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Frontiers of Electrical and Electronic Engineering

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ISSN (Print) 2095-2732 - ISSN (Online) 2095-2740
Published by Springer-Verlag

[2218 journals]

New compact UWB microstrip-fed printed planar antenna for wireless applications
- Abstract: Abstract A proposed circular patch antenna with notchcut fed by a simple microstrip line is described in this paper. It is designed for ultra-wideband (UWB) wireless communications and applications over the band 3.1–10.6 GHz. This antenna consists of a circular patch with notchcut fed by a microstrip line, one transition step, and a partial ground plane. The 2:1 voltage standing wave ratio (VSWR) bandwidth (S 11< − 10 dB) of the proposed antenna covers the entire UWB application range specified by Federal Communications Commission (FCC) that is from 3.1 to 10.6 GHz. The proposed antenna is able to achieve an impedance bandwidth about 8.6 GHz (2.4–11 GHz). The return loss, VSWR, radiation pattern, radiation efficiency, gain, group delay, and current distribution of the proposed antenna are included in this paper. The simulation results and proposed antenna design details are presented by CST Microwave Studio.
  PubDate: 2012-12-01
Improving power system dynamic performance using attuned design of dual-input PSS and UPFC PSD controller
- Abstract: Abstract The objective of this work is the coordinated design of controllers that can enhance damping of power system swings. With presence of flexible AC transmission system (FACTS) device as unified power flow controller (UPFC), three specific classes of the power system stabilizers (PSSs) have been investigated. The first one is a conventional power system stabilizer (CPSS); the second one is a dual-input power system stabilizer (dual-input PSS); and the third one is an accelerating power PSS model (PSS2B). Dual-input PSS and PSS2B are introduced to maintain the robustness of control performance in a wide range of swing frequency. Uncoordinated PSS and UPFC damping controller may cause unwanted interactions; therefore, the simultaneous coordinated tuning of the controller parameters is needed. The problem of coordinated design is formulated as an optimization problem, and particle swarm optimization (PSO) algorithm is employed to search for optimal parameters of controllers. Finally, in a system having a UPFC, comparative analysis of the results obtained from application of the dual-input PSS, PSS2B, and CPSS is presented. The eigenvalue analysis and the time-domain simulation results show that the dual-input PSS & UPFC and the PSS2B & UPFC coordination provide a better performance than the conventional single-input PSS & UPFC coordination. Also, the PSS2B & UPFC coordination has the best performance.
  PubDate: 2012-12-01
Multi-objective allocation of measuring system based on binary particle swarm optimization
- Abstract: Abstract Due to the size and complexity of power network and the cost of monitoring and telecommunication equipment, it is unfeasible to monitor the whole system variables. All system analyzers use voltages and currents of the network. Thus, monitoring scheme plays a main role in system analysis, control, and protection. To monitor the whole system using distributed measurements, strategic placement of them is needed. This paper improves a topological circuit observation method to minimize essential monitors. Besides the observability under normal condition of power networks, the observability of abnormal network is considered. Consequently, a high level of system reliability is carried out. In terms of reliability constraint, identification of bad measurement data in a given measurement system by making theme sure to be detectable is well done. Furthermore, it is maintained by a certain level of reliability against the single-line outages. Thus, observability is satisfied if all possible single line outages are plausible. Consideration of these limitations clears the role of utilizing an optimization algorithm. Hence, particle swarm optimization (PSO) is used to minimize monitoring cost and removing unobservable states under abnormal condition, simultaneously. The algorithm is tested in IEEE 14 and 30-bus test systems and Iranian (Mazandaran) Regional Electric Company.
  PubDate: 2012-12-01
A broadband helical loaded square cavity back antenna array
- Abstract: Abstract In this paper, a fundamental advancement of the basic helix design which expands to array having good bandwidth is proposed. The helix is inserted in a cavity. The result is a new antenna design that offers the performance characteristics and advantages of the conventional helix but in a much more compact physical size envelope. A 4-element rectangular helical array has been designed. For miniaturization and impedance matching, the helical wire is replaced by a rectangular cross sectioned strip. It has been observed that when the helix is inserted in a cavity, it behaves differently from a normal helical antenna. The effects of the cavity on the number of turns, the impedance of total antenna, and the reflection coefficient have been analyzed. The array is designed for 2.4 GHz. The return loss obtained is less than − 10 dB and the bandwidth is more than 1.3 GHz for the array.
