This document discusses a DC-DC converter for an ultracapacitor-boosted electric vehicle. Some key points:
1) An ultracapacitor can be used to boost a vehicle's battery during periods of high power demand like acceleration. Ultracapacitors provide extremely high power density for short pulses of energy.
2) A dual active bridge isolated bidirectional DC-DC converter is proposed to interface the ultracapacitor and battery. This allows two-way power flow and regulates the DC bus voltage while charging or discharging the ultracapacitor.
3) Simulation results show the waveforms of voltages and current during the charging and discharging of the ultracapacitor for different relationships between input voltages. The phase
The projected diode assisted Neutral Point Diode Clamed (NPC-MLI) with the photovoltaic system produces a maximum voltage gain that is comparatively higher than those of other boost conversion techniques. This paper mainly explores vector selection approach pulse-width modulation (PWM) strategies for diode-assisted NPC-MLI to obtain a maximum voltage gain without compromising in waveform quality. To obtain a high voltage gain maximum utilization of dc-link voltage and stress on the power switches must be reduced. From the above issues in the diode assisted NPC-MLI leads to vector selection approach PWM technique to perform capacitive charging in parallel and discharging in series to obtain maximum voltage gain. The operation principle and the relationship of voltage gain versus voltage boost duty ratio and switching device voltage stress versus voltage gain are theoretically investigated in detail. Owing to better performance, diode-assisted NPC-MLI is more promising and competitive topology for wide range dc/ac power conversion in a renewable energy application. Furthermore, theoretically investigated are validated via simulation and experimental results.
Carrier based hybrid pwm algorithm with reduced common mode voltageIAEME Publication
This document proposes a hybrid PWM algorithm to reduce common mode voltage variations in three-phase voltage source inverter fed induction motor drives. It presents a carrier-based approach to generate active zero state PWM techniques through addition of a zero sequence voltage. To further reduce harmonic distortion, a hybrid PWM technique is presented based on analysis of stator flux ripple. Simulation results on a v/f controlled induction motor drive show that the proposed algorithm minimizes common mode voltage variations compared to the space vector PWM algorithm.
This document summarizes a study on using STATCOM and UPFC devices to control power flow in a distribution system. It presents the mathematical models of STATCOM and UPFC, including their control design procedures. Simulation results show that STATCOM effectively regulates local reactive power load and UPFC controls real power flow by varying the phase angle of injected voltage. The study demonstrates how FACTS devices like STATCOM and UPFC can improve power flow control in distribution systems.
A new control methods for offshore grid connected wind energy conversion syst...IAEME Publication
This document summarizes a new control method for an offshore wind energy conversion system using a doubly fed induction generator and Z-source inverter. Two control methods are proposed - capacitor voltage control and DC-link voltage control. Simulation results show that for capacitor voltage control, the rotor speed tracks the maximum power point, extracted mechanical power tracks maximum turbine power, and capacitor voltage is kept constant. The power delivered to the grid matches the extracted mechanical power. DC-link voltage control maintains a constant DC-link voltage while capacitor voltage and power outputs vary with shoot-through time. Capacitor voltage control regulates power transfer more effectively.
Modified SVPWM Algorithm for 3-Level Inverter Fed DTC Induction Motor DriveIJPEDS-IAES
In this paper, a modified space vector pulse width modulation (MSVPWM)
algorithm is developed for 3-level inverter fed direct torque controlled
induction motor drive (DTC-IMD). MSVPWM algorithm simplifies
conventional space vector pulse width modulation (CSVPWM) algorithm for
multilevel inverter (MLI), whose complexity lies in sector/subsector/subsubsector
identification; which will commensurate with number of levels. In
the proposed algorithm sectors are identified as in two level inverter
and subsectors/sub-subsectors are identified by shifting the original reference
vector to sector 1 (S1). This is valid due to the fact that a three level space
vector plane is a composition of six two level space planes, and are
symmetrical with reference to six pivot states. Switching state/sequence
selection is also very important while dealing with SVPWM strategy for
MLI. In the proposed algorithm out of 27 available switching states apt
switching state is selected based on sector and subsector number, such that
voltage ripple is considerably less. To validate the proposed algorithm, it is
tested on a three level neutral point clamped (NPC) inverter fed DTC-IMD.
The performance of the MSVPWM algorithm is analyzed by comparing no
load stator current ripple of the three level DTC-IMD with two level
DTC-IMD. Significant reduction in steady state torque and flux ripple is
observed. Hence, reduced acoustic noise is a distinctive facet of the proposed
method.
In this paper, a three-phase load connected to a NPC three-level inverter is presented. To generate gate signals for the multilevel inverter, two commands are developed and compared: the phase disposition pulse width modulation (PDPWM) and the space vector pulse width modulation (SVPWM). DC supply is provided by photovoltaic cells. Boost converter controls the power transfer from photovoltaic generator. Due to nonlinear I-V characteristics of photovoltaic cells, a maximum power point tracking algorithm is adopted to maximize the output power, the nonlinear controller (sliding mode) is developed and simulated. To verify the effectivnesse of the introdueced controller, it is compared with the fuzzy logic controller. Matlab-simulink is used for simulation, analysis and interpretation the results of these controllers.
Study of power flow and transmission capacity in multi phase transmission linesIAEME Publication
This document summarizes a study comparing the power flow and transmission capacity of multi-phase transmission lines to three-phase lines. The study developed several performance characteristic curves relating to power flow and voltage stability for multi-phase systems. These included load end real and reactive power operating contour maps, reactive power loss characteristics, and voltage-power characteristics. Across all characteristics analyzed, the study found that multi-phase transmission systems have higher power handling capacity and are more secure from a voltage stability perspective compared to equivalent three-phase systems. Specifically, increasing the number of phases from three to four or twelve phases resulted in 10-20% greater reactive and real power transfer capacity while maintaining voltage stability.
The document summarizes a research paper that proposes using an artificial bee colony (ABC) algorithm to optimally place static var compensators (SVCs) in a power system to improve the voltage profile. The ABC algorithm is used to solve a multi-objective optimization problem to determine the optimal SVC location and size. The objectives are to minimize fuel costs, transmission losses, voltage deviations, and line flow limits. The algorithm is tested on the IEEE 30-bus test system and is able to improve the voltage profile compared to an optimal power flow without SVCs.
The projected diode assisted Neutral Point Diode Clamed (NPC-MLI) with the photovoltaic system produces a maximum voltage gain that is comparatively higher than those of other boost conversion techniques. This paper mainly explores vector selection approach pulse-width modulation (PWM) strategies for diode-assisted NPC-MLI to obtain a maximum voltage gain without compromising in waveform quality. To obtain a high voltage gain maximum utilization of dc-link voltage and stress on the power switches must be reduced. From the above issues in the diode assisted NPC-MLI leads to vector selection approach PWM technique to perform capacitive charging in parallel and discharging in series to obtain maximum voltage gain. The operation principle and the relationship of voltage gain versus voltage boost duty ratio and switching device voltage stress versus voltage gain are theoretically investigated in detail. Owing to better performance, diode-assisted NPC-MLI is more promising and competitive topology for wide range dc/ac power conversion in a renewable energy application. Furthermore, theoretically investigated are validated via simulation and experimental results.
Carrier based hybrid pwm algorithm with reduced common mode voltageIAEME Publication
This document proposes a hybrid PWM algorithm to reduce common mode voltage variations in three-phase voltage source inverter fed induction motor drives. It presents a carrier-based approach to generate active zero state PWM techniques through addition of a zero sequence voltage. To further reduce harmonic distortion, a hybrid PWM technique is presented based on analysis of stator flux ripple. Simulation results on a v/f controlled induction motor drive show that the proposed algorithm minimizes common mode voltage variations compared to the space vector PWM algorithm.
