Mohammad Amin Moqadasi; Mahmood Hoseini Ali Abadi; Hamid Radmanesh
Abstract
The present study discusses a new structure of single layer magnetic gear (SL-MG) with Halbach array in external rotor, which is named single layer magnetic gear with Halbach array (HSL-MG). The key point in this design is using three segment Halbach array instead of the conventional permanent magnets ...
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The present study discusses a new structure of single layer magnetic gear (SL-MG) with Halbach array in external rotor, which is named single layer magnetic gear with Halbach array (HSL-MG). The key point in this design is using three segment Halbach array instead of the conventional permanent magnets in magnetic pole pairs of external rotor in single layer magnetic gear, and this leads to increasing the magnetic couple between wound stator and permanent magnets of external rotor. Electromagnetic function and FEM two dimensional analysis are done on both magnetic gears and these two magnetic gears of wound stator are compared with each other. The results show that the magnetic gear under study has a higher torque density than its conventional version; therefore, this kind of magnetic gear is more suitable for low-speed engines and high torque direct drive applications.
Hamed Hekmati; Mohammad Siamaki; Arsalan Hekmati
Abstract
As a technology, superconductivity has had a great contribution to the advancement of medical science, electronics, astronomy and transportation. With the improvements in the field of superconductivity, the discovery of new materials with better properties, commercialization of these materials, and regarding ...
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As a technology, superconductivity has had a great contribution to the advancement of medical science, electronics, astronomy and transportation. With the improvements in the field of superconductivity, the discovery of new materials with better properties, commercialization of these materials, and regarding the importance of rotary equipment in major industry, trends in research and development of superconducting magnetic bearings is broadened day by day. High efficiency compared to the cost of manufacturing and maintenance of these bearings as well as the increasing need to economic save in key industry, could reinforce the tendency to use these bearings instead of conventional bearings. Superconducting magnetic bearings have various structures, all of which can be used for various applications. In recent decades efforts have been made to design new structures for specific applications. In this paper a general review of magnetic bearings’ history as well as their existing structures is investigated and the theoretical and experimental results have been presented for a studied bearing system.
E. Dehjoo; R. Haghmaram; A. Mosallnejad
Abstract
In this paper, the problem of starting an induction motor is investigated and a solution is presented. The large current and considerable torque pulsation of the starting can damage the motor and other consumers connected to the feed line, and increasing the startup time will cause more heat and damage ...
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In this paper, the problem of starting an induction motor is investigated and a solution is presented. The large current and considerable torque pulsation of the starting can damage the motor and other consumers connected to the feed line, and increasing the startup time will cause more heat and damage to the winding insulators. Various methods exist for startup of the induction motor, including the stator voltage control via wye-delta circuit breaker, autotransformer, and new methods such as soft starter, as well as methods for controlling the rotor's resistance, and control of V/f. However, in this research, by connecting a torsion spring between the motor shaft and the load, a new method of startup has been proposed. Therefore, due to the delay in the rotation of the load during the absorption of energy in the torsion spring it is possible to rotate loads with a torque beyond the motor starting torque, and to reduce the motor startup time as much as 77%. These cases increase the lifetime of the motor, and reduce economic costs.
Abolfazl Halvaei Niasar; Yahya Abdollahi
Abstract
Due to some inevitable restrictions during fabrication of permanent magnet brushless (PMBL) motors, some of them have neither sinusoidal nor trapezoidal back-EMF voltages, that we name them as non-ideal PMBL motors. Employing conventional control strategies of permanent magnet synchronous motors (PMSMs) ...
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Due to some inevitable restrictions during fabrication of permanent magnet brushless (PMBL) motors, some of them have neither sinusoidal nor trapezoidal back-EMF voltages, that we name them as non-ideal PMBL motors. Employing conventional control strategies of permanent magnet synchronous motors (PMSMs) and brushless DC motors (BLDCMs) leads to lower efficiency and performance and causes unwanted torque ripple, vibration and acoustic noises that in unfavourable for special applications. This paper investigates the torque response of non-ideal PMBL motor while is controlled with conventional control strategies and presents a novel torque ripple minimization method. Simulation results indicate the non-ideal PMBL motor by novel proposed method develops smoother torque and lower torque ripple rather than all mentioned control strategies.
