Recent Advances in Electrical & Electronic Engineering - Volume 12, Issue 2, 2019

Background: This paper presents a compensation technique to improve the efficiency of a microgrid (MG) in the distribution system. Methods: A Direct-Quadrature (D-Q) based compensation technique is proposed to mitigate the power quality issues in Microgrid on the load side. The proposed model is used to control and balance the power generation to load demand in MG under different loading conditions. Renewable Energy Source (RES) Photovoltaic (PV) and Wind based generations are considered as two micro generations and are integrated with the conventional power system. Result: The proposed model can be used as plug and play mode operation of MG. Conclusion: The performance of proposed compensation techniques is analyzed in the MATLAB / Simulink environment and the simulation results exhibit satisfactory controller action.

Background: The improvement of the voltage in power lines and the respect of the low voltage distribution transformer substations constraints (Transformer utilization rate and Voltage drop) are possible by several means: reinforcement of conductor sections, installation of new MV / LV substations (Medium Voltage (MV), Low Voltage (LV)), etc. Methods: Connection of mini-photovoltaic systems (PV) to the network, or to consumers in underserved areas, is a well-adopted solution to solve the problem of voltage drop and lighten the substation transformer, and at the same time provide clean electrical energy. PV systems can therefore contribute to this solution since they produce energy at the deficit site. Results: This paper presents the improvement of transformer substation constraints, supplying an end of low voltage electrical line, by inserting photovoltaic systems at underserved subscribers. Conclusion: This study is applied to a typical load pattern, specified to the consumers region.

Background: This study deals with the derivation of expressions for the current distribution and the input admittance of a circular loop antenna (CLA) over a lossy Earth in a series form. Methods: The analysis is based on the image method, Fourier series expansion and the direct integration of the vector potential. Result: The results for the current distribution of the study are in very good agreement with those corresponding results available in the literature, which checks the correctness of the formulations of the study. Conclusion: The provided solution in this paper is simple, straightforward and can be applied without performing any numerical integrations, which makes it preferred compared to the numerical solutions that are available in the literature.

Background: Continually in view of the fact that digital technology entered in the Operating Theatre (OT), surgery has moved out through one of the big revolutions in medical field. Robotic-Assisted Surgery (RAS) is a way of technological development in the medical environment, designed to thrash the limitations of Minimal Invasive Surgery (MIS). Surgical robots carry out operation with the motion control of manipulator joints on the patient. Precise and fine control of these robots is very imperative. Methods: The paper depicts the control methodology for surgical robots based on the combination of Sliding Mode Control (SMC) with Fuzzy Logic Control (FLC). The destructive chattering phenomenon in SMC is circumvented by espousing FLC in SMC. System stability is investigated using Lyapunov theorem. All numerical simulations have been carried out using MATLAB tool for 2 DOF robot manipulator formulated for trajectory tracking process which shows the efficacy of the proposed methodology. Results: The simulation results of FSMC are compared with the conventional SMC which represents the improvement of control law for the attainment of optimized results. Conclusion: The proposed methodology in the paper is very much suitable in controlling surgical robot during typical surgical operations. The effectiveness of proposed control methodology is shown using simulation studies in the paper.

Background: To effectively solve the segmentation problem with multi-target complex image, the chromatic aberration 2-D entropy threshold segmentation method based on Adaptive Step- Length Firefly Algorithm (ASLFA) is proposed in this paper. Methods: Firstly, the significance of image entropy value is analyzed and the threshold segmentation is proposed with maximum entropy principle. Then, in order to solve the problem of large amount and longtime of calculation in the threshold segmentation process, the improved firefly algorithm (FA) is proposed replacing the fixed step-length with adaptive step-length. Results: Finally, in order to make full use of the image information, the space distance of chromatic aberration is introduced and combined with FA. Conclusion: Contrast test of the proposed method and 2-D entropy threshold based on standard firefly algorithm (SFA) and genetic algorithm (GA) proves that the proposed method can improve the segmentation accuracy while ensuring the segmentation speed, and is suitable for fast and effective segmentation of multi-target images and complex images.

Background: In this paper, we propose a secure image watermarking technique which is applied to grayscale and color images. It consists in applying the SVD (Singular Value Decomposition) in the Lifting Wavelet Transform domain for embedding a speech image (the watermark) into the host image. Methods: It also uses signature in the embedding and extraction steps. Its performance is justified by the computation of PSNR (Pick Signal to Noise Ratio), SSIM (Structural Similarity), SNR (Signal to Noise Ratio), SegSNR (Segmental SNR) and PESQ (Perceptual Evaluation Speech Quality). Results: The PSNR and SSIM are used for evaluating the perceptual quality of the watermarked image compared to the original image. The SNR, SegSNR and PESQ are used for evaluating the perceptual quality of the reconstructed or extracted speech signal compared to the original speech signal. Conclusion: The Results obtained from computation of PSNR, SSIM, SNR, SegSNR and PESQ show the performance of the proposed technique.

