Search results for: wilkinson power divider
5108 Cascaded Transcritical/Supercritical CO2 Cycles and Organic Rankine Cycles to Recover Low-Temperature Waste Heat and LNG Cold Energy Simultaneously
Authors: Haoshui Yu, Donghoi Kim, Truls Gundersen
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Low-temperature waste heat is abundant in the process industries, and large amounts of Liquefied Natural Gas (LNG) cold energy are discarded without being recovered properly in LNG terminals. Power generation is an effective way to utilize low-temperature waste heat and LNG cold energy simultaneously. Organic Rankine Cycles (ORCs) and CO2 power cycles are promising technologies to convert low-temperature waste heat and LNG cold energy into electricity. If waste heat and LNG cold energy are utilized simultaneously in one system, the performance may outperform separate systems utilizing low-temperature waste heat and LNG cold energy, respectively. Low-temperature waste heat acts as the heat source and LNG regasification acts as the heat sink in the combined system. Due to the large temperature difference between the heat source and the heat sink, cascaded power cycle configurations are proposed in this paper. Cascaded power cycles can improve the energy efficiency of the system considerably. The cycle operating at a higher temperature to recover waste heat is called top cycle and the cycle operating at a lower temperature to utilize LNG cold energy is called bottom cycle in this study. The top cycle condensation heat is used as the heat source in the bottom cycle. The top cycle can be an ORC, transcritical CO2 (tCO2) cycle or supercritical CO2 (sCO2) cycle, while the bottom cycle only can be an ORC due to the low-temperature range of the bottom cycle. However, the thermodynamic path of the tCO2 cycle and sCO2 cycle are different from that of an ORC. The tCO2 cycle and the sCO2 cycle perform better than an ORC for sensible waste heat recovery due to a better temperature match with the waste heat source. Different combinations of the tCO2 cycle, sCO2 cycle and ORC are compared to screen the best configurations of the cascaded power cycles. The influence of the working fluid and the operating conditions are also investigated in this study. Each configuration is modeled and optimized in Aspen HYSYS. The results show that cascaded tCO2/ORC performs better compared with cascaded ORC/ORC and cascaded sCO2/ORC for the case study.Keywords: LNG cold energy, low-temperature waste heat, organic Rankine cycle, supercritical CO₂ cycle, transcritical CO₂ cycle
Procedia PDF Downloads 2495107 Aerodynamic Devices Development for Model Aircraft Control and Wind-Driven Bicycle
Authors: Yuta Moriyama, Tsuyoshi Yamazaki, Etsuo Morishita
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Several aerodynamic devices currently attract engineers and research students. The plasma actuator is one of them, and it is very effective to control the flow. The actuator recovers a separated flow to an attached one. The actuator is also inversely applied to a spoiler. The model aircraft might be controlled by this actuator. We develop a model aircraft with the plasma actuator. Another interesting device is the Wells turbine which rotates in one direction. The present authors propose a bicycle with the Wells turbine in the wheels. Power reduction is measured when the turbine is driven by an electric motor at the exit of a wind tunnel. Several Watts power reduction might be possible. This means that the torque of the bike can be augmented by the turbine in the cross wind. These devices are tested in the wind tunnel with a three-component balance and the aerodynamic forces and moment are obtained. In this paper, we introduce these devices and their aerodynamic characteristics. The control force and moment of the plasma actuator are clarified and the power reduction of the bicycle is quantified.Keywords: aerodynamics, model aircraft, plasma actuator, Wells turbine
Procedia PDF Downloads 2355106 Exposing Investor Sentiment In Stock Returns
Authors: Qiang Bu
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This paper compares the explanatory power of sentiment level and sentiment shock. The preliminary test results show that sentiment shock plays a more significant role in explaining stocks returns, including the raw return and abnormal return. We also find that sentiment shock beta has a higher statistical significance than sentiment beta. These finding sheds new light on the relationship between investor sentiment and stock returns.Keywords: sentiment level, sentiment shock, explanatory power, abnormal stock return, beta
Procedia PDF Downloads 1295105 Optimal Design and Simulation of a Grid-Connected Photovoltaic (PV) Power System for an Electrical Department in University of Tripoli, Libya
Authors: Mustafa Al-Refai
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This paper presents the optimal design and simulation of a grid-connected Photovoltaic (PV) system to supply electric power to meet the energy demand by Electrical Department in University of Tripoli Libya. Solar radiation is the key factor determining electricity produced by photovoltaic (PV) systems. This paper is designed to develop a novel method to calculate the solar photovoltaic generation capacity on the basis of Mean Global Solar Radiation data available for Tripoli Libya and finally develop a system design of possible plant capacity for the available roof area. MatLab/Simulink Programming tools and monthly average solar radiation data are used for this design and simulation. The specifications of equipments are provided based on the availability of the components in the market. Simulation results and analyses are presented to validate the proposed system configuration.Keywords: photovoltaic (PV), grid, Simulink, solar energy, power plant, solar irradiation