R. Alipour-Sarabi; Z. Nasiri-Gheidari; H. Oraee
Abstract
Resolvers, as magnetic position sensors, are increasingly used in motion-control systems. Due to electro-magnetic structure, they preserve more accurate and reliable operation than optical encoders in stressful conditions. Usually, to evaluate the performance of a resolver, total harmonic distortion ...
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Resolvers, as magnetic position sensors, are increasingly used in motion-control systems. Due to electro-magnetic structure, they preserve more accurate and reliable operation than optical encoders in stressful conditions. Usually, to evaluate the performance of a resolver, total harmonic distortion (THD) of output signals is calculated. In this study, by using analytical expressions, it is shown that THD of output signal is not a reliable indicator of the performance of a resolver.
Ali Khaksari; A. Rezazadeh; Majid Ebadifard
Abstract
This paper deals with the problem of designing a robust dynamic output feedback controller for the wind machine. This paper for the first time exploits the designing controller problem of the wind turbines in the presence of time varying delay and uncertain parameters. In this paper, a novel algorithm ...
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This paper deals with the problem of designing a robust dynamic output feedback controller for the wind machine. This paper for the first time exploits the designing controller problem of the wind turbines in the presence of time varying delay and uncertain parameters. In this paper, a novel algorithm is proposed which designs a proper controller based on the idea of Lyapunov Krasovskii functional and Finsler’s Lemma. To validate the result of the proposed algorithm, comparative simulation examples are given which are two different dimension turbines to investigate the performance of the design methodology as compared to those of previous approaches.
Alireza Rahimi; Khalil Kanzi
Abstract
In this paper, a physics-based analytical method is proposed in order to model the frequency behavior of laminated iron-core permanent magnet synchronous motor (PMSM). The proposed model consists of frequency-dependent lumped circuit parameters representing two parts; Iron-core and stator winding. These ...
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In this paper, a physics-based analytical method is proposed in order to model the frequency behavior of laminated iron-core permanent magnet synchronous motor (PMSM). The proposed model consists of frequency-dependent lumped circuit parameters representing two parts; Iron-core and stator winding. These frequency-dependent components represent the skin effect and proximity effect in conductors and eddy-currents effect in the core. The total parasitic capacitance is considered to be frequency-independent and estimated from measured impedance characteristics of the PMSM. In order to verify the accuracy of the proposed model, we compared the equivalent AC resistance and AC inductance of one phase of a counter-rotating PMSM calculated from the proposed analytical method with the 3D finite element analysis (FEA) results. Finally, the Impedance characteristic of the test PMSM calculated using the proposed method is verified by the impedance measurement data, which shows a good agreement. The method proposed in this paper can be used for modeling various high-frequency issues in variable speed drives (VSDs) such as electromagnetic interference (EMI), common-mode bearing currents, and long-cable effects on motor terminals.
Zhanna Gabbassova; Davoud Sedighizadeh; Alireza Sheikhi Fini; Mostafa Seddighizadeh
Abstract
Extending multiple robot motion planning in unknown workspaces is a interesting scope in the Robot motion planning that in this paper is considered. It is used from radiation robots sensors in order to detect their surroundings and positions of the other robots. In this article a new approach considering ...
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Extending multiple robot motion planning in unknown workspaces is a interesting scope in the Robot motion planning that in this paper is considered. It is used from radiation robots sensors in order to detect their surroundings and positions of the other robots. In this article a new approach considering two objectives is introduced. Finding safest path is as the first objective. The second objective is achieving a trajectory with minimum length. For finding the safest path, it is used from Voronoi Diagram (VD). To provide the safest path, minimizing the distance to the VS is as important criterion. Due to the VD is a geometric location with a distance from all obstacles to the workspace, therefore it is can be a suitable criteria for finding the safest path. For achieving the shortest path as the secondary objective, it is applied Euclidean distance the current position of the robot to goal position. Algorithm that applied for solving this problem is particle swarm optimization (PSO).
hosein salmani; ali reza rezazadeh
Abstract
In recent years, increasing of the non-dispatchable resources has posed serious challenges to day-ahead generation scheduling of the power system. Since these resources are random in nature, the issue of flexibility to cover the uncertainty and variability of those has become an important research topic. ...
