Integration of Thermoelectric Generator and Wireless Sensor Node Simulators

Abstract

under the Nuclear Energy Enabling Technologies Program's Advanced Sensors and Instrumentation Pathway aims to develop efficient and reliable thermoelectric generators (TEGs) for self-powered wireless sensor nodes (WSNs) for nuclear applications. The power harvesting technology has crosscutting significance to all U.S. Department of Energy Office of Nuclear Energy research and development programs, because the technology will enable self-powered WSNs in multiple nuclear reactor designs and spent fuel storage facilities using thermal energy available in a nuclear power plant or spent fuel storage facility. This project will address the technology gap that exists in realizing truly wireless sensor nodes due to the need for cables to connect to external power supplies and develop thermoelectric (TE) power harvesting devices to deliver sufficient power to drive the WSNs. The outcomes of the project will lead to significant advancement in sensors and instrumentation technology, reducing cost, improving monitoring reliability, and therefore enhancing safety. The self-powered WSNs could support the long-term safe and economical operation of all reactor designs and fuel cycle concepts, as well as spent fuel storage and many other nuclear science and engineering applications. Most wireless sensor network (comprising thousands of WSNs) applications require operation over extended periods of time beginning with their deployment. Network lifetime is extremely critical for most applications and is one of the limiting factors for energy-constrained networks. Based on the application, there are a wide range of different energy sources suitable for powering WSNs. A battery is traditionally used to power WSNs. The deployed WSN is required to last for a long time. Due to the finite amount of energy present in batteries, it is not feasible to replace batteries. Recently there has been a new surge in the area of energy harvesting where ambient energy in the environment can be utilized to prolong the lifetime of WSNs. Some of the sources of ambient energies are solar power, thermal gradient, human motion and body heat, vibrations, and ambient radio frequency energy. This report focuses on integrating TEG and WSN simulators with a directcurrent-to-direct-current (DC-DC) converter as an interface. A DC-DC converter is essential to balance a wide range of analog, digital, and radio loads acting on the energy source. Also, the voltage level generated by TEGs under varying temperature conditions could be low, irregular, and insufficient to operate a WSN; therefore, DC-DC is required to boost the voltage to a desired level. Most of the main problems with DC-DC converters used in a TEG system are related to impedance matching between the internal resistance of the TEG and the input resistance of the DC-DC converter. This report addresses the issue associated with dynamic impedance matching under varying temperature conditions in the effort to integrate TEGs and WSNs. In this effort, dynamic impedance matching algorithms like perturb and obse...