P1--A bidirectional DC-DC converter for renewable energy systems
مبدل DC-DC دو طرفه برای سیستم های انرژی تجدید پذیر
BULLETIN OF THE POLISH ACADEMY OF SCIENCES TECHNICAL SCIENCES Vol. 57, No. 4, 2009
S. JALBRZYKOWSKI, and T. CITKO
Abstract. To improve the energy quality, most of the renewable energy systems include an energy storage element charged by the bidirectional DC-DC converter. This paper proposes the bidirectional DC-DC converter which employs the two bridge configuration resonant class-E converters on the both sides of the isolating transformer. The low side converter is controlled as step up and the high side converter is controlled as step down. The proposed system is characterized by good dynamic properties and high efficiency because the converter transistors are switched in ZVS conditions. A theoretical analysis to provide relations for system design, and the laboratory model investigations to validate the system characteristic are given in the paper.
Key words: bidirectional, isolated, energy storage system, DC-DC converter.
واژه های کلیدی: دو طرفه، ایزوله، سیستم ذخیره انرژی، مبدل DC-DC.
P2--A Comparison of Single-Phase p-q Theory and UVT Based Control Algorithms for Single-Phase UPQC
مقایسه تک فاز تئوری PQ و الگوریتم های کنترل مبتنی بر UVT برای UPQCتک فاز
2010 Annual IEEE India Conference (INDICON)
Abstract— This paper employs a single-phase unified quality conditioner (UPQC), an integration of shunt and series active filters (APF), to perform voltage and supply current harmonics mitigation and power factor correction. Both the shunt and series APFs are realized using a single-phase, two leg voltage source inverter (VSI). For the series APF the control strategy is based on Unit Vector Template (UVT), while a comparison is made for the two control strategies namely UVT and single–phase p-q theory for shunt APF. In both of the control strategies the control is made over the fundamental supply current and fundamental supply voltage instead of the fast changing AFs current and voltage, thereby reducing the computational delay and number of required sensors. A dynamic model of the UPQC is developed in the MATLAB/SIMULINK enviournment and the simulation results demonstrating the power quality improvement in the system are presented for distorted supply and a combination of linear and non-linear load.
Keywords— Power Quality, UPQC, Harmonics, Power Factor Correction, voltage and current harmonic mitigation
واژه های کلیدی: کیفیت توان، UPQC، هارمونیک ها، اصلاح ضریب قدرت، ولتاژ و کاهش هارمونیکهای جریان
P3--A New Approach for High Efficiency Buck-Boost DC/DC Converters Using Series Compensation
رویکرد جدید برای بهره وری بالا باک ، بوست در مبدل DC / DC با استفاده از جبران سازی سری
Abstract - This paper proposesanew buck-boost DC/DC converters, which is connected in series to the power supply. The proposed circuit provides only differential voltage between the input voltage and the output voltage command. The power rating of a conventional circuit is dominated by the input voltage or the output voltage. In contrast, the voltage rating of the proposed circuit requires only the differential voltage between the input and output voltage. In addition, the series converter generates a positive and negative voltage to realize boost mode and buck mode, respectively. As a result, the power rating of the DC/DC converter can be drastically reduced. A new approach for series compensation converters is introduced in order to realize high efficiency and a reduction of power rating. Two new buck-boost converters and their control methods are proposed based on a new concept in which the proposed circuits consist of an Hbridge circuit and a power assist circuit. The H-bridge circuit is used in order to determine the polarity of the differential voltage. The power assist circuit controls the DC voltage of the H-bridge circuit depending on the output voltage command. In the proposed circuit, a flyback converter and inverting chopper are used as the power assist circuit. Simulation and experimental results are shown in order to demonstrate the advantages of the proposed converters in comparison with a conventional buckboost converter. A maximum efficiency of 98% was obtainedwith the proposed circuit. The proposed circuits can decrease losses by 2/3 in comparison with a conventional buck-boost converter. Therefore, the proposed converter can realize high efficiency and down-sizing in applications that require the output voltage to be closed to the input voltage.