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In recent years, increasing of the non-dispatchable resources has posed serious challenges to day-ahead generation scheduling of the power system. Since these resources are random in nature, the issue of flexibility to cover the uncertainty and variability of those has become an important research topic. Therefore, having flexible resources to cover changes in the generation of this resources during operation can play an important role in eliminating node imbalances, system reliability, providing the required flexible ramping reserve and reducing system operating costs. Among these flexible sources, we can mention fast-response dispatchable generation units such as gas units and combined cycle units. Therefore, in this paper, a mixed-integer two-stage and tri-level adaptive robust optimization has been used, which is solved by column-and-constraint generation decomposition-based algorithm in order to jointly clearing the energy and ramping reserve with the presence of fast response and flexible resources. The simulation results show the efficacy of the proposed model.
Modeling, analysis and design of electromechanical systems
Amirhossein Koushki; Zahra Nasiri Gheidari
Abstract
Coreless Permanent Magnet (CPM) machines are increasingly used in many industrial applications, such as automotive and aerospace applications, wind turbines, medical equipment, robotics, servo drives, and so on. In coreless permanent magnet DC machines, the rotor has a coreless winding structure and ...
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Coreless Permanent Magnet (CPM) machines are increasingly used in many industrial applications, such as automotive and aerospace applications, wind turbines, medical equipment, robotics, servo drives, and so on. In coreless permanent magnet DC machines, the rotor has a coreless winding structure and due to the absence of an iron core, the permanent magnet plays a significant role in these machines. Also, the shaft’s material can change the flux distribution and is another effective parameter on machine performance. Thus, in this paper, a typical coreless PMDC brushed machine is simulated and the effects of magnetization direction and the amount of the residual flux density of permanent magnet, and also the influence of ferromagnetic and non-ferromagnetic material of the shaft on machine performance, are studied and analyzed through three-dimensional finite element analysis. The results show that using a ferromagnetic shaft with a diametrical magnetized permanent magnet can improve the machine's performance in motor mode.
Modeling, analysis and design of electromechanical systems
Hamed Tahanian; Ahmad Darabi
Abstract
Magnetic hysteresis affects the performance of electromagnetic devices, e.g., motors, generators, and transformers. However, due to complex, non-linear, and multi-valued nature of this phenomenon, its accurate coupling to Finite Element Analysis (FEA) of these devices has been always a challenging task. ...
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Magnetic hysteresis affects the performance of electromagnetic devices, e.g., motors, generators, and transformers. However, due to complex, non-linear, and multi-valued nature of this phenomenon, its accurate coupling to Finite Element Analysis (FEA) of these devices has been always a challenging task. A novel approach has been presented in this paper for linking FEA to the Preisach model, which is known as the most accurate hysteresis model. An individual Preisach module has been considered for each field component of each element of the hysteresis material mesh. Hysteresis characteristics between each two successive time steps have been linearly approximated. An iterative algorithm has been proposed for obtaining field distributions along with parameters of these lines, simultaneously. The proposed method has been applied to a general magnetic circuit to predict its behavior over a given time span. Space distributions of flux density at some time steps, time variations of flux density and field intensity for one element, induced voltage, and hysteresis characteristics for some elements have been obtained. In contrast with most previous works, approach of this paper could reflect the details of hysteresis phenomenon, including minor loops, into the FEA. Also, it is applicable to problems with non-uniform and rotating field distributions.
Mohsen Atash Ab-Parvar; Hamed Hekmati; Alireza Siadatan; Mehdi Bigdeli; Arsalan Hekmati; Mehdi Bagheri
Abstract
Wind power as a renewable energy has the potential to become a clean energy source in almost all countries of the world but, there are lots of technical challenges that need to be addressed in advance. Wind speed variation (WSV) is one of the most important issues. Separate from its mechanical effects ...
