International Science Index

International Journal of Electrical and Computer Engineering

Induction Machine Bearing Failure Detection Using Advanced Signal Processing Methods
This article examines the detection and localization of faults in electrical systems, particularly those using asynchronous machines. First, the process of failure will be characterized, relevant symptoms will be defined and based on those processes and symptoms, a model of those malfunctions will be obtained. Second, the development of the diagnosis of the machine will be shown. As studies of malfunctions in electrical systems could only rely on a small amount of experimental data, it has been essential to provide ourselves with simulation tools which allowed us to characterize the faulty behavior. Fault detection uses signal processing techniques in known operating phases.
Adaptive Backstepping Control of Five-Bar Linkage Manipulator: A Fractional-Order Approach
This paper introduced a new adaptive control method for a five-bar linkage manipulator. The presented method is optimized by particle swarm optimization (PSO) algorithm. The controller is designed based upon fractional calculus and backstopping approach. The manipulator is a parallelogram unstable robot which has a nonlinear equation of motion and also has model uncertainties, and external disturbances can perturb the system. So, in order to achieve a good tracking performance, a PSO-optimized adaptive backstepping controller is developed based on a fractional calculus framework. To ensure closed-loop system stability, the controller is designed on the basis of fractional Lyapunov lemmas. Different simulations are carried out to confirm the theoretical achievements. The results reveal that the proposed approach is capable of controlling the system effectively.
Adaptive Synchronization of New Fractional-Order Chaotic Systems with Fractional Adaption Laws
Adaptive synchronization of fractional order chaotic systems is proposed in this paper. To authors best knowledge, fractional version of the described chaotic systems is introduced for the first time in this paper. Simulation of fractional version shows the chaotic behavior for the selected orders. Based on Lyapunov stability theory, the new type of stability analysis for the fractional order system are introduced. Using this stability analysis parameters adaption laws are obtained, and controllers are designed. Compared to the integer version of adaption laws for parameters, advantages of the designed adaptive controllers are shown. These advantages are on the control signals and synchronization errors. The simulation example has verified the performance.
Analysis of Ancient and Present Lightning Protection Systems of Large Heritage Stupas in Sri Lanka
Protection of heritage monuments against lightning has become extremely important as far as their historical values are concerned. When such structures are large and tall, the risk of lightning initiated from both cloud and ground can be high. This paper presents a lightning risk analysis of three giant stupas in Anuradhapura era (fourth century BC onwards) in Sri Lanka. The three stupas are Jethawaaramaya (269-296 AD), Abayagiriya (88-76 BC) and Ruwanweliseya (161-137 BC), the third, fifth and seventh largest ancient structures in the world. These stupas are solid brick structures consisting of a base, a near hemispherical dome and a conical spire on the top. The ancient stupas constructed with a dielectric crystal on the top and connected to the ground through a conducting material, was considered as the hypothesis for their original lightning protection technique. However, at present, all three stupas are protected with Franklin rod type air termination systems located on top of the spire. First, a risk analysis was carried out according to IEC 62305 by considering the isokeraunic level of the area and the height of the stupas. Then the standard protective angle method and rolling sphere method were used to locate the possible touching points on the surface of the stupas. The study was extended to estimate the critical current which could strike on the unprotected areas of the stupas. The equations proposed by (Uman 2001) and (Cooray2007) were used to find the striking distances. A modified version of rolling sphere method was also applied to see the effects of upward leaders. All these studies were carried out for two scenarios: with original (i.e. ancient) lightning protection system and with present (i.e. new) air termination system. The field distribution on the surface of the stupa in the presence of a downward leader was obtained using finite element based commercial software COMSOL Multiphysics for further investigations of lightning risks. The obtained results were analyzed and compared each other to evaluate the performance of ancient and new lightning protection methods and identify suitable methods to design lightning protection systems for stupas. According to IEC standards, all three stupas with new and ancient lightning protection system has Level IV protection as per protection angle method. However according to rolling sphere method applied with Uman’s equation protection level is III. The same method applied with Cooray’s equation always shows a high risk with respect to Uman’s equation. It was found that there is a risk of lightning strikes on the dome and square chamber of the stupa, and the corresponding critical current values were different with respect to the equations used in the rolling sphere method and modified rolling sphere method.
