Energy Conservation using Photovoltaic Plants Ivan Milenov and Vasil Dimitrov Page: 1-7 Abstract_Full_Text 1.72 MB Download: 58 times https://doi.org/10.6025/stj/2023/12/1/1-7 Abstract: Energy conservation and development are critical activities across countries. Optimum energy use ensures and protects the environment. In this work, we designed a solar energy system using photovoltaic cells. The use of photovoltaic cells helps the conversion of energy into electricity.
A Simplified Control Strategy Based on the Linearization of the Dynamic Model Combined with Trajectory Tracking Rosen Mitrev and Plamen Petrov Page: 8-14 Abstract_Full_Text 1.34 MB Download: 54 times https://doi.org/10.6025/stj/2023/12/1/8-14 Abstract: The automatic control of draglines has an edge over the manual control including greater efficiency. In this work, we advocated a simplified control strategy based on the linearization of the dynamic model combined with trajectory tracking and linear feedback control law. Using Lagrange formalism, we introduced the design which was tested in our work.
Metaheuristic Approaches with the Quadtree and the Harmony Search Method Stojanche Panov and Saso Koceski Page: 15-20 Abstract_Full_Text 598 KB Download: 54 times https://doi.org/10.6025/stj/2023/12/1/15-20 Abstract: Global path planning is an issue for which we advocated a new metaheuristic approach. This process has a combination of the search space separation capabilities of the Quadtree method and the optimisation capabilities of the Harmony Search method. After the proposition, we tested it and found it more efficient and resulting in high convergence.
Efficient RF Voltage Transformer with Bandpass Filter Characteristics M. Moreira, J. Bjurström, I. Katardjiev and V. Yantchev Page: 21-26 Abstract_Full_Text 871 KB Download: 61 times https://doi.org/10.6025/stj/2023/12/1/21-26 Abstract: A microwave bandpass filter with a large ratio between the output and the input impedance has been designed and fabricated. Consequently, it functions both as a voltage transformer and a bandpass filter or transfilter for brevity. It represents a two-port micro-acoustic resonator employing Lamb waves in a thin piezoelectric AlN film grown onto a Si carrier substrate with a center frequency of around 887 MHz. The transfilter has a transformer ratio of 10 and a voltage efficiency over 80%. The component has a small size (<0.5 mm2) and is shown to sustain power levels of 250 mW. It can be used in a variety of cases where both voltage amplification and frequency filtering are required. Examples include: charge pumps in RFID tags, energy scavenging, remotely triggered switches, wake-up radios in wireless networks, stand-by units in home electronics, etc.
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