  PubDate: 2012-12-01
Experimental investigation on frequency-dependent critical current of HTS tapes
- Abstract: Abstract Based on characteristics of alternating current (AC) critical current of high temperature superconducting (HTS) tapes on the frequency, this paper focuses on AC voltage-current (U-I) behaviors of two kinds of high temperature superconducting tapes, by which BSCCO and YBCO carrying different frequency AC currents are tested in liquid nitrogen temperature of 77 K. It is shown that the AC U-I characteristic curves of different tapes consist of two parts, that is, the resistive part and the hysteresis part. Additionally, the n values of the two parts and the relationship between AC critical current and frequency are obtained through experiments. The experimental results agree with calculated ones well, which is useful for the application of HTS tapes to power technology.
  PubDate: 2012-12-01
Modified sliding mode observer for wide speed range operation of brushless DC motor
- Abstract: Abstract This paper describes an adaptive gain sliding mode observer for brushless DC motor for large variations in speed. Sensorless brushless DC motor based on sliding mode observer exhibits multiple zero crossing in back electromotive force (EMF) which leads to commutation problems at low speed. In this paper, a modified sliding mode observer incorporating a speed component in the estimation of back EMF is proposed. It is found that after incorporating the speed component in the back EMF observer gain, multiple zero crossings at low speeds and phase shift at higher speeds are eliminated. The trapezoidal back EMF observer is implemented experimentally on a digital signal processor (DSP) board. The effectiveness of the proposed method is demonstrated through simulations and experiments.
  PubDate: 2012-12-01
Optimal location of interline power flow controller for controlling multi transmission line: A new integrated technique
- Abstract: Abstract In this paper, an interline power flow controller (IPFC) is used for controlling multi transmission lines. However, the optimal placement of IPFC in the transmission line is a major problem. Thus, we use a combination of tabu search (TS) algorithm and artificial neural network (ANN) in the proposed method to find out the best placement locations for IPFC in a given multi transmission line system. TS algorithm is an optimization algorithm and we use it in the proposed method to determine the optimum bus combination using line data. Then, using the optimum bus combination, the neural network is trained to find out the best placement locations for IPFC. Finally, IPFC is connected at the best locations indicated by the neural network. Furthermore, using Newton-Raphson load flow algorithm, the transmission line loss of the IPFC connected bus is analyzed. The proposed methodology is implemented in MATLAB working platform and tested on the IEEE-14 bus system. The output is compared with the genetic algorithm (GA) and general load flow analysis. The results are validated with Levenberg-Marquardt back propagation and gradient descent with momentum network training algorithm.
  PubDate: 2012-12-01
An improved cooperative spectrum detection algorithm for cognitive radio
- Abstract: Abstract The ability to detect the primary user’s signal is one of the main performances for cognitive radio networks. Based on the multi-different-cyclic-frequency characteristics of the cyclostationary primary user’s signal and the cooperation detection advantage of the multi-secondaryuser, the paper presents the weighted cooperative spectrum detection algorithm based on cyclostationarity in detail. The core of the algorithm is to detect the primary user’s signal by the secondary users’ cooperation detection to the multi-different-cyclic-frequency, and to make a final decision according to the fusion data of the independent secondary users’ detection results. Meanwhile, in order to improve the detection performance, the paper proposes a method to optimize the weight on basis of the deflection coefficient criterion. The result of simulation shows that the proposed algorithm has better performance even in low signal-to-noise ratio (SNR).
  PubDate: 2012-12-01
DSP based fuzzy controller for series parallel resonant converter
- Abstract: Abstract In this paper, digital signal processor (DSP) based fuzzy controller for series parallel resonant converter (SPRC) has been estimated, and the performance of the converter is analyzed by using state space model. The method to predict the steady-state and dynamic performance of the converter with load independent operation has been presented. The proposed converter has been analyzed with the closed-loop and open-loop conditions. The simple form of transfer function for SPRC is developed, and it is used to analyze the stability of the converter with closed-loop operation. The stability analysis of the converter is carried out by using frequency response plan. The fuzzy controller regulates the output voltage with change supply voltage and load disturbance. The controller performance of inductance capacitance inductance — T network (LCL-T) SPRC is compared with inductance inductance capacitance — T network (LLC-T) SPRC through simulation and experimental studies using TMS320F2407 processor.