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Wind power as a renewable energy has the potential to become a clean energy source in almost all countries of the world but, there are lots of technical challenges that need to be addressed in advance. Wind speed variation (WSV) is one of the most important issues. Separate from its mechanical effects on wind turbines (WTs), it causes electrical power variations on WT as well. Doubly Fed Induction Generators (DFIGs) and Maximum Power Point Tracking (MPPT) system have been helpful so far but some problems such as inertia still needed to be solved. Inertia in the WTs causes a delay on MPPT. This paper proposes a novel method to increase WTs output power in which a DFIG equipped with an energy storage system such as Ultra-capacitor helps MPPT system to track the wind variations rapidly by absorption or injection energy during the wind changes. The ultra-capacitor and control system are modeled and simulated in Matlab/Simulink® environment. The simulation results proofs that the proposed system can improve electrical power and increase electrical energy during WSVs. The simulation model will lead to more penetration of wind power and also enables engineers to optimize the system.
Control of Electromechanical systems
Ali Abdul Razzaq Altahir
Abstract
An electric drive controller for AC microgrids with renewable energy sources is a system that controls the flow of electricity in an alternating current (AC) microgrid. The role of distributed generation in the electricity industry has been expanding in recent years. Distributed (DGs) are small, scalable ...
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An electric drive controller for AC microgrids with renewable energy sources is a system that controls the flow of electricity in an alternating current (AC) microgrid. The role of distributed generation in the electricity industry has been expanding in recent years. Distributed (DGs) are small, scalable units, generally with a capacity of less than 10 MW which can be connected to the grid, distribution feeders or customer levels. Nowadays, the high penetration of distributed resources in power systems is increasing. Since these units can play an important role in electricity markets and provide ancillary services for system operators, integrating these resources within power systems has been considered. Therefore, this paper focuses on modelling, designing and simulating a suitable controller to ensure AC microgrids stability and stable performance (AC M.G) in both grid-connected and islanded modes. Meanwhile, all simulations have been fulfilled in MATLAB environment. After designing the controllers and ensuring the performance of their frequency response using the bode diagram and the system step response, these controllers were used to command the voltage and current in real scenarios. After applying the controllers, the performance has dramatically improved in the voltage and current controller presence. As a result, the controller can be programmed to respond into changes in the energy supply and demand, adjusting the output of the green resources and managing energy storage systems within the microgrid. This allows the system to operate in a stable and sustainable manner, even when there are fluctuations in the energy supply or demand.
monire taghvaei; nasim nayebpashaee
Abstract
RTV silicone rubber offers excellent high and low temperature resistance as well as UV and weathering resistance and has a bright future in the aerospace and electronics industries. On the other hand, the thermal decomposition behavior of polymeric materials significantly affects their aging process ...
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RTV silicone rubber offers excellent high and low temperature resistance as well as UV and weathering resistance and has a bright future in the aerospace and electronics industries. On the other hand, the thermal decomposition behavior of polymeric materials significantly affects their aging process and there are many studies on improving the specifications of nanocomposites by adding different types of nanoparticles. In this work, silicone rubber RTV nanocomposites with low content of modified nano-ZnO particles and pure RTV were compared in terms of their degradation behavior by heat and electrical stress. The coatings were prepared and the products were subjected to various experimental tests, including thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR) analysis. The TGA results of the study suggest that the residual weight of the aged samples is higher than that of the unaged samples. The FTIR analysis results show that the aging performance of Nano-RTV is better than that of RTV, which is concluded from the smaller absorption area of the functional groups of Si-CH3 and Si-O-Si. The numeric value of Critical flashover voltage in Nano-RTV coating was higher compared to the RTV coating as a result of the enhanced electrical insulation characteristics. This can confirm the improvement of thermal aging of Nano RTV compared to pure RTV and may prove useful to estimate the expected lifetime of the coatings, which is valuable for estimating the reliability of porcelain insulators
Modeling, analysis and design of electromechanical systems
Mehdi Aliahmadi; Alireza Ghaempanah; Javad Faiz
Abstract
Increasing loading without comparable change in the size of synchronous generators, causes end-winding force estimation become important. Therefore, design of an appropriate support to protect windings deterioration and damages by the above mentioned forces is critical. In slot-embedded portion of coils, ...
