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segunda-feira, 5 de janeiro de 2015
Consideration on The Improvement of Input Currents for Variable Frequency Drive by Reactors Author Kim Hee Moon Department of Ocean Systems Engineering Graduate School of Korea Maritime University
Consideration on The Improvement of Input Currents for Variable Frequency Drive by Reactors
Author Kim Hee Moon
Department of Ocean Systems Engineering Graduate School of Korea Maritime University
Abstract
AC line reactors and dc link reactors are widely used in variable frequency drives(VFDs) to improve the drive performance such as reducing input current harmonics,elevating input power factor,and protecting the drives from surges,etc.The effectiveness of both types of reactors in reducing input harmonics is affected by the loading of the drives and the system source impedance.In this paper,a simulation is performed to investigate of such factors.The rules to evaluate the needs and effectiveness using ac line or dc link reactors are proposed for practical applications
LOWPASS BROADBAND HARMONIC FILTER DESIGN A THESIS SUBMITTED TO THE GRADUATE SCHOOL OF NATURAL AND APPLIED SCIENCES OF MIDDLE EAST TECHNICAL UNIVERSITY BY HAZEM ZUBI
LOWPASS BROADBAND HARMONIC FILTER DESIGN
A THESIS SUBMITTED TO THE GRADUATE SCHOOL OF NATURAL AND APPLIED SCIENCES OF MIDDLE EAST TECHNICAL UNIVERSITY BY HAZEM ZUBI
IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN ELECTRICAL AND ELECTRONICS ENGINEERING
ABSTRACT
Department of Electrical and Electronics Engineering Supervisor: Asst. Prof. Dr. Ahmet M. Hava September 2005, 192 pages In this thesis an analytical design method of the improved broadband passive harmonic filter (IBF) for three phase diode rectifier front-end type adjustable speed drives is presented. The method is based on frequency domain modeling of the rectifier and filter. The success of the method involves accurate representation of the load harmonics. With the harmonics well defined, the harmonic and fundamental frequency equivalent circuits are utilized to analytically calculate the voltages/currents. Thus, the size and the performance of the filter can be optimized. The analytical method is verified via computer simulations and laboratory experiments. Also a performance comparison of various passive harmonic filters for three-phase diode rectifier front-end type adjustable speed drives is provided. The comparison involves the input current total harmonic distortion, input power factor, rectifier voltage regulation, energy efficiency, size, and cost. The parallel/series harmonic resonance problem related issues are addressed and unbalanced operation performance investigated. The comparison is based on analysis and computer simulations and the results are validated by laboratory experiments
LINK FULL THESIS
http://www.eee.metu.edu.tr/~hava/hazem-thesis-LOWPASS%20BROADBAND%20HARMONIC%20FILTER%20DESIGN.pdf
domingo, 4 de janeiro de 2015
The Importance of Acceptable Electrical Power Quality to the Drilling Industry Worldwide Ian C Evans, Harmonic Solutions (Oil & Gas), Ras Al Khaimah, United Arab Emirates
The Importance of Acceptable Electrical Power Quality to the Drilling
Industry Worldwide
Ian C Evans, Harmonic Solutions (Oil & Gas), Ras Al Khaimah, United Arab Emirates
Copyright 2013, SPE/IADC Middle East Drilling Technology Conference and Exhibition
This paper was prepared for presentation at the SPE/IADC Middle East Drilling Technology Conference and Exhibition held in Dubai, UAE, 7–9 October 2013.
Abstract
Electrical power quality is routinely taken for granted by oil and drilling industries worldwide despite the fact that the quality of electrical power is fundamental to the safety and operational integrity of drilling rigs and oil production platforms worldwide, without exception. US$100m’s are lost each year, direct and indirectly, due to poor quality of power. Currently some offshore safety authorities are considering the imposition of strict limits on harmonic voltage distortion in their jurisdiction. Harmonic voltage distortion may become a regulatory issue in the future. This paper examines the salient harmonic and power quality issues onboard drilling rigs with full SCR drilling packages, as well the more recent hybrid (mixed SCR and VFD drives) and full VFD (variable frequency drive) drilling packages. With SCR drives the main problems are harmonic voltage distortion, line notching and voltage spikes which destroys capacitors inside equipment. Low generator power factor is also often an operational problem. For VFDs, harmonic voltage distortion is also a problem but increasingly so is excessive common mode voltage caused by VFD operation which disrupts susceptible electronic equipment. The paper will offer advice on proven solutions for common power quality problems and introduce a remote/local power quality monitoring system which can be easily retrofitted to existing rigs and platforms.