Procedia PDF Downloads 2905104 The Oppressive Boss and Employees' Authoritarianism: The Relation between Suppression of Voice by Employers and Employees' Preferences for Authoritarian Political Leadership
Authors: Antonia Stanojević, Agnes Akkerman
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In contemporary society, economically active people typically spend most of their waking hours doing their job. Having that in mind, this research examines how socialization at the workplace shapes political preferences. Innovatively, it examines, in particular, the possible relationship between employees’ voice suppression by the employer and the formation of their political preferences. Since the employer is perceived as an authority figure, their behavior might induce spillovers to attitudes about political authorities and authoritarian governance. Therefore, a positive effect of suppression of voice by employers on employees' preference for authoritarian governance is expected. Furthermore, this relation is expected to be mediated by two mechanisms: system justification and power distance. Namely, it is expected that suppression of voice would create a power distance organizational climate and increase employees’ acceptance of unequal distribution of power, as well as evoke attempts of oppression rationalization through system justification. The hypotheses will be tested on the data gathered within the first wave of Work and Politics Dataset 2017 (N=6000), which allows for a wide range of demographic and psychological control variables. Although a cross-sectional analysis to be used at this point does not allow for causal inferences, the confirmation of expected relationships would encourage and justify further longitudinal research on the same panel dataset, in order to get a clearer image of the causal relationship between employers' suppression of voice and workers' political preferences.Keywords: authoritarian values, political preferences, power distance, system justification, voice suppression
Procedia PDF Downloads 2555103 Mobile Cloud Middleware: A New Service for Mobile Users
Authors: K. Akherfi, H. Harroud
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Cloud Computing (CC) and Mobile Cloud Computing (MCC) have advanced rapidly the last few years. Today, MCC undergoes fast improvement and progress in terms of hardware (memory, embedded sensors, power consumption, touch screen, etc.) software (more and more sophisticated mobile applications) and transmission (higher data transmission rates achieved with different technologies such as 3Gs). This paper presents a review on the concept of CC and MCC. Then, it discusses what has been done regarding middleware in CC and MCC. Later, it shows the architecture of our proposed middleware along with its functionalities which will be provided to mobile clients in order to overcome the well-known problems (such as low battery power, slow CPU speed and, little memory etc.).Keywords: context-aware, cloud computing, middleware, mobile cloud computing
Procedia PDF Downloads 4425102 Impact of Charging PHEV at Different Penetration Levels on Power System Network
Authors: M. R. Ahmad, I. Musirin, M. M. Othman, N. A. Rahmat
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Plug-in Hybrid-Electric Vehicle (PHEV) has gained immense popularity in recent years. PHEV offers numerous advantages compared to the conventional internal-combustion engine (ICE) vehicle. Millions of PHEVs are estimated to be on the road in the USA by 2020. Uncoordinated PHEV charging is believed to cause severe impacts to the power grid; i.e. feeders, lines and transformers overload and voltage drop. Nevertheless, improper PHEV data model used in such studies may cause the findings of their works is in appropriated. Although smart charging is more attractive to researchers in recent years, its implementation is not yet attainable on the street due to its requirement for physical infrastructure readiness and technology advancement. As the first step, it is finest to study the impact of charging PHEV based on real vehicle travel data from National Household Travel Survey (NHTS) and at present charging rate. Due to the lack of charging station on the street at the moment, charging PHEV at home is the best option and has been considered in this work. This paper proposed a technique that comprehensively presents the impact of charging PHEV on power system networks considering huge numbers of PHEV samples with its traveling data pattern. Vehicles Charging Load Profile (VCLP) is developed and implemented in IEEE 30-bus test system that represents a portion of American Electric Power System (Midwestern US). Normalization technique is used to correspond to real time loads at all buses. Results from the study indicated that charging PHEV using opportunity charging will have significant impacts on power system networks, especially whereas bigger battery capacity (kWh) is used as well as for higher penetration level.Keywords: plug-in hybrid electric vehicle, transportation electrification, impact of charging PHEV, electricity demand profile, load profile
Procedia PDF Downloads 2755101 Evaluation of the Power Generation Effect Obtained by Inserting a Piezoelectric Sheet in the Backlash Clearance of a Circular Arc Helical Gear
Authors: Barenten Suciu, Yuya Nakamoto