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Increasing loading without comparable change in the size of synchronous generators, causes end-winding force estimation become important. Therefore, design of an appropriate support to protect windings deterioration and damages by the above mentioned forces is critical. In slot-embedded portion of coils, the forces could be adjusted by teeth and slot wedges. Normally, the ends of coils have no external support and it is necessary to provide it. Synchronous generators have been considered reliable if accurate end winding forces are evaluated and taken into account in the design process of the external support. The topic based on the current literature is reviewed. Structure of end windings and different analytical and numerical techniques for forces estimation are discussed. The current state of the art is reviewed and more successful developments are introduced. At the end, the area of research which needs more attention in the future to advance the subject is identified.
Ali Asghar Sarabadani; reza latifi; ali reza rezazadeh
Abstract
The increasing growth of the technology and industry of electric propulsion, and consequently the growth of the industry of electric energy storage systems, including batteries, have raised challenges such as optimizing the charging process and storage of electric energy. One of the important factors ...
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The increasing growth of the technology and industry of electric propulsion, and consequently the growth of the industry of electric energy storage systems, including batteries, have raised challenges such as optimizing the charging process and storage of electric energy. One of the important factors in optimizing the charging process is reducing the time interval. Hence, today, topologies such as fast charging and stations equipped with this topologies are expanding. Quick charging topologies reduce the length of the charging process by optimizing the electric charge circuit and optimizing the design of switching elements and its control system. This paper first examines the electric vehicle charging system in terms of the standards that classify the input voltage level as well as the technologies that increase the flexibility and efficiency of the electric vehicle charging system. Technologies such as unidirectional and bi-directional charging system, inductive and conductive charging system, integrated and non-integrated systems are presented and discussed in this article. In the second step, these systems are transformed into switching components and features such as the possibility of development with renewable energy production systems, the possibility of injecting power from the electric vehicle energy storage system into the power grid to provide part of the power required at peak demand and also The complexity and multiplicity of key elements have been examined and compared.
Modeling, analysis and design of electromechanical systems
Amin Nobahari; Antti Lehikoinen
Abstract
Finite element (FE) method, is the most popular numerical approach to low-frequency electromagnetic modeling, especially in the field of electrical machines. Although FE method is nowadays widely used by experts, still it can find widespread efforts toward additional developments that make it more applicable ...
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Finite element (FE) method, is the most popular numerical approach to low-frequency electromagnetic modeling, especially in the field of electrical machines. Although FE method is nowadays widely used by experts, still it can find widespread efforts toward additional developments that make it more applicable to various problems. This paper takes a look at the state of the arts in the electromagnetic modeling of electrical machines via FE analysis. The addressed subjects cover new techniques for loss calculation in electrical machines, the state of art toward more efficient computation, which is a serious challenge for numerical methods, and modeling efforts for the hysteresis phenomenon. The paper tries to address a portion of the recent hot topics of FE analysis of electrical machines. The authors believe that the paper will give a brief but useful insight into the challenges and developments of FE applications in electrical machine analysis, as the most practical numerical tool in this area.
Hassan Ebrahimirad
Abstract
Nowadays, increasing energy efficiency is the economical and fastest way to generate electricity in the world. Therefore, the importance of energy saving has been considered for many years in Iran, but the allocation of subsidies to energy production sector has led to the lack of a logical and specific ...
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Nowadays, increasing energy efficiency is the economical and fastest way to generate electricity in the world. Therefore, the importance of energy saving has been considered for many years in Iran, but the allocation of subsidies to energy production sector has led to the lack of a logical and specific solution to reduce energy consumption and is still one of the main challenges in Iran's economy since paying insufficient attention to energy saving in all applications. Due to the climate of Iran, the use of evaporative coolers for cooling and air conditioning is very common in summer, but installed electromotors in these coolers are one of the high-consumption equipment in peak hours which the upgrade of them can have a significant impact on reducing the peak of energy consumption in the country. From this point of view, Brushless DC (BLDC) motors, as high-efficiency electromotor type, have been investigated for evaporative cooler application.In this paper, the technology development procedure of these BLDC motors for evaporative coolers in the country is presented and at the end, the results of production of this type of electromotors by seven domestic companies and their operation these coolers are presented.