Computational Analysis of Thermal Degradation in Wind Turbine Spars' Equipotential Bonding Subjected to Lightning Strikes
Rotor blades of large, modern wind turbines are highly susceptible to downward lightning strikes, as well as to triggering upward lightning; consequently, it is necessary to equip them with an effective lightning protection system (LPS) in order to avoid any damage. The performance of existing LPSs is affected by carbon fibre reinforced polymer (CFRP) structures, which lead to lightning-induced damage in the blades, e.g. via electrical sparks. A solution to prevent internal arcing would be to electrically bond the LPS and the composite structures such that to obtain the same electric potential. Nevertheless, elevated temperatures are achieved at the joint interfaces because of high contact resistance, which melts and vaporises some of the epoxy resin matrix around the bonding. The produced high-pressure gasses open up the bonding and can ignite thermal sparks. The objective of this paper is to predict the current density distribution and the temperature field in the adhesive joint cross-section, in order to check whether the resin pyrolysis temperature is achieved and any damage is expected. The finite element method has been employed to solve both the current and heat transfer problems, which are considered weakly coupled. The mathematical model for electric current includes Maxwell-Ampere equation for induced electric field solved together with current conservation, while the thermal field is found from heat diffusion equation. In this way, the current sub-model calculates Joule heat release for a chosen bonding configuration, whereas the thermal analysis allows to determining threshold values of voltage and current density not to be exceeded in order to maintain the temperature across the joint below the pyrolysis temperature, therefore preventing the occurrence of outgassing. In addition, it provides an indication of the minimal number of bonding points. It is worth to mention that the numerical procedures presented in this study can be tailored and applied to any type of joints other than adhesive ones for wind turbine blades. For instance, they can be applied for lightning protection of aerospace bolted joints. Furthermore, they can even be customized to predict the electromagnetic response under lightning strikes of other wind turbine systems, such as nacelle and hub components.
Tabu Random Algorithm for Guiding Mobile Robots
The use of optimization algorithms is common across a large number of diverse fields. This work presents the use of a hybrid optimization algorithm applied to a mobile robot tasked with carrying out a search of an unknown environment. The algorithm is then applied to the multiple robots case, which results in a reduction in the time taken to carry out the search. The hybrid algorithm is a Random Search Algorithm fused with a Tabu mechanism. The work shows that the algorithm locates the desired points in a quicker time than a brute force search. The Tabu Random algorithm is shown to work within a simulated environment using a validated mathematical model. The simulation was run using three different environments with varying numbers of targets. As an algorithm, the Tabu Random is small, clear and can be implemented with minimal resources. The power of the algorithm is the speed at which it locates points of interest and the robustness to the number of robots involved. The number of robots can vary with no changes to the algorithm resulting in a flexible algorithm.
Validation of Solar Photovoltaic Inverter Harmonics Behaviour at Different Power Levels in a Test Network
Grid connected solar PV inverters need to be compliant to standard regulations regarding unwanted harmonic generation. This paper gives an introduction to harmonics, solar PV inverter voltage regulation and balancing through compensation and investigates the behaviour of harmonic generation at different power levels. Practical measurements of harmonics and power levels with a power quality data logger were made, on a test network at a university in Germany. The test setup and test results are discussed. The major finding was that between the morning and afternoon load peak windows when the PV inverters operate under low solar insolation and low power levels, more unwanted harmonics are generated. This has a huge impact on the power quality of the grid as well as capital and maintenance costs. The design of a single-tuned harmonic filter towards harmonic mitigation is presented.