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Power generation effect, obtained by inserting a piezo- electric sheet in the backlash clearance of a circular arc helical gear, is evaluated. Such type of screw gear is preferred since, in comparison with the involute tooth profile, the circular arc profile leads to reduced stress-concentration effects, and improved life of the piezoelectric film. Firstly, geometry of the circular arc helical gear, and properties of the piezoelectric sheet are presented. Then, description of the test-rig, consisted of a right-hand thread gear meshing with a left-hand thread gear, and the voltage measurement procedure are given. After creating the tridimensional (3D) model of the meshing gears in SolidWorks, they are 3D-printed in acrylonitrile butadiene styrene (ABS) resin. Variation of the generated voltage versus time, during a meshing cycle of the circular arc helical gear, is measured for various values of the center distance. Then, the change of the maximal, minimal, and peak-to-peak voltage versus the center distance is illustrated. Optimal center distance of the gear, to achieve voltage maximization, is found and its significance is discussed. Such results prove that the contact pressure of the meshing gears can be measured, and also, the electrical power can be generated by employing the proposed technique.Keywords: circular arc helical gear, contact problem, optimal center distance, piezoelectric sheet, power generation
Procedia PDF Downloads 1565100 Evaluation of MPPT Algorithms for Photovoltaic Generator by Comparing Incremental Conductance Method, Perturbation and Observation Method and the Method Using Fuzzy Logic
Authors: Elmahdi Elgharbaoui, Tamou Nasser, Ahmed Essadki
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In the era of sustainable development, photovoltaic (PV) technology has shown significant potential as a renewable energy source. Photovoltaic generators (GPV) have a non-linear current-voltage characteristic, with a maximum power point (MPP) characterized by an optimal voltage, and depends on environmental factors such as temperature and irradiation. To extract each time the maximum power available at the terminals of the GPV and transfer it to the load, an adaptation stage is used, consisting of a boost chopper controlled by a maximum power point tracking technique (MPPT) through a stage of pulse width modulation (PWM). Our choice has focused on three techniques which are: the perturbation and observation method (P&O), the incremental conductance method (InCond) and the last is that of control using the fuzzy logic. The implementation and simulation of the system (photovoltaic generator, chopper boost, PWM and MPPT techniques) are then performed in the Matlab/Simulink environment.Keywords: photovoltaic generator, technique MPPT, boost chopper, PWM, fuzzy logic, P&O, InCond
Procedia PDF Downloads 3155099 Cognitive Relaying in Interference Limited Spectrum Sharing Environment: Outage Probability and Outage Capacity
Authors: Md Fazlul Kader, Soo Young Shin
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In this paper, we consider a cognitive relay network (CRN) in which the primary receiver (PR) is protected by peak transmit power $\bar{P}_{ST}$ and/or peak interference power Q constraints. In addition, the interference effect from the primary transmitter (PT) is considered to show its impact on the performance of the CRN. We investigate the outage probability (OP) and outage capacity (OC) of the CRN by deriving closed-form expressions over Rayleigh fading channel. Results show that both the OP and OC improve by increasing the cooperative relay nodes as well as when the PT is far away from the SR.Keywords: cognitive relay, outage, interference limited, decode-and-forward (DF)
Procedia PDF Downloads 5035098 RS Based SCADA System for Longer Distance Powered Devices
Authors: Harkishen Singh, Gavin Mangeni
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This project aims at building an efficient and automatic power monitoring SCADA system, which is capable of monitoring the electrical parameters of high voltage powered devices in real time for example RMS voltage and current, frequency, energy consumed, power factor etc. The system uses RS-485 serial communication interface to transfer data over longer distances. Embedded C programming is the platform used to develop two hardware modules namely: RTU and Master Station modules, which both use the CC2540 BLE 4.0 microcontroller configured in slave / master mode. The Si8900 galvanic ally isolated microchip is used to perform ADC externally. The hardware communicates via UART port and sends data to the user PC using the USB port. Labview software is used to design a user interface to display current state of the power loads being monitored as well as logs data to excel spreadsheet file. An understanding of the Si8900’s auto baud rate process is key to successful implementation of this project.Keywords: SCADA, RS485, CC2540, labview, Si8900
Procedia PDF Downloads 2915097 Efficiency Enhancement of Photovoltaic Panels Using an Optimised Air Cooled Heat Sink
Authors: Wisam K. Hussam, Ali Alfeeli, Gergory J. Sheard
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Solar panels that use photovoltaic (PV) cells are popular for converting solar radiation into electricity. One of the major problems impacting the performance of PV panels is the overheating caused by excessive solar radiation and high ambient temperatures, which degrades the efficiency of the PV panels remarkably. To overcome this issue, an aluminum heat sink was used to dissipate unwanted heat from PV cells. The dimensions of the heat sink were determined considering the optimal fin spacing that fulfils hot climatic conditions. In this study, the effects of cooling on the efficiency and power output of a PV panel were studied experimentally. Two PV modules were used: one without and one with a heat sink. The experiments ran for 11 hours from 6:00 a.m. to 5:30 p.m. where temperature readings in the rear and front of both PV modules were recorded at an interval of 15 minutes using sensors and an Arduino microprocessor. Results are recorded for both panels simultaneously for analysis, temperate comparison, and for power and efficiency calculations. A maximum increase in the solar to electrical conversion efficiency of 35% and almost 55% in the power output were achieved with the use of a heat sink, while temperatures at the front and back of the panel were reduced by 9% and 11%, respectively.Keywords: photovoltaic cell, natural convection, heat sink, efficiency
