Adaptive Maximum Power Point Finding Using Direct VOC/2 Tracking Method with Microwatt Power Consumption for Energy Harvesting
Chew, ZJ; Zhu, M
Date: 15 November 2017
Journal
IEEE Transactions on Power Electronics
Publisher
Institute of Electrical and Electronics Engineers (IEEE)
Publisher DOI
Abstract
Maximum power transfer occurs in many energy harvesters at their half open-circuit voltage (VOC/2). A novel implementation method of maximum power point finding based on the VOC/2 method is presented by exploiting the capacitor charging voltage across a capacitor connected in parallel with the energy harvester. The presented technique ...
Maximum power transfer occurs in many energy harvesters at their half open-circuit voltage (VOC/2). A novel implementation method of maximum power point finding based on the VOC/2 method is presented by exploiting the capacitor charging voltage across a capacitor connected in parallel with the energy harvester. The presented technique has a specifically designed high-pass filter which has a peak output voltage that corresponds to the VOC/2 of the energy harvester. The control circuit filters and differentiates the voltage across the smoothing capacitor to directly determine the timing of reaching the VOC/2 of the energy harvester without having to find the VOC first, and is fully implemented using discrete analog components without the need of a microcontroller, leading to low power consumption of the method. In this paper, the control circuit is used in conjunction with a full wave diode bridge rectifier and a dc-dc converter to harvest energy from a piezoelectric energy harvester (PEH) as the studied case. The PEH was subjected to various strain levels at low frequencies from 2 to 10 Hz. Experimental results show that the implemented circuit is adaptive to various vibration amplitudes and frequencies and has a maximum power point finding efficiency of up to 98.28% with power consumption as low as 5.16 μW.
Engineering
Faculty of Environment, Science and Economy
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