Theses & Dissertations
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PublicationDesign and simulation of 33/11 kV transformer protection using MATLAB simulink( 2024)Transformer protection approaches priorities differential protection, with attempts to enhance based on comparing no fault and internal fault scenarios. When a failure occurs, it's important to remove the transformer from the operational zone as soon as possible to avoid damage to the coils. Differential protection identifies faults in the protection zone and disconnects it appropriately. Such relays are commonly employed in protecting electrical equipment because of their high sensitivity and reliability. The differential protection requires the transformer's input power match its output power. Under regular settings, there is no current flowing through the relay coil when the secondary current is suitable. When a problem evolves, the currents will not be balanced. To activate the circuit breakers and isolate the faulted transformer, trip signal will be sent by the relay. Therefore, this study is focused on the design of the differential relay protection for transformer protection 33/11 kV. Then the effect of designated relay analyzed whether it’s successfully detected whenever the fault occurs within transformers protected zone. The whole power system was modelled and simulated, including the transformer and circuit breaker with an external fault at various locations are randomly set on the system based on previous studies.
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PublicationComparative analysis of permanent magnet synchronous motor performance by using fuzzy logic with PI controller( 2024)This study investigates the performance of Permanent Magnet Synchronous Motors (PMSMs) under the control of a Fuzzy Logic Controller (FLC) with a Proportional-Integral (PI) controller. PMSMs are widely recognized for their high efficiency, reliability, and low maintenance requirements, making them suitable for various industrial applications such as robotics, aerospace, and electric vehicles. Despite the prevalent use of PI controllers, they often struggle with the nonlinear dynamics of PMSMs, leading to significant overshoot, prolonged settling times, and sensitivity to parameter variations. These challenges can result in suboptimal performance and increased system wear and tear. To address these issues, this research explores the implementation of an FLC, which is adept at managing imprecision and uncertainty in system behavior without requiring an exact mathematical model. The study utilizes MATLAB Simulink to design and simulate both PI with FLC systems for PMSM speed control. Key performance metrics, including speed accuracy, transient response, and system stability, were rigorously evaluated under various operating conditions. Simulation results indicate that the FLC outperforms the PI controller, offering enhanced transient response, reduced overshoot, and quicker settling times. Additionally, the FLC's auto-tuning capability allows for easier adjustments and better adaptability to varying industrial environments, increasing its practical applicability. This study concludes that the FLC provides a more robust and adaptive control strategy for PMSMs, presenting a valuable alternative to traditional PI control methods in industrial applications.
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Publication3D localization of moisture distribution in rice silo using RTI based on Wi-Fi signal( 2022)Rice is a staple food which conveys a sign of local culture throughout Asia, particularly in South Asia, and it is consumed daily, either as cooked rice or indirectly as rice flour. Several measures are aimed at raising national rice production for the next few years as expected to see rising demand and falling supply. Researchers discovered that, in order to ensure an adequate supply of domestic output, appropriate silo facilities together with good agriculture practices should be addressed to resolve this prolonged issue in the agricultural industry. A silo's main purpose is to protect grain crops from the environment, especially moisture build-up, pest infestation, and fungal load. Therefore, grain storage is part of an important aspect of quality assurance in post-harvest activities. One of the main issues is the moisture content of the rice during storage. The current state of the art for moisture measurement of rice in a silo is based on grab sampling or very much relies on single rod sensors placed at random locations during measurement. The moisture content of stored rice is directly dependent on the surrounding and environmental factors which in turn affects the quality and economic value of the rice. In addition, the moisture content needs to be measured frequently for prompt action. Until today, the current sensor is very localized and the continuous measurement microwave sensor is very costly. There is also no commercially available 3D volumetric measurement of rice moisture content in the silo. This research reported preliminary work using a off-the-shelf wireless device i.e., esp8266 which can be placed around the silo to measure the change of moisture. A new technique has been proposed in this research, which uses a more accurate reconstruction of the image generated by radio tomography based on Wi-Fi signals. The technique is based on the Hybrid Tikhonov-LASSO (HTL) combines the advantage of Tikhonov and the LASSO method, which achieved the reconstructed image is cleaner. Also used Regression-based machine learning (ML) on RF Tomographic Imaging which can provide 3D moisture content measurements to localize the moisture distribution in storage. This proposed technique can detect multiple levels of localized moisture distributions in the silo with high accuracies, depending on the size and shape of the sample under test. Unlike other approaches proposed in open literature or employed in the sector, the proposed system can be deployed to provide continuous monitoring of the moisture distribution in silos.