Seyed Reza Mortezaeei; Mahmood Hosseini Aliabadi; Shahram Javadi
Abstract
The purpose of this paper is to present an Analytical Predict the Electromagnetic Field Density in surface mounted permanent magnet synchronous motors based on a subdomain field model. In this paper, which is one of a series of four, a 2-d analytical method for predicting field distribution in one SMPMSM ...
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The purpose of this paper is to present an Analytical Predict the Electromagnetic Field Density in surface mounted permanent magnet synchronous motors based on a subdomain field model. In this paper, which is one of a series of four, a 2-d analytical method for predicting field distribution in one SMPMSM is presented. In the presented method, Maxwell’s equations have been solved in different regions in pseudo-Cartesian coordinates system taking into account the non-homogeneous boundary conditions. The domain of the magnetic field is divided into four subdomains, viz. magnets, air gap, stator core and outer region. The governing equations and the boundary conditions to the interfaces between these subdomains are formulated in polar coordinate. The analytical prediction is validated by corresponding finite-element method. In future articles, we intend to study the effect of eccentricity on the distribution of magnetic fields in all areas of the motor at one slot less permanent magnet motor.
Hossein Azizi Moghadam; Masood Saeidi; Abolfazl Vahedi; omid Rezaei; Shervin Salehirad
Abstract
synchronous reluctance motors are among the most popular electric motors today, due to their relatively good features, but the important thing to consider about these motors is to calculate and estimate their rotor position, and failure to do so may cause damage in their control system. Therefore, many ...
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synchronous reluctance motors are among the most popular electric motors today, due to their relatively good features, but the important thing to consider about these motors is to calculate and estimate their rotor position, and failure to do so may cause damage in their control system. Therefore, many methods such as sensorless, hall-effect, GMR, encoder, etc. were used to compute and estimate the rotor position, each of which has its own advantages and disadvantages. Besides, in many articles, the effect of positional error and the effect of this error on the control system and the method of dealing with this chronic problem are not analytically stated, and only this phenomenon has been studied in operation. Whereas, in this paper, firstly, a variety of conventional methods available for estimating and calculation the rotor position of synchronous reluctance motors briefly is introduced, and then investigated the effect of the error on the control system and at the end, the results of simulation and mathematical analyzes the impact of this error on the control system is presented.
iman sadeghi
Abstract
This paper contains an investigation about using electric buses alternatively in a BRT line in Tehran. In order to reach this purpose driving cycle of electric bus for different bus routes are simulated and studied. Also with the aim to choose the pilot route, several criteria such as, air and noise ...
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This paper contains an investigation about using electric buses alternatively in a BRT line in Tehran. In order to reach this purpose driving cycle of electric bus for different bus routes are simulated and studied. Also with the aim to choose the pilot route, several criteria such as, air and noise pollution, traffic characteristics, numbers of passengers on each route have been considered. Hence, Azadi terminal to Tehran-Pars intersection route has been selected. In addition, characteristics and specifications of proposed propulsion and energy storage system based on driving cycle simulation results of different routes in Tehran are determined.In this study, designing a storage system (battery) and main characteristics including total capacity and battery capacity based on the amount of daily activity, number of daily round trips, average energy consumption of the route and daily electrical power consumption of each bus and the battery charging and discharging ranges and total inverter and motor efficiency will be determined.
Control of Electromechanical systems
Mohsen Dashtbani; Majid Hasanzadeh; Reza Roshanfekr
Abstract
The conventional direct torque control (DTC) method suffers a flux drop at low speeds, which is due to the long selection of zero (neutral) voltage vectors in these speed areas. Past studies with the continuous switch of direct and reverse active vectors to achieve proper flux adjustment, this procedure ...
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The conventional direct torque control (DTC) method suffers a flux drop at low speeds, which is due to the long selection of zero (neutral) voltage vectors in these speed areas. Past studies with the continuous switch of direct and reverse active vectors to achieve proper flux adjustment, this procedure causes high and consecutive overshoots in the hysteresis band that causes a sharp increase in the switching frequency and increase in the torque and current ripple, which means decrease in the drive efficiency. In this article, a modified method for setting the standard DTC current is introduced, which can be achieved by controlling only one band (low or high band) at low speeds. The introduced method by reducing the selection of zero voltage vectors and at the same time minimizing the number of reverse voltage vectors prevents the loss of flux in low speed areas. In addition, it is effective in reducing torque ripple and current in low speed mode and a significant reduction in switching frequency will also be achieved. The effectiveness of the proposed method in the simulation which is done in MATLAB software will be proved.