Design and Development of an Autonomous Underwater Vehicle for Irrigation Canal Monitoring
Indus river basin’s irrigation system in Pakistan is extremely complex, spanning over 50,000 km. Maintenance and monitoring of this demands enormous resources. This paper describes the development of a streamlined and low-cost autonomous underwater vehicle (AUV) for the monitoring of irrigation canals including water quality monitoring and water theft detection. The vehicle is a hovering-type AUV, designed mainly for monitoring irrigation canals, with fully documented design and open source code. It has a length of 17 inches, and a radius of 3.5 inches with a depth rating of 5m. Multiple sensors are present onboard the AUV for monitoring water quality parameters including pH, turbidity, total dissolved solids (TDS) and dissolved oxygen. A 9-DOF Inertial Measurement Unit (IMU), GY-85, is used, which incorporates an Accelerometer (ADXL345), a Gyroscope (ITG-3200) and a Magnetometer (HMC5883L). The readings from these sensors are fused together using directional cosine matrix (DCM) algorithm, providing the AUV with the heading angle, while a pressure sensor gives the depth of the AUV. 2 sonar-based range sensors are used for obstacle detection, enabling the vehicle to align itself with the irrigation canals edges. 4 thrusters control the vehicle’s surge, heading and heave, providing 3 DOF. The thrusters are controlled using a proportional-integral-derivative (PID) feedback control system, with heading angle and depth being the controller’s input and the thruster motor speed as the output. A flow sensor has been incorporated to monitor canal water level to detect water-theft event in the irrigation system. In addition to water theft detection, the vehicle also provides information on water quality, providing us with the ability to identify the source(s) of water contamination. Detection of such events can provide useful policy inputs for improving irrigation efficiency and reducing water contamination. The AUV being low cost, small sized and suitable for autonomous maneuvering, water level and quality monitoring in the irrigation canals, can be used for irrigation network monitoring at a large scale.
Design Optimization of Doubly Fed Induction Generator Performance by Differential Evolution
Doubly fed induction generators (DFIG) due to its advantages like speed variation and four-quadrant operation, find its application in wind turbines. DFIG besides supplying power to grid has to support reactive power (kvar) under grid voltage variations, should contribute minimum fault current during faults, have high efficiency, minimum weight, adequate rotor protection during crow-bar-operation and many more at speeds from +30% to -30% of rated speed. To achieve the above optimum performance, a good electro-magnetic design of DFIG is required. In this paper, a simple and heuristic global optimization (differential evolution) has been used. Variables considered are lamination details such as slot dimensions, diameters, air gap length and generator stator and rotor stack length. Two operating conditions have been considered; voltage and speed variations. Constraints included were reactive kvar supplied to grid and limiting fault current and torque. The optimization has been executed separately for two objective functions; maximum efficiency and weight reduction. Subsequent calculations led to the conclusion that designs determined through differential evolution help in determining an optimum electrical design for each objective function.
Mixed Convection Heat Transfer of Copper Oxide-Heat Transfer Oil Nanofluid in Vertical Tubes
In this paper, experiments were conducted to investigate the heat transfer of CuO- HTO nanofluid laminar flow in vertical smooth and microfin tubes as the surface temperature is constant. The effect of adding the nanoparticle to base fluid and Richardson number on the heat transfer enhancement is investigated as Richardson number increase from 0.1 to 0.7. The experimental results demonstrate that the combined forced-natural convection heat transfer rate may be improved significantly with an increment of mass nanoparticle concentration from 0% to 1.5%. In this experiment, a new correlation is also proposed to predict the mixed convection heat transfer rate of CuO-HTO nanofluid flow. The maximum deviation of both correlations is less than 14%. Moreover, a new correlation is presented to estimate the Nusselt number inside vertical smooth and microfin tubes as Rayleigh number is between 2´105 to 6.8´106 with the maximum deviation of 12%.
The Effect of Phonetics Factors in Interpretation of Japanese Degree Adverbs
Japanese degree adverbs can be explained in different ways, which is hard for Japanese learners to comprehend. For instance, when ‘tyotto’ is used as a degree word, it can be interpreted literally or not. In the sentence ‘Ano mise, tyotto oishi yo. zehi iku to ii yo.’, ‘tyotto’ can be interpreted as a high degree contextually. Despite pragmatic factors, phonetics factors can also affect the interpretation of such ‘tyotto’. Concentrating on the pattern of ‘tyotto +adjective’, the paper aims to investigate the correlation between the interpretation of ‘tyotto’ and the phonetic factors in some specific contexts based on a listening experiment via PRAAT. It is also investigated that how the phonetic factors affect the interpretation of high degree adverbs, including ‘soutou’ , ‘totemo’ , ‘kanari’ and ‘sugoku’. In the experiment, Japanese speakers listened to sentences which were composed of degree adverbs and adjectives in different intonations and judged which degree the sentences expressed. Two conclusions can be drawn from the experiment results. Firstly, for adverbs expressing a high degree, in the pattern of ‘degree adverb + adjective’, either degree adverb or adjective is pronounced in a higher pitch, or both are highly pronounced, a higher degree can be expressed. Besides, with the insertion of geminate consonant and the extension of the vowel, the longer the duration of the degree adverb becomes, the higher degree can be expressed. Secondly, for ‘tyotto’, which expresses a low degree, the interpretation will be influenced by both phonetic and contextual factors. Phonetically, there are three factors causing ‘tyotto’ to be interpreted as a common degree or a high degree. The three factors are the high pitch of the modified adjective, the extended silence period of the geminate consonant and the change in the intonations of ‘tyotto’. In some contexts just like the comparison sentences, no matter how ‘tyotto + adjective’ is pronounced, ‘tyotto’ tends to be interpreted as a low degree literally.
