Showing papers in "Canadian Journal of Electrical and Computer Engineering-revue Canadienne De Genie Electrique Et Informatique in 2019"

A Novel MPPT Method Based on Cuckoo Search Algorithm and Golden Section Search Algorithm for Partially Shaded PV System

Abstract: Partial shading is a common and difficult problem to be solved in a photovoltaic (PV) system. Numerous efforts have been introduced to mitigate this problem. Some commonly used approaches are deploying some metaheuristic (MH) algorithm to track the multiple-peak $P - V$ curve of partially shaded PV system. Cuckoo search (CS) is a new optimization algorithm based on the MH approach. It has been used to solve an optimization problem in many applications, including the maximum power point tracking (MPPT) problem. The CS algorithm performs well in tracking the global maximum power point (GMPP). However, just like any other MH algorithm, there is still a dilemmatic trading between their accuracy and the tracking time needed to find GMPP. This paper proposes a new MPPT algorithm by combining the CS algorithm with golden section search (GSS) to take beneficial features from both the algorithms. To validate the proposed algorithm, it is evaluated with various cases of partial shading. The simulation and experimental results show a noticeable performance improvement compared with the original CS algorithm and other MH algorithms.

Optimal Coordination of Double Primary Directional Overcurrent Relays Using a New Combinational BBO/DE Algorithm

Abstract: The optimal relay coordination (ORC) problem for directional overcurrent relays (DOCRs) has been solved by many conventional and modern optimization algorithms. All these studies were based on the common assumption that all DOCRs are numerical, digital “hardware-based,” static, or electromechanical. Unfortunately, the transition between these technologies does not happen instantaneously, so protection engineers could see different models of these protective relays in some real electric power systems. Moreover, when old electromechanical, static, and digital relays are replaced with the latest state-of-the-art numerical relays, the older relays are kept as backup protective devices. Some called them “primary” and “local-backup” relays, whereas others called them “main-1” and “main-2” relays. The reason behind the second terminology is the chance that the old relays could act ahead of the numerical relays. In this paper, a realistic mathematical model of the ORC problem is formulated and solved using a new hybrid evolutionary algorithm. To judge whether this realistic ORC problem is completely/partially solvable or not, the IEEE 6-bus, 15-bus, and 42-bus test systems are simulated. The results prove that the technique is an effective tool to indicate which relay sets accept/do not accept this double primary relay strategy.

Energy Storage in Distribution System Planning and Operation: Current Status and Outstanding Challenges

Abstract: It is no exaggeration to state that power systems presently undergo a paradigm shift. Driven by an urgent desire to mitigate the effects of global warming and a foreseen end to the world’s fossil fuel resources, an increasing tendency toward renewable energies is fostered by the international community. On the other hand, distributed generation and electric vehicle adoption are altering load nature and profile. Therefore, energy storage (ES) becomes a necessity for its ability to bridge the gap between the dynamically changing supply and demand in addition to other ancillary services it can provide. Meanwhile, advances in smart grid technologies enable escalating the incorporation of new technologies with more efficient control schemes and energy management algorithms. This paper presents an overview on the employment of ES technologies in planning and operation of distribution systems through the literature survey. The problem of sizing and siting ES units in distribution systems is first introduced. The state of the art of the technology is summarized, and some outstanding issues to be addressed through future research are highlighted.

A Review of Self-Seeded RSOA Based on WDM PON

Abstract: The colorless technology has been offered as a solution to decrease the cost in wavelength-division multiplexed passive optical network (WDM PON). The self-seeded reflective semiconductor optical amplifier (SS-RSOA) based on WDM PON has been proved to be a promising solution among colorless operations. In this paper, the principles, transmission limitations, and recent research of SS-RSOA based on the WDM-PON technology are reviewed. This paper aims to provide a broad perspective on the status of the SS-RSOA technology to researchers and application engineers who work with solutions in colorless operations. A list of more than 60 research publications on the subject has also been appended for a quick reference.