This document summarizes a study on using STATCOM and UPFC devices to control power flow in a distribution system. It presents the mathematical models of STATCOM and UPFC, including their control design procedures. Simulation results show that STATCOM effectively regulates local reactive power load and UPFC controls real power flow by varying the phase angle of injected voltage. The study demonstrates how FACTS devices like STATCOM and UPFC can improve power flow control in distribution systems.
A new control methods for offshore grid connected wind energy conversion syst...IAEME Publication
This document summarizes a new control method for an offshore wind energy conversion system using a doubly fed induction generator and Z-source inverter. Two control methods are proposed - capacitor voltage control and DC-link voltage control. Simulation results show that for capacitor voltage control, the rotor speed tracks the maximum power point, extracted mechanical power tracks maximum turbine power, and capacitor voltage is kept constant. The power delivered to the grid matches the extracted mechanical power. DC-link voltage control maintains a constant DC-link voltage while capacitor voltage and power outputs vary with shoot-through time. Capacitor voltage control regulates power transfer more effectively.
Modified SVPWM Algorithm for 3-Level Inverter Fed DTC Induction Motor DriveIJPEDS-IAES
In this paper, a modified space vector pulse width modulation (MSVPWM)
algorithm is developed for 3-level inverter fed direct torque controlled
induction motor drive (DTC-IMD). MSVPWM algorithm simplifies
conventional space vector pulse width modulation (CSVPWM) algorithm for
multilevel inverter (MLI), whose complexity lies in sector/subsector/subsubsector
identification; which will commensurate with number of levels. In
the proposed algorithm sectors are identified as in two level inverter
and subsectors/sub-subsectors are identified by shifting the original reference
vector to sector 1 (S1). This is valid due to the fact that a three level space
vector plane is a composition of six two level space planes, and are
symmetrical with reference to six pivot states. Switching state/sequence
selection is also very important while dealing with SVPWM strategy for
MLI. In the proposed algorithm out of 27 available switching states apt
switching state is selected based on sector and subsector number, such that
voltage ripple is considerably less. To validate the proposed algorithm, it is
tested on a three level neutral point clamped (NPC) inverter fed DTC-IMD.
The performance of the MSVPWM algorithm is analyzed by comparing no
load stator current ripple of the three level DTC-IMD with two level
DTC-IMD. Significant reduction in steady state torque and flux ripple is
observed. Hence, reduced acoustic noise is a distinctive facet of the proposed
method.
In this paper, a three-phase load connected to a NPC three-level inverter is presented. To generate gate signals for the multilevel inverter, two commands are developed and compared: the phase disposition pulse width modulation (PDPWM) and the space vector pulse width modulation (SVPWM). DC supply is provided by photovoltaic cells. Boost converter controls the power transfer from photovoltaic generator. Due to nonlinear I-V characteristics of photovoltaic cells, a maximum power point tracking algorithm is adopted to maximize the output power, the nonlinear controller (sliding mode) is developed and simulated. To verify the effectivnesse of the introdueced controller, it is compared with the fuzzy logic controller. Matlab-simulink is used for simulation, analysis and interpretation the results of these controllers.
Study of power flow and transmission capacity in multi phase transmission linesIAEME Publication
This document summarizes a study comparing the power flow and transmission capacity of multi-phase transmission lines to three-phase lines. The study developed several performance characteristic curves relating to power flow and voltage stability for multi-phase systems. These included load end real and reactive power operating contour maps, reactive power loss characteristics, and voltage-power characteristics. Across all characteristics analyzed, the study found that multi-phase transmission systems have higher power handling capacity and are more secure from a voltage stability perspective compared to equivalent three-phase systems. Specifically, increasing the number of phases from three to four or twelve phases resulted in 10-20% greater reactive and real power transfer capacity while maintaining voltage stability.
The document summarizes a research paper that proposes using an artificial bee colony (ABC) algorithm to optimally place static var compensators (SVCs) in a power system to improve the voltage profile. The ABC algorithm is used to solve a multi-objective optimization problem to determine the optimal SVC location and size. The objectives are to minimize fuel costs, transmission losses, voltage deviations, and line flow limits. The algorithm is tested on the IEEE 30-bus test system and is able to improve the voltage profile compared to an optimal power flow without SVCs.
IJCER (www.ijceronline.com) International Journal of computational Engineerin...ijceronline
This document discusses optimal placement of flexible AC transmission system (FACTS) devices on transmission lines to maximize power transfer capability while maintaining stability. It presents a two-stage approach using conventional methods and fuzzy logic. In the first stage, optimal location of a shunt FACTS device is determined for a series-compensated transmission line. In the second stage, fuzzy logic determines the optimal placement. The method is applied to a 13.8kV, 6*350MVA, 360km transmission line. It is observed that the optimal shunt FACTS device location shifts towards the generator side as the level of series compensation increases.
Development of a Novel Three Phase Grid-Tied Multilevel Inverter TopologyIAES-IJPEDS
The conventional line-commutated ac-to-dc converters/ inverters have square-shaped line current. It contains higher-order harmonics which generates EMI and it causes more heating of the core of distribution or power transformers. PWM based inverters using MOSFET/IGBT have higher switching losses, and the power handling capability and reliability are quite low in comparison to thyristors/ SCR. A thyristor based forced commutated inverters are not suitable for PWM applications due to the problems of commutation circuits. A pure sinusoidal voltage output or waveform with low harmonic contents is most desirable for ac load using dc to ac conversion. This paper presents a new multilevel inverter topology in which three phase ac- to-dc converter circuits are used in inversion mode by controlling the switching angle. Due to natural commutation, no separate circuit is required for synchronization. In this paper simulation and analysis are done for grid-tied three-phase 6-pulse, Two three-phase, 3-pulse and 12-pulse converter. These converters are analysed for different battery voltage and different switching angle combinations in order to reduce the total harmonic distortion (THD). Three-phase harmonic filters are further added to the grid side to reduce the harmonic content in the line current. A comparative study of these converters is also presented in this paper.
Towards An Accurate Modeling of Frequency-dependent Wind Farm Components Unde...IJAPEJOURNAL
This document describes modeling the components of a wind farm in order to accurately simulate its transient response under lightning conditions. It details models for the wind turbines, transformers, transmission lines, surge arresters, and other components. The models include frequency dependence to capture transient behavior. The wind farm model is implemented and validated in ATP/EMTP software. Comparison is made between models with and without frequency dependence. This accurate modeling of wind farm components allows simulation of the transient response and analysis of lightning hazards.
New Dead-Time Compensation Method of Power Inverter Using Carrier Based Sinus...IJECEIAES
A new dead-time compensation method of power inverter circuits is suggested and presented in this paper. The proposed method utilizes carrier based sinusoidal pulse width modulation technique to produce driving signals of the inverter power switches with dead-time correction capability. The proposed method able to eliminate dead-time effects such as reducing the waveform distortion of the inverter output current, and increasing the fundamental component amplitude of output current. An analysis of the proposed method is presented. Some computer simulations were carried out to investigate the principle operation, and to test performance of the new method. The developed method was validated through experimental test of H-bridge voltage source inverter circuits. The data obtained from the computer simulation and prototype experiments have confirmed that that the proposed method worked well compensating the dead-time in the voltage source power inverter circuits.
This document summarizes a research paper that proposes and analyzes a multilevel line-commutated inverter topology for solar PV-based grid-connected inverters. The proposed topology uses a multi-winding transformer to provide multiple voltage levels and reduce harmonic distortion in the line current compared to a conventional square-wave inverter. A three-level implementation is modeled in Simulink and experimentally tested. Simulation and experimental results show the proposed topology reduces total harmonic distortion and improves power transfer characteristics compared to a conventional line-commutated inverter.
This document discusses a two-level voltage source converter (VSC) with a third-harmonic injection bus-clamping space vector modulation (SVM) strategy. It aims to further investigate this topology compared to other common VSC topologies. The modulation strategy implements bus-clamping SVM through triangle-comparison-based pulse width modulation. The strategy is investigated using simulations of a passive RL load and an active induction motor load. Simulation results show the impact on total harmonic distortion and motor performance from using this bus-clamping control strategy.