Design and Performance Analysis of Double-Sided Inner-Rotor and Inner-Stator Permanent Magnet Axial Flux Synchronous Generator for Wind Turbine Applications
This paper explains the design and simulation of the two topologies inner-stator and inner-rotor axial flux permanent magnet synchronous generator (AFPMSG), the design is followed through diameter to length ratio (D²L) approach to calculate the designing parameters. Double-sided inner-rotor structure and inner-stator structure topologies are designed. These both topologies are suitable for wind turbine applications, an inner-stator design is better for direct coupling to the wind turbine. The comparative performance analysis of output power and back electromotive force (EMF) Voltage is analyzed of inner-stator and inner-rotor structures. The design and constructions characteristics are considered to simulate the results and to observe the output power and voltages through the 3-D finite element method (FEM) analysis, magnetic flux density distribution is calculated as well. According to the findings inner-stator structure machine has more output power and voltage due to low flux linkages but in the inner-rotor structure has lower performance due to the high flux linkages.
A Comprehensive Review of Axial Flux Machines and Its Applications
This paper presents a thorough review concerning the design types of axial flux permanent magnet machines (AFPM) in terms of different features such as construction, design, materials, and manufacturing. Particular emphasis is given on the design and performance analysis of AFPM machines. A comparison among different permanent magnet machines is also provided. First of all, early and modern axial flux machines are mentioned. Secondly, rotor construction of different axial flux machines is described, then different stator constructions are mentioned depending upon the presence of slots and stator back iron. Then according to the arrangement of the rotor stator structure the machines are classified into single, double and multi-stack arrangements. Advantages, disadvantages and applications of each type of rotor and stator are pointed out. Finally on the basis of the reviewed literature merits, demerits, features and application of different axial flux machines structures are explained and clarified. Thus, this paper provides connection between the machines that are currently being used in industry and the developments of AFPM throughout the years.
Modular Harmonic Cancellation in a Multiplier High Voltage Direct Current Generator
Generation of high DC voltages is necessary for testing the insulation material of high voltage AC transmission lines with long lengths. The harmonic and ripple contents of the output DC voltage supplied by high voltage DC circuits require the use of costly capacitors to smooth the output voltage after rectification. This paper proposes a new modular multiplier high voltage DC generator with embedded Cockcroft-Walton circuits that achieves a negligible harmonic and ripple contents of the output DC voltage without the need for costly filters to produce a nearly constant output voltage. In this new topology, Cockcroft-Walton modules are connected in series to produce a high DC output voltage. The modules are supplied by low input AC voltage sources that have the same magnitude and frequency and shifted from each other by a certain angle to eliminate the harmonics from the output voltage. The small ripple factor is provided by the smoothing column capacitors and the phase shifted input voltages of the cascaded modules. The constituent harmonics within each module are determined using Fourier analysis. The viability of the proposed DC generator for testing purposes and the effectiveness of the cascaded connection are confirmed by numerical simulations using Matlab/simulink.