  PubDate: 2012-12-01
RTDS hardware implementation and simulation of SHAF for mitigation of harmonics using p-q control strategy with PI and fuzzy logic controllers
- Abstract: Abstract The main objective of this paper is to develop PI and fuzzy controllers to analyze the performance of instantaneous real active and reactive power (p-q) control strategy for extracting reference currents of shunt active filters (SHAFs) under balanced, unbalanced, and balanced non-sinusoidal conditions. When the supply voltages are balanced and sinusoidal, both controllers converge to the same compensation characteristics. However, if the supply voltages are distorted and/or unbalanced sinusoidal, these controllers result in different degrees of compensation in harmonics. The p-q control strategy with PI controller is unable to yield an adequate solution when source voltages are not ideal. Extensive simulations were carried out with balance, unbalanced, and non-sinusoidal conditions. Simulation results validate the superiority of fuzzy logic controller over PI controller. The three-phase four-wire SHAF system is also implemented on a real-time digital simulator (RTDS hardware) to further verify its effectiveness. The detailed simulation and RTDS hardware results are included.
  PubDate: 2012-12-01
Co-regulated gene module detection for time series gene expression data
- Abstract: Abstract It is important to detect interaction effect of multiple genes during certain biological process. In this paper, we proposed, from systems biology perspective, the concept of co-regulated gene module, which consists of genes that are regulated by the same regulator(s). Given a time series gene expression data, a hidden Markov modelbased Bayesian model was developed to calculate the likelihood of the observed data, assuming the co-regulated gene modules are known. We further developed a Gibbs sampling strategy that is integrated with reversible jump Markov chain Monte Carlo to obtain the posterior probabilities of the co-regulated gene modules. Simulation study validated the proposed method. When compared with two existing methods, the proposed approach significantly outperformed the conventional methods.
  PubDate: 2012-12-01
Journal title change
- PubDate: 2012-12-01
Experimental verification of chopper fed DC series motor with ANN controller
- Abstract: Abstract In this article an artificial neural network (ANN) has been designed for the control of DC series motor through a DC chopper (DC-DC buck converter). The proportional-integral-derivative (PID)-ANN speed controller controls the motor voltage by controlling the duty cycle of the chopper thereby the motor speed is regulated. The PID-ANN controller performances are analyzed in both steady-state and dynamic operating condition with various set speeds and various load torques. The rise time, maximum overshoot, settling time, steadystate error, and speed drops are taken for comparison with conventional PID controller and existing work. The training samples for the neuron controller are acquired from the conventional PID controller. The PID-ANN controller performances are analyzed in respect of various load torques and various speeds using MATLAB simulation. Then the designed controllers were experimentally verified using an NXP 80C51 based microcontroller (P89V51RD2BN). It was found that the hybrid PIDANN controller with DC chopper can have better control compared with conventional PID controller.
  PubDate: 2012-12-01
Line-start permanent magnet synchronous motors versus induction motors: A comparative study
- Abstract: Abstract Line-start permanent magnet synchronous motors are suitable candidates for substitution of induction motors in many constant-speed applications. This paper compares steady-state and dynamic performances of these motors. The efficiency, power factor, stator currents, and rotor bars currents are considered for steady-state performance analysis whereas the rotor speed, electromagnetic torque, and stator and rotor currents are investigated for dynamic performance analysis. For this purpose, time stepping finite element method is used to analyze the performance of motors in both full-load and no-load conditions. Results demonstrate the superior performance of the line-start permanent magnet synchronous motor in steady-state condition and the improved dynamic performance of the induction motor. Finally, economic calculations indicate that the extra cost of the line-start permanent magnet synchronous motor with respect to the induction motor is rapidly compensated by energy saving due to a more efficient operation.
  PubDate: 2012-12-01
The fusion of classifier outputs to improve partial discharge classification
- Abstract: Abstract The detection of partial discharge signals and classifying its patterns is an area of interest in the analysis of defects in high voltage cables. This paper investigates a filter-bank based approach to extract frequency domain based features to represent partial discharge signals. By applying the fast Fourier transform, the sampled partial discharge data are mapped into equivalent discrete frequency bins, which are then grouped into N equal sub-bands and also octave sub-bands, each providing N-dimensional features for partial discharge pattern classification. Two classifiers, namely, the support vector machine and the sparse representation classifier, are implemented and their outputs are fused, in order to improve the accuracy of classifying partial discharge. Classification accuracy is also compared with wavelet domain based octave frequency sub-band features.