Background: This paper investigates the detailed study on the performance of Brushless DC (BLDC) motors with sudden application of loads, by using different control techniques. The increasing trend of usage of accurate control, high torque, low noise and higher efficiency for Electric Vehicles has appealed the attention Researcher in BLDC motors. So, BLDC motors can act a substitute for the conventional motors like Switched Reluctance motors, Induction Motors etc. Methods: A Fractional Order Propositional-Integral Derivative (FOPID) controller has been proposed in this paper. The parameters FOPID controller is tuned with Particle Swarm (PSO) algorithm based on Integral Absolute Time Error (IATE) rule. A comparative analysis has been carried out in this paper by simulating the BLDC motor in MATLAB/Simulink and conducting experimental setup in the laboratory. Results: The results reveal that the performance of FOPID controller is better regarding settling time, steady state error and ripple factor in the speed response with sudden load application. Conclusion: In reference to the analysis, it can be summarized that the best tuned Fractional Order PID can perform better than the PID. The digital controller isimplemented using ccs-studio and tested in the DSPms320f28335 board.

Background: This paper describes the design of 5 V to 6 kV DC-DC converter by using a switching regulator with Cockroft-Walton (C-W) voltage multiplier for a high voltage power supply module. Methods: The proposed design consists of Pulse Width Modulation (PWM) controller circuit, voltage multiplier, and feedback signal. A single unit of 5 V input triggers LT1618 controller circuit to generate 20 V which then produces 300 V from LT8331 output that is connected to diode-capacitor multiplier circuit to achieve final 6 kV. A negative feedback signal is required to stabilize an output voltage. With the implementation of C-W voltage multiplier technique, the output is boosted up as required from the input signal voltage 5 V DC. Results: The LTspice simulation results indicate that the proposed DC converter can generate 6.20 kV. Line regulation of 17 % and the load regulation of 14 % are obtained based on the proposed design. Conclusion: The proposed design is suitable for high voltage power supply module.

Background: Currently, how to measure the magnetic field accurately is a difficulty in the study of strong magnetic field. Methods: This paper summarizes several methods of measurement techniques for strong pulsed magnetic field presently, the principles and characteristics of various measurement methods are compared and analyzed. The maximum measurement intensity of electromagnetic induction method can reach 103T. The magneto-optical effect method of Faraday can measure the magnetic field intensity of 0.1~10T, and the measurement error is within 10-2T. Results: The MOKE effect can measure a magnetic field intensity up to 100T, with an error 3×10-2T. The Zeeman effect can be measured in a magnetic field intensity of 1~20T. Conclusion: The existential problems of various methods are described. Lastly, some solutions are proposed according to the existential problems, and the development of measurement techniques for strong pulsed magnetic field in the future is prospected.

Background: Differential relay is normally used to detect faults in Synchronous Generator (SG) stator windings. Nevertheless, detection of ground fault depends on the generator grounding type. For high impedance grounding, the ground faults near the neutral terminal of the stator windings are not detectable by the differential relay. So, the ability to identify the internal fault of SG is a very important task for stable and safe operation of power systems. Methods: Accurate algorithms for fault detection and classification based on Recurrent Neural Network (RNN) are suggested in this paper. RNNs are trained using different data available from SG MATLAB/ SIMULINK model. Simulation of different fault scenarios based on LabVIEWTM program is discussed. The studied fault scenarios include; fault type, location, resistance and fault inception angle. The RNN based algorithm is experimentally tested using an actual SG. Practical design and implementation of the proposed fault detector and classifier are presented. The hardware system is designed and built to acquire the currents at both ends of SG terminals. Results: The presented results confirm the effectiveness of the proposed algorithm to detect minor ground faults near the neutral terminal (less than 5% of stator winding). Conclusion: The experimental analysis shows that the proposed RNN detects and classifies the internal faults correctly, fastly and remain stable after the faults occur.

Background: Since the distribution networks are passive until Distributed Generation (DG) is not being installed into them, the stability issues occur in the distribution system after the integration of DG. Methods: In order to assure the simplicity during the calculations, many approximations have been proposed for finding the system's parameters i.e. Voltage, active and reactive powers and load angle, more efficiently and accurately. This research presents an algorithm for finding the Norton's equivalent model of distribution system with DG, considering from receiving end. Norton's model of distribution system can be determined either from its complete configuration or through an algorithm using system's voltage and current profiles. The algorithm involves the determination of derivative of apparent power against the current (dS/dIL) of the system. Results: This work also verifies the accuracy of proposed algorithm according to the relative variations in the phase angle of system's impedance. This research also considers the varying states of distribution system due to switching in and out of DG and therefore Norton's model needs to be updated accordingly. Conclusion: The efficacy of the proposed algorithm is verified through MATLAB simulation results under two scenarios, (i) normal condition and (ii) faulty condition. During normal condition, the stability factor near to 1 and change in dS/dIL was near to 0 while during fault condition, the stability factor was higher than 1 and the value of dS/dIL was away from 0.