Application of Variable Inductors in a DC/DC Converter to Increase the Operat...theijes
This document summarizes a research paper that proposes using variable inductors in a Cuk DC/DC converter to increase the operating range of a maximum power point tracker (MPPT) at low solar irradiation levels. The variable inductors allow the inductance to decrease at higher currents, reducing component size and cost while maintaining continuous conduction mode over a wider load range. This extends the operating range of the MPPT controller to recover more solar energy during periods of low light or partial shading. Computer simulations using PSCAD/EMTDC validated the effectiveness of the proposed converter design with variable inductance.
An Implementation Mechanisms of SVM Control Strategies Applied to Five Levels...IJPEDS-IAES
In the area of the energy control with high voltage and power, the multilevel inverters constitute a relatively recent research orientation. The current applications of this technology are in the domains of the high voltage (over hundred kV), variable speed drives, transport and distribution of a good quality of electrical energy (HVDC, FACTS system, ....). To improve the output voltage for such inverters, many different modulation strategies have been developed. Among these strategies, the SVM (Space Vector Modulation). The technique provide the nearest switching vectors sequence to the reference vector without involving trigonometric functions and provide the additional advantages of superior harmonic quality. In this paper, we analyze different mechanisms of the output voltage synthesis and the problem of even order harmonic production. With the proposed a new trajectory SVM, which can eliminate all the even order harmonics for five levels inverter. Show clearly how to deduce the trajectories from the sequences allowing to have better performances among several possible trajectories. It is dedicated to the application of two particular trajectories.
In recent years, studies have been investigated the effectiveness of UPFC and TCSC in increasing power transfer capability. However, the effectiveness of these FACTS devices in increasing power transfer capability when the load is non-linear has not been established in a comparative study yet. This paper will explore the steady-state performance of the UPFC and TCSC as impedance compensation models. The effectiveness of both FACTS devices are investigated when they are installed in multi-machine systems with different non-linear load models. Simulation results demonstrate that, upon installing UPFC, more active and reactive powers are received at the sending end bus for different types of non-linear load models. In addition, both active and reactive powers are more sensitive in changing the modulation index of the converters. Furthermore, both the active and reactive powers are less sensitive to the non-linearity of the load model type. However, active and reactive powers in case of installing TCSC are only sensitive in changing the firing angle (α) when it is between 90º to 110º. Therefore, results from this study clearly encourage the effectiveness of UPFC in comparison to TSCS in terms of increasing power transfer capability applied to non-linear load models.
State-space averaged modeling and transfer function derivation of DC-DC boost...TELKOMNIKA JOURNAL
This paper presents dynamic analysis of a boost type DC-DC converter for high-brightness LED (HBLED) driving applications. The steady state operation in presence of all system parasitics has been discussed for continuous conduction mode (CCM). The state-space averaging, energy conservation principle and standard linearization are used to derive ac small signal control to inductor current open-loop transfer function of the converter. The derived transfer function can be further used in designing a robust feed-back control network for the system. In the end frequency and transient responses of the derived transfer function are obtained for a given set of component values, hence to provide a useful guide for control design engineers.
Circuit-based method for extracting the resistive leakage current of metal ox...journalBEEI
Resistive leakage current based condition assessment of metal oxide surge arrester (MOSA) is one of the most extensively employed technique to monitor its degradation. An extraction method is customarily required to extract the resistive component from the total leakage current. The existing methods to extract the resistive current are complex and less accurate. Therefore, this paper describes a simple and accurate circuit-based method to extract the resistive current using equivalent model and measured leakage current of the arrester. The accuracy of the proposed method is validated through experimental results on ABB’s 120 kV surge arrester, EMTP and QuickField software simulations. The performance of the method is also analyzed and verified experimentally on 72, 180 and 240 kV rated ABB’s surge arresters. The obtained results of resistive leakage current have shown the maximum error of 0.001%. Simple and easier computational steps with higher accuracy are the key benefits of the proposed technique.
The document summarizes a study on using a high step-up zeta converter fed by a solar PV panel for a DC drive application. Key points:
- A zeta converter with a coupled inductor and capacitor multiplier is used to achieve high step-up voltage conversion from a 15-40V solar PV panel input.
- Steady-state analysis of the converter in continuous conduction mode shows it can achieve a voltage gain of (1+n) where n is the turns ratio of the coupled inductor.
- Simulation results using Matlab/Simulink validate the converter design and show it can provide the required output voltage for a DC drive from the solar PV input with high efficiency for resist
Phase shedding in multiphase buck converters to improve the efficiencyIAEME Publication
This document summarizes a research paper that analyzes phase shedding in multiphase buck converters to improve efficiency. The paper simulates a multiphase buck converter with 1, 2, and 3 phases. It finds that using fewer phases at light loads improves efficiency, while more phases are needed at higher loads to reduce ripple. Specifically, 1 phase is most efficient below 0.76A, 2 phases from 0.72A to 1.04A, and 3 phases above 1.04A. Comparing the stages, efficiency increases from 82.01% to 97.57% as load and number of phases increases. Therefore, phase shedding allows a multiphase converter to automatically adjust the number of active phases
Modelling of Variable Frequency Synchronous Buck ConverterIAES-IJPEDS
n this paper, novel small-signal averaged models for dc–dc converter operating at variable switching frequency are derived. This is achieved by separately considering the on-time and the off-time of the switching period. The derivation is shown in detail for a synchronous buck converter. The Enhanced Small Signal (ESSA) Model is derived for the synchronous buck converter. The equivalent series inductance (ESL) is also considered in this modelling. The buck converter model is also simulated in MATLAB and the result is also presented.
Karnataka PGCET Electrical Science - Part B 2018 syllabusEneutron
This document contains the syllabus and model question paper for the electrical sciences subject area of Biomedical Engineering & Medical Electronics.
The syllabus covers topics like human anatomy and physiology, biomedical instrumentation, medical imaging systems, signals and systems/DSP, biomedical signal processing, and medical image processing.
The model questions are divided into two sections - Section I contains one mark questions, Section II contains two mark questions. The questions test knowledge of topics like biomedical transducers, medical devices, imaging modalities, filtering, segmentation, etc.
However, the model question papers for Sections I and II are not fully provided in the document. They need to be appended by the Instrumentation Board of Studies.
Modelling of Virtual Synchronous Converter for Grid-Inverter Synchronization ...IAES-IJPEDS
In this paper, virtual synchronous converter (VSCon) is been developed
which mimic the behavior of synchronous generator as in order to have fast
synchronization between the inverter with the grid. This synchronization is
important before can sent the power among inverter-grid connection. This
technique can also been applied at the distributed generated sources when are
connected to the local microgrids. Here, the frequency and voltage
synchronization also can be controlled at the same time some improvement
on synchronous generator mathematical model that is suitable to be
implemented into the inverter control. The whole unit of VSCon is operated
and simulated in Matlab/Simulink in order to observe all consequences
during synchronizing the voltage, frequency and phase-angle. It has been
verified by the simulation circuit where, the power converter can be
synchronized with the microrids without using a PLL unit for self
synchronization. This VSCon technique has proven that, by applying the
concept of the synchronous generator model in inverter control, it can cause
the inverter to behave as generator system, which does not required any
phase information from the grid in order to be synchronized.
