Self-powered synchronized switching techniques and pulse frequency modulation switched-cap DC-DC converter for piezoelectric energy harvesting system

• Main Authors: Weian Chen, 陳韋安
• Other Authors: Hsin-Shu Chen
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/gh2327

碩士 === 國立臺灣大學 === 電子工程學研究所 === 107 === In this thesis, we expect vibration energy can transfer to electronic energy by piezoelectric device, harvesters can be installed around vibration sources to harvest energy from ambient vibrations, The output from a piezoelectric energy harvester is in alternating current (AC) form, and needs to be transformed into direct current (DC) form to supply electronic devices by an interface circuit. After interface circuit usually consists of a DC/DC converter to supply the blue-tooth wireless sensor. This thesis consists of AC-DC interface circuit and DC-DC converter. The output from a piezoelectric energy harvester is non-ideal it cause power -loss, so we can use Synchronized switching techniques to improve output-power, conventional Synchronized switching techniques need another power to control switch signal. This thesis fist presents self-powered的Synchronized Switching Harvesting on an Inductor(SSHI)interface circuit. The control signal is auto generated by MOS switch, peak detector and the comparator without external power.t According to measurement results, this chip has maximum output power of 21.3 μW when operating with a piezoelectric harvester with current amplitude 30 μA, operating frequency 120 Hz and internal static capacitance 6.7 nF. Compared to the standard interface circuit, this chip provides 161% output power (use T25HVG2 process) This thesis presents switched-cap DC/DC convertor adopts discrete-time pulse frequency modulation (PFM) control to achieve the design goals of low control power a without inductor. According to the measurement results, this chip has a peak efficiency of 62.8 % with 5 V input voltage and lock on 1.3V-1.33 voltage。