A green hybrid energy harvesting system for rotational motion

This thesis describes a novel, innovative high power density electromagnetic energy harvester device powered by rotational motion. The primary aim of the thesis was to develop high power density energy scavenging device extracting power from rotational motion. In this thesis, a novel permanent magnet array based energy harvesting device is developed and a charging circuit was prototyped to extract the power generated by energy harvester and deliver it to battery. The design of the rotational energy harvester improves the performance, and the use of the axial flux permanent magnets enables inducing strong magnetic field in the coil, which resulted in large induced voltage.;Most of the research work published in the scientific journals has used ambient vibrations in the environment as the energy source. These devices have not achieved the desired power levels, which can enable their practical real life implantations as reliable energy harvesting sources. Most of the rotational motion energy harvesters published in the scientific journals also have not been able to achieve high power density levels. The rotational motion energy harvesters have very important applications such as tire pressure sensing, and MEMS sensors in the automobile, as wells as flywheel rotating mechanisms. In this work, it is demonstrated that in many applications, a rotational energy harvester can offer significant improvements in power density over its vibration-driven counterparts.;In this thesis, using axial flux permanent magnet arrays, a prototype of rotational electromagnetic energy harvester was developed. The rotational motion was coupled to rotor in the laboratory to generate the rotational torque. This creates a relative angular speed between rotor and stator, which enable the power to be generated. The novel approach used in the design enables magneto static coupling between coils and permanent magnets that leads to higher flux change and greater induced voltage, which eventually lead to high power output.;The detailed analysis of the magnetic material and air gap flux density distribution is conducted in the thesis work. The detailed analytical model of the rotational energy harvested was created and implement using Matlab(TM). The FEM modeling of the rotational motion energy harvester was created in FEM simulation software ANSYS Maxwell(TM). The result of both analytical and FEM simulation matched well with the experimental data collected on the generator. A detailed optimization procedure of boost converter was implemented using Matlab(TM) in order to maximize the power in the circuit. Using a novel approach to reduce the transformer losses in the boost converter was developed which reduced the circuit losses. The final charging circuit tests were conducted on the energy harvester. The power output of 2.5 Watts was calculated from a single harvester. The device generated open circuit voltage of 6.3V and short circuit current of 0.355 A at 2200 RPMs. Under maximum power transfer a single harvester delivered 0.6 W of power to load resistance of 18.2 ohms.