Procedia PDF Downloads 1435096 A Comparative Study on Optimized Bias Current Density Performance of Cubic ZnB-GaN with Hexagonal 4H-SiC Based Impatts
Authors: Arnab Majumdar, Srimani Sen
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In this paper, a vivid simulated study has been made on 35 GHz Ka-band window frequency in order to judge and compare the DC and high frequency properties of cubic ZnB-GaN with the existing hexagonal 4H-SiC. A flat profile p+pnn+ DDR structure of impatt is chosen and is optimized at a particular bias current density with respect to efficiency and output power taking into consideration the effect of mobile space charge also. The simulated results obtained reveals the strong potentiality of impatts based on both cubic ZnB-GaN and hexagonal 4H-SiC. The DC-to-millimeter wave conversion efficiency for cubic ZnB-GaN impatt obtained is 50% with an estimated output power of 2.83 W at an optimized bias current density of 2.5×108 A/m2. The conversion efficiency and estimated output power in case of hexagonal 4H-SiC impatt obtained is 22.34% and 40 W respectively at an optimum bias current density of 0.06×108 A/m2.Keywords: cubic ZnB-GaN, hexagonal 4H-SiC, double drift impatt diode, millimetre wave, optimised bias current density, wide band gap semiconductor
Procedia PDF Downloads 3505095 Optimization of Multiplier Extraction Digital Filter On FPGA
Authors: Shiksha Jain, Ramesh Mishra
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One of the most widely used complex signals processing operation is filtering. The most important FIR digital filter are widely used in DSP for filtering to alter the spectrum according to some given specifications. Power consumption and Area complexity in the algorithm of Finite Impulse Response (FIR) filter is mainly caused by multipliers. So we present a multiplier less technique (DA technique). In this technique, precomputed value of inner product is stored in LUT. Which are further added and shifted with number of iterations equal to the precision of input sample. But the exponential growth of LUT with the order of FIR filter, in this basic structure, makes it prohibitive for many applications. The significant area and power reduction over traditional Distributed Arithmetic (DA) structure is presented in this paper, by the use of slicing of LUT to the desired length. An architecture of 16 tap FIR filter is presented, with different length of slice of LUT. The result of FIR Filter implementation on Xilinx ISE synthesis tool (XST) vertex-4 FPGA Tool by using proposed method shows the increase of the maximum frequency, the decrease of the resources as usage saving in area with more number of slices and the reduction dynamic power.Keywords: multiplier less technique, linear phase symmetric FIR filter, FPGA tool, look up table
Procedia PDF Downloads 3835094 Fusionopolis: The Most Decisive Economic Power Centers of the 21st Century
Authors: Norbert Csizmadia
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The 21st Century's main power centers are the cities. More than 52% of the world’s population lives in cities, in particular in the megacities which have a population over 10 million people and is still growing. According to various research and forecasts, the main economic concentration will be in 40 megacities and global centers. Based on various competitiveness analyzes and indices, global city centers, and city networks are outlined, but if we look at other aspects of urban development like complexity, connectivity, creativity, technological development, viability, green cities, pedestrian and child friendly cities, creative and cultural centers, cultural spaces and knowledge centers, we get a city competitiveness index with quite new complex indicators. The research shows this result. In addition to the megacities and the global centers, with the investigation of functionality, we got 64 so-called ‘fusiononopolis’ (i.e., fusion-polis) which stand for the most decisive economic power centers of the 21st century. In this city competition Asian centers considerably rise, as the world's functional city competitiveness index is being formed.Keywords: economic geography, human geography, technological development, urbanism
Procedia PDF Downloads 3525093 Smart Grids in Morocco: An Outline of the Recent Development, Key Drivers and Recommendations for Future Implementation
Authors: Mohamed Laamim, Aboubakr Benazzouz, Abdelilah Rochd, Abdellatif Ghennioui, Abderrahim El Fadili
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Smart grids have recently sparked a lot of interest in the energy sector as they allow for the modernization and digitization of the existing power infrastructure. Smart grids have several advantages in terms of reducing the environmental impact of generating power from fossil fuels due to their capacity to integrate large amounts of distributed energy resources. On the other hand, smart grid technologies necessitate many field investigations and requirements. This paper focuses on the major difficulties that governments face around the world and compares them to the situation in Morocco. Also presented in this study are the current works and projects being developed to improve the penetration of smart grid technologies into the electrical system. Furthermore, the findings of this study will be useful to promote the smart grid revolution in Morocco, as well as to construct a strong foundation and develop future needs for better penetration of technologies that aid in the integration of smart grid features.Keywords: smart grids, microgrids, virtual power plants, digital twin, distributed energy resources, vehicle-to-grid, advanced metering infrastructure
