Energy Harvesting for Wireless and Less-Wired Sensors in Gas Turbines

Sammanfattning: Four types of energy harvesters aimed for gas turbine applications were developed during this thesis. The unique gas turbine environment shaped the design- and material choices. A semiconductor thermoelectric harvester was built for a location in the gas turbine with active cooling at 600°C, with 800°C wall temperature. The thesis covers the material synthesis, design, assembly and proof-of-concept tests of this harvester at 800°C. A metal thermoelectric harvester was also built, but instead for locations without active cooling. The harvester design is long metal strips, capable of reaching active cooling far away. This harvester was successfully used to power wireless sensors and reached 290 μW power output after power management electronics. Two different types of piezoelectric harvesters were developed, both consisting of coupled off-the-shelf cantilevers. The development included simulations, analytic models and assembly/measurements on harvesters. The first design was a 2-degree-of-freedom folded coupled harvester which after optimizations achieved a minimum of 2.75 V in the frequency range 92-162 Hz with peak power output of 1.80 mW. The second design was a 4-degree-of-freedom self-tuning harvester, showing increased 3 dB-bandwidth from 8 Hz to 12 Hz with the use of a sliding weight.