Low Power And High Efficiency Rectifying Circuit For Piezoelectric Energy Harvesting Applications

• Main Author: Mustapha, Ain Atiqa
• Format: Thesis
• Language: English; English
• Published: UTeM 2016
• Subjects: T Technology (General); TK Electrical engineering. Electronics Nuclear engineering
• Online Access: http://eprints.utem.edu.my/id/eprint/18654/1/Low%20Power%20And%20High%20Efficiency%20Rectifying%20Circuit%20For%20Piezoelectric%20Energy%20Harvesting%20Applications%2024%20Pages.pdf; http://eprints.utem.edu.my/id/eprint/18654/2/Low%20Power%20And%20High%20Efficiency%20Rectifying%20Circuit%20For%20Piezoelectric%20Energy%20Harvesting%20Applications.pdf; http://eprints.utem.edu.my/id/eprint/18654/; https://plh.utem.edu.my/cgi-bin/koha/opac-detail.pl?biblionumber=100943

Piezoelectric cantilever generated a voltage particularly dependent on the magnitude of vibration source and the resonant frequency. The magnitude of the electrical output from the energy harvester is dependent on the size of the device as well as the acceleration level of the vibration source. The type of piezoelectric used for this research is PSI-5A4E which is unimorph standard quick- mount extension sensor. The characteristics ofPSI-5A4E such as resonance frequency value, electrical equivalent circuit, the desired acceleration level, optimum power and optimum output voltage when connected to open circuit were investigated. The experiment has been set up to investigate the value of resonance frequency. After a series of experiment, the resulted value of resonance frequency is 61 Hz. To describe the electrical equivalent circuit for the piezoelectric generator, the PSI-5A4E is seen as a Norton equivalent of a voltage source, Vp, with internal impedance, Zp. This can be used to describe the power transfer from piezoelectric generator to a load. PSI-5A4E material has a capacitance of Cp=260nF. At resonance frequency, 61Hz, the complex conjugate load inductor is calculated to be L= 26.18H. There are two values of g-level were used for the analysis: 0.1g and 3g. To determine the optimum output power, subjected to the 61Hz resonance frequency and 0.1g and 3g level values, the experiment was conducted by varying the external load resistance from 1 on to 1 Mn. As a result, at 100k!1 load resistance, the optimum output is 0.38uW and 1.217uW for 0.1g and 3g-level respectively. Piezoelectric produced AC electrical energy which needs to be rectified first into DC before powering electronic devices. Concerning this goal, the simulation and experiment of various types of passive and active rectifiers have been carried out and been compared among each other. Full wave bridge rectifier (FWBR) is the conventional due to its simplicity and ready available. Howeyer, this option would not be compatible when operating at low voltage level because the voltage generated from the piezoelectric energy harvester could be less than that being required to operate the diodes. For this reason, low voltage operated rectifying circuit is vital for piezoelectric energy harvesting application. Various types of rectifiers are being used in the experiment whereby the characteristics of each rectifier is being studied and compared in order to identify the most suitable with high efficient rectifier to be integrated with piezoelectric energy harvester. For passive rectifier, the arrangements of the rectifier is in a form of full bridge and are tested with different type of diodes namely as standard diodes, zener diodes, Schottky diodes and MOSFETs. For active rectifier, the synchronous rectification method has been investigated. The output voltage and efficiency for all rectifiers has been compared. From the experimental results, active MOSFET op-amp rectifier has shown an efficiency of 96% and 98% for acceleration level of 0.1g and 3g respectively which is reported as the highest efficiency among all the other types of rectifier.