LINK ORIGINAL
http://www.harmonicsolutions-oilandgas.com/wp-content/uploads/2014/08/SPE_IADC_166773-MS_The-Importance-of-Acceptable-Electrical-Power-Quality-to-the-Drilling-Industry-Worldwide_17th-August-2013_XXXX.pdf
The Price of Poor Power Quality Ian C Evans, Harmonic Solutions Co. UK and Michael J Richards, Algozen Corporation, Canada
The Price of Poor Power Quality
Ian C Evans, Harmonic Solutions Co. UK and Michael J Richards, Algozen Corporation, Canada
Abstract
Electric drives, both DC drives (often called “SCR drives” in the industry) and AC variable frequency drives (VFDs), are commonplace on drilling rigs and offshore installations. Their operation can significantly degrade the quality of electric power, resulting in loss of operational capability, equipment failure with subsequent down-time in addition to presenting safety concerns. Marine classification bodies have rules to limit harmonic voltage distortion but these are rarely policed. The quality and security of electric power are absolutely crucial to the operational integrity of any drilling rig or offshore installation, irrespective of type or class. Any failure or malfunction of equipment due to poor power quality can result in severe or disastrous consequences. This paper looks at the main problems associated with poor power quality, including excessive harmonic voltage distortion, line notching (SCR drives) and voltage spikes attributed to SCR drives; these are all traditional ‘harmonics problems’. However, the introduction of large VFDs has resulted in significant increases in ‘common mode voltage’ problems which can be extremely problematic; even to the point where rigs are being taken off-hire due to major equipment being deemed ‘dangerous’. On another rig, the gas detection system failed when the top drive VFD was running due to this problem. This paper will provide a practical understanding of each problem and how they can be resolved. The paper also introduces an inexpensive, yet powerful, remote power quality monitoring system which can be easily retrofitted to monitor all aspects of land-rig and offshore rig power quality, including waveforms and harmonic spectrums. The data is available locally with the capability to transmit the information via the internet to anywhere in the World.
LINK FULL PAPER ORIGINAL
https://www.google.com.br/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&cad=rja&uact=8&ved=0CC4QFjAC&url=http%3A%2F%2Fwww.aade.org%2Fapp%2Fdownload%2F6857647004%2FAADE-11-NTCE-07.pdf&ei=QnSpVKLzJdOTNtLxgogH&usg=AFQjCNHm05m6r6W9vVUSJZlCLLT4ATHEkQ&sig2=DuFagJEuZCRiGxGxUUqrig
LINK ALTERNATIVE
https://copy.com/fyS9nLkVUXPffmPB
Harmonics Reduction Techniques in Renewable Energy Interfacing Gonverters Ali M. Eltamaly, Ph.D King Saud University Saudi Arabia
INTRODUCTION
In the recent years there has been growing interest in renewable energy generation along with growing demands for development of a suitable interface system. Low harmonics in line current of the converters used in the utility interface.
Controlled and uncontrolled converters are used widely in the utility interface of renewable energy systems to reduce cost, harmonic contents in line currents. A detailed third harmonic current injection technique reduce the harmonic contents in line currents of controlled and uncontrolled converters that used in renewable energ'y applications. The approach is based on circulaling third harmonic current from DC link current to line currents of controlled and uncontrolled converters to reduce its THD. A new injected current shape is computed from analysis to achieve sinusoidal utility line currents. A controllable single switch boost converter conrrccted in shunt is employed to circulate the new injected current shape. A method to implement the proposed approach under varying load condition is shown. Analysis,d esign,l imitations,s imulationa nd experimentarl esult are presented. In modern Power electronics converters, three-phase controlled converter is commonly used.