Hasan Mashayekh; Alireza Rezazadeh
Abstract
An accurate estimation of battery model parameters is essential for dynamic simulation of electric vehicles. Generally, parameterizing battery models are difficult and complex. Therefore it requires powerful estimation algorithms to overcome time-consuming and computational costs. In this paper, the ...
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An accurate estimation of battery model parameters is essential for dynamic simulation of electric vehicles. Generally, parameterizing battery models are difficult and complex. Therefore it requires powerful estimation algorithms to overcome time-consuming and computational costs. In this paper, the dynamic parameters of a battery model were estimated at 8 different temperatures and under the hysteresis effect. The estimation is based on a hybrid algorithm of particle swarm optimization and grey wolf optimizer. By this hybridization the ability of exploitation in particle swarm optimization and the ability of exploration in grey wolf optimizer improved and both variants were empowered. The algorithm was implemented to estimate parameter values by minimizing the error between experimental data and the predicted results to find an optimal solution for an accurate model. Following a comparison with G.Plett’s, the results indicated that the proposed algorithm can reach higher precision in the battery behavior because of the lower error possibility.
Mahmudreza Changizian; abbas Shoulaie
Abstract
Abstract—The starting-up strategy is an important issue for voltage source convert-high voltage direct current (VSC-HVDC) system. If a VSC-HVDC system starts up without any auxiliary system or improved control system, overvoltage and inrush current will occur. This large overvoltage can cause serious ...
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Abstract—The starting-up strategy is an important issue for voltage source convert-high voltage direct current (VSC-HVDC) system. If a VSC-HVDC system starts up without any auxiliary system or improved control system, overvoltage and inrush current will occur. This large overvoltage can cause serious damage on the DC capacitors and this large inrush current at turn-on may destroy the switches in converter. Starting-up VSC-HVDC has two steps. In this paper, starting-up steps in a three-phase two-level VSC-HVDC system is studied with details. The effect of capacitor and inductor sizes and also circuit breaker closing time on overvoltage and inrush current in first step are investigated attentively. Possible methods for control overvoltage and inrush currents during this step are presented, and a comparison has been made between them in terms of power dissipation and cost. Eventually, the best auxiliary starting-up system is selected in terms of costs. In addition, the second step of starting-up is also examined and the circuit performance for increasing the DC link voltage is described in this step. Also, a simple control method is proposed for controlling the inrush current in second step. This method controls the inrush current without imposing additional costs and losses on the system. Substantial simulations conducted on PSCAD/EMTDC platform. It is worth mentioning this paper is an extended version of the paper accepted at the 34th Power System Conference (PSC 2019).
Modeling, analysis and design of electromechanical systems
Alireza Sheikhi Fini
Abstract
Iran is one of the known countries that has unfavorable energy efficiency, therefore the policy makers of the country have put the correction of this situation on the agenda. This paper has been compiled to review and study the basics of the road map for the development of high-efficiency building technologies ...
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Iran is one of the known countries that has unfavorable energy efficiency, therefore the policy makers of the country have put the correction of this situation on the agenda. This paper has been compiled to review and study the basics of the road map for the development of high-efficiency building technologies and to present a picture of the current state of these technologies in the country. In this paper, the necessity and importance of these technologies and the necessity of developing a road map for this development are expressed. Gathering all the upstream documents in the field of these technologies, the current state of the technology and its characteristics, actors and stakeholders are examined. The strengths and weaknesses in the country for the development of energy-efficient technologies in the building sector have been identified, then the threats and opportunities caused by external factors (outside the country), which stand in the way of the development of energy-efficient technologies in the building sector inside the country, has been studied. A drawing of the existing situation is also provided. This article is useful and effective for policymakers and planners, managers and officials, researchers and academics, industrialists and builders, and in other words, all stakeholders in the field of electricity industry.
