Adaptive switched capacitor voltage boost for thermoelectric generation
Thermoelectric generators (TEG) and other forms of energy harvesting often provide voltages that are not directly usable by traditional electronics as levels are too low from the TEG. While increasing the number of thermoelectric elements can ultimately increase the power output, there is a tradeoff between size and power. By implementing charge pumps, a proposed circuit technique is described that can boost the TEG output to levels that can be used for energy harvesting applications. Current voltage boost circuits for TEGs simply boost a voltage by a set amount. The proposed circuit consists of an analog chip, to provide several charge pump stages as well as a dynamic latched comparator for analog to digital conversion (ADC), and a digital circuit, to control the stages of the charge pump and adaptively boost the voltage to within a specific range rather than an unchangeable, fixed multiplication. Due to the possibility that the polarity of the TEG’s output voltage can reverse, dependent on environmental changes, the first charge pump stage is designed to allow for polarity switching to ensure the output is always at a positive voltage. Additionally, to improve energy efficiency, the digital controller’s state machine uses constant voltage Maximum Power Point Tracking (MPPT). Finally, the digital controller can adjust the number of charge pump stages to maintain a desired output voltage range. The manner in which these features are implemented are discussed. Future work will still be necessary for ensuring maximum circuit efficiency, adjust behavior, and to ensure durability of the system.
Computer Engineering|Electrical engineering|Energy
Brito, Rene Alfredo, "Adaptive switched capacitor voltage boost for thermoelectric generation" (2016). ETD Collection for University of Texas, El Paso. AAI10151336.