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

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

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 simulatio

Substation Ground Grid Design Using FEM Analysis

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

Emotionally intelligent chatbots-designing for empathy and emotional support: A review

The integration of emotional Intelligence into chatbots for empathy and support has brought dramatic development to many sectors. The development has led researchers to continue experimenting and studying diverse design techniques (novel and existing) to find the method(s) that best suit the building of emotionally intelligent chatbots. To address this challenge, this paper provides a reviewed literature that extracted features such as the work done, findings, limitations, and the design techniques adopted to either improve an existing model or design a new model. Findings from the reviewed papers indicate that the reviewed paper mostly used the sequence-to-sequence (seq2seq) model framework while incorporating it with other design techniques to improve on the seq2seq model. This is done based on the domain the model is built. However, other design techniques adopted by other reviewed papers are conditional variational auto-encoder, transformers, and a host of others. Although the researchers also incorporated other models with their main design technique to have a better system model

Evaluating the impact of injecting the 3050MW Mambilla power plant into the Nigerian grid network

The study aims to evaluate the impact of the injection of the 3050 MW Mambilla power plant into the Nigerian National Grid (NNG). To achieve this aim, line and bus data were collated from National Control Centre, Osogbo. The Mambilla power plant was injected at the Makurdi and Jalingo buses respectively in view of determining the optimal injection point. Load flow analysis employing the Newton Raphson technique was first performed without the Mambilla power plant injected into the NNG. The simulation was repeated for the respective power plant injection scenarios. For each case, the voltage profile and line losses were obtained accordingly. Total Voltage Deviations (TVDs) for the various scenarios were computed and used to determine the optimal point of injecting the Mambilla 3050MW power plant to NNG. All simulations were implemented using MATLAB software (version 2020b). A loss of 872.8 MW and 874.1 MW was observed in the network when the Mambilla power plant was injected at Makurdi and Jalingo bus respectively with respect to a base case loss of 876.1 MW. This corresponds to a reduction in a power loss of 0.36% and 0.12% respectively. A TVD of 0.0052 and 0.0169 was observed when the Mambilla power plant was injected at Makurdi and Jalingo buses respectively.  This implies that the voltage condition of the network is better when Mambilla was injected at the Makurdi bus. Hence, the Makurdi bus was identified as the optimal point for injecting the Mambilla 3050 MW power plant since it resulted in a better reduction of the system losses and overall voltage profile improvement of the network

Comparative assessment of the phytochemicals of the leaves and seeds of pigeon pea (Cajanus Cajan (L.) Huth) plant

The pigeon pea plant is one of the plants cultivated in the semi-arid tropics; it is widely cultivated in Nigeria. It is utilized as food and serves medicinal purposes. This study was carried out with the aim of assessing the phytochemicals. Pigeon pea leaves and seeds were purchased from farmers in Uromi, Edo state, and Rumugbo phase-2, Obia Akpor Local government area of Port Harcourt, Nigeria. The phytochemical components of both the fresh and dried leaves and seeds were determined using the standard method and the results obtained from this study showed that in both the fresh and dried leaves of pigeon peas alkaloids, flavonoids, terpenoids, steroids, phytosteroids, saponins, tannins, phenol, anthraquinones, quinones, xanthoproteins, and phlobatannin were detected while the acidic compound was absent. While in the fresh and dried seeds of pigeon pea, results obtained revealed that alkaloids, flavonoids, terpenoids, steroids, phytosteroids, saponins, anthraquinones, and quinones were present while tannins, phenol, xanthoproteins, phlobatannin, and acidic compound were absent. Phytochemical compounds of the ethanolic extract of the fresh and dried leaves and seeds of pigeon peas were determined using Gas Chromatography - Mass Spectroscopy and a total of 30, 13, 32, and 38 bioactive constituents were detected in the fresh leaves, dried leaves, fresh seeds, and dried seeds respectively using their retention times (RT) and mass-to-charge ratios (m/z)