LINK FULL PAPER
http://faculty.ksu.edu.sa/eltamaly/Documents/[3].pdf
LINK ALTERNATIVE
https://copy.com/IApswwIOUqPR0xNt
sábado, 3 de janeiro de 2015
Study on the component analysis of harmonic current to specify the cause of fault in electrical power line Author Park, Chan Heon
ABSTRACT
Development of power semiconductors has promoted to the advancement of large static power converters. Due to use of these converters, the power quality has become a very important and highly controversial issue in today's industrial environments. Converters of the supplied 60Hz ac to dc or to variable frequency ac power offers more precise speed control and increased efficiencies for many industrial processes. These advantages have accelerated wide spread usage of static power converters. However, these advantages cause disadvantages of increased sensitivity to both the quality of power supplied by the utility and the quality of the power inside the industrial facility. With these trends of industrial environments, both electric utilities and end users of electric power are increasingly concerned about quality of electric power. And the harmonic problem becomes one of the most important issues on the power quality problems. Therefore, this thesis aimed to represents theoretical study, occurence examples, and countermeasure of harmonics. Therefore, in this thesis also introduces terms and generation of harmonics characters based on different loads and clarified the areas of harmonic problems on the industrial facilities. In end of this thesis, it has been discussed for controlling of harmonics. Chapter 3 provided the guidelines for the harmonics level referenced from Korea, Japan, and IEEE std 519-1992. In chapter 4, this thesis presents the results of example study as regards a fault owing to OCGR(Over Current Ground Relay) and another fault owing to N phase line in main transformer of substation. Chapter 5 illustrates the delivered reference for power filters, and suggest real time PQM(Power Quality Management) system to diagnosis harmonics. This paper wishes to express that these study results may contribute to localization of power filters and to resolution of harmonic problems.
segunda-feira, 29 de dezembro de 2014
Design of an LCL-Filter for the Three-Parallel Operation of a Power Converter in Wind Turbines DONG-KEUN YOON AJOU UNIVERSITY
Permanent Magnet Synchronous Generators (PMSG) are widely used in variable-speed wind turbines. However, the power devices must support high currents to get their high-power rating because the PMSG is connected directly to the grid through a back-to-back converter. Therefore, the rated current of the power device can be reduced to one third of the rated value by using a three-parallel operation. The low switching frequency of a high power system may cause an increase in the harmonics found in the output current.
This paper proposes a design scheme for an LCL-filter used for three-parallel operation of a power converter in 2MW-wind turbines. An appropriate design method of the delta configured LCL-filter is also proposed to improve the output power quality in the system. A novel design method for the inner inductance of the LCL-filter is proposed in order to overcome the existing trial and error methods used in designing the filter. LCL-filters typically have a problem with a reduced power factor (PF), due to the capacitor used. To improve the poor PF, a simple compensation method is also proposed. The simulation and experimental results demonstrate that the grid current harmonics are low and the PF is improved.
Research on High Efficiency Non-Isolated Push-Pull Converters with Continuous Current in Solar-Battery Systems Yan Li, Trillion Q. Zheng, and Qian Chen
Research on High Efficiency Non-Isolated Push-Pull Converters with Continuous Current in Solar-Battery SystemsYan Li, Trillion Q. Zheng, and Qian Chen
Abstract
In order to improve the output efficiency of solar cells and to extend the life span of batteries, the input currents of converters are required to be continuous. If low output voltage ripple is required at the same time, it is obvious that the application of basic two-order converters (such as Buck and Boost derived converters) will not be good enough. In this paper, a lot of non-isolated push-pull converters (NIPPCs) with continuous current will be introduced due to their lower current stress, higher efficiency and better EMC performance. By decomposing the converters into push-pull cells, inductor and free-wheeling diodes, two families of NIPPCs based on single inductor and coupled inductor separately are systematically generated. Furthermore, characteristics analyses for some of the generated converters are also shown in this paper. Finally, two prototypes based on the corresponding typical topologies are built in the lab to verify the theoretical outcomes.
LINK
http://jpe.or.kr/archives/view_articles.asp?seq=852
A Novel Circuit Configuration of UPS with Auxiliary Inverter and Its Specific Control Implementations Katsuya Hirachi and Mutsuo Nakaoka
A Novel Circuit Configuration of UPS with Auxiliary Inverter and Its Specific Control Implementations
Katsuya Hirachi and Mutsuo Nakaoka
RESEARCH AND DEVELOPMENT DIVISION POWER SUPPLY COMPANY,YUASA,OSAKA JAPAN.
DEPT. OF ELECTRICAL AND ELECTRONICS ENGINEERING YAMAGUCHI UNIVERSITY
YAMAGUCHI JAPAN
Abstract
The rapid expansion of small computers over the last 10-odd years has brought about great changes in the circumstances affecting UPSs. There are strong demands that UPSs become much smaller and lighter, and more economical, which has resulted in the wide application of the circuit topology without transformer. A disadvantage of such UPS topology is that the DC link voltage is very high, which invites decreased reliability and increased cost of battery bank. Some circuit configurations were proposed to eliminate this disadvantage, but they still had problems. In this paper, a novel circuit configuration which eliminates these problems is proposed and evaluated by the experimental results of prototype UPS.