A Novel Cost Optimization Method for Mobile Cloud Computing by Capacity Planning of Green Data Center With Dynamic Pricing

Abstract: Due to the large volume of data, high processing time, and power consumption, operators are looking for ways to reduce the energy consumption and subsequently optimize the energy consumption of data centers. Appropriate pricing of services and control of user demands along with considering renewable energy in the data center lead to a reduction in energy consumption of both users and data centers. The proposed methods for simultaneous reduction in the cost of energy consumption and an increase in the number of processed demands in data centers are not very practical. This paper proposed the capacity planning with dynamic pricing algorithm considering different factors in energy consumption reduction in green data centers of the fourth/fifth generation of mobile system networks delivering mobile cloud computing services. The proposed algorithm determines the optimal number of servers and addresses the tradeoff between the cost of operation and the delay of services. A penalty function for cost was derived and various scenarios were designed and different qualities of services were considered using the Lyapunov optimization to set up the simulation environment. The provided results illustrate the efficiency of the proposed scheme and validate the mathematical model.

Dynamic Phasor Modeling of LCC-HVDC Systems: Unbalanced Operation and Commutation Failure

Abstract: This paper develops a dynamic phasor model of a line-commutated converter high-voltage direct current (LCC-HVDC) system that includes unbalanced operation and commutation failure. This model is beneficial in studying the behavior of the HVDC systems under asymmetrical faults, and it complements the conventional transient simulation-based methods. Equally, importantly, the model includes the representation of commutation failure that may arise as a result of severe faults. Due to its selectivity of the considered harmonics, the developed model has markedly less computational intensity than an electromagnetic transient (EMT) simulation model. This gives the model a distinct advantage in the study of large-signal transients of the LCC-HVDC systems, particularly where repetitive simulations are required. Validation of the proposed model is done using a detailed EMT model of the CIGRE monopolar LCC-HVDC benchmark.

Discretization of the Firefly Algorithm for Home Care

Abstract: This paper aims to solve the problem of home-care routing by using a metaheuristic inspired by nature which is the firefly (FF) algorithm. A good discretization and correction of the solution was provided to maintain the advantages of such an algorithm on this combinatorial problem. Even if the problem is only an extension of the vehicle routing problem with time windows (TWVRP), the human aspect hardens it so that any abuse of a constraint can destroy the feasibility or reduce the services quality. Hard constraints concern the precedence between cares and a patient cares synchronization, while soft constraints concern time windows preferences. The problem in this paper also takes into account overtime and the painfulness of home workers. The main purpose is to minimize the routing total duration and to maximize the constraints satisfaction. The results on two examples show that the discrete version of the FF algorithm gives a better total travel time and better satisfies the constraints.

A New Method to Minimize Overall Torque Ripple in the Presence of Phase Current Shift Error for Three-Phase BLDC Motor Drive

Abstract: Torque ripple is always problematic in brushless dc (BLDC) motor drive. It is caused by nonsymmetric commutating phase current rate and phase current shift error. The latter is inevitable even in the latest sensor/sensorless BLDC motor control and drive. In this paper, a simple, robust, and low-cost method of minimizing overall torque ripple in the presence of phase current shift error is presented. It works and manages well to maintain the torque ripple increase within 10% even with 27° phase current shift, compared with more than 25% torque ripple increase without any compensator. The proposed technique is theoretically elucidated in detail, and the performance is verified via MATLAB/Simulink simulation and experiments.

Temperature Estimation and Vibration Monitoring for Induction Motors and the Potential Application in Electrical Submersible Motors

Abstract: Condition monitoring is essential for the reliable operation of induction motors. Temperature estimation serves as a basis for motor protection. Developing accurate and real-time temperature calculation algorithms is critical for thermal and overload protection for induction motors. Vibration monitoring is a widely used approach for induction motors’ fault diagnosis. Vibration signals are usually analyzed by time-, frequency-, or time–frequency-domain signal processing methods. Recent advancement of fault diagnosis by machine learning makes intelligent approaches feasible. Although decades of efforts have been put on condition monitoring of regular induction motors, electrical submersible motors operating in a very unique downhole environment in the oil industry have not received much attention. Currently, electrical submersible motors rely on downhole monitoring tools to transmit temperature and vibration data measured by sensors from downhole to the surface; however, such data are transmitted at a slow rate, and there are no fault diagnosis algorithms in place. An advanced condition monitoring and fault diagnosis method for electrical submersible motors is needed in the near future. In this paper, a literature review is conducted on temperature estimation and vibration monitoring techniques for induction motors, the state-of-the-art methods are summarized, and their potential application in electrical submersible motors are recommended.