State-of-the-art methods for sentiment prediction

Social media sentiment analysis has become a trendy issue recently. It is used and supported by numerous organizations across many industries due to its useful applications. To obtain insights, marketers are keen to hear what customers have to say. The difficulties in acquiring, deciphering, and extracting useful information from the vast amount of data that is constantly generated have multiplied. Crunching social data is still difficult, despite advances in technology and increased computational power. This well-organized study is devoted to comprehending the current state of sentiment analysis as a whole, including typical techniques, gaps, and methodologies. This study uses a logical approach to find, acquire empirical data, critically evaluate, and integrate the findings of all relevant to respond to certain research questions about the specified research topic. Additionally, this research defines the various sentiment analysis types and methods. This study holds its significance in light of these two contributions

Optimal sizing of a hybrid photovoltaic/fuel cell grid-connected power system including hydrogen storage

The global energy demand is enormous, yet nonrenewable resources such as fossil fuels, and nuclear power are insufficient to satisfy it. Renewable energy will eventually be the better option. This study investigates the design and optimization of a hybrid photovoltaic / fuel cell (PV/FC) energy system with an H2 tank linked to the grid. The primary objective of this research is to design and size a PV/FC energy system with an H2 storage tank to supply the energy needs of a university ICT center that is connected to an inconsistent grid. HOMER's energy-balance algorithms were used to determine the best design architecture. Using mean solar radiation data (22 years) obtained for the University of Benin ICT Center, hourly simulations were performed to determine the optimum configuration in terms of size, cost, and performance of the energy system. Findings revealed that a hybrid PV/FC power system with a 400 kW solar array, a 250 kW FC, a 240 kW inverter, and a 150 kW electrolyzer with an H2 tank of 700 kg will reliably supplement the inconsistent grid with a high proportion (92%) of renewable resources at $0.1052/kWh. An energy cost reduction of approximately 88 percent and a return on investment of 200 percent with a present value of$98,251,110 could be obtained in less than 2 years over the traditional grid/diesel systems. Using an ideally sized PV/FC hybrid system will alleviate Nigeria's electrical challenges, impeding the country's economic growth. Furthermore, hybrid PV/FC power systems can reduce CO2 emissions, resulting in a more environmentally friendly and sustainable environment

Comparative analysis of the economics and reliability of pure solar energy and utility supply

The increasing demand for energy and the need to transition to renewable sources has led to a growing interest in the use of solar energy. This paper conducts a comparative analysis of the economy and reliability of pure solar energy systems and utility supply in a small load area. The energy requirement of the chosen load area was estimated and the appropriate sizing of the solar system was made. The study uses the payback period method to estimate the economy and the Monte Carlo method to estimate the reliability. Load estimation was performed to determine the appropriate solar systems, which were then modelled using PVSyst. The results of the study show that solar energy can be a cost-effective and reliable alternative to utility supply; with a consistent maintenance cost of 4 % per annum, the return on investment was calculated to be 14.1 % per annum at a supply current tariff of ₦ 61.34 per kWh. The payback period showed that the investment in a solar photovoltaic (PV) system can be recovered in six years and nine months (6 years, 9 months). The Monte Carlo simulation demonstrated the reliability of the energy supply in a solar PV system compared to the Nigerian utility supply with the reliability index of the solar system being 93.81 % and that of the utility supply at 55.73 %

Fabrication of a GSM-based intruder detection system prototype based on ultrasonic sensor

The design and construction of GSM based ultrasonic intruder detection system for detecting an intruder through a protected environment was carried out and presented in this paper. An alarm is triggered when intrusion is detected through the use of ultrasonic sensor. Also, SMS is sent in the form of text to the owner’s mobile number via the GSM module being installed. The configuration and coordination required for the system units to function effectively were carried out by a programmed ATMEGA16 microcontroller. AC and DC voltage supplies were incorporated into the system to provide a constant power supply. The fabricated system was tested and found to work successfully in accordance with the target design specifications carried out as the intruder was successfully detected and SMS sent