Index DC/DC converters, High efficiency, battery applications, flyback converter, inverting chopper
شاخص: مبدل DC / DC، راندمان بالا، باتری برای حالات کاربردی، مبدل FLYBACK، چاپر معکوس
P4--A New Approach to Sensorless Control Method for Brushless DC Motors
یک روش جدید به روش کنترل بدون سنسور برای موتورهای بدون جاروبک DC
Tae-Sung Kim, Byoung-Gun Park, Dong-MyungLee, Ji-Su Ryu, and Dong-Seok Hyun
International Journal of Control, Automation, and Systems, vol. 6, no. 4,pp. 477-487, August 2008
Abstract:This paper proposes a new position sensorless drive for brushless DC (BLDC) motors. Typical sensorless control methods such as the scheme with the back-EMF detection method show high performance only at a high speed range because the magnitude of the back-EMF is dependent upon the rotor speed. This paper presents a new solution that estimates the rotor position by using an unknown input observer over a full speed range. In the proposed method, a trapezoidal back-EMF is modelled as an unknown input and the proposed unknown input observer estimating a line-to-line back-EMF in real time makes it possible to detect the rotor position. In particular, this observer has high performance at a low speed range in that the information of a rotor position is calculated independently of the rotor speed without an additional circuit or complicated operation process. Simulations and experiments have been carried out for the verification of the proposed control scheme.
Keywords:BLDC motor, full speed range, sensorless control, unknown input observer.
واژه های کلیدی: موتور BLDC، محدوده سرعت کامل، کنترل بدون سنسور، مشاهده گر ورودی ناشناخته .
P5--A New Control Strategy for Bi-Directional DC-DC Converter in Electrical Vehicle
یک استراتژی کنترل جدید برای تبدیل دو جهته DC-DC در برق خودرو
Abstract –In order to improve the drive system efficiency，a boost/buck bi-directional DC-DC converter which can regulate the DC-link voltage according to optimal efficiency curve is added between the battery and the traditional voltage source inverters (VSI) supplying a motor. The traditional control approach for the bi-directional DC-DC converter is based on the analog control concept. However, it is not the best choice in digital control environment. In this paper, a new control strategy with a digital control concept is presented which can achieve a smooth switching between the boost and buck operation state using only one controller. The small-signal model of the controller is built and the relationship between the out power and the DC-link voltage stability is discussed. The PMSM drive system in electric vehicles (EV) is modeled using MATLAB/simulink and a operation condition in EV is simulated to verify the above theoretical analysis. The simulation and theoretical analysis results match with good agreement.
P6--A New Model of Economic Dispatch Considering Energy Conservation and Environmental Protection in Electricity Market
مدل جدید اقتصادی پخش بار با توجه به حفاظت انرژی و حفاظت محیط زیست در بازار برق
2012 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of Hainan University
The power system economic dispatch model was improved, which only considered the feathers of cost and emission. The conception of energy conservation factor is suggested. Established a new model of economic dispatch considering energy conservation and environmental protection in electricity market, then, used it in a simulation system to verify its effectiveness. The new model gives a preliminary exploration and attempt on the implementation of the energy conservation power generation dispatch.
Keywords- Electricity Market; Economic Dispatch; Energy Conservation Dispatch; Energy Conservation Factor
کلمات کلیدی: بازار برق. پخش بار اقتصادی؛ انرژی حفاظت از پخش بار. فاکتور حفاظتانرژی
P7-- A new single ended fault location algorithm for combined transmission line considering fault clearing transients without using line parameters
الگوریتم ترکیبی محل خطا جدید برای خط انتقال با توجه به خطا پاکسازی گذرا بدون استفاده از پارامترهای خط
Ismail Niazy, Javad Sadeh
2012 Elsevier Ltd. All rights reserved.
In this paper a new single ended fault location method is proposed for underground cable combined with overhead lines. In this algorithm fault clearing high frequency transients are used instead of fault-generated transients and the line parameters are not needed. In the proposed algorithm, samples just from voltage transients generated by fault clearing action of circuit breaker are taken from the sending end of the cable line. Applying wavelet transform, the first three inceptions of traveling waves to the fault locator are detected. Using these, the proposed algorithm at first identifies fault section, overhead or cable, and then wave speed is calculated and at last location of fault is determined accurately. Because of using only voltage samples taken from one terminal, it is simple and economic and does not need to GPS and data communication and synchronization. Extensive simulations carried out using SimPowerSystem toolbox of MATLAB, confirm the capabilities and high accuracy of the proposed method under different system and fault conditions.