A Contradiction Handling Consolidation Procedure Using U₄ for Databases
In this paper U₄ is a many-valued logic based on set theory having the logic states: true (T), false (F), uncertain (U), and impossible (Ø). U₄ solves the paradoxes of material implication and future contingents and so is an important contribution to many-valued logic and artificial intelligence. The consolidation procedure for U₄ has five parts: i) Initially for contradictions A, ¬A are assigned uncertain status because the principle of non-contradiction is applied. This is a preliminary, A = U, ¬A = U. ii) A review of the contradiction seeks more information on the topics of A and ¬A. This process checks the veracity of A and ¬A. iii) If there is insufficient information to determine truth, then A and ¬A remain uncertain and a probability could be assigned to them: 0 ≤ P(A) ≤ 1 and P(¬A) = 1 – P(A). Both A and ¬A are retained in the knowledge base, having a logical uncertain status and probability. iv) If there is sufficient information to clarify the contradiction, then truth could be assigned to A and falsity to ¬A. A = T, ¬A = F. Belief revision then follows the Levi identity. v) If A and ¬A are paradoxical then the logical status, A = ¬ A = {U = Ø = T = F}, can be assigned. The findings show that information in a non-classical database using U₄ may be kept free of contradictions. This method may be employed in systems using automated reasoning and especially for safety hazards. This contradiction handling criteria for U₄ meets Belnap’s important criteria of ‘How a Computer Should Think’.
Study on Low Jitter Fast High-Current Circuits for Storage Capacitor Discharge by Using Metal-Oxide-Semiconductor Gated Thyristors
Metal Oxide Semiconductor (MOS) Gated Thyristors (MGTs) are spreading out though Triggered-Spark Gap Switches (T-SGSs) are still widely used to discharge energy storage capacitors. The T-SGSs generally require a bulky high-voltage trigger source. Moreover, time deviations or jitters of the T-SGSs are too high to be allowed in some applications of accurate time controls. For these reasons we designed and tested high-current circuits for capacitor discharge by using a kind of power electronic device, the MGT. The circuits consist of an energy storage capacitor, one MGT alone or two MGTs connected in parallel, and a load. The load was a non-inductive ceramic resistor or a thin copper wire. As a low inductance current probe, a Current Viewing Resistor (CVR) was connected in series between the MGT and the load to measure the switched fast high-current. For the time sensing, optical fibers and optoelectronic converters were applied to find the jitters. Outputs of those sensors were measured by digital oscilloscopes. Test results showed that the circuits had lower jitters compared to our former circuit with the T-SGS. It can be inferred from the measured current that the jitters, whether by one MGT or by two MGTs, were small enough to be applied to the fast high-current circuit.
Naturally Damaged Wind Turbine Blade Bearing Fault Diagnosis Using Discrete/Random Separation and Fast Kurtogram Methods
Wind turbine blade bearings are vital components which are able to pitch the blades and optimize the electrical energy output. The blade bearing failure can lead the turbine to lose control or even shut down and further result in the reduction of energy production. However, for very low rotation speed blade bearings, the weak fault and compound fault vibration features are masked by many noise disturbances making condition monitoring and fault diagnosis (CMFD) challenging in many cases. In this paper, the sample of our experiment is a naturally damaged large-scale and low rotation speed blade bearing with over 15 years of working age. Two denoising methods discrete/random separation (DRS) and fast kurtogram, are used to minimize the noise and extract weak and compound fault features. These two methods can verify and complement with each other to improve the diagnostic accuracy. The results show that the proposed methods are able to effectively diagnose the naturally damaged slow speed blade bearing fault types, but they require long sampling time for extremely low rotation speed cases.
Influence of Sr(BO₂)₂ Doping on Superconducting Properties of (Bi,Pb)-2223 Phase
Chemical doping with different elements and compounds at various amounts represents the most suitable approach to improve the superconducting properties of bismuth-based superconductors for technological applications. In this paper, the influence of partial substitution of Sr(BO2)2 for SrO on the phase formation kinetics and transport properties of (Bi,Pb)-2223 HTS have been studied for the first time. Samples with nominal composition Bi₁.₇Pb₀.₃Sr₂₋ₓCa₂Cu₃Oy[Sr(BO₂)₂]ₓ, x=0, 0.0375, 0.075, 0.15, 0.25, were prepared by the standard solid state processing. The appropriate mixtures were calcined at 845 °C for 40 h. The resulting materials were pressed into pellets and annealed at 837 °C for 30 h in air. Superconducting properties of undoped (reference) and Sr(BO₂)₂-doped (Bi,Pb)-2223 compounds were investigated through X-ray diffraction (XRD), resistivity (ρ) and transport critical current density (Jc) measurements. The surface morphology changes in the prepared samples were examined by scanning electron microscope (SEM). XRD and Jc studies have shown that the low level Sr(BO₂)₂ doping (x=0.0375-0.075) to the Sr-site promotes the formation of high-Tc phase and leads to the enhancement of current carrying capacity in (Bi,Pb)-2223 HTS. The doped sample with x=0.0375 has the best performance compared to other prepared samples. The estimated volume fraction of (Bi,Pb)-2223 phase increases from ~25 % for reference specimen to ~70 % for x=0.0375. Moreover, strong increase in the self-field Jc value was observed for this dopant amount (Jc=340 A/cm²), compared to an undoped sample (Jc=110 A/cm²). Pronounced enhancement of superconducting properties of (Bi,Pb)-2223 superconductor can be attributed to the acceleration of high-Tc phase formation as well as the improvement of inter-grain connectivity by small amounts of Sr(BO₂)₂ dopant.
