A Compact Multi-Input Power Conversion System with High Time-Efficiency Inductor–Sharing Technique for Thermoelectric Energy Harvesting Applications

2015 ◽  
Vol 25 (01) ◽  
pp. 1640007 ◽  
Author(s):  
Chia-Lun Chang ◽  
Tai-Cheng Lee

A compact multi-input thermoelectric energy harvesting system implemented in a 0.18[Formula: see text][Formula: see text]m CMOS technology is proposed to extract electrical energy from human body heat. By combining the techniques on inductor sharing and bidirectional power converter, the harvesting- and regulating-stage circuits in conventional energy harvesting system can be merged into a single-stage circuit. With the proposed duty-cycle-based strategy for maximum power extraction and the high-efficiency timing scheme for inductor sharing, the proposed multi-input thermoelectric energy harvesting system can ensure optimal power transfer from each thermoelectric energy source without sacrificing power conversion efficiency (PCE) and maximum output power capability. The peak PCE is achieved at 58.5%, the maximum end-to-end output power is 2.43[Formula: see text]mW, and the maximum output power capability is 32.4[Formula: see text]mW while the storage capacitor is fully charged.

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2192 ◽  
Author(s):  
Chengbin Yu ◽  
Young Seok Song

Graphene aerogel-supported phase change material (PCM) composites sustain the initial solid state without any leakage problem when they are melted. The high portion of pure PCM in the composite can absorb or release a relatively large amount of heat during heating and cooling. In this study, these form-stable PCM composites were used to construct a thermoelectric power generator for collecting electrical energy under the external temperature change. The Seebeck effect and the temperature difference between the two sides of the thermal device were applied for thermoelectric energy harvesting. Two different PCM composites were used to collect the thermoelectric energy harvesting due to the different phase transition field in the heating and cooling processes. The graphene nano-platelet (GNP) filler was embedded to increase the thermal conductivities of PCM composites. Maximum output current was investigated by utilizing these two PCM composites with different GNP filler ratios. The thermoelectric energy harvesting efficiencies during heating and cooling were 62.26% and 39.96%, respectively. In addition, a finite element method (FEM) numerical analysis was conducted to model the output profiles.


2014 ◽  
Vol 976 ◽  
pp. 159-163 ◽  
Author(s):  
Roberto Ambrosio ◽  
Hector Gonzalez ◽  
Mario Moreno ◽  
Alfonso Torres ◽  
Rafael Martinez ◽  
...  

In this work is presented a study of a piezoelectric energy harvesting device used for low power consumption applications operating at relative low frequency. The structure consists of a cantilever beam made by Lead Zirconate Titanate (PZT) layer with two gold electrodes for electrical contacts. The piezoelectric material was selected taking into account its high coupling coefficients. Different structures were analyzed with variations in its dimensions and shape of the cantilever. The devices were designed to operate at the resonance frequency to get maximum electrical power output. The structures were simulated using finite element (FE) software. The analysis of the harvesting devices was performed in order to investigate the influence of the geometric parameters on the output power and the natural frequency. To validate the simulation results, an experiment with a PZT cantilever with brass substrate was carried out. The experimental data was found to be very close to simulation data. The results indicate that large structures, in the order of millimeters, are the ideal for piezoelectric energy harvesting devices providing a maximum output power in the range of mW


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