Procedia PDF Downloads 1405092 Tuberculosis and Associated Transient Hyperglycaemia in Peri-Urban South Africa: Implications for Diabetes Screening in High Tuberculosis/HIV Burden Settings
Authors: Mmamapudi Kubjane, Natacha Berkowitz, Rene Goliath, Naomi S. Levitt, Robert J. Wilkinson, Tolu Oni
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Background: South Africa remains a high tuberculosis (TB) burden country globally and the burden of diabetes – a TB risk factor is growing rapidly. As an infectious disease, TB also induces transient hyperglycaemia. Therefore, screening for diabetes in newly diagnosed tuberculosis patients may result in misclassification of transient hyperglycaemia as diabetes. Objective: The objective of this study was to determine and compare the prevalence of hyperglycaemia (diabetes and impaired glucose regulation (IGR)) in TB patients and to assess the cross-sectional association between TB and hyperglycaemia at enrolment and after three months of follow-up. Methods: Consecutive adult TB and non-TB participants presenting at a TB clinic in Cape Town were enrolled in this cross-sectional study and follow-up between July 2013 and August 2015. Diabetes was defined as self-reported diabetes, fasting plasma glucose (FPG) ≥ 7.0 mmol·L⁻¹ or glycated haemoglobin (HbA1c) ≥ 6.5%. IGR was defined as FPG 5.5– < 7.0 mmol·L⁻¹ or HbA1c 5.7– < 6.5%. TB patients initiated treatment. After three months, all participants were followed up and screened for diabetes again. The association between TB and hyperglycaemia was assessed using logistic regression adjusting for potential confounders including sex, age, income, hypertension, waist circumference, previous prisoner, marital status, work status, HIV status. Results: Diabetes screening was performed in 852 participants (414 TB and 438 non-TB) at enrolment and in 639 (304 TB and 335 non-TB) at three-month follow-up. The prevalence of HIV-1 infection was 69.6% (95% confidence interval (CI), 64.9–73.8 %) among TB patients, and 58.2% (95% CI, 53.5–62.8 %) among the non-TB participants. Glycaemic levels were much higher in TB patients than in the non-TB participants but decreased over time. Among TB patients, the prevalence of IGR was 65.2% (95% CI 60.1 - 69.9) at enrollment and 21.5% (95% CI 17.2-26.5) at follow-up; and was 50% (45.1 - 54.94) and 32% (95% CI 27.9 - 38.0) respectively, among non-TB participants. The prevalence of diabetes in TB patients was 12.5% (95% CI 9.69 – 16.12%) at enrolment and 9.2% (95% CI, 6.43–13.03%) at follow-up; and was 10.04% (95% CI, 7.55–13.24%) and 8.06% (95% CI, 5.58–11.51) respectively, among non-TB participants. The association between TB and IGT was significant at enrolment (adjusted odds ratio (OR) 2.26 (95% CI, 1.55-3.31) but disappeared at follow-up 0.84 (0.53 - 1.36). However, the TB-diabetes association remained positive and significant both at enrolment (2.41 (95% CI, 1.3-4.34)) and follow-up (OR 3.31 (95% CI, 1.5 - 7.25)). Conclusion: Transient hyperglycaemia exists during tuberculosis. This has implications on diabetes screening in TB patients and suggests a need for diabetes confirmation tests during or after TB treatment. Nonetheless, the association between TB and diabetes noted at enrolment persists at 3 months highlighting the importance of diabetes control and prevention for TB control. Further research is required to investigate the impact of hyperglycaemia (transient or otherwise) on TB outcomes to ascertain the clinical significance of hyperglycemia at enrolment.Keywords: diabetes, impaired glucose regulation, transient hyperglycaemia, tuberculosis
Procedia PDF Downloads 1505091 Design and Implementation of Grid-Connected Photovoltaic Inverter
Authors: B. H. Lee
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Nowadays, a grid-connected photovoltaic (PV) inverter is adopted in various places like as home, factory, because grid-connected PV inverter can reduce total power consumption by supplying electricity from PV array. In this paper, design and implementation of a 300 W grid-connected PV inverter are described. It is implemented with TI Piccolo DSP core and operated at 100 kHz switching frequency in order to reduce harmonic contents. The maximum operating input voltage is up to 45 V. The characteristics of the designed system that include maximum power point tracking (MPPT), single operation and battery charging are verified by simulation and experimental results.Keywords: design, grid-connected, implementation, photovoltaic
Procedia PDF Downloads 4115090 Minimum Half Power Beam Width and Side Lobe Level Reduction of Linear Antenna Array Using Particle Swarm Optimization
Authors: Saeed Ur Rahman, Naveed Ullah, Muhammad Irshad Khan, Quensheng Cao, Niaz Muhammad Khan
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In this paper the optimization performance of non-uniform linear antenna array is presented. The Particle Swarm Optimization (PSO) algorithm is presented to minimize Side Lobe Level (SLL) and Half Power Beamwidth (HPBW). The purpose of using the PSO algorithm is to get the optimum values for inter-element spacing and excitation amplitude of linear antenna array that provides a radiation pattern with minimum SLL and HPBW. Various design examples are considered and the obtain results using PSO are confirmed by comparing with results achieved using other nature inspired metaheuristic algorithms such as real coded genetic algorithm (RGA) and biogeography (BBO) algorithm. The comparative results show that optimization of linear antenna array using the PSO provides considerable enhancement in the SLL and HPBW.Keywords: linear antenna array, minimum side lobe level, narrow half power beamwidth, particle swarm optimization