Increasing the Frequency of Laser Impulses with Optical Choppers with Rotational Shafts
Optical choppers are among the most common optomechatronic devices, utilized in numerous applications, from radiometry to telescopes and biomedical imaging. The classical configuration has a rotational disk with windows with linear margins. This research points out the laser signals that can be obtained with these classical choppers, as well as with another, novel, patented configuration, of eclipse choppers (i.e., with rotational disks with windows with non-linear margins, oriented outwards or inwards). Approximately triangular laser signals can be obtained with eclipse choppers, in contrast to the approximately sinusoidal – with classical devices. The main topic of this work refers to another, novel device, of choppers with shafts of different shapes and with slits of various profiles (patent pending). A significant improvement which can be obtained (with regard to disk choppers) refers to the chop frequencies of the laser signals. Thus, while 1 kHz is their typical limit for disk choppers, with choppers with shafts, a more than 20 times increase in the chop frequency can be obtained with choppers with shafts. Their transmission functions are also discussed, for different types of laser beams. Acknowledgments: This research is supported by the Romanian National Authority for Scientific Research, through the project PN-III-P2-2.1-BG-2016-0297.
Review of Strategies for Hybrid Energy Storage Management System in Electric Vehicle Application
Electric Vehicles (EV) appear to be gaining increasing patronage as a feasible alternative to Internal Combustion Engine Vehicles (ICEVs) for having low emission and high operation efficiency. The Electrical Vehicle (EV) energy storage systems are required to handle high energy and power density capacity constrained by limited space, operating temperature, weight and cost. The choice of strategies for energy storage evaluation, monitoring and control remains a challenging task. This paper presents review of various energy storage technologies and recent researches in battery evaluation techniques used in electric vehicle applications. It also underscores strategies for the hybrid energy storage management and control schemes for the improvement of electric vehicle stability and reliability. Recent advancement in battery technology as electrical energy storage medium has consequently been studied. The battery parameter metrics, existing estimation and control strategies in electric vehicle system application are being clearly emphasized by reviewing 250 related scholarly articles. The existing estimation strategies and battery state evaluation models in technical literature are classified and different methodologies used were evaluated and compared to determine the feasibility and efficiency of the hybrid energy storage management components. The study reveals that despite the advances recorded in battery technologies, to authors’ best knowledge there is still no cell which possesses both the optimum power and energy densities among other requirements, for electrical vehicle application. However combination of two or more energy storages as hybrid and allowing the advantageous attributes from each device to be utilized is a promising solution. The review also reveal that State of Charge (SoC) is the most crucial method for battery estimation. The conventional method of SoC measurement is however questioned in the literature and adaptive algorithms that includes all model of disturbances are being proposed. The review further suggests that heuristic-based approach is commonly adopted in the development of strategies for hybrid energy storage system management. The alternative approach which is optimization-based is found to be more accurate but are memory and computational intensive and as such not recommended in most real-time applications.
A Hybrid of Thevenin and Norton Equivalence Theorems That Is Analogous to an Equivalence Theorem of Electromagnetics
According to the conventional perception, Thevenin and Norton equivalence theorems do not apply when calculating responses at all parts of circuits other than the load location. It is believed that the responses everywhere can be determined only by back substituting the responses determined at the load location into the original circuit. On the other hand, analogous to an electromagnetic source equivalence theorem, we presented a hybrid of Thevenin and Norton equivalence theorems wherein such a back substitution procedure is not needed. We provided a numerical example wherein a bulky circuit is split into two sub-circuits that were solved by means of different methods.