Efficient Parallel and Serial Systolic Structures for Multiplication and Squaring Over GF(${2^{m}}$ )

Abstract: In this paper, we present efficient parallel and serial systolic structures for combined multiplication and squaring over GF( ${2^{m}}$ ). The proposed structures have the advantage of computing both modular multiplication and squaring simultaneously for fast execution of modular exponentiation. They share the same hardware components for both operations and this gives them the advantage of saving more space than the case of using a separate structure for each operation. In addition, they have a regular structure and local communication between the processing elements and this makes them more efficient for VLSI implementation. Complexity analysis of the proposed designs and the existing most recent and efficient designs indicates that the proposed serial design has 31.7% lower area-time (AT) complexity than the previously reported most recent serial one. In addition, the proposed parallel design has a significant lower AT complexity over the recent efficient parallel designs by at least 96.9%.

Measurement-Based Characteristic Curves for Voltage Stability and Control at the Point of Interconnection of Wind Power Plants

Abstract: In this paper, the measurement-based characteristic curves, reactive power–voltage ( $Q$ – $V$ ) curve and reactive power–active power–voltage ( $Q$ – $P$ – $V$ ) curve, are developed for voltage stability and control at the point of interconnection (POI) between a wind power plant (WPP) and a utility grid. The procedure to obtain an effective $Q$ – $V$ curve using the supervisory control and data acquisition (SCADA) measurement data is proposed. The SCADA data used in this paper were recorded in 2016 at the POI of a 27-MW WPP currently in operation in Newfoundland and Labrador (NL), Canada. Each $Q$ – $V$ curve is created for a particular month using the SCADA data corresponding to a very narrowly defined active power range, so the active power is considered constant as the conventional $Q$ – $V$ curve concept. The MATLAB curve fitting toolbox is used to realize the most fit mathematical equations for $Q$ – $V$ and $Q$ – $P$ – $V$ curves. The developed $Q$ – $V$ and $Q$ – $P$ – $V$ curves can be used for the data-driven voltage control for WPPs; and the $Q$ – $V$ curves can also be used for the voltage stability evaluation.

Channel Estimation and Equalization of Underwater Acoustic MIMO-OFDM Systems: A Review Estimation du canal et l’égalisation des systèmes MEMS-MROF acoustiques sous-marins: une revue

Abstract: High-speed underwater acoustic (UWA) communication is challenging due to limited bandwidth, extended multipath spread, severe Doppler effect, and large transmission loss. The use of multiple transducers at both transmitter and receiver increases the spatial diversity of the system, and orthogonal frequency-division multiplexing (OFDM) solves the problem of limited bandwidth due to its high spectral efficiency. Thus, the combination of multiple-input multiple-output (MIMO) and OFDM shifts the UWA communication to a whole new level; however, at the same time, it also increases the design challenges for the development of such systems. Intersymbol interference, intercarrier interference, and cochannel interference are introduced in the received signal by the extended multipath and Doppler shifts along with different types of noises due to the noisy acoustic channel. Therefore, many channel estimation and equalization schemes are developed for the UWA MIMO-OFDM communication systems. In this paper, these schemes are thoroughly reviewed, summarized, categorized, and compared with other similar algorithms in terms of complexity and performance while pointing out the prevailing research problems. Resume —La communication acoustique sous-marine a haute vitesse (ASM) est un defi en raison de la bande passante limitee, de la propagation multi-trajets etendue, de l’effet Doppler grave et de la perte importante de transmission. L’utilisation de plusieurs transducteurs a la fois emetteur et recepteur augmente la diversite spatiale du systeme, et le multiplexage par repartition orthogonale de la frequence (MROF) resout le probleme de la bande passante limitee en raison de son efficacite spectrale elevee. Ainsi, la combinaison de multi-entrees multi-sorties (MEMS) et MROF deplace la communication ASM a un tout autre niveau; Cependant, dans le meme temps, cela augmente egalement les defis de conception pour le developpement de tels systemes. Les interferences intersymboles, interferences entre porteuses et le brouillage dans le meme canal (cochannel) sont introduits dans le signal recu par les decalages etendus sur trajets multiples et Doppler, ainsi que par differents types de bruits dus au canal acoustique bruyant. Par consequent, de nombreux schemas d’estimation et d’egalisation de canal sont developpes pour les systemes de communication ASM MEMS-MROF. Dans cet article, ces schemas sont examines, resumes, classes et compares a d’autres algorithmes similaires en termes de complexite et de performances, tout en soulignant les problemes de recherche courants.

