Design and Implementation of Efficient Energy Converters for Mechanical and Thermal Energy Harvesting

This thesis research is aimed at designing a combination of an alternating current (AC) to direct current (DC) converter and a DC to DC converter to be used in an innovative piezoelectric and thermoelectric energy harvesting system, by simulating and comparing commercially proven respective AC/DC and DC/DC converters. The HiSEC (Highway Sensing and Energy Conversion) module which encompasses the piezoelectric and thermoelectric materials is intended to be buried underneath the roadway, where mechanical vibrations produced by vehicles and solar energy produced from sunlight are capturing energy and converting it to useable power. A wide range of AC to DC and DC to DC converters can be used to assist in energy harvesting applications, depending on the amount of efficiency required in each system. A number of converter circuits have been designed, simulated and tested within the 12" x 12" HiSEC modules to test the efficiency and reliability of each. Alternative energy harvesting systems in most cases require a regulated voltage output in order to store power into a regulated power source such as rechargeable batteries. The energy that is captured and stored in the form of batteries is needed to provide sensors and communication systems with a reliable source of energy to be self-sustainable. The full functionality of the HiSEC module is tested using an electromechanical testing machine such as the MTS Acumen Machine to evaluate the voltage regulation, load optimization, and efficiency of the converter circuit used. This thesis work reports a designed and simulated AC to DC and DC to DC converter using circuit simulation software to be tested with piezoelectric and thermoelectric materials, respectively. The simulated and tested converter developed in this work is a novel electronic device that is a two input-one output compact converter that allows for reliability and high conversion efficiency.