Development of a Firmware Downloader for AVR Microcontrollers for Educational Purposes
This paper introduces the development of a firmware downloader for students attending microcontroller-related courses taught by the authors In the courses, AVR microcontroller experiment kits are used for programming exercise and the AVR microcontroller is programmed through a serial communication interface using a bootloader preinstalled on it. To use the bootloader, a matching firmware downloader that runs on a host computer and communicates with the bootloader is also required. When firmware downloading is completed, the serial port used for it needs to be closed. If the downloaded firmware uses serial communication, the serial port needs to be reopened in a serial terminal. As a result, the programmer of the AVR board switches from the downloader program and the serial terminal and vice versa. It is a simple task but quite a hassle to do each time new firmware needs downloading. To provide a more convenient programming environment for the courses, the authors developed a downloader program that includes a serial terminal in it. The program operates in downloader or terminal mode and the mode switching is performed automatically; therefore manual mode switching is not necessary. The feature provides a more convenient development environment by eliminating the need for manual mode switching each time firmware downloading is required.
Defects Classification of Stator Coil Generators by Phase Resolve Partial Discharge
This paper proposed a phase resolve partial discharge (PRPD) shape method to classify types of defect stator coil generator by using off-line PD measurement instrument. The recorded PRPD, by using the instruments MPD600, can illustrate the PRPD patterns of partial discharge of unit’s defects. In the paper, two of large units, No.2 and No.3, in Inalum hydropower plant, North Sumatera, Indonesia is adopted in the experimental measurement. The proposed PRPD shape method is to mark auxiliary lines on the PRPD patterns. The shapes of PRPD from two units are marked with the proposed method. Then, four types of defects in IEC 60034-27 standard is adopted to classify the defect types of the two units, which types are microvoids (S1), delamination tape layer (S2), slot defect (S3) and internal delamination (S4). Finally, the two units are actually inspected to validate the availability of the proposed PRPD shape method.
Modelling and Technical Assessment of Multi-Motor for Electric Vehicle Drivetrains by Using Electric Differential
This paper presents a technical assessment of an electric vehicle with two independent rear-wheel motor and an improved traction control system. The electric differential and the control strategy have been implemented to assure that in a straight trajectory, the two rear-wheels run exactly at the same speed, considering the same/different road conditions under the left and right side of the wheels. In case of turning to right/left, the difference between the two rear-wheels speeds assures a vehicle trajectory without sliding, thanks to a harmony between the electric differential and the control strategy. The present article demonstrates a complete model and analysis of a traction control system, considering four different traction scenarios, for two independent rear-wheels motors for electric vehicles. Furthermore, the vehicle model, including wheel dynamics, load forces, electric differential, and control strategy, is designed and verified by using MATLAB/Simulink environment.
Technical Assessment of Utilizing Electrical Variable Transmission Systems in Hybrid Electric Vehicles
The Electrical Variable Transmission (EVT), an electromechanical device, can be considered as an alternative solution to the conventional transmission system utilized in Hybrid Electric Vehicles (HEVs). This study present comparisons in terms of fuel consumption, power split, and state of charge (SoC) of an HEV containing an EVT to a conventional parallel topology and a series topology. To this end, corresponding simulations of these topologies are all performed in presence of control strategies enabling battery charge-sustaining and efficient power split. The power flow through the components of the vehicle are attained, and fuel consumption results of the considered cases are compared. The investigation of the results indicates utilizing EVT can provide significant added values in HEV configurations. The outcome of the current research paves its path for implementation of design optimization approaches on such systems in further research directions.