Sag and Flicker Reduction Using Hysteresis-Fuzzy Control-Based SMES Unit

Abstract: The issue of power quality is one of the prominent factors in determining the reliability of power systems. It is inevitable to consider power quality issues and include appropriate mitigation techniques in the design of any future power system project construction. Voltage sag and flicker are the two most common short disturbance types of power quality issues that frequently occur in power systems. A widely accepted mitigation strategy to enhance the power quality of disturbed networks is by connecting a flexible ac transmission system. In this paper, a superconducting magnetic energy storage (SMES) unit along with hysteresis-fuzzy controller to suppress the severe impacts of voltage sag and flicker events on the power quality of a power system is proposed, implemented, and tested. The proposed SMES configuration with hysteresis current control and fuzzy logic controller is effective, simple, and easy to implement. Simulation results show the ability of the proposed SMES controller in compensating sag and/or flicker distortions.

Operational Parameters Affecting Harmonic Resonance in Electrical Submersible Pump Systems

Abstract: Electrical submersible pump (ESP) systems in the oil field have unique features due to the long cabling effect. The electrical system for a typical ESP installation consists of a variable frequency drive (VFD), a multi-tap step-up transformer, a surface cable, a downhole main cable, a motor lead extension (MLE) cable, and an electrical submersible motor. A load filter is usually required in a VFD-ESP system. In this paper, several operational parameters that can significantly affect operating conditions of an ESP system are demonstrated through field measurements and simulation of a practical ESP system currently in operation in Alberta, Canada. The simulation model is also validated by comparing with field measurement data. This analysis is beneficial to field engineers and ESP system operators to understand better the impacts of equipment parameter settings.

Analysis of the Three-Phase Inverter Power Efficiency of a BLDC Motor Drive Using Conventional Six-Step and Inverted Pulsewidth Modulation Driving Schemes

Abstract: In this paper, the three-phase inverter power efficiency of a brushless DC (BLDC) motor drive is analyzed theoretically and verified experimentally. An inverted pulsewidth modulation driving scheme has higher power efficiency than a conventional six-step driving scheme, particularly under low rotor speed due to less diode conduction power loss of Sync metal–oxide–semiconductor field-effect transistors (MOSFETs). However, the difference in the power efficiency decreases as the rotor speed increases; for a rotor speed above 1000 r/min, the difference in the power efficiency is negligible. In addition, the power efficiency of the inverted driving scheme drops further than one for the conventional six-step driving scheme with sampling frequency increase. It is due to the additional switching power loss of Sync MOSFET. The theoretical analysis of power loss in a three-phase inverter verifies the experimental results.

