable insulations in service and consequently the value of tan delta increases with aging time of the cables.

Minimum flying capacitor for N-level capacitor DC/DC boost converter

This paper proposes a multilevel flying capacitor dc/dc boost converter (FCBC) with a small capacitance of the flying capacitor for the reduction of converter size. In this paper, the design methods for the boost inductor and the flying capacitor in the n-level FCBC are principally and experimentally confirmed. Furthermore, the boost inductor is designed based on maximum product of voltage-time, regardless the number of level. Meanwhile, the minimum capacitance of the flying capacitor is designed based on the maximum switching device voltage stress, regardless of the output voltage ripple influences. Moreover, the achieved maximum efficiency of the designed three-level FCBC is 98.5% at the output power of 1 kW. Finally, the effectiveness of small capacitances of the flying capacitor in the three-level and five-level FCBCs is analyzed. The characteristics of the distorted voltage across the input voltage source and the boost inductor, and the distorted current to the output side (output capacitor and load) are investigated with several capacitances of the flying capacitors in the three-level and five-level FCBCs. As a result, it is experimentally confirmed that the distorted voltage is drastically reduced by increasing the number of level. Besides, the distorted current is almost the same although the number of level is increased. Therefore, based on the experimental results, it is shown that small capacitance of the flying capacitor can be used in the n-level FCBC without compromising the stability of converter operation.

Interleaved high boost ratio Marx topology DC-DC converter

This paper proposes an interleaved high boost ratio three-stage Marx topology DC-DC boost converter (MTBC). In the proposed circuit, the parallel connection is applied at the input side in order to reduce the conduction loss and the copper loss. Meanwhile the multi-stage connection is applied at the output side in order to reduce the voltage rating of switching devices. In addition, with the interleaved switching scheme, the maximum current stress at a bottom switching device of the stage-I is reduced and the equivalent frequency at the output side becomes twice of the switching frequency. As a result, the inductance of the output inductor is reduced compared to that of a synchronized switching scheme. In addition, with the interleaved switching scheme, the output inductor volume is also reduced. Two prototypes of the three-stage MTBC are experimentally verified in order to confirm the converter design and the operation. Besides, the achieved maximum efficiency of the three-stage MTBC prototype with the synchronized switching scheme is 94.5% at the output power of 500 W.

Modular multi-stage Marx topology for high boost ratio DC/DC converter in HVDC

The paper proposes a high boost ratio of modular Marx topology DC-DC boost converter (MTBC). In the proposed converter, the parallel-connection is applied at the input side and multi-stage connection is applied at the output side. Then, the conduction loss and the voltage rating of switching components can be reduced. Therefore, with the proposed circuit configuration, high efficiency of the high boost ratio DC-DC converter is achieved. The efficiency is measured under various input voltages. As a result, the achieved maximum efficiency of the prototype 3-stage MTBC is 95% when the output power is 500 W.

Parameters Analysis of 4-level Capacitor-Clamped Boost Converter with Hard-Switching and Soft-Switching Implementation