Procedia PDF Downloads 5425089 Comparison of Constitutional Systems in Religious and Secular States (Iran and Turkey as Role Models)
Authors: Eman Muhammad Rashwan
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The identity of the state in many Middle East countries today, between secularity and religiousness, is an important and controversial question. Specially after the sweeping repels in number of countries that put Islamic parties in power. In this paper two role model states in this respect, are under examination to answer the question of how their identity that was expressed in their constitutions influenced the allocation of power between different state authorities. In the beginning both the criteria used to define the two concepts of secularity and religiousness, and the reason why these two states are particularly chosen for comparison, are explained. The situation in Turkey is firstly indicated. The constitutional system shows that power is divided between parliament, cabinet and the president. The first two authorities have the most significant powers, and generally, the system in Turkey is similar to many other secular states in the world. But when the research moves to the system in Iran, the importance of comparison starts to appear. In this section, the nature of Islamic Shi’a of Iran Republic is discussed, and also its influence on the main and unique authorities of this religious state, which don`t only include the president and council of ministers, but also The Supreme Leader and The Council of Guardians. This paper doesn`t aim to favor a one system over another, and doesn`t discuss the influences of the two systems on the social or economic situation in the two model states. The aim of this paper is to study the influence of excluding, and applying religion in respect to allocation of power in constitutions.Keywords: comparative law, constitutional systems, secular states, religious states
Procedia PDF Downloads 4185088 The Analysis and Simulation of TRACE in the Ultimate Response Guideline for Chinshan BWR/4 Nuclear Power Plant
Authors: J. R. Wang, H. T. Lin, H. C. Chen, C. Shih, S. W. Chen, S. C. Chiang, C. C. Liu
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In this research, TRACE model of Chinshan BWR/4 Nuclear Power Plant (NPP) has been developed for the simulation and analysis of Ultimate Response Guideline (URG). The main actions of URG are the depressurization and low pressure water injection of reactor and containment venting. This research focuses to verify the URG efficiency under Fukushima-like conditions. Trace analysis results show that the URG can keep the PCT below the criteria 1088.7 K under Fukushima-like conditions. It indicated that Chinshan NPP was safe.Keywords: BWR, trace, safety analysis, URG
Procedia PDF Downloads 6085087 Implementation of a Novel Modified Multilevel Inverter Topology for Grid Connected PV System
Authors: Dhivya Balakrishnan, Dhamodharan Shanmugam
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Multilevel converters offer high power capability, associated with lower output harmonics and lower commutation losses. Their main disadvantage is their complexity requiring a great number of power devices and passive components, and a rather complex control circuitry. This paper proposes a single-phase seven-level inverter for grid connected PV systems, With a novel pulse width-modulated (PWM) control scheme. Three reference signals that are identical to each other with an offset that is equivalent to the amplitude of the triangular carrier signal were used to generate the PWM signals. The inverter is capable of producing seven levels of output-voltage levels from the dc supply voltage. This paper proposes a new multilevel inverter topology using an H-bridge output stage with two bidirectional auxiliary switches. The new topology produces a significant reduction in the number of power devices and capacitors required to implement a multilevel output using the asymmetric cascade configuration.Keywords: asymmetric cascade configuration, H-Bridge, multilevel inverter, Pulse Width Modulation (PWM)
Procedia PDF Downloads 3505086 A New PWM Command for Cascaded H-Bridge Multilevel Increasing the Quality and Reducing Harmonics
Authors: Youssef Babkrani, S. Hiyani, A. Naddami, K. Choukri, M. Hilal
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Power Quality has been a problem ever since electrical power was invented and in recent years, it has become the main interest of researchers who are still concerned about finding ways to reduce its negative influence on electrical devices. In this paper we aim to improve the power quality output for H- bridge multilevel inverter used with solar Photovoltaic (PV) panels, we propose a new switching technique that uses a pulse width modulation method (PWM) aiming to reduce the harmonics. This new method introduces a sinusoidal wave compared with modified trapezoidal carriers used to generate the pulses. This new trapezoid carrier waveform is being implemented with different sinusoidal PWM dispositions such as phase disposition (PWM PD), phase opposition disposition (PWM POD), and (PWM APOD) alternative phase opposition disposition and compared with the conventional ones. Using Matlab Simulink R2014a the line voltage and total harmonic distortions (THD) simulated and the quality are increased in spite of variations of DC introduced.Keywords: carrier waveform, phase disposition (PD), phase opposition disposition (POD), alternative phase opposition disposition (APOD), total harmonics distortion (THD)