رمانمبدل دو طرفه چند سطحی با تقویت کتتده باک بوست DC-DC
A novel noninverting boost-buck dc-dc converter topology is presented, applicable when both sides of the converter need to have the same grounding. It is based on the back-to-back connection of two n-level diode-clamped converter legs, and allows bidirectional power flow. A simplified topology is proposed for unidirectional power flow applications. Two new pulse width modulation strategies with different advantages are proposed to operate the converter guaranteeing dc-link capacitor voltage balance in every switching cycle for all possible operating conditions and using small capacitance values. The semiconductor device losses are analytically compared to the losses in a conventional two-level boost-buck converter. The analysis yields a higher efficiency for the multilevel converter, especially as the number of levels increases. Experimental results are presented to validate the good converter performance in a five-level converter prototype.
Index Terms—Dc-dc power conversion, multilevel systems,pulse width modulated power converters, pulse width modulation.
P9--A Novel LQR Based Optimal Tuning Method for IMP-Based Linear Controllers of Power Electronics/Power Systems
رمان LQR بر اساس روش بهینه تنظیم برای کنترل خطی IMP-بر اساس الکترونیک قدرت / سیستمقدرت
This paper presents a new method for tuning linear controllerssuchasProportional-Integrating(PI) and Proportional-Resonant(PR)structureswhicharefrequently usedindifferentpowerelectronicandpowersystemapplications.Thosecontrollersareplacedwithina general structureofferedbytheInternalModelPrinciple(IMP)of control theory. In this paper, the first perspective uses the wellknownconceptofLinearQuadraticRegulator(LQR)to address the problem as a regulation problem. Matrixof the LQRdesignisthenfinelyadjustedinordertoassuredesired transientresponseforthesystem.ThesecondperspectiveisbasedonredefiningtheLQRprobleminordertomakeit capableofaddressingtheoptimaltrackingproblem. Two specificexamplesofthemethodapplications,oneinaUPS inverter system and the other one in a DG system, as applied to tuningofaPRand aPIcontrollerarestudiedindetail.Both examplesaresimulatedinPSCADandtheresultsconfirm analytical derivations.
P10--A SIMPLE METHOD FOR POWER LOSS ESTIMATION IN PWM INVERTER-FED MOTORS
یک روش ساده برای برآورد تلفات توان دراینورتر PWM و موتورهایFED
This paper presents a simple power loss estimation method for inverter-fed low power AC asynchronous and synchronous motors. The method uses a simulation based DC/AC converter power loss estimation based on datasheet parameters and load characteristics like measured phase resistance and current phase delay. A current control scheme is used to impose a constant current at various speeds. Using this approach both asynchronous and synchronous motors can be used as a load. Total power loss is measured as the DC Link current by an amperemeter avoiding the use of complicated measurement systems.
Keywords: power loss estimation, PWM parameters, Induction Motor, Synchronous Reluctance,
P13--AI Based Economic Load Dispatch Incorporating Wind Power Penetration
پخش بار بار اقتصادی AI بر اساس گنجاندن ضریب قدرت باد
Economic Load Dispatch (ELD) is one of the most important problems to be solved in the operation and planning of a power system. Its objective is to schedule the power generation properly in order to minimize the total operational cost. Renewable energy resources such as wind power have significant attention in recent years in power system field. It reduces fuel consumption and also benefits in curbing emission. But wind power penetration into conventional systems due to its intermittent nature has some implications like security concerns. Thus a reasonable trade off is required between system risk and operational cost. In this papera bi-objective economic dispatch problem considering wind power penetration is formulated. A fuzzy membership function is used to represent the dispatch of wind power into the conventional system. A particle swarm optimization algorithm, Genetic algorithm and a bacteria-foraging technique are adopted to develop a dispatch scheme compromising both the economic and security requirements. The results of all these 3 proposed techniques are compared. Numerical analyses are reported based on a typical IEEE-30-bus with six-generator test power system to show the validity and applicability of the proposed approaches.