Development of Transmission and Packaging for Parallel Hybrid Light Commercial Vehicle
The hybrid electric vehicle is widely accepted as a promising short to mid-term technical solution due to noticeably improved efficiency and low emissions at competitive costs. Retro fitment of hybrid components into a conventional vehicle for achieving better performance is the best solution so far. But retro fitment includes major modifications into a conventional vehicle with a high cost. This paper focuses on the development of a P3x hybrid prototype with rear wheel drive parallel hybrid electric Light Commercial Vehicle (LCV) with minimum and low-cost modifications. This diesel Hybrid LCV is different from another hybrid with regard to the powertrain. The additional powertrain consists of continuous contact helical gear pair followed by chain and sprocket as a coupler for traction motor. Vehicle powertrain which is designed for the intended high-speed application. This work focuses on targeting of design, development, and packaging of this unique parallel diesel-electric vehicle which is based on multimode hybrid advantages. To demonstrate the practical applicability of this transmission with P3x hybrid configuration, one concept prototype vehicle has been build integrating the transmission. The hybrid system makes it easy to retrofit existing vehicle because the changes required into the vehicle chassis are a minimum. The additional system is designed for mainly five modes of operations which are engine only mode, electric-only mode, hybrid power mode, engine charging battery mode and regenerative braking mode. Its driving performance, fuel economy and emissions are measured and results are analyzed over a given drive cycle. Finally, the output results which are achieved by the first vehicle prototype during experimental testing is carried out on a chassis dynamometer using MIDC driving cycle. The results showed that the prototype hybrid vehicle is about 27% faster than the equivalent conventional vehicle. The fuel economy is increased by 20-25% approximately compared to the conventional powertrain.
Hybrid Anomaly Detection Using Decision Tree and Support Vector Machine
Intrusion detection systems (IDS) are the main components of network security. These systems analyze the network events for intrusion detection. The design of an IDS is through the training of normal traffic data or attack. The methods of machine learning are the best ways to design IDSs. In the method presented in this article, the pruning algorithm of C5.0 decision tree is being used to reduce the features of traffic data used and training IDS by the least square vector algorithm (LS-SVM). Then, the remaining features are arranged according to the predictor importance criterion. The least important features are eliminated in the order. The remaining features of this stage, which have created the highest level of accuracy in LS-SVM, are selected as the final features. The features obtained, compared to other similar articles which have examined the selected features in the least squared support vector machine model, are better in the accuracy, true positive rate, and false positive. The results are tested by the UNSW-NB15 dataset.
Real Time Monitoring and Control of Proton Exchange Membrane Fuel Cell in Cognitive Radio Environment
The generation of electric power from a proton exchange membrane (PEM) fuel cell is influenced by temperature, pressure, humidity, flow rate of reactant gaseous and partial flooding of membrane electrode assembly (MEA). Among these factors, temperature and cathode flooding are the most affecting parameters on the performance of fuel cell. This paper describes the detail design and effect of these parameters on PEM fuel cell. Performance of all parameters was monitored, analyzed and controlled by using 5KWatt PEM fuel cell. In the real-time data communication for remote monitoring and control of PEM fuel cell, a normalized least mean square algorithm in cognitive radio environment is used. By the use of this method, probability of energy signal detection will be maximum which solved the frequency shortage problem. So the monitoring system hanging out and slow speed problem will be solved. Also from the control unit, all parameters are controlled as per the system requirement. As a result, PEM fuel cell generates maximum electricity with better performance.
Effect of the Levitation Screen Sizes on Magnetic Parameters of Tracking System
Analytical expressions for inductances, current, ampere-turns, excitation winding, maximum width, coordinates of the levitation screen (LS) are derived for the calculation of electromagnetic devices based on tracking systems with levitation elements (TS with LS). Taking into account the expression of the complex magnetic resistance of the screen, the dependence of the screen width on the heating temperature of the physical and technical characteristics of the screen material and the relationship of the geometric dimensions of the magnetic circuit is established. Analytic expressions for a number of functional dependencies characterizing complex parameter relationships in explicit form are obtained and analyzed.
Generation of Numerical Data for the Facilitation of the Personalized Hyperthermic Treatment of Cancer with An Interstital Antenna Array Using the Method of Symmetrical Components
The method of moments combined with the method of symmetrical components is used for the analysis of interstitial hyperthermia applicators. The basis and testing functions are both piecewise sinusoids, qualifying our technique as a Galerkin one. The dielectric coatings are modeled by equivalent volume polarization currents, which are simply related to the conduction current distribution, avoiding in that way the introduction of additional unknowns or numerical integrations. The results of our method for a four dipole circular array, are in agreement with those already published in literature for a same hyperthermia configuration. Apart from being accurate, our approach is more general, more computationally efficient and takes into account the coupling between the antennas.