Browsing by Author "Huang, Kai-Jie"

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A Sustainable Soil Energy Harvesting System With Wide-Range Power-Tracking Architecture
(2019-10-01)
Ou, I-Che
;
Yang, Jia-Ping
;
Liu, Chia-Hung
;
Huang, Kai-Jie
;
Tsai, Kun-Ju
For wide-range deployment of wireless sensing nodes in power- and size-constrained Internet of Things applications, self-sustaining wireless sensors without batteries are needed. The energy supply for these ubiquitous sensing devices should harness environmental energy sources to avoid frequent battery replacement and pollution. This paper presents a new soil energy harvesting system with a power management integrated circuit (IC) for wide-range maximum power point tracking (MPPT). The output power of a soil energy cell varies widely according to the soil moisture and soil contents. To extract the maximum amount of energy from the soil, high-efficiency power management with adaptive dc-dc conversion ratios and an MPPT mechanism is essential. The proposed system is implemented with a high-efficiency dc-dc converter IC in a 0.18-mu m CMOS process. The design achieves a peak tracking efficiency of 90.5% in the throughput power range from 56 mu W to 1 mW at an output voltage of 3 V and system efficiency exceeding 65% over an input resistance range of the soil energy source; the peak system efficiency is 73.9%. A demonstration was undertaken of the soil energy harvesting system lighting an LED array without any chemical batteries.
A Wide-Range Capacitive DC-DC Converter with 2D-MPPT for Soil/Solar Energy Extraction
(2018-01-01)
Ou, I-Che
;
Yang, Jia-Ping
;
Liu, Chia-Hung
;
Huang, Kai-Jie
;
Tsai, Kun-Ju
This paper presents a capacitive DC-DC converter with adaptive DC-DC conversion ratios and maximum power point tracking (MPPT) for soil and solar energy extraction. To overcome the varying input power ranges of the soil/solar energy sources, a two-dimension power tracking loop with time-based current slope detection was employed. The design was fabricated in a 0.18 mu m CMOS process, achieving >80% efficiency in a throughput power range of 360 mu W to 25mW in the soil mode and from 400 mu W to 10mW in the solar mode while the peak system efficiency is 89.5%.