A Novel Clustering Framework for Stream Data Un nouveau cadre de classifications pour les données de flux

Abstract: There is a growing tendency for developing real-time clustering of continuous stream data. In this regard, a few attempts have been made to improve the off-line phase of stream clustering methods, whereas these methods almost use a simple distance function in their online phase. In practice, clusters have complex shapes, and therefore, measuring the distance of incoming samples to the mean of asymmetric microclusters might mislead incoming samples to irrelevant microclusters. In this paper, a novel framework is proposed, which can enhance the online phase of all stream clustering methods. In this manner, for each microcluster for which its population exceeds a threshold, a classifier is exclusively trained to capture its boundary and statistical properties. Thus, incoming samples are assigned to the microclusters according to the classifiers⣙ scores. Here, the incremental NaAˉve Bayes classifier is chosen, due to its fast learning property. DenStream and CluStream as the state-of-the-art methods were chosen and their performance was assessed over nine synthetic and real data sets, with and without applying the proposed framework. The comparative results in terms of purity, general recall, general precision, concept change traceability, computational complexity, and robustness against noise over the data sets imply the superiority of the modified methods to their original versions.

Dynamic Weighted Majority Approach for Detecting Malicious Crowd Workers

Abstract: Crowdsourcing is a paradigm that utilizes human intelligence to solve problems that computers cannot yet solve. However, the introduction of human intelligence into computations has also resulted in new challenges in quality control. These challenges originate from the malicious behaviors of crowd workers. Malicious workers are workers with hidden motives, who either simply sabotage a task or provide arbitrary responses to attain some monetary compensation. Recently, many studies have tried to detect and reduce the impact of malicious workers. The mechanisms vary from using ground truth to peer review by experts. Although the use of such mechanisms may increase the overall quality of outputs, it also imposes overhead costs in terms of money and/or time, with such costs being often remarkable and contradictory to the philosophy of crowdsourcing. In this paper, a novel dynamic weighted majority method is introduced to detect malicious workers based on a new malicious metric. Effectiveness of the proposed methodology is then showed by presenting the experimental results.

Optimal Traction Forces for Four-Wheel Rovers on Rough Terrain

Abstract: This paper addresses the minimization of the risk of wheel slippage for a popular class of rovers. In the absence of any constraints on the system (e.g., force/torque balance and maximum motor torques), the optimal traction solution is known to be that with equal “friction requirements” (ratios of tractive to normal force) for all wheels. Nevertheless, the current state of the art is to routinely perform computationally expensive constrained optimization because of the presumed importance of the constraints in a real system. The contribution of this paper is a thorough investigation of the configuration space for four-wheel rovers, driving straight over rough terrain, in search of configurations where the unconstrained optimal answer does or does not satisfy the constraints, and, thus, is or is not valid. Equal “friction requirements” are added to the four-wheel rover’s system of quasi-static equations and a valid solution is sought to this augmented system of equations. It is found that the equal “friction requirements” solution is almost always valid, except for the case where two of the wheels are wedged against opposing vertical faces, a highly unusual and unlikely scenario. Therefore, we can conclude that computationally expensive constrained optimization is not required to achieve traction control for four-wheel rovers.

Analysis of Switching Overvoltage and Suppression Measures in UHV Transmission Lines

Abstract: As the ultrahigh-voltage (UHV) projects are rapidly developing, it is necessary to investigate the problems involved in overvoltage and insulation, thereby providing a technical basis for future UHV projects. The switching overvoltage of closing no-load lines was simulated and analyzed here using two kinds of typical UHV network structures: the power plant to the grid system and the grid-to-grid system. Different factors, such as line length, mode of operation on the power plant side, and short-circuit capacity, are considered. It is possible for lines shorter than 60 km to eliminate the closing resistor, determined by calculating the probability of flashover. We analyzed the phase selection closing in depth to inhibit the switching overvoltage and considered the factors such as phase deviation and the length of the line. Finally, the applicability of phase selection closing is put forward for lines of different lengths.

Analysis of Bootstrap Circuit Operation With an Inverted PWM Drive Scheme for a Three-Phase Inverter for a Brushless DC Motor Drive

Abstract: A bootstrap circuit for operating the high-side insulated-gate bipolar transistor of a three-phase inverter for a brushless dc motor drive is analyzed theoretically to avoid under voltage lockout by minimizing the discharge of a bootstrap capacitor (BSC). Unlike various methods of reducing the discharge of BSCs, which limits the controllability of the motor speed/torque, a proposed inverted PWM driving scheme has no limit to the controllability while maintaining the proper voltage level for a BSC. This method is verified experimentally in this paper.