P14--An Integral Battery Charger With Power Factor Correction for Electric Scoote
یک شارژر انتگرالی باتری با ضریب توان برای Scooteبرقی
Gianmario Pellegrino, Member, IEEE, Eric Armando, and Paolo Guglielmi, Member, IEEE
IEEE TRANSACTIONS ON POWER ELECTRONICS, VOL. 25, NO. 3, MARCH 2010
Abstract—This paper presents an integral battery charger for an electric scooter with high voltage batteries and interior-permanentmagnet motor traction drive. The battery charger is derived from the power hardware of the scooter, with the ac motor drive that operates as three-phase boost rectifier with power factor correction capability. The control of the charger is also integrated into the scooter control firmware that is implemented on a fixed-point DSP controller. Current-controlled or voltage-controlled charge modes are actuated according to the requirements of the battery management system, that is embedded into the battery pack. With respect to previous integrated chargers, the ac current is absorbed at unitary power factor with no harmonic distortion. Moreover,no additional filtering is needed since the pulsewidth modulation ripple is minimized by means of phase interleaving. The feasibility of the integral charger with different ac motors (induction motor, surface-mounted phase modulation motor) is also discussed, by means of a general model purposely developed for three-phase ac machines. The effectiveness of the proposed battery charger is experimentally demonstrated on a prototype electric scooter,equipped with two Li-ion battery packs rated 260 V, 20 Ah.
Index Terms—AC motor drives, AC motor modelling, ac–dc power conversion, battery chargers, interleaved converter, road vehicle electric propulsion.
P15--Analysis of 3-Phase Superconducting Fault Current Limiters in Power Systems With Inhomogeneous Quenching
تجزیه و تحلیل 3 فاز ابررسانا جریان محدود کننده در سیستم های قدرت ناهمگن
Diaa-Eldin A. Mansour,Member, IEEE, and Doaa M. Yehia
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, VOL. 23, NO. 3,JUNE 2013
Abstract—The limitation behavior of a 3-phase superconducting fault current limiter (SFCL) in power systems is greatly affected by inhomogeneous quenching among phases, where it can lead to increasing current limitation burden upon some phase units.Accordingly, this paper aims to analyze the behavior of SFCL with inhomogeneous quenching among phases. A model is developed for the resistive type SFCL using PSCAD/EMTDC software considering the transition from superconducting state to normal conducting state through flux flow state. Inhomogeneous quenching is represented in two different ways, either as an inhomogeneity in Ic value or an inhomogeneity innvalue. Different types of faults including symmetrical and unsymmetrical faults are studied. For each case, the influence of inhomogeneous quenching on current limitation and corresponding voltage drop across units is evaluated. From the obtained results, it is found that the most severe case appears for line-to-line fault. Therefore, the effect of inhomogeneity degree is discussed for this fault type.
Index Terms—Current limitation burden, inhomogeneous quenching, superconducting fault current limiter (SFCL),symmetrical, unsymmetrical faults.
واژه ها شاخص: محدودیت جریان بار ، فرآیند کوئیچینگ ناهمگن، محدودکننده جریان خطا ابررسانا (SFCL)، متقارن، خطاهای نامتقارن.
Electrical Power and Energy Systems 32 (2010) 478–48
This paper presents a novel and efficient optimisation approach based on the ant colony optimization (ACO) for solving the economic dispatch (ED) problem with non-smooth cost functions. In order to improve the performance of ACO algorithm, three additional techniques, i.e. priority list, variable reduction, and zoom feature are presented. To show its efficiency and effectiveness, the proposed ACO is applied to two types of ED problems with non-smooth cost functions. Firstly, the ED problem with valve-point loading effects consists of 13 and 40 generating units. Secondly, the ED problem considering the multiple fuels consists of 10 units. Additionally, the results of the proposed ACO are compared with those of the conventional heuristic approaches. The experimental results show that the proposed ACO approach is comparatively capable of obtaining higher quality solution and faster computational time.