Representing Tap-changer Transformers in Conic Relaxation Optimal Power Flowsinventionjournals
Conic optimization has been applied optimal power flow (OPF) problem recently. Present conic relaxation OPFs only consider for the continuous decision variables, and the transformer tap ratios have not been treated as optimization variables. Based on angle relaxed branch power flow, an extended branch power flow model with tap-changer transformers is proposed. The tap-changer transformers were modeled with bilinear functions. Then the McCormick envelopes were deployed to exactly reformulate the bilinear functions with linear constrains. The effectiveness of the proposed method is demonstrated by the simulation results obtained in the test systems
Throughput improvement of ieee 802.15.4 based medicaliaemedu
This document discusses improving the throughput of IEEE 802.15.4 based medical ad-hoc sensor networks that are used for home healthcare monitoring. These networks experience degraded throughput due to interference from co-existing Wi-Fi networks operating in the same 2.4GHz spectrum. The paper studies the impact of Wi-Fi interference on throughput and uses Clear Channel Assessment (CCA) to improve throughput. Experiments were conducted using Texas Instruments sensor motes and showed that CCA improved throughput by 63% by avoiding transmissions when interference was detected.
PI Controller based MPPT for a PV SystemIOSR Journals
This document presents a PI controller-based MPPT technique for a photovoltaic system. It introduces the need for renewable energy sources and MPPT controllers. A PV cell model and characteristics are described. The MPPT technique uses a PI controller connected to a boost converter to track the maximum power point of the PV array in real-time by adjusting the voltage. Simulation results show the MPPT controller is able to quickly track the MPP and boost the output voltage, improving efficiency compared to a system without MPPT.
Correlation of information technology trends with strategic managementiaemedu
The document discusses the correlation between information technology trends and strategic management. It argues that information technology is now a critical resource for competitive advantage and that strategic management must take IT into account. Specifically, IT can help companies reduce costs, increase flexibility, and develop new strategies to outperform competitors. The document also notes that while India's IT industry is large, many startups do not adopt new technologies quickly due to risks and lack of infrastructure support. Overall, the document advocates that lasting competitive advantage requires using IT together with strategic management to add value to companies.
A modern two dof controller for grid integration with solar power generatoriaemedu
1. The document describes a solar power generation system connected to the power grid using a two degree of freedom (DOF) controller.
2. A 100 kW solar power generator is connected to a 25 kV power grid through a three-level inverter and LC filter to generate clean sinusoidal voltage.
3. Simulation results show the solar inverter output voltage waveform is cleaned up from switching frequency harmonics using the LC filter.
Isae 2011 A HYBRID CONTROLLER DESIGN FOR KEEPING CONSTANT VOLTAGE AND CURREN...Pandu Sandi Pratama
This document summarizes a presentation on modeling and control of a gas metal arc welding (GMAW) system. [1] A proportional controller is proposed to maintain constant output welding voltage for the GMAW power supply. [2] A fuzzy-sliding mode controller is proposed for the wire feeding unit to keep the output welding current constant by adjusting the electrode feed rate. [3] Simulation results show the hybrid controller using these two controllers achieves better performance than a conventional PID controller in terms of rise time, settling time, and steady state error of the output current.
IJCER (www.ijceronline.com) International Journal of computational Engineerin...ijceronline
This document discusses optimal placement of flexible AC transmission system (FACTS) devices on transmission lines to maximize power transfer capability while maintaining stability. It presents a two-stage approach using conventional methods and fuzzy logic. In the first stage, optimal location of a shunt FACTS device is determined for a series-compensated transmission line. In the second stage, fuzzy logic determines the optimal placement. The method is applied to a 13.8kV, 6*350MVA, 360km transmission line. It is observed that the optimal shunt FACTS device location shifts towards the generator side as the level of series compensation increases.
Development of a Novel Three Phase Grid-Tied Multilevel Inverter TopologyIAES-IJPEDS
The conventional line-commutated ac-to-dc converters/ inverters have square-shaped line current. It contains higher-order harmonics which generates EMI and it causes more heating of the core of distribution or power transformers. PWM based inverters using MOSFET/IGBT have higher switching losses, and the power handling capability and reliability are quite low in comparison to thyristors/ SCR. A thyristor based forced commutated inverters are not suitable for PWM applications due to the problems of commutation circuits. A pure sinusoidal voltage output or waveform with low harmonic contents is most desirable for ac load using dc to ac conversion. This paper presents a new multilevel inverter topology in which three phase ac- to-dc converter circuits are used in inversion mode by controlling the switching angle. Due to natural commutation, no separate circuit is required for synchronization. In this paper simulation and analysis are done for grid-tied three-phase 6-pulse, Two three-phase, 3-pulse and 12-pulse converter. These converters are analysed for different battery voltage and different switching angle combinations in order to reduce the total harmonic distortion (THD). Three-phase harmonic filters are further added to the grid side to reduce the harmonic content in the line current. A comparative study of these converters is also presented in this paper.
Towards An Accurate Modeling of Frequency-dependent Wind Farm Components Unde...IJAPEJOURNAL
This document describes modeling the components of a wind farm in order to accurately simulate its transient response under lightning conditions. It details models for the wind turbines, transformers, transmission lines, surge arresters, and other components. The models include frequency dependence to capture transient behavior. The wind farm model is implemented and validated in ATP/EMTP software. Comparison is made between models with and without frequency dependence. This accurate modeling of wind farm components allows simulation of the transient response and analysis of lightning hazards.
New Dead-Time Compensation Method of Power Inverter Using Carrier Based Sinus...IJECEIAES
A new dead-time compensation method of power inverter circuits is suggested and presented in this paper. The proposed method utilizes carrier based sinusoidal pulse width modulation technique to produce driving signals of the inverter power switches with dead-time correction capability. The proposed method able to eliminate dead-time effects such as reducing the waveform distortion of the inverter output current, and increasing the fundamental component amplitude of output current. An analysis of the proposed method is presented. Some computer simulations were carried out to investigate the principle operation, and to test performance of the new method. The developed method was validated through experimental test of H-bridge voltage source inverter circuits. The data obtained from the computer simulation and prototype experiments have confirmed that that the proposed method worked well compensating the dead-time in the voltage source power inverter circuits.
This document summarizes a research paper that proposes and analyzes a multilevel line-commutated inverter topology for solar PV-based grid-connected inverters. The proposed topology uses a multi-winding transformer to provide multiple voltage levels and reduce harmonic distortion in the line current compared to a conventional square-wave inverter. A three-level implementation is modeled in Simulink and experimentally tested. Simulation and experimental results show the proposed topology reduces total harmonic distortion and improves power transfer characteristics compared to a conventional line-commutated inverter.
This document discusses a two-level voltage source converter (VSC) with a third-harmonic injection bus-clamping space vector modulation (SVM) strategy. It aims to further investigate this topology compared to other common VSC topologies. The modulation strategy implements bus-clamping SVM through triangle-comparison-based pulse width modulation. The strategy is investigated using simulations of a passive RL load and an active induction motor load. Simulation results show the impact on total harmonic distortion and motor performance from using this bus-clamping control strategy.
Application of Variable Inductors in a DC/DC Converter to Increase the Operat...theijes
This document summarizes a research paper that proposes using variable inductors in a Cuk DC/DC converter to increase the operating range of a maximum power point tracker (MPPT) at low solar irradiation levels. The variable inductors allow the inductance to decrease at higher currents, reducing component size and cost while maintaining continuous conduction mode over a wider load range. This extends the operating range of the MPPT controller to recover more solar energy during periods of low light or partial shading. Computer simulations using PSCAD/EMTDC validated the effectiveness of the proposed converter design with variable inductance.
An Implementation Mechanisms of SVM Control Strategies Applied to Five Levels...IJPEDS-IAES
In the area of the energy control with high voltage and power, the multilevel inverters constitute a relatively recent research orientation. The current applications of this technology are in the domains of the high voltage (over hundred kV), variable speed drives, transport and distribution of a good quality of electrical energy (HVDC, FACTS system, ....). To improve the output voltage for such inverters, many different modulation strategies have been developed. Among these strategies, the SVM (Space Vector Modulation). The technique provide the nearest switching vectors sequence to the reference vector without involving trigonometric functions and provide the additional advantages of superior harmonic quality. In this paper, we analyze different mechanisms of the output voltage synthesis and the problem of even order harmonic production. With the proposed a new trajectory SVM, which can eliminate all the even order harmonics for five levels inverter. Show clearly how to deduce the trajectories from the sequences allowing to have better performances among several possible trajectories. It is dedicated to the application of two particular trajectories.