  PubDate: 2012-12-01
Modeling and optimization of induction cooking by the use of magneto-thermal finite element analysis and genetic algorithms
- Abstract: Abstract Induction cooking has several advantages compared to traditional heating system; however, to obtain best efficiency, it is essential to have an inductor giving homogeneous temperature on the pan bottom. For this aim, we propose a structure of inductor with four throats containing coils and optimize their distribution. In this paper, first we model magneto-thermal phenomenon of the system by a finite element method (FEM) for the mean to determine the distribution of temperature on the pan bottom by taking the nonlinearity of system. This study shows that a temperature distribution is not homogeneous. Second, with the aim to have homogeneous temperature distribution on the pan bottom, the optimal determination of throats distribution and their dimensions is obtained by genetic algorithms (GAs). The optimized structure permits to satisfy our aim.
  PubDate: 2012-09-01
Time-varying optimal distributed fusion white noise deconvolution estimator
- Abstract: Abstract White noise deconvolution has a wide range of applications including oil seismic exploration, communication, signal processing, and state estimation. Using the Kalman filtering method, the time-varying optimal distributed fusion white noise deconvolution estimator is presented for the multisensor linear discrete time-varying systems. It is derived from the centralized fusion white noise deconvolution estimator so that it is identical to the centralized fuser, i.e., it has the global optimality. It is superior to the existing distributed fusion white noise estimators in the optimality and the complexity of computation. A Monte Carlo simulation for the Bernoulli-Gaussian input white noise shows the effectiveness of the proposed results.
  PubDate: 2012-09-01
New classes of sequence families with low correlation by using multiplicative and additive characters
- Abstract: Abstract For an odd prime p, a new sequence family of period p m − 1, size (M − 1)p mr is proposed using multiplicative and additive characters. The upper bound for the maximum magnitude of nontrivial correlations of the sequence family is derived using well-known character sums. The upper bound is shown to be $(r + 1)\sqrt {p^m } + 3$ , which meets the Welch bound asymptotically.
  PubDate: 2012-09-01
Artificial neural network approach for analyzing mutual coupling in a rectangular MIMO antenna
- Abstract: Abstract Awideband rectangular patch antenna resonating at 3.5 GHz and 8 GHz frequencies is developed on a flexible substrate, which can be used for wearable applications. The proposed antenna gives a wide impedance bandwidth of 116%, operating from 2.5 GHz to 9.5 GHz, covering most of the ultra-wideband (UWB) operating frequency range. A two-element multiple-input multiple-output (MIMO) system is developed using the proposed antenna, and the mutual coupling between the two antennas for various separations and frequencies is analyzed by using artificial neural networks (ANNs). The neural structure is trained by using different ANN algorithms and a comparative study is made between them. It is shown that, quasi-Newton (QN) and quasi-Newton multi layer perceptron (QN-MLP) algorithms are better in terms of training, testing errors, and correlation coefficient.
  PubDate: 2012-09-01
Progress in research on ice accretions on overhead transmission lines and its influence on mechanical and insulating performance
- Abstract: Abstract Atmospheric ice accretion on transmission lines is of great danger to the security of service of electrical power system. This paper reviews the progress in research dealing with the formation of ice accretions on transmission lines and the effects of ice on the mechanical and electrical performance of transmission lines. The results show that ice accretions on transmission lines can be categorized into five types: glaze, hard rime, soft rime, hoar frost, and snow and sleet. In all types of ice accretions, glaze grown in a wet regime is of the greatest danger to the transmission lines. Meteorological conditions, terrain and geographic conditions, and some other factors significantly influence the ice accumulation speed and the ice amount. Drastic decrease of mechanical property and electric property as a result of severe icing is the main reason for ice accidents. The amount of ice, the asymmetrical ice accretion, and the asynchronous ice shedding can considerably change the conductor strain, conductor sag, variation amount of the span, displacement of the insulator string, and the tension difference. The amount and type of ice, the uniformity of ice accumulation, and the conductivity of freezing water have significant influence on the flashover voltage of ice-covered insulators.
  PubDate: 2012-09-01