1. UKM Learning and Research Repository
2. PHD Thesis / Tesis PHD
3. Institute of Microengineering and Nanoelectronics / Institut Kejuruteraan Mikro dan Nanoelektronik (IMEN)

Title:	Design and modelling of extremely low frequency mems piezoelectric micro power generator for biomedical applications
Authors:	Moh'd H.S. Alrashdan (P42263)
Supervisor:	Azrul Azlan Hamzah, Prof. Madya Dr.
Keywords:	Micro power generator Vibration energy Human body Electric energy
Issue Date:	19-Jan-2016
Description:	Piezoelectric micro-power generator (PMPG) converts mechanical vibration energy into electric energy from human body via piezoelectric effects. In cardiac pacemakers, the use of PMPG eliminates the need for a traditional lithium iodide battery replacement. This thesis covers modelling, optimization, simulation and fabrication process development of PMPG that, is able to harvest the human body mechanical vibration to be converted into usable electrical power in low frequency range (1-100) Hz. Transformer model is used for PMPG modelling in sensor mode, where PMPG can be represented as AC current source connected in parallel with capacitor and resistor. For optimization purposes, Taguchi method with eight control parameters are utilized. Signal-to-noise (S/N) ratio analysis, and ANOVA analysis is performed to determine the optimum design. COMSOL Multiphysics ver. 4.2 is used in 18 different simulations. Both Taguchi and ANOVA confirm the same results of determining the parameter of having the most influence on the generated electric energy density. The maximum output energy density is 0.942 J/m3 at 26Hz first mode resonance frequency. COMSOL Multiphysics ver. 4.2 is used for PMPG simulation at optimized parameter, Eigen frequency analysis for the first six modes of operation for PMPG frequencies are: 26 Hz, 105 Hz, 204 Hz, 1492 Hz, 2492 Hz, and 2653 Hz. The first mode of operation is selected as operation mode and shows that 93 percent of PMPG's total displacement and output power was produced in the range of 25-27 Hz. Transient analysis performed at 26 Hz reaches the steady state after 0.2 s with output peak voltage is 3.5 V power density of 0.376W/cm3. Pb(ZrxTi1-x)O3 (PZT) thin films deposition using RF sputtering is characterized at morphotropic phase boundary (MPB). The influence of plasma parameter (RF power, Ar gas content and pressure) is studied to deposit the optimum Pb Zr 0.52 Ti 0.48 O3 thin film with 1.5μm thickness. Energy Dispersion Spectroscopy (EDS) is used to analyze the chemical composition of deposited PZT thin film and found that 250 W of RF power, 15mT of Ar gas pressure, and 18 Sccm of Ar gas content is necessary for Pb Zr 0.52 Ti 0.48 O3 thin film deposition. An XRD technique is used to study phase formation in optimized PZT thin film. The perovskite phase (100, 110, and 111,200) is observed with maximum peak intensity of 1200 counts/ second for 110 phase, piezoelectric constant d33 of 413 pm/v and 0.68 electromechanical coupling coefficient. The PMPG fabricated parameters has 10 μm SU8 proof mass, 200nm Au /20 nm Cr interdigitate electrode, 1.5 μm functioning PZT layer and 200 nm Si3N4 on 10 μm Si substrate. The Fabricated PMPG parameter vibrate at 61 Hz with power density of 0.29 W/cm3 and can supply 3.33AC voltage, 2.19V DC voltage to the final load. The PMPG modeling, simulation and fabrication results are in same order which make PMPG presented suitable to power most of small electronic devices including cardiac pacemaker at frequency below 100 Hz.,Ph.D.
Pages:	215
Publisher:	UKM, Bangi
Appears in Collections:	Institute of Microengineering and Nanoelectronics / Institut Kejuruteraan Mikro dan Nanoelektronik (IMEN)

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