In recent years, studies have been investigated the effectiveness of UPFC and TCSC in increasing power transfer capability. However, the effectiveness of these FACTS devices in increasing power transfer capability when the load is non-linear has not been established in a comparative study yet. This paper will explore the steady-state performance of the UPFC and TCSC as impedance compensation models. The effectiveness of both FACTS devices are investigated when they are installed in multi-machine systems with different non-linear load models. Simulation results demonstrate that, upon installing UPFC, more active and reactive powers are received at the sending end bus for different types of non-linear load models. In addition, both active and reactive powers are more sensitive in changing the modulation index of the converters. Furthermore, both the active and reactive powers are less sensitive to the non-linearity of the load model type. However, active and reactive powers in case of installing TCSC are only sensitive in changing the firing angle (α) when it is between 90º to 110º. Therefore, results from this study clearly encourage the effectiveness of UPFC in comparison to TSCS in terms of increasing power transfer capability applied to non-linear load models.
State-space averaged modeling and transfer function derivation of DC-DC boost...TELKOMNIKA JOURNAL
This paper presents dynamic analysis of a boost type DC-DC converter for high-brightness LED (HBLED) driving applications. The steady state operation in presence of all system parasitics has been discussed for continuous conduction mode (CCM). The state-space averaging, energy conservation principle and standard linearization are used to derive ac small signal control to inductor current open-loop transfer function of the converter. The derived transfer function can be further used in designing a robust feed-back control network for the system. In the end frequency and transient responses of the derived transfer function are obtained for a given set of component values, hence to provide a useful guide for control design engineers.
Circuit-based method for extracting the resistive leakage current of metal ox...journalBEEI
Resistive leakage current based condition assessment of metal oxide surge arrester (MOSA) is one of the most extensively employed technique to monitor its degradation. An extraction method is customarily required to extract the resistive component from the total leakage current. The existing methods to extract the resistive current are complex and less accurate. Therefore, this paper describes a simple and accurate circuit-based method to extract the resistive current using equivalent model and measured leakage current of the arrester. The accuracy of the proposed method is validated through experimental results on ABB’s 120 kV surge arrester, EMTP and QuickField software simulations. The performance of the method is also analyzed and verified experimentally on 72, 180 and 240 kV rated ABB’s surge arresters. The obtained results of resistive leakage current have shown the maximum error of 0.001%. Simple and easier computational steps with higher accuracy are the key benefits of the proposed technique.
The document summarizes a study on using a high step-up zeta converter fed by a solar PV panel for a DC drive application. Key points:
- A zeta converter with a coupled inductor and capacitor multiplier is used to achieve high step-up voltage conversion from a 15-40V solar PV panel input.
- Steady-state analysis of the converter in continuous conduction mode shows it can achieve a voltage gain of (1+n) where n is the turns ratio of the coupled inductor.
- Simulation results using Matlab/Simulink validate the converter design and show it can provide the required output voltage for a DC drive from the solar PV input with high efficiency for resist
Phase shedding in multiphase buck converters to improve the efficiencyIAEME Publication
This document summarizes a research paper that analyzes phase shedding in multiphase buck converters to improve efficiency. The paper simulates a multiphase buck converter with 1, 2, and 3 phases. It finds that using fewer phases at light loads improves efficiency, while more phases are needed at higher loads to reduce ripple. Specifically, 1 phase is most efficient below 0.76A, 2 phases from 0.72A to 1.04A, and 3 phases above 1.04A. Comparing the stages, efficiency increases from 82.01% to 97.57% as load and number of phases increases. Therefore, phase shedding allows a multiphase converter to automatically adjust the number of active phases
Modelling of Variable Frequency Synchronous Buck ConverterIAES-IJPEDS
n this paper, novel small-signal averaged models for dc–dc converter operating at variable switching frequency are derived. This is achieved by separately considering the on-time and the off-time of the switching period. The derivation is shown in detail for a synchronous buck converter. The Enhanced Small Signal (ESSA) Model is derived for the synchronous buck converter. The equivalent series inductance (ESL) is also considered in this modelling. The buck converter model is also simulated in MATLAB and the result is also presented.
Karnataka PGCET Electrical Science - Part B 2018 syllabusEneutron
This document contains the syllabus and model question paper for the electrical sciences subject area of Biomedical Engineering & Medical Electronics.
The syllabus covers topics like human anatomy and physiology, biomedical instrumentation, medical imaging systems, signals and systems/DSP, biomedical signal processing, and medical image processing.
The model questions are divided into two sections - Section I contains one mark questions, Section II contains two mark questions. The questions test knowledge of topics like biomedical transducers, medical devices, imaging modalities, filtering, segmentation, etc.
However, the model question papers for Sections I and II are not fully provided in the document. They need to be appended by the Instrumentation Board of Studies.
Modelling of Virtual Synchronous Converter for Grid-Inverter Synchronization ...IAES-IJPEDS
In this paper, virtual synchronous converter (VSCon) is been developed
which mimic the behavior of synchronous generator as in order to have fast
synchronization between the inverter with the grid. This synchronization is
important before can sent the power among inverter-grid connection. This
technique can also been applied at the distributed generated sources when are
connected to the local microgrids. Here, the frequency and voltage
synchronization also can be controlled at the same time some improvement
on synchronous generator mathematical model that is suitable to be
implemented into the inverter control. The whole unit of VSCon is operated
and simulated in Matlab/Simulink in order to observe all consequences
during synchronizing the voltage, frequency and phase-angle. It has been
verified by the simulation circuit where, the power converter can be
synchronized with the microrids without using a PLL unit for self
synchronization. This VSCon technique has proven that, by applying the
concept of the synchronous generator model in inverter control, it can cause
the inverter to behave as generator system, which does not required any
phase information from the grid in order to be synchronized.
Representing Tap-changer Transformers in Conic Relaxation Optimal Power Flowsinventionjournals
Conic optimization has been applied optimal power flow (OPF) problem recently. Present conic relaxation OPFs only consider for the continuous decision variables, and the transformer tap ratios have not been treated as optimization variables. Based on angle relaxed branch power flow, an extended branch power flow model with tap-changer transformers is proposed. The tap-changer transformers were modeled with bilinear functions. Then the McCormick envelopes were deployed to exactly reformulate the bilinear functions with linear constrains. The effectiveness of the proposed method is demonstrated by the simulation results obtained in the test systems
Throughput improvement of ieee 802.15.4 based medicaliaemedu
This document discusses improving the throughput of IEEE 802.15.4 based medical ad-hoc sensor networks that are used for home healthcare monitoring. These networks experience degraded throughput due to interference from co-existing Wi-Fi networks operating in the same 2.4GHz spectrum. The paper studies the impact of Wi-Fi interference on throughput and uses Clear Channel Assessment (CCA) to improve throughput. Experiments were conducted using Texas Instruments sensor motes and showed that CCA improved throughput by 63% by avoiding transmissions when interference was detected.
PI Controller based MPPT for a PV SystemIOSR Journals
This document presents a PI controller-based MPPT technique for a photovoltaic system. It introduces the need for renewable energy sources and MPPT controllers. A PV cell model and characteristics are described. The MPPT technique uses a PI controller connected to a boost converter to track the maximum power point of the PV array in real-time by adjusting the voltage. Simulation results show the MPPT controller is able to quickly track the MPP and boost the output voltage, improving efficiency compared to a system without MPPT.
Correlation of information technology trends with strategic managementiaemedu
The document discusses the correlation between information technology trends and strategic management. It argues that information technology is now a critical resource for competitive advantage and that strategic management must take IT into account. Specifically, IT can help companies reduce costs, increase flexibility, and develop new strategies to outperform competitors. The document also notes that while India's IT industry is large, many startups do not adopt new technologies quickly due to risks and lack of infrastructure support. Overall, the document advocates that lasting competitive advantage requires using IT together with strategic management to add value to companies.
