Recent Advances in Electrical & Electronic Engineering - Volume 15, Issue 7, 2022

Background: Ferroresonance is a complex electrical phenomenon, which has long been considered a problem for power utilities. Besides, founding mitigation techniques, researchers have also devoted their efforts to predicting the occurrence of ferroresonance in susceptible networks. The study requires mathematically suitable transformer models for computer simulations. Objective: The objective of this paper is to study ferroresonance and examine the stability of the system when source voltage changes gradually from a low value to a high value. Methods: To meet the objective, the first thing required is to find an appropriate circuit model. The saturable core transformer is represented by its nonlinear dynamic model. With the help of that model, a Simulink block diagram has been developed in MATLAB. The Simulink model is examined under various circuit conditions and the stability of the system is analyzed at different stages. Results: It has been found that the system passes through a series of period-doubling bifurcation and ultimately reaches chaos. Conclusion: The model and the method used in this paper can be used as a very helpful tool as well as a powerful technique to understand the effect of specific parameters in the final behavior of the ferroresonance phenomenon.

Background: The automobile industry has traditionally been paper-intensive. Such a glut of paperwork presents an organizational challenge for both the financial institution and the customer. Deciding how to store and organize such paperwork presents a further challenge since much of the information contained therein is of a confidential nature. In today's highly electronic world, the array of disparate technologies available for interacting with customers is expanding rapidly. Vehicles and commercial vehicles must be maintained relatively often and therefore, documents appertaining to each maintenance must be locatable. The frequency with which the documents are produced increases the burden of keeping track of the necessary documents. Objective: The objective of developing a new innovative electronic management device system is an attempt to ease the burden of keeping track of and making available the necessary documents for maintaining one or more vehicles. Methods: The present paper relates to an electronic document management device, system, and method for storing, requesting, and accessing all vehicle-related documents. The designed electronic device includes a non-transitory medium with a computer-readable program code embodied therein. The computer-readable program code, on execution by one or more processors, configures the electronic device to receive the first one or more set(s) of trigger input(s). The device accesses one or more remote database comprising of non-personalised as well as personalised electronic documents after detecting the receipt of the first set of trigger inputs and stores information relevant to the set of trigger inputs from the non-personalised and personalised electronic documents in the database of the electronic device. Results: The results consist of an electronic device that can receive one or more first sets of trigger inputs and can access one or more remote databases comprising a non-personalized electronic document and a personalized electronic document and store information at least partially relevant to the one or more first set of trigger inputs. Conclusion: The designed machine has been proved to be efficient by involving innovative ideas, design consisting of a device manufactured for the transparency and user friendly for saving the vehicle documents, such as RC, pollution, insurance, service, driving license, vehicle specification, etc. by linking the concerned department with the user.

Background: The large-scale distributed new energy integrations bring about various non-ideal grid situations, which could deteriorate the control performance of grid-connected converters. Objective: This study aims to improve the control performance of the grid-connected converters when the grid is non-ideal. Methods: Firstly, a neutral point clamped (NPC) three-level grid-connected converter was studied, and the characteristics of the non-ideal grid were analyzed in detail. Then, a real-time signal extraction method called generalized sliding discrete Fourier transform (GSDFT) has been proposed to extract the non-ideal signals, e.g., harmonic components and negative sequence components, based on which a double closed-loop control strategy was designed to improve the control performance of the grid-connected converters when the grid is non-ideal. Results: The experimental results show that the converter double closed-loop control strategy in the non-ideal grid environment is suitable for a variety of non-ideal grid environments, and the gridconnected effect is good. Conclusion: Firstly, this paper analyzes the characteristics of non-ideal grid and establishes the mathematical model of NPC three-level grid-connected converter in non-ideal grid environment. Secondly, aiming at the problem of characteristic harmonics and negative sequence components in non-ideal power grid, a real-time and fast extraction method of non-ideal signals based on generalized sliding discrete Fourier transform is proposed. Finally, taking the three-phase grid current of grid-connected converter as the control target, the closed-loop control strategy of non-ideal signal extraction based on GSDFT is designed, and a good control effect is achieved.