P17--application of pattern search method to power system valve-point economic load dispatch
استفاده از روش جستجوی پترن سرچ در سیستم قدرت نقطه سوپاپ توزیع بار اقتصادی
J.S. Al-Sumait, A.K. AL-Othman, J.K. Sykulski
Elsevier--Electrical Power and Energy Systems 29 (2007) 720–730
Direct search (DS) methods are evolutionary algorithms used to solve constrained optimization problems. DS methods do not require any information about the gradient of the objective function at hand, while searching for an optimum solution. One of such methods is pattern search (PS) algorithm. This study presents a new approach based on a constrained pattern search algorithm to solve well-known power system economic load dispatch problem (ELD) with valve-point effect. For illustrative purposes, the proposed PS technique has been applied to various test systems to validate its effectiveness. Furthermore, convergence characteristics and robustness of the proposed method has been assessed and investigated through comparison with results reported in literature. The outcome is very encouraging and proves that pattern search (PS) is very applicable for solving power system economic load dispatch problem.
P18--Comparative performance analysis of Thyristor and IGBT based induction motor soft starters
تجزیه و تحلیل عملکرد مقایسه ای تریستور و IGBT بر اساس شروع نرم موتور القایی
Ahmed Riyaz, Atif Iqbal, Shaikh Moinoddin, SK. MoinAhmed, Haitham Abu-Rub
International Journal of Engineering, Science and Technology Vol. 1, No. 1, 2009, pp. 90-105
In this paper the performance of a split-phase motor and a three-phase induction motor drives for soft starting is evaluated. The papersystematicallyinvestigatesandcomparesthecharacteristicsofavariablevoltagefedinduction motordrivefortwo differenttypesofsoftstarters;onebasedonIGBT andanotherbasedonThyristor.Experimentalvalidationisdoneusinganaloguecircuitbasedsystem,developedinthelaboratory.Thenoveltyoftheworkliesinthedevelopmentofsimpleand flexible models for simulation purpose and their experimental validation.
Keywords:Variable speed electric drives, Soft starter, Thyristor, IGBT
کلید واژه ها: درایوهای سرعت متغیر الکتریکی و سافت استارتر، تریستور، IGBT
P19--Comparison of SVC and STATCOM in StaticVoltage Stability Margin Enhancement
مقایسه SVC و STATCOM در افزایش حاشیه پایداری ولتاژ استاتیک
Mehrdad Ahmadi Kamarposhti and Mostafa Alinezhad
World Academy of Science, Engineering and Technology 50 2009
Abstract—One of themajor causes of voltage instability is thereactivepower limitof thesystem.Improvingthesystem's reactive power handling capacity via Flexible AC transmission System (FACTS)devicesisaremedyforpreventionofvoltageinstabilityand hence voltage collapse. In this paper, the effects of SVC and STATCOMinStaticVoltageStabilityMarginEnhancementwillbestudied.ACandDC representationsofSVCandSTATCOM areused in the continuation power flow process in static voltage stabilitystudy. The IEEE-14 bus systemis simulated to test the increasingloadability. It is found that these controllers significantly increase the loadability margin of power systems.
P20--Control and operation of distributed generation in distribution systems
کنترل و بهره برداری از مولدهای تولید پراکنده در سیستم های توزیع
Pukar Mahat,Zhe Chen, Birgitte Bak-Jensen
Elsevier, Electric Power Systems Research81 (2011) 495–502
Many distribution systems nowadays have significant penetration of distributed generation (DG) and thus, islanding operation of these distribution systems is becoming a viable option for economical and technical reasons. The DG should operate optimally during both grid-connected and island conditions, which can be achieved with change in operating strategy. Many islanding detection techniques have been developed but little work has been done to detect grid re-connection. This paper presents strategies to operate DG in grid connected and islanded modes and a new grid re-connection detection algorithm, which uses average rate of change of frequency (Af5) and real power shift (RPS), in the islanded mode. RPS will increase or decrease the power set point of the generator with increasing or decreasing system frequency, respectively. Simulation results show that the proposed method can operate the DG efficiently and is effective in detecting grid-reconnection.
Keywords:Droop control,Grid re-connection detection,Islanding detection,Isochronous control,Isochronous control with feedback,Power factor control
واژه های کلیدی: افت کنترل، شبکه تشخیص مجدد اتصال، تشخیص جزیره ای، کنترل همزمان دنباله، کنترل همزمان دنباله با بازخورد، کنترل ضریب قدرت