A modern two dof controller for grid integration with solar power generatoriaemedu
1. The document describes a solar power generation system connected to the power grid using a two degree of freedom (DOF) controller.
2. A 100 kW solar power generator is connected to a 25 kV power grid through a three-level inverter and LC filter to generate clean sinusoidal voltage.
3. Simulation results show the solar inverter output voltage waveform is cleaned up from switching frequency harmonics using the LC filter.
Isae 2011 A HYBRID CONTROLLER DESIGN FOR KEEPING CONSTANT VOLTAGE AND CURREN...Pandu Sandi Pratama
This document summarizes a presentation on modeling and control of a gas metal arc welding (GMAW) system. [1] A proportional controller is proposed to maintain constant output welding voltage for the GMAW power supply. [2] A fuzzy-sliding mode controller is proposed for the wire feeding unit to keep the output welding current constant by adjusting the electrode feed rate. [3] Simulation results show the hybrid controller using these two controllers achieves better performance than a conventional PID controller in terms of rise time, settling time, and steady state error of the output current.
Optimization of surface finish during milling of hardened aisi4340 steel with...iaemedu
The document describes an investigation to optimize surface finish during milling of hardened AISI4340 steel using minimal fluid application. Response surface methodology was used to develop a mathematical model for predicting surface roughness. Experiments were designed using a central composite design with pressure at the fluid injector, frequency of pulsing, and fluid application rate as factors. The model was validated against experimental results, which matched well with the predicted values.
Comparative analysis of a cascaded seven level and five level mli based distr...IAEME Publication
This document summarizes a research paper that compares a cascaded seven-level and five-level multilevel inverter-based distribution static synchronous compensator (DSTATCOM) for compensating harmonics and reactive power using reference frame theory. The paper presents the configuration of a DSTATCOM using a cascaded multilevel inverter with five levels and seven levels. It describes the operation and switching states of the five-level and seven-level inverters. It also discusses the reference current control strategy used, which generates the reference currents required to compensate load current harmonics and reactive power based on instantaneous real-power theory. The control scheme aims to maintain the DC bus voltage constant. The proposed DSTATCOM system is
This paper addresses the approach to improve the efficiency of the quasi Z-source inverter. In order to increase the efficiency the reduction of conduction losses is one way to approach. Sequentially to decrease the conduction losses in the quasi z-source inverter the replacement of diode is replacing with switches is proposed which is also called as synchronous rectification. The paper represents basics of the approach, analysis and comparison of the power losses of the traditional and proposed designs of the grid connected PV-system with quasi z-source inverter system. The proposed approach validated on the computer simulations in the MATLAB environment.
This document presents the small-signal AC modeling and closed-loop control of a three-phase interleaved boost converter. It begins with an introduction to boost converters and motivates the use of multiphase interleaved topologies. It then describes the development of a state-space averaged model for the three-phase converter by identifying the different circuit states over a switching period and deriving the corresponding state equations. These are then linearized around an operating point to obtain the small-signal AC model. Finally, it discusses the use of a Type III compensator in the closed-loop control system to improve frequency response and regulate the output voltage under load variations.
MLI Power Topologies and Voltage Eminence: An Exploratory Reviewijeei-iaes
Due to their performances and inherent edges, particularly in medium-voltage and dynamic applications, multilevel inverters have received associate degree increasing attention in universe industrial applications. This paper deals with a review of the most structure electrical converter topologies additionally their commonest derived and hybrid structures quoted in previous analysis works. It additionally encompasses associate degree investigation on voltage harmonic elimination and THD estimation. For that reason, the paper summarizes the foremost relevant modulation techniques used to date to boost the output voltage quality. Theoretical formulas elicited within the literature, for calculating the output voltage THD higher and lower bounds area unit reportable and verified by adequate simulations.
Modified T-type topology of three-phase multi-level inverter for photovoltaic...IJECEIAES
In this article, a three-phase multilevel neutral-point-clamped inverter with a modified t-type structure of switches is proposed. A pulse width modulation (PWM) scheme of the proposed inverter is also developed. The proposed topology of the multilevel inverter has the advantage of being simple, on the one hand since it does contain only semiconductors in reduced number (corresponding to the number of required voltage levels), and no other components such as switching or flying capacitors, and on the other hand, the control scheme is much simpler and more suitable for variable frequency and voltage control. The performances of this inverter are analyzed through simulations carried out in the MATLAB/Simulink environment on a threephase inverter with 9 levels. In all simulations, the proposed topology is connected with R-load or RL-load without any output filter.
A seven level cascaded multilevel dstatcom for compensation of reactive power...IAEME Publication
This document describes a seven-level cascaded multilevel DSTATCOM system for compensating reactive power and harmonics. It uses a cascaded H-bridge multilevel inverter with either phase shifted PWM or level shifted PWM modulation techniques. Simulation results show the system is able to compensate load current harmonics and reactive power, reducing the total harmonic distortion of source currents from 36.89% to 4.37% with a seven-level inverter using phase shifted PWM. The DSTATCOM provides unity power factor correction at the point of common coupling.
Application of soft switching in DC-DC converter has achieved a remarkable success in power electronics technology in terms of reduction in switching losses, improve in power density, minimization of electromagnetic interference (EMI) and reduction in the volume of DC-DC converters. Quite a number of soft switching techniques had been reported in the past four decades. This paper aims at providing a review of various soft switching techniques, based on topology, the location of the resonant network, performance characteristics, and principles of operation. In addition, converters area of application, advantages as well as limitations are also highlighted.
DC-DC Converter With Multiple Inputs For Hybrid Electric Vehicles Application.IRJET Journal
This document describes a proposed DC-DC converter with multiple inputs for use in hybrid electric vehicles. The converter has three sources of electricity: a battery, photovoltaic panel, and fuel cell. It can power the load from any combination of these sources. The control mechanism manages power distribution in an efficient way. Simulation results show the converter increases the output voltage as required and can continue operating even if certain inputs are unavailable. It provides a reliable power supply for electric and hybrid vehicles.
This paper proposes a non-isolated soft-switching bidirectional dc/dc converter for interfacing energy storage in DC microgrid. The proposed converter employs a half-bridge boost converter at input port followed by a LCC resonant tank to assist in soft-switching of switches and diodes, and finally a voltage doubler circuit at the output port to enhance the voltage gain by two times. The LCC resonant circuit also adds a suitable voltage gain to the converter. Therefore, overall high voltage gain of the converter is obtained without a transformer or large number of multiplier circuit. For operation in buck mode, the high side voltage is divided by half with capacitive divider to gain higher step-down ratio. The converter is operated at high frequency to obtain low output voltage ripple, reduced magnetics and filters. Zero voltage turn-on is achieved for all switches and zero current turn-on and turn-off is achieved for all diodes in both modes i.e., buck/boost operation. Voltage stress across switches and diode is clamped naturally without external snubber circuit. An experimental prototype has been designed, built and tested in the laboratory to verify the performance of the proposed converter.
Bidirectional full bridge dc-dc converter with flyback snubber for photovolta...IAEME Publication
This document describes a bidirectional full-bridge DC-DC converter with a flyback snubber circuit for photovoltaic applications. The converter allows for stepped-up voltage from a solar cell to charge a battery. It uses a current-fed full-bridge on the low voltage side and a voltage-fed bridge on the high voltage side, with an isolation transformer in between. A flyback snubber is used to clamp voltage spikes caused by current differences, reducing stress on the active switches. Simulation results show the converter successfully steps up 6V solar output to over 15V for battery charging. The flyback snubber regulates voltages while improving reliability.
This document describes using active disturbance rejection control (ADRC) for controlling a single-stage photovoltaic system connected to the electrical grid. It compares ADRC to the conventional perturb and observe (P&O) control method. ADRC combined with incremental conductance (ADRC-IC) is used for maximum power point tracking (MPPT) control. ADRC is also used to control the inverter to regulate the DC bus voltage and ensure unity power factor injection into the grid. The system aims to maximize power extraction from the PV array and regulate power injection into the grid with low harmonics.