Procedia PDF Downloads 2785085 Study on the Impact of Default Converter on the Quality of Energy Produced by DFIG Based Wind Turbine
Authors: N. Zerzouri, N. Benalia, N. Bensiali
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This work is devoted to an analysis of the operation of a doubly fed induction generator (DFIG) integrated with a wind system. The power transfer between the stator and the network is carried out by acting on the rotor via a bidirectional signal converter. The analysis is devoted to the study of a fault in the converter due to an interruption of the control of a semiconductor. Simulation results obtained by the MATLAB/Simulink software illustrate the quality of the power generated at the default.Keywords: doubly fed induction generator (DFIG), wind energy, PWM inverter, modeling
Procedia PDF Downloads 3055084 Tandem Concentrated Photovoltaic-Thermoelectric Hybrid System: Feasibility Analysis and Performance Enhancement Through Material Assessment Methodology
Authors: Shuwen Hu, Yuancheng Lou, Dongxu Ji
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Photovoltaic (PV) power generation, as one of the most commercialized methods to utilize solar power, can only convert a limited range of solar spectrum into electricity, whereas the majority of the solar energy is dissipated as heat. To address this problem, thermoelectric (TE) module is often integrated with the concentrated PV module for waste heat recovery and regeneration. In this research, a feasibility analysis is conducted for the tandem concentrated photovoltaic-thermoelectric (CPV-TE) hybrid system considering various operational parameters as well as TE material properties. Furthermore, the power output density of the CPV-TE hybrid system is maximized by selecting the optimal TE material with application of a systematic assessment methodology. In the feasibility analysis, CPV-TE is found to be more advantageous than sole CPV system except under high optical concentration ratio with low cold side convective coefficient. It is also shown that the effects of the TE material properties, including Seebeck coefficient, thermal conductivity, and electrical resistivity, on the feasibility of CPV-TE are interacted with each other and might have opposite effect on the system performance under different operational conditions. In addition, the optimal TE material selected by the proposed assessment methodology can improve the system power output density by 227 W/m2 under highly concentrated solar irradiance hence broaden the feasible range of CPV-TE considering optical concentration ratio.Keywords: feasibility analysis, material assessment methodology, photovoltaic waste heat recovery, tandem photovoltaic-thermoelectric
Procedia PDF Downloads 655083 Active-Material Variation Analysis of a Lithium-Ion Battery
Authors: Muhammad Husnat Khalid, Stephan Bihn, Dirk Uwe Sauer, Nisai Fuengwarodsakul
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To combat the effects of climate change, lithium-ion batteries are getting a lot of attention for energy storage. However, due to its diverse range of applications extending from small electronics equipment to energy storage systems, its output requirements, as well as limitations, vary significantly. Many efforts are underway to increase the power and energy output of the cells without any significant compromise on their size and weight. In this paper, different active materials are explored for an existing cell Kokam that initially has graphite as anode and NCO as cathode material. The Pareto front optimization tool is then utilized to pick a cell that gives the optimum results in terms of energy, power, or both. The parameter variation of the cells is done in the MATLAB application ISEA Cell and Pack Database (ICPD) created by the Institute of Power Electronics and Electrical Drives (ISEA) RWTH Aachen, University that creates the physical-chemical model of the existing cells.Keywords: battery storage system, lithium-ion battery, active material variation, cell design optimization
Procedia PDF Downloads 905082 The Stability Study of Large-Scale Grid-Tied Photovoltaic System Containing Different Types of Inverter
Authors: Chen Zheng, Lin Zhou, Bao Xie, Xiao Du, Nianbin Shao
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Power generated by large-scale photovoltaic plants (LSPVPs) is usually transmitted to the grid through several transformers and long distance overhead lines. Impedance of transformers and transmission lines results in complex interactions between the plant and the grid and among different inverters. In accordance with the topological structure of LSPV in reality, an equivalent model containing different inverters was built and then interactions between the plant and the grid and among different inverters were studied. Based on the vector composition principle of voltage at the point of common coupling (PCC), the mathematic function of PCC voltage in regard to the total power and grid impedance was deduced, from which the uttermost total power to guarantee the system stable is obtained. Taking the influence of different inverters numbers and the length of transmission lines to the system stability into account, the stability criterion of LSPV containing different inverters was derived. The result of simulation validated the theory analysis in the paper.Keywords: LSPVPs, stability analysis, grid impedance, different types of inverter, PCC voltage
Procedia PDF Downloads 2995081 Computational Fluid Dynamics (CFD) Calculations of the Wind Turbine with an Adjustable Working Surface
