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Electrical and Electronic Engineering - Volume:17 Issue: 4, Dec 2021

Iranian Journal of Electrical and Electronic Engineering
Volume:17 Issue: 4, Dec 2021

  • تاریخ انتشار: 1400/04/12
  • تعداد عناوین: 13
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  • M. Ghotbi-Maleki, R. Mohammadi Chabanloo* Page 1733

    Expansion of power system causes short-circuit currents (SCC) of networks to exceed the tolerable SCCs of equipment. The utilization of fault current limiter (FCL) in such networks is needed to address this issue. This paper presents a new method for optimal allocation of FCLs to restrain the SCCs under permissible value. In this method, it is suggested to select a line as FCL location where the addition of FCL to this line will have the greatest impact on reducing the SCC of buses which their SCCs exceed the permissible value (known as exceeded buses). Since the optimization algorithms are not capable for optimal allocation of FCL especially in large networks, therefore, the proposed FCL allocation method is presented in the form of a computational process. In this computational process, the candidate lines for FCL location are firstly prioritized by a new index based on the effect of location of FCL on the reduction of SCCs. Then, the FCL size is determined by solving a quadratic equation firstly presented in this paper. The proposed method is implemented on networks with different sizes, and the obtained results show the performance of the proposed method over previous FCL allocation methods.

    Keywords: Fault Current Limiter, Impedance Matrix of Network, Optimal Location, Optimal Size, Sensitivity Analysis, Short-Circuit Current
  • S. A. Karimi, S. Mirzakuchaki* Page 1750

    Various methods have been proposed to detect the attention and perception of an operator during tasks such as radar monitoring. Due to the high accuracy of electroencephalographic signals, it is utilized for systems based on brain signal. The event-related potential (ERP) technique has been widely used for testing theories of perception and attention. Brain-computer Interface (BCI) provides the communication link between the human’s brain and an external device. In this article, we propose a method to investigate the attention of operators of very sensitive monitoring devices, in particular, the operators of navy ships’ radars in detecting fighter aircrafts. Using a Visual Stimuli, which was shown to the subjects prior to the test, the protocol utilized in this paper yielded a very high accuracy (up to 87%), which makes it a robust method to use in such conditions. Linear LDA and non-linear SVM classifiers were utilized in processing the output signal. Although several P300 systems have been used to detect attention using pattern recognition techniques, the novelty of this study is that attention detection is used for the first time for a radar operator which resulted in acceptable accuracy.

    Keywords: P300, Event-Related Potential, Radar, Visual Stimuli, Attention
  • A. Ghayebloo*, S. Shiri Page 1856

    In this paper, a conceptual study on switching intervals in the classic direct torque control (DTC) method and a novel modified method have been proposed. In the switching table of classic DTC, the switching vectors have been changed in sectors with 60 degrees intervals and their boundaries are fixed. In this study, these fixed boundaries and length of switching intervals have been challenged and proved that the performance of the classic DTC can be improved with modified intervals with different lengths and boundaries. The final proposed switching table not also benefits simplicity of implementation as classic DTC switching table, but also it offers better performance especially in the aspect of low torque ripples. The proposed final switching table has been derived by a two-stage optimization process and the results have been proved by simulation results.

    Keywords: Classic DTC, Switching Intervals, Optimality Aspects, Induction Motor
  • F. Amiri, M. H. Moradi* Page 1912

    In this paper, a coordinated control method for LFC and SMES systems based on a new robust controller is designed. The proposed controller is used to compensate for frequency deviations related to the power system, to prevent excessive power generation in conventional generators during load disturbances, and to reduce power fluctuations from wind power plants. The new robust controller does not require the measurement of all the power system states and it only uses the output feedback. It also has a higher degree of freedom than the conventional robust controllers (conventional output feedback) and thus it helps improve the system control. The proposed control method is highly robust against load and distributed generation resources (wind turbine) disturbances and it is also robust against the uncertainty of the power system parameters. The proposed method is compared under several scenarios with the coordinated control method for LFC and SMES systems based on Moth Swarm Algorithm-optimized PID controller, the LFC system based on Moth Swarm Algorithm-optimized PID controller with SMES, the coordinated control method for LFC and SMES systems based on Robust Model Predictive Control, and the LFC system based on optimized PID controller without SMES and it puts on satisfactory performance. The simulation was performed in MATLAB.