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PublicationDevelopment of automated testing kit for assessing psychomotor skills acquired by performing thinking aloud-technique( 2024)Earlier studies indicate that proficiency in engineering, also referred to academically as 'psychomotor skill,' can be evaluated by contrasting the expertise of individuals within the field. The current evaluation methods, utilizing reports and written tests, primarily gauge students' accomplishments in the cognitive domain, falling short in assessing their proficiency in the psychomotor domain. The newer assessment method is needed to assess the elusive component of laboratory experiences in engineering technology laboratory experiment. This study aims to devise a method for quantifying psychomotor skills specifically within the context of engineering technology laboratory experiments. The measuring instrument, an Automated Engineers Testing Kit consists of a several LCD displays containing a thinking-aloud suggestion display and a few buttons for selection purpose. A Circuit Box with partially completed circuit and a basic tool to create an electric circuit was used during the research experiment as a part of the research plan. The instrument has been designed with two power supply options (adapter and battery mode) and the collected data is stored in the memory card to make it more mobile. The experimental research was based on an experiment using the quasi-experimental design technique that is "Non-equivalent control group design" is used to gather data from both the treatment and control groups. A number of 60 students for treatment group and 60 students for control group were recruited to diagnose the incomplete circuit and construct the circuit with necessary connections. This experiment research has shown that there is a statistically significant difference in psychomotor skill using thinking- aloud technique of treatment group measured before (pre-test mean = 60.45) and after (post-test mean = 89.31) exposure to laboratory experiment experience, and between the control group. The findings of this study reveal correlations between psychomotor skill levels and the proficiency in constructing circuits. The successful development and deployment of an 'Automated Engineers Testing Kit' present a promising avenue for emphasizing practical learning outcomes assessment in engineering laboratory experiments.
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PublicationModel system identification and adaptive controller design for R600a vapour compression refrigeration system( 2024)The research undertaken in this thesis is an investigation of the model system identification and adaptive controller design for R600a vapour compression refrigeration system. A refrigeration system removes heat from a thermally insulated compartment to keep the temperature inside the chamber below the ambient temperature and maintain it at a constant temperature with minimal variation or change in temperature. To address global ecological goals, a more environmentally friendly and energy-efficient refrigerant, R600a, has been proposed to replace R134a. R600a boasts a very low ozone depletion potential (ODP) and a global warming potential (GWP) of less than 20. However, the increased sensitivity of R600a to changes in temperature poses a critical challenge. Even slight pressure fluctuations can result in significant temperature variations. Therefore, meticulous management of the R600a refrigerant pressure is crucial for maintaining consistent and reliable system operation. To accommodate its usage, a Variable Speed Compressor and an Adaptive PID controller were developed in this research. To define the parameters of the adaptive controller, the modelling of the R600a characteristics was first performed through a closed-loop identification method using an autoregressive moving average with exogenous input (ARX) model and an autoregressive moving average with exogenous input (ARMAX) model. From the research conducted, it can be concluded that the best model for the vapour compression refrigeration system with a variable-speed compressor running R600a refrigerant setup in this research is ARMAX with a polynomial order of 221. ARMAX 221 has the best fit of 82.01%, a Final Prediction Error (FPE) of 0.02728, and a mean square error (MSE) of 0.02725. Based on the developed ARMAX model, it is then concluded that the best PID-based adaptive controller for this setup is an adaptive PD controller, which has a settling time of 972 s, a Steady State Error (SSE) of 0±0.30oC an overshoot of 1.8oC at the Peak time of 714 s. In conclusion, all the objectives of this research have been achieved. First, the vapour compression refrigeration system has been modified to have Variable Speed Compressor capability. Second, a real time black box model of VCRS using an R600a refrigerant system has been developed, which improves the accuracy of cooling control. Finally, an adaptive controller for the variable speed compressor of the vapour compression refrigeration system using R600a refrigerant has designed. The major contributions of this thesis are the model-tuned adaptive controller has a good transient response and a high degree of stability, as demonstrated by the real-time implementation results and the experiment demonstrated that the controller is capable of successfully tracking, regulating, and rejecting disturbances at a set point.