Low-Power Highly Reliable SET-Induced Dual-Node Upset-Hardened Latch and Flip-Flop

Abstract: It appears that the relentless pursuit of Moore’s law scaling from one generation of process technology to the next increases circuit vulnerability to single-event transient (SET)-induced double-node upset (SEDU). In this paper, we present a novel SEDU-hardened latch. The latch consists of a new 16-transistor (16T) SEDU-hardened storage cell and a C-type output buffer. The latch exhibits 25% lower power consumption, is 81% faster, and also shows 86% lower power-delay product than the existing SEDU-hardened latches. In addition, we present the first SEDU-hardened flip-flop that exhibits negative hold time. The proposed SEDU-hardened flip-flop is 29% faster, consumes 50% lower dynamic power and 25% lower static power, has 45% lower setup time, and uses 27% lower area than the existing partial SEDU-hardened flip-flop.

Transformation Method of Nonlinear Mathematical Models of the DC Series Drive into the Form of Modified Recurrent Neural Network

Abstract: The method of transformation of a nonlinear mathematical model of an electromechanical object to the form of a modified artificial recurrent neural network has been further developed. The method makes it possible to use knowledge about the object for the synthesis of a recurrent neural network (RNN) structure and the computation of their coefficients. Nonlinearities in the proposed RNN were realized by expanding the input signal space of the network, using the normalized signals of polynomial terms. Mathematical transformations were performed for a model of thyristor-based electric drive with a dc motor of series excitation. In the electric drive model, different nonlinearities were set, namely, the magnetic flux and inductance of the motor winding dependence on the motor current and its derivative, the thyristor converter gain from the reference voltage, and the dependence of the moment of inertia on the speed. An accuracy estimation for the models in the form of an RNN was made.

Fault-Tolerant DSP Core Datapath Against Omnidirectional Spatial Impact of SET

Abstract: Fault due to the single-event transient (SET) on digital signal processing (DSP) cores has not been thoroughly studied in the research community. Moreover, as the technology scaling becomes more intense, the impact of transient fault now becomes visible both in temporal and spatial domains. Few techniques have been presented in the literature that simultaneously address temporal and the spatial effects of transient fault. However, none of these approaches consider the omnidirectional spatial propagation of transient fault. Furthermore, these approaches have failed to consider the impact of transient fault on switching elements. This calls for methodology to tackle both the temporal and omnidirectional spatial effects of the transient fault on DSP cores. The proposed approach tackles these issues and presents a novel methodology to generate a low-cost fault-tolerant DSP core datapath against temporal (kc-cycle) and omnidirectional spatial (km-unit) impacts of SET.

Toward a Way to Benchmark Multilevel Inverter Topologies Based on Level to Components Ratio

Abstract: This paper introduces a generalized platform for the design selection of multilevel inverters (MLIs) topologies for any industry, especially in low- and medium-power applications. This platform is novel as it combines the component count and stress in any MLI in a normalized unique score. Each MLI topology is designed to match specific criteria to meet a specific application, which introduces diversified sets of merits and demerits in each case. Therefore, choosing a suitable MLI topology for the specific application is rather a difficult, time-consuming, and complex process. Moreover, the comparison can only be conducted between MLI topologies that fall under the same category. This paper introduces a comprehensive study to propose a new benchmark (BM) which can be used to compare MLI topologies regardless of their constructions or oriented applications. Each MLI topology gets a BM score based on comparative factors that evaluate its components quantitatively and qualitatively. Thus, comparing different types of MLI topologies is a simple process of comparing their calculated BM scores leading to better well-informed choice. First, the proposed BM-derived forms are discussed. Then, the proposed methodology is illustrated by applying to various types of MLI topologies including conventional and recently introduced ones.