    Keywords: Robust Controller, Load-Frequency Control, Coordinated Control, Uncertainty of the Power System
  • M. Ahmadinia, J. Sadeh* Page 1927

    In this paper, an accurate fault location scheme based on phasor measurement unit (PMU) is proposed for shunt-compensated transmission lines. It is assumed that the voltage and current phasors on both sides of the shunt-compensated line have been provided by PMUs. In the proposed method, the faulted section is determined by presenting the absolute difference of positive- (or negative-) sequence current angles index, firstly. After determining faulted section, the voltage phasor at the shunt-compensator terminal is estimated via the sound section. The faulted section can be assumed as a perfect transmission line that synchronized voltage and current phasors at one end and voltage phasor at the other end are available. Secondly, a new fault location algorithm is presented to locate the precise fault point in the faulted section. In this algorithm, the location of the fault and the fault resistance are calculated simultaneously by solving an optimization problem, utilizing the heuristic Particle Swarm Optimization (PSO) method. The simulation results in MATLAB/SIMULINK platform demonstrate the high performance of the proposed method in finding the fault location in shunt-compensated transmission lines. The proposed scheme has high accuracy for both symmetrical and asymmetrical fault types and high fault resistance.

    Keywords: Fault Location, Shunt-Compensated Transmission Line, Phasor Measurement Unit (PMU), Fault Section Estimation, Partially Data Available, Particle Swarm Optimization
  • M. Habibzadeh, S. M. Mirimani* Page 1931

    The role of energy management in hybrid and electric vehicles (EVs) is an important concern to enhance operational performance and provide the defined efficiency targets in transportation. The power conversion stage as an interface between storage units and the DC-link of the three-phase inverter forms a major challenge in EVs. In this study, a control approach for DC-bus voltage, which utilizes a hybrid energy storage system (HESS) for EV applications, has been proposed. A high-energy-density battery pack and an ultra-capacitor, which owns a high-power density, form the hybrid energy storage system. The proposed approach allows full utilization of the stored energy in the storage devices, and also adds a voltage boost feature to the DC-bus. In the proposed control structure, a motor drive based on SVM-DTC is used to track the flux and torque components using regulators with the space vector modulation. The optimal DC-bus voltage can be tracked by incorporating the motor drive stage with a HESS. This integration results in less processed power. This article presents the simulation results toward confirming and verifying the effectiveness of the proposed approach.

    Keywords: Battery, DC, DC Converter, Electric Vehicles, Hybrid Energy Storage System (HESS), Ultra-Capacitor (UC)
  • S. V. Akram, R. Singh, A. Gehlot, A. K. Thakur* Page 1941

    Waste management is crucial for maintaining the hygienic environment in urban cities. The establishment of a reliable and efficient IoT system for waste management is based on integrating low power and long-range transmission protocol. Low Power Wide Area Network (LPWAN) is specially designed for the aforementioned requirement of IoT. LoRa (Long Range) is an LPWAN transmission protocol that consumes low power for long-range transmission. In this study, we are implementing long-range (LoRa) communication and cloud applications for real-time monitoring of the bins. The customized sensor node and gateway node are specifically designed for sensing the level of bins using ultrasonic sensor and communicating it to the cloud via long-range and internet protocol connectivity. Blynk and cayenne are the two cloud-based applications for storing and monitoring the sensory data receiving from the gateway node over internet protocol (IP). The customization of nodes6 and utilization of two cloud-based apps are the unique features in this study. In the future, we will implement blockchain technology in the study for enabling a waste-to-model platform.

    Keywords: ESP 8266 Wi-Fi, LPWAN, LoRa, Ultrasonic Sensor, Waste Management
  • H. Ghonoodi*, M. Hadjmohammadi Page 1992

    In this paper a novel design is presented for a dual-band LC oscillator, using an analytical approach. The core of the proposed circuit contains a cross-coupled CMOS LC oscillator with two serried LC tanks so that the inductors of these tanks have mutual inductance. There are some switches in the circuit that directly changes mutual inductance to produce two different frequencies. This technique increases the oscillation amplitude in the same power consumption that leads to the decrement of phase noise. In other words, using two serried LC tank compensates the injected phase noise from switches. The symmetrical structure is another advantage of the presented design that makes it possible to be used in multiphase oscillator. To assess the quality of the proposed circuit, a dual-band quadrature LC oscillator has been designed to oscillate at 3.6 GHz and 6.4 GHz with 1.5 V supply and 1 mA current consumption, with TSMC 0.18 CMOS practical model. Lastly, simulation results confirm the correctness of analytical results and high proficiency of the proposed design.

    Keywords: Dual Band Oscillator, Phase Noise, RF CMOS, Analysis
  • A. Pathan*, T. Memon Page 2011

    FPGA’s block memory may be programmed as a single or dual-port RAM/ROM module that leads to an area-efficient implementation of memory-based systems. In this contest, various works of carrying out an optimized implementation of simple to complex DSP systems on embedded building blocks may be seen. The multiplier is a core element of the DSP systems, and in implementing a memory-based multiplier, it is observed that one of the operands is kept constant, hence leading the design to a constant-coefficient multiplication. This paper shows Virtex-7 FPGA’s dual-port ROM-based implementation of an 8x8 variable-coefficient multiplier that may be used in several simple to complex DSP applications. The novelty of the proposed design is to configure the block ROM in dual-port mode and, hence, get four partial products in two clock cycles and introduce two unconventional adder approaches for partial product addition. This approach leads to fully resource utilization and the provision of a variable-coefficient multiplier. The work also shows the comparison of proposed architecture with already existing memory-based implementations and concludes the work as a novel step towards the efficient memory-based implementation of multiplier core.

