Energy Harvesting for Wireless and Less-Wired Sensors in Gas Turbines
Doktorsavhandling, 2019

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.

coupled harvester

piezoelectric harvester


Energy harvester

thermoelectric harvester

harsh environment



Opponent: Prof. Eric Yeatman, Department of Electrical and Electronic Engineering, Imperial College London, United Kingdom


Elof Köhler

Chalmers, Mikroteknologi och nanovetenskap (MC2), Elektronikmaterial och system

Impact of designed asymmetries on the effective bandwidth of a backfolded piezoelectric energy harvester

Sensors and Actuators, A: Physical,; Vol. 292(2019)p. 77-89

Artikel i vetenskaplig tidskrift

Achieving increased bandwidth for 4 degree of freedom self-tuning energy harvester

Journal of Sound and Vibration,; Vol. 420(2018)p. 165-173

Artikel i vetenskaplig tidskrift

Simulation and experimental demonstration of improved efficiency in coupled piezoelectric cantilevers by extended strain distribution

Sensors and Actuators, A: Physical,; Vol. 229(2015)p. 136-140

Artikel i vetenskaplig tidskrift

High temperature energy harvester for wireless sensors

Smart Materials and Structures,; Vol. 23(2014)p. Art. no. 095042-

Artikel i vetenskaplig tidskrift

Analytic modeling of a high temperature thermoelectric module for wireless sensors

Journal of Physics: Conference Series,; Vol. 557(2014)

Paper i proceeding

Metal Thermoelectric Harvester for Wireless Sensors - E. Köhler, T.M.J. Nilsson and P. Enoksson

The development of low power electronics and more efficient wireless communication has led to an increase in the use of wireless sensors, both with new sensor applications but also by replacing existing wired sensors with wireless solutions. One of the key reasons for replacing a wired sensor with a wireless sensor is to reduce the amount of wires used, reducing both the cost of the wires and the time needed to install a sensor.

However, wireless sensors require a power source to function. A battery is often preferred with the combination of high energy content, low self-discharge and low cost. If for some reason the environment is not suitable for batteries (e.g. if the temperature is too high, if the sensor is inaccessible under long periods of time or the peak power is too high) the battery should be replaced or combined with other power source solutions. Also, even if the wireless sensor can be battery powered for many years it can be beneficial to combine it with an energy harvester to increase the life time further. To have, for example, a car or a truck to go into service only to change sensor batteries is impractical.

The unique gas turbine environment and the high demands associated with the aerospace industry has shaped the outcome of this thesis. Various gas turbines located in test facilities in Europe has contributed to the vibrational- and temperature data used in this project and has also been subject to harvester measurements for powering wireless sensors. The gas turbines in these test facilities can have thousands of sensors, with many of them requiring difficult wire placements. In these harsh environments the complexities of wireless sensors increase as well. However, one of the key reasons for replacing a wired sensor with a wireless or less-wired sensor is to reduce the amount of wires used, reducing both the cost of wires and the time needed to install/debug the sensor. Reduced weight can also be an additional reason for wireless sensors, e.g. in aircraft gas turbines.

Developing energy harvesters for gas turbines is a combination of energy conversion and survivability in harsh environments. It requires aerospace grade materials and cables and sometimes that electronics are placed far away from the harvester. This approach gives a different prerequisite of the harvester designs than if the harvesters are investigated without considering a specific application. Another consequence of this approach is the aim and presentation of the harvester results, with more focus on connectivity with a wireless sensor system than the more conventional power output/efficiency of the energy harvesters.

Sensors Towards Advanced Monitoring and Control of Gas Turbine Engines (STARGATE)

Europeiska kommissionen (EU) (EC/FP7/314061), 2012-11-01 -- 2015-10-31.


Hållbar utveckling

Innovation och entreprenörskap






Rymd- och flygteknik

Övrig annan teknik

Annan elektroteknik och elektronik



Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 4598


Chalmers tekniska högskola


Opponent: Prof. Eric Yeatman, Department of Electrical and Electronic Engineering, Imperial College London, United Kingdom

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