Comparators are basic building elements for designing modern analog and mixed signal systems. Speed and resolution are two important factors which are required for high speed applications. This paper presents a design for an on chip high-speed dynamic latched comparator for high frequency signal digitization. The dynamic latched comparator consists of two cross coupled inverters comprising a total of 9 MOS transistors. The measured and simulation results show that the dynamic latched comparator design has higher speed, low power dissipation and occupying less active area compared to double tail latched and preamplifier based clocked comparators. A new fully dynamic latched comparator which shows lower offset voltage and higher load drivability than the conventional dynamic latched comparators has been designed. With two additional inverters inserted between the input-stage and output-stage of the conventional double-tail dynamic comparator, the gain preceding the regenerative latch stage was improved and the complementary version of the output-latch stage, which has bigger output drive current capability at the same area, was implemented.
Three-Level DTC Based on Fuzzy Logic and Neural Network of Sensorless DSSM Us...IJPEDS-IAES
This paper presents a direct torque control is applied for salient-pole double star synchronous machine without mechanical speed and stator flux linkage sensors. The estimation is performed using the extended Kalman filter known by it is ability to process noisy discrete measurements. Two control approaches using fuzzy logic DTC, and neural network DTC are proposed and compared. The validity of the proposed controls scheme is verified by simulation tests of a double star synchronous machine. The stator flux, torque, and speed are determined and compared in the above techniques. Simulation results presented in this paper highlight the improvements produced by the proposed control method based on the extended Kalman filter under various operation conditions.
Optimization techniques for harmonics minimization in cascaded hybrid multile...eSAT Journals
Abstract
Recent advancements in the field of power electronics have made possible the worldwide application of converters in dc power source utilization, uninterruptible power supplies, electric motor speed control, switched mode power supplies, flexible alternating current transmission systems devices including static synchronous compensator and their controls. Power semiconductor devices such as converters have been emerged as powerful devices in the power industries. As such, harmonics free output of inverters is assuming extreme importance. Over the past decades, depending upon the topologies and control strategies, numerous optimization techniques have been proposed for desired output waveform. This paper presents a review of optimization techniques used for multilevel inverters. The pros and cons of optimization techniques are discussed. The objective of these optimization techniques is to find out the optimum firing angles of multilevel inverters, which results in minimum harmonics. As a preferred option for proposed work, reduction of total harmonic distortion with the aid of particle swarm optimization technique to multilevel inverters is suggested.
Keywords: Power Converters, Multilevel Inverters (MLI), Cascaded Hybrid Bridge (CHB), Modulation, Switching Frequency, Harmonic Distortions.
Impact of Thyristor Controlled Series Capacitor Insertion on Short-circuit Ca...IJAPEJOURNAL
This research paper presents a study on phase to earth fault short-circuit calculation with fault resistance on a single transmission line 400 kV in eastern Algerian transmission networks at Algerian Company of Electricity and Gas (Sonelgaz Group) compensated by series Flexible AC Transmission System (FACTS) i.e. Thyristor Controlled Series Capacitor (TCSC) installed in midline. The facts are used for controlling transmission voltage, power flow, reactive power, and damping of power system oscillations at high power transfer levels. The direct impacts of TCSC insertion on the total impedance, active power and reactive power a electrical transmission line and also parameters of short-circuit : symmetrical currents, line currents, symmetrical voltages and line voltages are carried out. More the effects of injected voltage by TCSC for three case studies are presented.
This paper presents a new single switched inductor-capacitor coupled transformer-less high gain DC-DC converter which can be used in renewable energy sources like PV, fuelcell in which the low DC output voltage is to be converted into high dc output voltage. With the varying low input voltages, the output of DC-DC converter remains same and does not change. A state space model of the converter is also presented in the paper. This constant output voltage is obtained by close loop control of converter using PID controller. High voltage gain of 10 is obtained without use of transformer. All the simulations are done in MATLAB-SIMULINK environment.
This review article summarizes control and applications of modular multilevel converters (MMC). It describes the main switching module topologies used in MMC, including the standard half-bridge configuration and full-bridge topology that allows active fault current reduction. It also discusses methods for balancing capacitor voltages and the voltage and current modulation techniques used for MMC control. Finally, it outlines the main MMC applications in high voltage direct current transmission and offshore wind farms.
In this paper, a Wavelet modulated isolated two-stage three-phase bidirectional AC-DC converter is proposed for electric vehicle (EV) charging systems. Half-bridge resonant CLLC converter is proposed due to its high efficiency, wide gain range, galvanic isolation and bidirectional power flow. Wavelet modulation technique is used for three-phase six leg AC-DC converter due to its benefits of high DC component and lower harmonic contents. The proposed two-stage converter is developed and simulated in MATLAB Simulink environment. The contribution of this paper is on the implementation and performance analysis of Wavelet modulation in bidirectional AC-DC converters. The results show that Wavelet modulation is suitable to be implemented for the proposed bidirectional converter. The performance of the proposed converter delivers very low output voltage ripple and total harmonic distortion output current of less than 10% which is within the expected results.
Similar to Dc dc converter for ultracapacitor boosted electric vehicle (20)
Tech transfer making it as a risk free approach in pharmaceutical and biotech iniaemedu
Tech transfer is a common methodology for transferring new products or an existing
commercial product to R&D or to another manufacturing site. Transferring product knowledge to the
manufacturing floor is crucial and it is an ongoing approach in the pharmaceutical and biotech
industry. Without adopting this process, no company can manufacture its niche products, let alone
market them. Technology transfer is a complicated, process because it is highly cross functional. Due
to its cross functional dependence, these projects face numerous risks and failure. If anidea cannot be
successfully brought out in the form of a product, there is no customer benefit, or satisfaction.
Moreover, high emphasis is in sustaining manufacturing with highest quality each and every time. It
is vital that tech transfer projects need to be executed flawlessly. To accomplish this goal, risk
management is crucial and project team needs to use the risk management approach seamlessly.
Integration of feature sets with machine learning techniquesiaemedu
This document summarizes a research paper that proposes a novel approach for spam filtering using selective feature sets combined with machine learning techniques. The paper presents an algorithm and system architecture that extracts feature sets from emails and uses machine learning to classify emails and generate rules to identify spam. Several metrics are identified to evaluate the efficiency of the feature sets, including false positive rate. An experiment is described that uses keyword lists as feature sets to train filters and compares the proposed approach to other spam filtering methods.
Effective broadcasting in mobile ad hoc networks using gridiaemedu
This document summarizes a research paper that proposes a new grid-based broadcasting mechanism for mobile ad hoc networks. The paper argues that flooding approaches to broadcasting are inefficient and cause network congestion. The proposed approach divides the network into a hierarchical grid structure. When a node needs to broadcast a message, it sends the message to the first node in the appropriate grid, which is then responsible for updating and forwarding the message within that grid. Simulation results showed the grid-based approach outperformed other broadcasting protocols and was more reliable, efficient and scalable.
Effect of scenario environment on the performance of mane ts routingiaemedu
The document analyzes the effect of scenario environment on the performance of the AODV routing protocol in mobile ad hoc networks (MANETs). It studies AODV performance under different scenarios varying network size, maximum node speed, and pause time. The performance is evaluated based on packet delivery ratio, throughput, and end-to-end delay. The results show that AODV performs best in some scenarios and worse in others, indicating that scenario parameters significantly impact routing protocol performance in MANETs.
