Design enhancement of windbelt electric generator for low power devices / Andrea Genin C. Reyes, Eduardo P. Reyes, Jarwen Grason A. Reyes, Timothy Joseph G. Tormo

Bachelor's thesis

College of Engineering Bachelor of Science in Electronics Engineering Technological University of the Philippines 2016

Includes bibliographic references and index.

This project focused on enhancing the windbelt design as an electric generator for low power devices. The windbelt was one of the innovative ideas in the field of energy conversion. It harnesses wind energy and converts it into electrical energy that can power up low power devices. The windbelt is composed of a frame, a belt, a coil and a pair of magnets. The introduction of wind to the belt will cause the belt to vibrate in the principle of aeroelastic flutter. The magnets will oscillate above the coil which will generate current through electromagnetic induction. Experiments showed that variations of some parameters of the windbelt increased its efficiency. The aim of the study is to determine the optimum state of each of the parameters of the prototype and constructing it using locally available materials on the market.
Materials characterization technique was the method employed in this research. Characterization of materials focuses on enhancing the design between structure, properties, and efficiency. The following design parameters were belt material, magnet-type, belt length and tension, magnet placement, frame dimension, number of coil turns and distance of coil to magnet. Numerous experiments of each of the parameters were conducted to know what state the parameter will yield the highest output voltage and current. During series of experiments, the prototype was subjected to constant testing condition for consistency of those data gathered on different parameters. After obtaining the optimized parameters, the data were gathered and analysed on Matlab through curve-fitting technique.
Since the generated current was alternating and small, solutions of connecting a bridge-type rectifier, filter and regulator was implemented. The bridge-type rectifier circuit converts the AC into pulsating DC and the smoothing capacitor filter decreases the ripple of the DC voltage. The LTC 3108 is an Integrated Circuit with a regulator and charge controller as one of its application circuit. The final output voltage was 4.87 V and the final output current was 1-3mA ranging. Using the output voltage and current, the Li-Ion battery had been charged. The charge control application circuit prolongs the battery's life. The rectifier, filter, IC and battery were constructed on the Integrated Circuit Box for aesthetics and presentability.
The prototype was implemented to three different areas after the experimentation.
During implementation, the prototype produced significant outputs for validation of the outputs obtained on the experiments.
The results showed that the optimum type of the belt was latex rubber that has a width of 19.05mm and length of 435mm stretched to 585mm frame. The optimum magnet location is at 290mm away from the edge of the frame. The optimum coil was copper magnetic wire with #31 AWG size. Its optimum diameters were 92mm outer and 30mm inner diameters with 1000 turns. The optimum magnet is Neodymium Iron Boron with dimensions of 25mm diameter x 3 mm thickness. A mathematical model was devised by analysing the data through curve fitting. Such recommendations could be creating an array of windbelt connected in series/parallel to produce higher voltage/current.