    Keywords: Block Memory, Digital Signal Processing, FPGA, Multiplier
  • A. Karimpour*, A. M. Amani, M. Karimpour, M. Jalili Page 2024

    This paper studies the voltage regulation problem in DC microgrids in the presence of variable loads. DC microgrids generally include several Distributed Generation Units (DGUs), connected to electrical loads through DC power lines. The variable nature of loads at each spot, caused for example by moving electric vehicles, may cause voltage deregulation in the grid. To reduce this undesired effect, this study proposes an incentive-based load management strategy to balance the loads connected to the grid. The electricity price at each node of the grid is considered to be dependent on its voltage. This guide moving customers to connect to cheaper connection points, and ultimately results in even load distribution. Simulations show the improvement in the voltage regulation, power loss, and efficiency of the grid even when only a small portion of customers accept the proposed incentive.

    Keywords: DC Microgrid, Voltage Regulation, Load Management, Variable Energy Price
  • S. A. Rahman*, S. Birhan, E. D. Mitiku, G. T. Aduye, P. Somasundaram Page 2036

    Aim of this paper is to attain the highest voltage sag and swell compensation using a direct converter-based DVR topology. The projected DVR topology consists of a direct converter with bidirectional switches, a multi winding transformer with three primary windings and secondary winding and a series transformer. When voltage swell occurs in a phase, the same phase voltage can be utilized to mitigate the swell as huge voltage exists in the phase where swell has occurred. So it is possible to mitigate an infinite amount of swell. In all the DVR topologies, the converter is only used to synthesize the compensating voltage. The range of voltage sag mitigation depends upon the magnitude of input voltage available for the converter. If this input voltage of the direct converter is increased, then the range of voltage compensation could also be increased. Input voltage of the direct converter is increased using the multi winding transformer. The direct converter is synthesizing the compensating voltage. This compensating voltage is injected in series with the supply voltage through the series transformer and the sag is mitigated. In this proposed topology, the input voltage for the direct converter is increased by adding the three phase voltages using a multi winding transformer. Thus the voltage sag compensating range of this topology is increased to 68% and the swell compensating range is 500%. Ordinary PWM technique has been used to synthesize the PWM pulses for the direct converter and the THD of the compensated load voltage is less than 5%. This topology is simulated using MATLAB Simulink and the results are shown for authentication.

    Keywords: Dynamic Voltage Restorer (DVR), Direct Converter, Bidirectional Switch, Multi Winding Transformer, Ordinary PWM, MATLAB Simulink
  • A. Chaabane*, M. Guerroui Page 2041

    A new design of a Coplanar Waveguide-Fed (CPW) Ultra Wideband (UWB) Rhombus-shaped antenna for Ground Penetrating Radar (GPR) applications is designed and discussed in this work. The antenna has a simple design which is composed by a rhombus-shaped patch and a modified ground plane. The working bandwidth is improved by removing the metal from the upper part of the ground plane surrounding the patch and by introducing a corrugation geometry in the ground plane. The proposed antenna was designed on a low-cost FR4-substrate having a compact size of 0.2721λ0×0.2093λ0×0.0157λ0 at 3.14 GHz. All the simulations were carried out by using the commercially software CST Microwave StudioTM. The simulated results show that the designed antenna covers an UWB extending from 3.14 GHz to 13.82 GHz (125.94%) and indicate excellent radiation performances throughout the operating bandwidth. The measured bandwidth is nearly extending between 3.95 GHz and 13.92 GHz (111.58%). Besides, the antenna bandwidth response was checked in close proximity to a mass of Concrete. The obtained results are satisfactory and assure the efficiency of the designed antenna to work as a GPR antenna.

    Keywords: Ultra Wideband (UWB) Antenna, Rhombus-Shaped Antenna, Ground Penetrating Radar (GPR)
  • J. Sepaseh, N. Rostami*, M. R. Feyzi Page 2043

    A new axial magnetic gear (AMG) with enhanced torque density and reduced cogging torque is proposed in this paper. In the new structure, the direction and width of permanent magnets in high-speed rotor are changed and permanent magnets are removed from the modulator while the low-speed rotor remains unchanged. The torque density of the proposed magnetic gear is enhanced by using an appropriate direction and pole pitch for permanent magnets of high-speed rotor. The proposed AMG is compared with recent structures in the literature with the highest torque density. Three-dimensional (3D) finite element analyses are employed to obtain the cogging torque and torque density. The results of the analysis indicate that not only torque density increases but also cogging torque decreases dramatically.

    Keywords: Coaxial Magnetic Gear, Axial Magnetic Gear, Cogging Torque, 3D Finite Element Method