LINK
http://jpe.or.kr/archives/view_articles.asp?seq=79
LINK DIRECT
http://manuscript.jpe.or.kr/ltkPSWeb/pub/pubfpfile.aspx?ppseq=79
A Three-Phase High Frequency Semi-Controlled Battery Charging Power Converter for Plug-In Hybrid Electric Vehicles Mahmoud M. Amin and Osama A. Mohammed†
Dept. of Electrical and Computer Eng., Florida International University, Florida, United States
Abstract
This paper presents a novel analysis, design, and implementation of a battery charging three-phase high frequency semicontrolled power converter feasible for plug-in hybrid electric vehicles. The main advantages of the proposed topology include high efficiency; due to lower power losses and reduced number of switching elements, high output power density realization, and reduced passive component ratings proportionally to the frequency. Additional advantages also include grid economic utilization by insuring unity power factor operation under different possible conditions and robustness since short-circuit through a leg is not possible. A high but acceptable total harmonic distortion of the generator currents is introduced in the proposed topology which can be viewed as a minor disadvantage when compared to traditional boost rectifiers. A hysteresis control algorithm is proposed to achieve lower current harmonic distortion for the rectifier operation. The rectifier topology concept, the principle of operation, and control scheme are presented. Additionally, a dc-dc converter is also employed in the rectifier-battery connection. Test results on 50-kHz power converter system are presented and discussed to confirm the effectiveness of the proposed topology for PHEV
application.
LINK ORIGINAL
http://jpe.or.kr/archives/view_articles.asp?seq=536
LINK DIRECT
http://manuscript.jpe.or.kr/ltkPSWeb/pub/pubfpfile.aspx?ppseq=536
Reduction of Total Harmonic Distortion in Inverters Driving a Compressor using Active Power Filter with Phase Delay Compensation
Reduction of Total Harmonic Distortion in Inverters Driving a Compressor
using Active Power Filter with Phase Delay Compensation
Lim,Chan-Gyu
School of Electronics Engineering, Major in Control System
Graduate School, Kyungpook National University Daegu, Korea
(Supervised by Professor Choi, Jong-Woo)
In recent years, there has been a considerable interest in the active power filters and power quality contaminated by non-linear load. Among the power filters, a shunt active filter is most preferable to protect the consumers from the power line with an harmonic load current. This paper describes the active power filter to comply with harmonics current regulation(IEC 61000-3-12) effective for the inverter air-conditioners whose operating current is more than 16A. The validity of the proposed compensating method has been verified by the experimental results for a shunt active power filter controlled by all pass filter to compensate a phase delay of harmonics. It was shown that the total harmonic distortion (THD) of the air-conditioner inverter has been much reduced to 6% from 54%. It is expected that the proposed active power filter is effective to the competitiveness of the air-conditioner inverter and the reduction of harmonic damage such as power line loss, power device overheating.
A thesis submitted to the Council of the Graduate School of Kyungpook National University in partial fulfillment of the requirements for the degree of Master of Science. in December, 2013.
LINK
http://www.mediafire.com/view/9d091coag56oxx6/FILTRO_ACTIVO_AR_CONDICIONADO.pdf
Harmonics and Inter-harmonics Estimation of Power Signal using Filter Banks LIN YOUNG BIN DEPARTMENT OF ELECTRICAL ENGINEERING CHUNGBK NATIONAL UNIVERSITY KOREA
ABSTRACT This paper proposes a new method which combines filter bank system and adaptive filtering for the parameters estimation of the harmonics and the inter-harmonics of power signals. The proposed method decomposes the input power signal by designing the filter bank system. This filter bank has binary tree structure, and uses the fundamental filter banks successively in each decomposing stage. The fundamental filter bank separates the odd harmonic and the even harmonic components to reduce the spectral leakage. The adaptive filter is applied to the each harmonic component for the accurate parameter estimation. And the inter-harmonic component parameters are estimated through the error signal of the adaptive filter. The amplitudes and the frequency estimation of the each harmonic and inter-harmonic are carried out by the recursive method. To demonstrate the performance of the method, computer simulations are performed to the synthesized signals.
LINK
https://www.mediafire.com/?3d1zacmct6rfwhz
sexta-feira, 26 de dezembro de 2014
R. RICHTER ELECTRICAL MACHINERY volume III TRANSFORMERS Translated from the German ilzh. NA Golubeva
R. RICHTER ELECTRICAL MACHINERY volume III TRANSFORMERS Translated from the German ilzh. NA Golubeva edited by prof. T * Petrova Approved GUUZ NKTP as textbook for energy technical colleges
LINK ORIGINAL ( FORMAT DJVU )
http://mexalib.com/download/60042
terça-feira, 23 de dezembro de 2014
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