This paper presents a nonlinear Integral backstepping control approach based on field oriented control technique, applied to a Double Star Induction Machine ‘DSIM’ feed by two power voltage sources. We present this technique of integral backstepping by using reduced and complete Model of DSIM. The objective is to improve the robustness of machine under internal parameter variation with nonlinear Integral backstepping control. The robustness test results obtained by simulation prove the effectiveness of control with using complete model of DSIM.In the majority of the isolated areas, the diesel generator is the principal source of electric power. For these areas, the price of extension of the electrical supply network is prohibitory and the price of fuel increases radically with insulation. The continuous fall in the prices of the generators based on renewable energy and the increasing reliability of these systems led to a greater use of the sources of renewable energy for the generation of electric power in the isolated areas. The diesel generators can incorporate in a network with other sources in base of renewable energies in order to create a new network known as distributed network. More recently intermittent renewable resources such as the wind power were considered as a distributed generation which is seen as being deployed to reduce the total emissions. The distributed generation equipment sets causing electric disturbances result in destabilizing the global network as well as pollutant, for these reason, system D-FACTS comes to answer all the concern of the customers, manufacturers, suppliers and the managers of the distributed network .This paper presents parameters analysis of 4-level capacitor-clamped boost converter with hard-switching and soft-switching implementation. Principally, by considering the selected circuit structure of the 4-level capacitor-clamped boost converter and appropriate pulse width modulation (PWM) switching strategy, the overall converter volume able to be reduced. Specifically, phase-shifted of 120° of each switching signal is applied in the 4-level capacitor-clamped boost converter in order to increase the inductor current ripple frequency, thus the charging and discharging times of the inductor is reduced. Besides, volume of converters is greatly reduced if very high switching frequency is considered. However, it causes increasing of semiconductor losses and consequently the converter efficiency is affected. The results show that the efficiency of 2-level conventional boost converter and 4-level capacitor-clamped boost converter are 98.59% and 97.67%, respectively in hard-switching technique, and 99.31% and 98.15%, respectively in soft-switching technique. Therefore, by applying soft-switching technique, switching loss of the semiconductor devices is greatly minimized although high switching frequency is applied. In this study, passive lossless snubber circuit is selected for the soft-switching implementation in the 4-level capacitor-clamped boost converter. Based on the simulation results, the switching loss is approximately eliminated by applying soft-switching technique compared to the hard-switching technique implementation.This paper presents the summary of a detailed literature review on the topic of energy conservation project funding as energy conservation is seen as a less important operational activity in many third world countries, particularly in India, because it is still considered to be an unnecessary expenditure. Such an important activity in many organizations in India takes the back seat as there is no clear management vision and policy for energy conservation. When procurement manager is obliged to buy based on L1 policy (Lowest quoted price) most of the Energy Conservation Measures (ECM) are not available at that price. Energy conservation is yet to be everyone’s concern in most of the organizations. When it is supposed to be a top-down approach, in reality it remains some less important activities carried out as a formality. There is a need to have paradigm shift, particularly in the top management and it is time that we do not see it as expenditure to implement an energy conservation project but an investment that will continue to give return as long as the equipment is in operation or the facility is functional. Policies and guidelines need to be modified so that there are no conflicts between the departments for implementing the energy conservation projects.This paper presents a Stand-alone Hybrid Renewable Energy System (SHRES) as an alternative to fossil fuel based generators. The Photovoltaic (PV) panels and wind turbines (WT) are designed for the Malaysian low wind speed conditions with battery Energy Storage (BES) to provide electric power to the load. The appropriate sizing of each component was accomplished using Non-dominated Sorting Genetic Algorithm (NSGA-II) and Multi-Objective Particle Swarm Optimization (MOPSO) techniques. The optimized hybrid system was examined in MATLAB using two case studies to find the optimum number of PV panels, wind turbines system and BES that minimizes the Loss of Power Supply Probability (LPSP) and Cost of Energy (COE). The hybrid power system was connected to the AC bus to investigate the system performance in supplying a rural settlement. Real weather data at the location of interest was utilized in this paper. The results obtained from the two scenarios were used to compare the suitability of the NSGA-II and MOPSO methods. The NSGA-II method is shown to be more accurate whereas the MOPSO method is faster in executing the optimization. Hence, both these methods can be used for techno-economic optimization of SHRES.Attempting to reduce the existing electricity consumption bill, as well as the stability and non-outage grid recharge with the lowest possible cost and suitable quality, is one of the most important goals for those interested in energy around the world. This paper study the circumstances surrounding the Egyptian society to find the best solutions to a achieved this goals, and it was found that solar energy is one of the best alternatives available for energy. Firstly will be study the electricity consumption bill, slice prices and a program was made to calculate the consumption invoice moreover another program for quick estimation to the proposed solar system.The proposed system provides a smart integration between the solar system and grid, where the supply sustainability and the optimal cost are considered. This configuration allows the two sources separately or simultaneously supply the loads depending on photovoltaic extracted energy. Operational analysis of the proposed system will discussed in this paper. The proposed system consists of solar cells, charge controller, batteries and inverter plugged to automatic transfer switches (ATS) using Programmable Logic Control (PLC). The system grantee a safe and reliable load feeding independently on the grid status. The system durability is the most depicted feature through the modelling and experimentally results. A typical case studies for about four years of non-outages photovoltaic-grid hybrid supply (the implemented system) will be presented and discussed.