Background: The existing literature depicts that since the advent of the hybrid permanent magnet switched-flux memory motor (HPMSF-MM), comprehensive research is focused on the design of three (3)-phase HPMSF-MM topologies, which limits their practical safety crucial design application range or scope, namely, in electric vehicle (EV). Objective: This research work aims to design a novel five (5)-phase fault-tolerant HPMFS-MM using the synergy of two key PMs, namely, a neodymium magnet (NdFeB) and Alnico magnet, also known as low coercive force (LCF) with an intrinsic overload fault detection capacity and excellent flux-regulation capacity to extend it practical application scope. Methods: This research paper employs finite element analysis (FEA) via ANSYS Maxwell electromagnetic software in designing, simulation, and analyzing the proposed fault-tolerant HPMSF-MM. Results: The key merit of the Proposed HPMSF-MM is the exhibition of an overload fault protection mechanism via an injection of a reversed temporary control pulse current into the field winding (FW) in the event of an overload fault condition to demagnetize the Alnico PM configuration to ensure that, almost all the generated flux are short-circuited via the design stator-core without linking the designed rotor as in the case of normal operation is effectively verified via the flux-linkage analysis in this paper. Conclusion: The proposed HPMFS-MM can effectively demonstrate its intrinsic overload fault detection mechanism, due to its tremendous flux-regulating or weakening capacity, in addition to its fault-tolerant teeth implementation merit of ensuring physical motor winding phase isolation in an event of a fault.

Background: The independent suspension winding in the dual-winding bearingless motor reduces the power density of the motor, and the amplitude of radial magnetic suspension force is affected by the limited slot space. As for the single-winding bearingless brushless direct current motor (BL-BLDCM), although preliminary researches have been carried out, a detailed analysis of its electromagnetic suspension characteristics is lacking. Objective: The magnetic suspension force mathematical model and electromagnetic suspension characteristics are analyzed through a single winding BL-BLDCM with a 12-slot/tooth stator and a 6-pole Permanent Magnet (PM) rotor. Methods: First, the structure and working principle of the motor are introduced, and the mathematical model of the magnetic suspension is derived. Then, through Maxwell software, a twodimensional finite element model of the single-winding BL-BLDCM is established. Finally, the variation of the controllable magnetic suspension force and the coupling radial force along the vertical axis with the key structural parameters such as the air gap length, the PM pole arc coefficient, and the PM thickness are studied. Results: The law of radial controllable magnetic suspension force and the coupling radial force along the vertical axis changing with related parameters is given, and the analytical model of radial magnetic suspension force is verified. Conclusion: The proposed radial suspension force mathematical model is effective; the analysis results of electromagnetic suspension characteristics can provide a reference for the optimal design of single winding BL-BLDCM.

Background: As the frequency of transformer winding faults becomes higher and higher, the frequency response analysis used to detect the winding status has attracted more and more attention. At present, there is still a lack of reliable and intelligent technologies for detecting the state of transformer windings in this field. Methods: In this paper, a transformer winding deformation diagnosis method based on centroid analysis of 3D frequency response curve is proposed. A 3D coordinate system is established with frequency, amplitude, and phase as the x, y, and z, respectively. The proposed method calculates the centroid of each 3D frequency response curve through an algorithm, and establishes a 3D coordinate system with the centroid of the normal winding 3D frequency response curve as the origin. The deviation distance and deviation angle between the centroid of mass of the 3D frequency response curve of the faulty winding in different frequency bands and the centroid of the 3D frequency response curve of the normal winding and the correlation coefficient of the traditional Frequency Response Analysis (FRA) curve. are calculated. The deviation distance and angle of the centroid and the correlation coefficient of the calculated frequency band are input as features into the Support Vector Machine (SVM) for intelligent diagnosis to achieve fault classification and optimizing its parameters with three optimization algorithms respectively. Results: The fault classification is realized by analyzing the distribution intervals of the centroids of the 3D frequency response curves of the three simulated faults. The accuracy of fault diagnosis using the 3D frequency response curve feature is significantly higher than the accuracy when using the traditional FRA curve feature and it proves the effectiveness of the proposed method. Conclusion: The proposed model can effectively identify different fault types and the diagnostic rate of the fault type is 100%.

Background: The overall performance of the hybrid electric vehicle is mainly governed by the energy storage systems characteristics with respect to their power and energy density. The batteries have a good energy density, while the Supercapacitor (SC) has a good power density. Methods: This paper presents a hybrid auxiliary source combined with a battery and the supercapacitor to use both characteristics of auxiliary energy source for Hybrid Electric Vehicle (HEV) application. The PI control technique manages the power flow so that the supercapacitor fulfills the transient power, and the battery supplies the steady-state power. The parameters of controllers are tuned by Ziegler Nichols and the frequency response-based method. Results: The performance of the controller is evaluated by error coefficients (IAE, ISE, ITAE and ITSE). The model with different tuning parameters is simulated for fixed and variable reference inputs. The speed, dc bus voltage, and error coefficients are evaluated for the battery alone and battery- SC combinations. Conclusion: The value of error-based parameters suggests that controller parameters tuned by the frequency response-based method provide better results. The error coefficients for batterysupercapacitor combination are lower than battery-alone systems indicating the better performance of hybrid input.