Journal of Advances in Science and Engineering

Design and optimisation of wireless power transfer system for charging mobile phone

Cynthia A. Okafor — 2024-01-31

In light of the technological challenges in the current research trend of Wireless Power Transfer systems in today’s world, this paper puts forward innovative calculations, models, implementation and methods for optimising the coupling coil combining the state-of-the-art of the existing research. The results and analysis were done using MATLAB/SIMULINK. Wireless charging technology enables wireless power transfer from a power source (e.g., a charge) to a load (e.g., a mobile device) across an air gap. The technology provides convenience and a better user experience. Recently, wireless charging has been rapidly evolving from theories toward standards, and being adopted in commercial products, especially mobile phones and portable devices using wireless charging has many benefits. First, it improves user-friendliness as the hassle of connecting cable is removed. Different brands and models of devices can also use the same charger. Secondly, it eliminates the constant replacement or damage of the phone charging port. Thirdly, it enhances flexibility, especially for devices for which battery replacement or cable connection or charging is costly, hazardous or infeasible e.g. (body-implanted sensor) flouting wireless charging can provide on-demand power, avoiding an overcharging problem and minimising energy cost. The winder's power transfer system uses inductively coupled i.e. coupled magnetic fields to transfer electromagnetic energy from a charging base to a receiver in a portable device. This paper intends to achieve the wireless charging of mobile phones, optimise the efficiency of the charger, and simulate the circuit using MATLAB.

Analysis of the transient conditions of a three–phase induction motor

S. E. Ogunbor — 2024-02-28

The aim of this study is to build an experimental work bench and simulate a 4.1 kW (5.5HP) three phase induction motor in order to investigate the machine's transient behavior under various fault conditions. The method used in this study entails performing a series of experiments to determine the per phase parameters of the induction motor, such as no load tests, blocked rotor tests, and DC tests, and then implementing a model for the machine using MATLAB/Simulink in a graphical user interface environment. The machine's corresponding parameters were used to represent the model, and simulation was performed. The collected data were examined to identify the machine's operating characteristics under normal and transient circumstances. Results from this study reveals that the open circuit fault decays more slowly than the short circuit fault, and the peak current is almost twice that of the starting current. Although the transient is brief in duration and therefore unlikely to produce significant heating, it may cause high mechanical strains on the windings. The results demonstrates that the transient characteristics of an induction motor under various fault conditions may be determined entirely via computer simulation

Substation Ground Grid Design Using FEM Analysis

Abraham Akhikpemelo — 2024-01-31

A reliable substation earthing system is critical for power system stability and safety. This study presents the design and analysis of an electrical substation grounding system using the Finite Element Method (FEM) to ensure the safety of personnel and equipment. The design methodology, based on IEEE standards, was implemented using ETAP 16.0 software, considering a substation with a maximum expected short-circuit current of 40 kA. A two-layer soil model was used, and a square ground grid configuration (100 m x 100 m) was analyzed with and without vertical ground rods. The results demonstrate that while the overall ground resistance values were similar for both configurations (0.435 Ω with rods, 0.433 Ω without), the design with ground rods successfully maintained the calculated touch voltage (2391.4 V) below the tolerable limit (2832.5 V). Conversely, the design without ground rods was deemed unsafe, as the touch voltage (3876.3 V) exceeded the safety threshold. The findings confirm that FEM analysis is a reliable and effective tool for a detailed and realistic assessment of substation grounding systems, providing a flexible framework for designing grids that account for both present safety requirements and future system upgrades.