A Study of 4-level DC-DC Boost Inverter with Passive Component Reduction Consideration

This study is to analyze design principles of boost inductor and capacitor used in the 4-level DC-DC boost converter to realize size reduction of passive component referring to their attributes. The important feature of this circuit is that most of the boost-up energy is transferred from the capacitor-clamped to the output side which the small inductance can be used at the input side. The inductance of the boost inductor is designed by referring the inductor current ripple. On the other hand, the capacitance of the capacitor-clamped is designed by considering voltage stress on semiconductor devices and also the used switching frequency. Besides that, according to the design specifications, the required inductance in 4-level DC-DC boost converter is decreased compared to a conventional conventional DC-DC boost converter. Meanwhile, voltage stress on semiconductor device is depending on the maximum voltage ripple of the capacitor-clamped. A 50 W 4-level DC-DC boost converter prototype has been constructed. The results show that the inductor current ripple was 1.15 A when the inductors, 1 mH and 0.11 mH were used in the conventional and 4-level DC-DC boost converters, respectively. Thus, based on the experimental results, it shows that the reduction of passive components by referring to their attributes in 4-level DC-DC boost converter is achieved. Moreover, the decreasing of voltage stress on the semiconductor devices is an advantage for the selection of low ON-resistance of the devices which will contribute to the reduction of the semiconductor conduction loss. The integration result of boost converter and H-bridge inverter is also shown.

A Single Phase 7-Level Cascade Inverter Topology with Reduced Number of Switches on Resistive Load by Using PWM

This paper discussing design principles of inverter structure with reduced number of semiconductor devices of seven levels symmetric H-bridge multilevel inverter (MLI) topology. The aim of this paper is to design an inverter circuit with reduction of semiconductor losses, converter size and development cost. The H-bridge and auxiliary structures were considered in order to achieve seven levels output voltage. The performance of design circuit is compared with conventional seven levels structure in terms of voltage output. The circuit development consists of seven switches and three diode. A basic modulation technique is used to confirm the designed circuit. The results show that the designed circuit is able to convert seven level output voltage with low total harmonics distortion (THD) in voltage fundamental output. According to the results, fundamental output voltage is increased up to 8.314%, and the THD is decreased up to 0.81% compared to the conventional seven level inverter.

A Study on 3-phase Interleaved DC-DC Boost Converter Structure and Operation for Input Current Stress Reduction

This paper analyses a 3-phase interleaved DC-DC boost converter for the conversion of low input voltage with high input current to higher DC output voltage. The operation of the 3-phase interleaved DC-DC boost converter with multi-parallel of boost converters is controlled by interleaved of switching signals with 120 degrees phase-shifted. Therefore, with this circuit configuraion, high input current is evenly shared among the parallel units and consequently the current stress is reduced on the circuit and semiconductor devices and contributes reduction of overall losses. The simulation and hardware results show that the current stress and the semiconductor conduction losses were reduced approximately 33% and 32%, respectively in the 3-phase interleaved DC-DC boost converter compared to the conventional DC-DC boost converters. Furthermore, the use of interleaving technique with continuous conduction mode on DC-DC boost converters is reducing input current and output voltage ripples to increase reliability and efficiency of boost converters.This article presents the new control structure for a Direct Current Motor (DC Motor) using the flatness-control principle. Basic on the mathematical model of DC Motors, the author demonstrates the application ability of the fatness-control theory to control the DC Motor, and then calculates the parameters and proposes the structure of the flatness-controller. The proposed structure is built and ran on Matlab-Simulink software to verify the system efficiency. The simulation results show that the quality of the control system is very good, especially in case of the flatness controller combined with PID controller to eliminate static error when the parameters of the DC Motor have been not known accurately.

Parameters design evaluation in 3-level flying capacitor boost converter

Flying capacitor boost converter (FCBC) is one of the possible power converter for high power applications such as solar systems and electric vehicles system and so on. The aim of this paper is to establish relationship between the capacitance of the flying capacitor and output voltage ripple. 3-level FCBC prototype has been constructed for parameters design confirmation. Experimental result shows that the input current ripple is within design value. By identifying the input current ripple, the inductance of the boost inductor is estimated and it needs approximately only 25% compared to the 2-level conventional boost converter. Besides, 3-level FCBC only requires inductor core volume of 35% compared to the 2-level conventional boost converter. Moreover, it is confirmed that the relationship between the capacitance of the flying capacitor and output voltage ripple is independent. This finding is concretely proven by the simulation and experimental results. Therefore, the boost inductor and capacitance of the flying capacitor can be designed independently without considering output voltage ripple.