Adaptive job scheduling with load balancing for workflow applicationiaemedu
This document discusses adaptive job scheduling with load balancing for workflow applications in a grid platform. It begins with an abstract that describes grid computing and how scheduling plays a key role in performance for grid workflow applications. Both static and dynamic scheduling strategies are discussed, but they require high scheduling costs and may not produce good schedules. The paper then proposes a novel semi-dynamic algorithm that allows the schedule to adapt to changes in the dynamic grid environment through both static and dynamic scheduling. Load balancing is incorporated to handle situations where jobs are delayed due to resource fluctuations or overloading of processors. The rest of the paper outlines the related works, proposed scheduling algorithm, system model, and evaluation of the approach.
This document summarizes research on transaction reordering techniques. It discusses transaction reordering approaches based on reducing resource conflicts and increasing resource sharing. Specifically, it covers:
1) A "steal-on-abort" technique that reorders an aborted transaction behind the transaction that caused the abort to avoid repeated conflicts.
2) A replication protocol that attempts to reorder transactions during certification to avoid aborts rather than restarting immediately.
3) Transaction reordering and grouping during continuous data loading to prevent deadlocks when loading data for materialized join views.
The document discusses semantic web services and their challenges. It provides an overview of semantic web technologies like WSDL, SOAP, UDDI, and OIL which are used to build semantic web services. The semantic web architecture adds semantics to web services through ontologies written in OWL and DAML+OIL. Key approaches to semantic web services include annotation, composition, and addressing privacy and security. However, semantic web services still face challenges in achieving their full potential due to issues in representation, reasoning, and a lack of real-world applications and data.
Website based patent information searching mechanismiaemedu
This document summarizes a research paper on developing a website-based patent information searching mechanism. It discusses how patent information can be used for technology development, rights acquisition and utilization, and management information. It describes different types of patent searches including novelty, validity, infringement, and state-of-the-art searches. It also evaluates and compares two major patent websites, Delphion and USPTO, in terms of their search capabilities and features.
Revisiting the experiment on detecting of replay and message modificationiaemedu
This document summarizes a research paper that proposes methods for detecting message modification and replay attacks in ad-hoc wireless networks. It begins with background on security issues in wireless networks and types of attacks. It then reviews existing intrusion detection systems and security techniques. Related work that detects attacks using features from the media access control layer or radio frequency fingerprinting is also discussed. The paper aims to present a simple, economical, and platform-independent system for detecting message modification, replay attacks, and unauthorized users in ad-hoc networks.
1) The document discusses the Cyclic Model Analysis (CMA) technique for sequential pattern mining which aims to predict customer purchasing behavior.
2) CMA calculates the Trend Distribution Function from sequential patterns to model purchasing trends over time. It then uses Generalized Periodicity Detection and Trend Modeling to identify periodic patterns and construct an approximating model.
3) The Cyclic Model Analysis algorithm is applied to further analyze the patterns, dividing the domain into segments where the distribution function is increasing or decreasing and applying the other techniques recursively to fully model the cyclic behavior.
Performance analysis of manet routing protocol in presenceiaemedu
This document analyzes the performance of different routing protocols in a mobile ad hoc network (MANET) under hybrid traffic conditions. It simulates a MANET with 50 nodes moving at speeds up to 20 m/s using the AODV, DSDV, and DSR routing protocols. Traffic included both constant bit rate and variable bit rate sources. Results found that AODV had lower average end-to-end delay and higher packet delivery ratios than DSDV and DSR as the percentage of variable bit rate traffic increased. AODV also performed comparably under both low and high node mobility scenarios with hybrid traffic.
Performance measurement of different requirements engineeringiaemedu
This document summarizes a research paper that compares the performance of different requirements engineering (RE) process models. It describes three RE process models - two existing linear models and the authors' iterative model. It also reviews literature on common RE activities and issues with descriptive models not reflecting real-world practices. The authors conducted interviews at two Indian companies to model their RE processes and compare them to the three models. They found the existing linear models did not fully capture the iterative nature of observed RE processes.
This document proposes a mobile safety system for automobiles that uses Android operating system. The system has two main components: a safety device and an automobile base unit. The safety device allows users to monitor the vehicle's location on a map, check its status, and control functions remotely. It communicates with the base unit in the vehicle using GPRS. The base unit collects data from sensors, determines the vehicle's GPS location, and can execute control commands like activating the brakes or switching off the engine. The document provides details on the design and algorithms of both components and includes examples of Java code implementation. The goal is to create an intelligent, secure and easy-to-use mobile safety system for vehicles using embedded systems and Android
Efficient text compression using special character replacementiaemedu
The document describes a proposed algorithm for efficient text compression using special character replacement and space removal. The algorithm replaces words with non-printable ASCII characters or combinations of characters to compress text files. It uses a dynamic dictionary to map words to their symbols. Spaces are removed from the compressed file in some cases to further reduce file size. Experimental results show the algorithm achieves better compression ratios than LZW, WinZip 10.0 and WinRAR 3.93 for various text file types while allowing lossless decompression.
The document discusses agile programming and proposes a new methodology. It provides an overview of existing agile methodologies like Scrum and Extreme Programming. Scrum uses short sprints to define tasks and deadlines. Extreme Programming focuses on practices like test-first development, pair programming, and continuous integration. The document notes drawbacks like an inability to support large or multi-site projects. It proposes designing a new methodology that combines the advantages of existing methods while overcoming their deficiencies.
Adaptive load balancing techniques in global scale grid environmentiaemedu
The document discusses various adaptive load balancing techniques for distributed applications in grid environments. It first describes adaptive mesh refinement algorithms that partition computational domains using space-filling curves or by distributing grids independently or at different levels. It also discusses dynamic load balancing using tiling and multi-criteria geometric partitioning. The document then covers repartitioning algorithms based on multilevel diffusion and the adaptive characteristics of structured adaptive mesh refinement applications. Finally, it discusses adaptive workload balancing on heterogeneous resources by benchmarking resource characteristics and estimating application parameters to find optimal load distribution.
A survey on the performance of job scheduling in workflow applicationiaemedu
This document summarizes a survey on job scheduling performance in workflow applications on grid platforms. It discusses an adaptive dual objective scheduling (ADOS) algorithm that takes both completion time and resource usage into account for measuring schedule performance. The study shows ADOS delivers good performance in completion time, resource usage, and robustness to changes in resource performance. It also describes the system architecture used, which includes a planner and executor component. The planner focuses on scheduling to minimize completion time while considering resource usage, and can reschedule if needed. The executor enacts the schedule on the grid resources.
A survey of mitigating routing misbehavior in mobile ad hoc networksiaemedu
This document summarizes existing methods to detect misbehavior in mobile ad hoc networks (MANETs). It discusses how routing protocols assume nodes will cooperate fully, but misbehavior like packet dropping can occur. It describes several techniques to detect misbehavior, including watchdog, ACK/SACK, TWOACK, S-TWOACK, and credit-based/reputation-based schemes. Credit-based schemes use virtual currencies to provide incentives for nodes to forward packets, while reputation-based schemes track nodes' past behaviors. The document aims to survey approaches for mitigating the impact of misbehaving nodes in MANET routing.
A novel approach for satellite imagery storage by classifyiaemedu
This document presents a novel approach for classifying and storing satellite imagery by detecting and storing only non-duplicate regions. It uses kernel principal component analysis to reduce the dimensionality and extract features of satellite images. Fuzzy N-means clustering is then used to segment the images into blocks. A duplication detection algorithm compares blocks to identify duplicate and non-duplicate regions. Only the non-duplicate regions are stored in the database, improving storage efficiency and updating speed compared to completely replacing existing images. Support vector machines are used to categorize the non-duplicate blocks into the appropriate classes in the existing images.
A self recovery approach using halftone images for medical imageryiaemedu
This document summarizes a proposed approach for securely transferring medical images over the internet using visual cryptography and halftone images. The approach uses error diffusion techniques to generate a halftone host image from the grayscale medical image. Shadow images are then created from the halftone host image using visual cryptography algorithms. When stacked together, the shadow images reveal the secret medical image. The halftone host image also contains an embedded logo that can be extracted to verify the integrity of the reconstructed image without a trusted third party.