Browsing by Author "Mwinyiwiwa, Bakari M.M."

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    Developing a Laptop Power Adaptor for 12 V and 24 V Solar PV Source
    (IEEE, 2023-05-22) Chilumba, Lulu; Mushi, Aviti Thadei; Mwinyiwiwa, Bakari M.M.
    Rural and urban areas of developing countries such as Tanzania suffer from lack of reliable electricity supply. This situation limits the usage of portable electronic gadgets such as laptops, and mobile phones. This paper designs and simulates a laptop charger adapter using a DC-DC single ended primary inductor converter (SEPIC). This charging adapter accepts two voltage levels of varying sources of solar photovoltaic (PV) power. Its output is constant DC at 19.5 V and maximum 100 W power while input is either the variable 12 V or 24 V solar PV power source. The maximum power point (MPPT) algorithm is integrated with proportional integral (PI) controller to achieve the desired output. This design was validated numerically using the MATLAB/Simulink environment. Several results are presented showing the performance with the cases of varying solar irradiation from 800 W/m 2 to 1000 W/m 2 or vice versa. These simulation results indicate possibility of future work of the viability to fabricate the adaptor and test it in laboratory and in field.
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    MPPT DC-DC Buck-Boost Converter for Off Grid Hybrid Solar-Wind-Battery System in Ikuza Island, Tanzania
    (Tanzania Journal of Engineering and Technology (TJET), 2023-11-14) Nassoro, Nassoro Sadick; Msigwa, Consalva Joseph; Mushi, Aviti Thadei; Mwinyiwiwa, Bakari M.M.
    Ikuza Island in Kagera-Tanzania faces lack of electricity due to cost challenges of extending the grid by marine cables and other transmission facilities. These makes such endeavour not appealing to the supply authority due to those higher charges. Therefore, this paper undertakes to design hybrid renewable energy sources for the island by specifically focusing on the buck-boost converter for the energy conversion from these renewable resources. The design of the bidirectional buck-boost converter for maximum power point tracking in off-grid hybrid renewable energy systems is multifaceted due to the inhomogeneity nature of the renewable energy sources. The bidirectional buck-boost converter, solar PV, wind-based generator, and energy storage system are designed and simulated in MATLAB/Simulink software. The designed system is tested with varying solar irradiance (750 to 1000 W/m2), temperature (20 to 25C) and wind speed (150 to 157.5 radians/s) at constant load of 260 A while load variation involved varying the load current from 0 to 260 A at solar irradiance, temperature, and wind speed of 1000 W/m2, 25 C and 157.5 radians/s, respectively. The variation of DC link bus voltage at different load conditions is reported. The simulation results show that the designed converter is able to maintain DC link voltage at 600 V. Moreover, the DC link voltage shows a maximum drop of approximately 0.67% during the constant load condition. Contrarily, a significant improvement is observed when the designed converter operates with the hybrid system of solar PV, PMSG-based wind generator and with energy storage system.