Authors: Zdzislaw Kaminski, Zbigniew Czyz, Krzysztof Skiba
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This paper discusses the CFD simulation of a flow around a rotor of a Vertical Axis Wind Turbine. Numerical simulation, unlike experiments, enables us to validate project assumptions when it is designed and avoid a costly preparation of a model or a prototype for a bench test. CFD simulation enables us to compare characteristics of aerodynamic forces acting on rotor working surfaces and define operational parameters like torque or power generated by a turbine assembly. This research focused on the rotor with the blades capable of modifying their working surfaces, i.e. absorbing wind kinetic energy. The operation of this rotor is based on adjusting angular aperture α of the top and bottom parts of the blades mounted on an axis. If this angular aperture α increases, the working surface which absorbs wind kinetic energy also increases. The operation of turbines is characterized by parameters like the angular aperture of blades, power, torque, speed for a given wind speed. These parameters have an impact on the efficiency of assemblies. The distribution of forces acting on the working surfaces in our turbine changes according to the angular velocity of the rotor. Moreover, the resultant force from the force acting on an advancing blade and retreating blade should be as high as possible. This paper is part of the research to improve an efficiency of a rotor assembly. Therefore, using simulation, the courses of the above parameters were studied in three full rotations individually for each of the blades for three angular apertures of blade working surfaces, i.e. 30 °, 60 °, 90 °, at three wind speeds, i.e. 4 m / s, 6 m / s, 8 m / s and rotor speeds ranging from 100 to 500 rpm. Finally, there were created the characteristics of torque coefficients and power as a function of time for each blade separately and for the entire rotor. Accordingly, the correlation between the turbine rotor power as a function of wind speed for varied values of rotor rotational speed. By processing this data, the correlation between the power of the turbine rotor and its rotational speed for each of the angular aperture of the working surfaces was specified. Finally, the optimal values, i.e. of the highest output power for given wind speeds were read. The research results in receiving the basic characteristics of turbine rotor power as a function of wind speed for the three angular apertures of the blades. Given the nature of rotor operation, the growth in the output turbine can be estimated if angular aperture of the blades increases. The controlled adjustment of angle α enables a smooth adjustment of power generated by a turbine rotor. If wind speed is significant, this type of adjustment enables this output power to remain at the same level (by reducing angle α) with no risk of damaging a construction. This work has been financed by the Polish Ministry of Science and Higher Education.Keywords: computational fluid dynamics, numerical analysis, renewable energy, wind turbine
Procedia PDF Downloads 2055080 Grid-Connected Doubly-Fed Induction Generator under Integral Backstepping Control Combined with High Gain Observer
Authors: Oluwaseun Simon Adekanle, M'hammed Guisser, Elhassane Abdelmounim, Mohamed Aboulfatah
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In this paper, modeling and control of a grid connected 660KW Doubly-Fed Induction Generator wind turbine is presented. Stator flux orientation is used to realize active-reactive power decoupling to enable independent control of active and reactive power. The recursive Integral Backstepping technique is used to control generator speed to its optimum value and to obtain unity power factor. The controller is combined with High Gain Observer to estimate the mechanical torque of the machine. The most important advantage of this combination of High Gain Observer and the Integral Backstepping controller is the annulation of static error that may occur due to incertitude between the actual value of a parameter and its estimated value by the controller. Simulation results under Matlab/Simulink show the robustness of this control technique in presence of parameter variation.Keywords: doubly-fed induction generator, field orientation control, high gain observer, integral backstepping control
Procedia PDF Downloads 3495079 Performance Improvement of The Nano-Composite Based Proton Exchange Membranes (PEMs)
Authors: Yusuf Yılmaz, Kevser Dincer, Derya Saygılı
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In this study, performance of PEMs was experimentally investigated. Coating on the cathode side of the PEMs fuel cells was accomplished with the spray method by using NaCaNiBO. A solution having 0,1 gr NaCaNiBO +10 mL methanol was prepared. This solution was taken out and filled into a spray. Then the cathode side of PEMs fuel cells was cladded with NaCaNiBO by using spray method. After coating, the membrane was left out to dry for 24 hours. The PEM fuel cells were mounted to the system in single, double, triple and fourfold manner in order to spot the best performance. The performance parameter considered was the power to current ratio. The best performance was found to occur at the 300th second with the power/current ratio of 3.55 Watt/Ampere and on the fourfold parallel mounting after the coating; whereas the poorest performance took place at the 210th second, power to current ratio of 0.12 Watt/Ampere and on the twofold parallel connection after the coating.Keywords: nano-composites, proton exchange membranes, performance improvement, fuel cell
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