Piezoelectric energy harvesters in the road pavement are developed and studied to collect energy from the passing vehicles. A numerical model based on the Westergaard's stress model is proposed to calculate the three dimensional stress distribution in the pavement and the power generation from the piezoelectric harvesters placed inside the pavement. Piezoelectric patch, plate and beam harvesters are designed. Based on proposed numerical models, simulations are conducted to reveal the effects of vehicle velocity as well as the location and size of the Piezo-electric harvesters on the generated power. Optimally designed plate energy harvester attached with four cantilever harvesters generates up to around 28 W electrical power with the assumption of continuum vehicle passing the pavement by 22.2 m/s. This power can be used to collect enough energy in 2 hours to raise the ice temperature with the thickness of 1 cm, covering a 5 m wide road by 20 degree Celsius. / February 2017

The work described in this thesis is aimed at developing a novel piezoelectric cantilever energy harvesting circuit, so that more energy can be obtained from a particular piezoelectric harvester than is possible using conventional circuits. The main focus of the work was to design, build and test a proof of principle system, and not a commercial version, so as to determine any limitations to the circuit. The circuit functions by cancelling the capacitive output reactance of the piezoelectric harvester with a simulated inductance, and is based on an idea proposed by Qi in 2011. Although Qi's approach demonstrated that the circuit could function, the system proved too lossy, and so a less lossy version is attempted here. Experimental and software simulations are provided to verify the theoretical predictions. A prototype amplified inductor circuit was simulated and tested. From the simulation results, although harmonic current losses were found in the circuit, it was found that the circuit should produce an amplified effective inductance and a maximum output power of 165mW. The effective inductance is derived from the voltage across the 2H inductor, and this voltage is amplified and applied to the circuit via an inverter, to provide an extra simulated inductance, so that the overall inductance can be resonated with the piezoelectric harvester output capacitance. Hence the capacitive impedance of the harvester is nearly cancelled. The study and analysis of the amplified inductor circuit was carried out for a single cantilever harvester. Both open loop and closed loop testing of the system were carried out. The open loop test showed that the concept should function as predicted. The purpose of the closed loop test was to make the system automatically adjust for different resonance frequencies. The circuit was tested at 52Vpp inverter output voltage, and demonstrated a harvested power of 145.5mW. Experimental results show that the harvester output power is boosted from 8.8mW as per the manufacturer data sheet to 145.5mW (16.5 times). This is approximately double the power available using circuits described in the literature.

This thesis is focused on design of piezoelectric energy harvester with additional nonlinear stiffness. Linear generator has very narrow resonance frequency bandwidth. It makes the resonance mechanism very sensitive to tuning up of the resonance frequency and it can be tuned only for one narrow vibration peak. The main idea for using of the vibration energy harvester with nonlinear stiffness is to make resonance frequency bandwidth wider, so the generator will be useable for more excitation frequencies. In this thesis is used generator Midé V21BL and additional nonlinear stiffness is realized with permanent magnets.

Diphenylalanine peptide (Phe-Phe or FF) is a very promising bio-material in the future wearable electronics application due to its self-assembly into nanotubes and nanoribbons with high shear piezoelectric coefficient which is comparable to traditional inorganic piezoelectric materials. In order to efficiently harvest piezoelectric response, alignment and unidirectional polarization of FF nanotubes are required. Most prior works show that there mainly two methods to achieve the alignment and unidirectional polarization. They are epitaxial growth and meniscus-driven dip-coating. However, they still have some disadvantages like low productivity or harsh conditions. In this work, we use inkjet printing technology to develop a scalable, programmable and patterns designable process for the fabrication of FF nanotubes. Most prior works use toxic solvent 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) to dissolve FF peptide. In our work, the ink only contains sustainable and ecofriendly solvent like acetic acid and ethylene glycol. In the inkjet printing process, patterns can be perfectly printed on the substrate of graphene and ethyl cellulose. The direction and length of FF nanoribbons are controllable. Aligned FF nanoribbons can be observed in the printed devices. Orthorhombic crystal structure is characterized by SEM and XRD. The piezoelectric performance of the device with aligned FF nanoribbons is much higher than the random FF based devices. The FF piezoelectric nanogenerator generates voltage, current, and power density of up to 1.49 V, 10.5 nA, and 4.4 nW/cm2, respectively, under a force of 50 N. Our results show the promising future of FF-based piezoelectric devices in self-powered and wearable electronics application. / Diphenylalanine peptide (Phe-Phe eller FF) är ett mycket lovande biomaterial i den framtida bärbara elektronikapplikationen pågrund av dess självmontering till nanorör och nanorband med hög piezoelektrisk koefficient som är jämförbar med traditionella oorganiska piezoelektriska material. För att effektivt skörda piezoelektrisk respons krävs inriktning och enkelriktad polarisering av FF-nanorör. De flesta tidigare arbeten visar att det huvudsakligen finns tvåmetoder för att uppnå inriktning och enkelriktad polarisering. De är epitaxiell tillväxt och menisk-driven dopp-beläggning. Men de har fortfarande vissa nackdelar som låg produktivitet eller svåra förhållanden. I detta arbete använder vi bläckstråleutskriftsteknik för att utveckla en skalbar, programmerbar och mönsterdesignbar process för tillverkning av FF-nanorör. De flesta tidigare verk använder giftigt lösningsmedel 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) för att lösa upp FF-peptid. I vårt arbete innehåller bläcket endast hållbara och miljövänliga lösningsmedel som ättiksyra och etylenglykol. I bläckstråleutskriftsprocessen kan mönster tryckas perfekt på substratet av grafen och etylcellulosa. Riktningen och längden på FF nanoband är kontrollerbara. Justerade FF-nanoband kan observeras i de utskrivna enheterna. Ortorhombisk kristallstruktur kännetecknas av SEM och XRD. Den piezoelektriska prestandan hos enheten med justerade FF-nanoband är mycket högre än de slumpmässiga FF-baserade enheterna. FF piezoelektriska nanogeneratorn genererar spänning, ström och effekttäthet på upp till 1,49 V, 10,5 nA respektive 4,4 nW/cm2 med en kraft på 50 N. Våra resultat visar den lovande framtiden för FF-baserade piezoelektriska enheter i sig själv -driven och bärbar elektronikapplikation.

Diphenylalanine peptide (Phe-Phe or FF) is a very promising bio-material in the future wearable electronics application due to its self-assembly into nanotubes and nanoribbons with high shear piezoelectric coefficient which is comparable to traditional inorganic piezoelectric materials. In order to efficiently harvest piezoelectric response, alignment and unidirectional polarization of FF nanotubes are required. Most prior works show that there mainly two methods to achieve the alignment and unidirectional polarization. They are epitaxial growth and meniscus-driven dipcoating. However, they still have some disadvantages like low productivity or harsh conditions. In this work, we use inkjet printing technology to develop a scalable, programmable and patterns designable process for the fabrication of FF nanotubes. Most prior works use toxic solvent 1,1,1,3,3,3-hexafluoro2-propanol (HFIP) to dissolve FF peptide. In our work, the ink only contains sustainable and ecofriendly solvent like acetic acid and ethylene glycol. In the inkjet printing process, patterns can be perfectly printed on the substrate of graphene and ethyl cellulose. The direction and length of FF nanoribbons are controllable. Aligned FF nanoribbons can be observed in the printed devices. Orthorhombic crystal structure is characterized by SEM and XRD. The piezoelectric performance of the device with aligned FF nanoribbons is much higher than the random FF based devices. The FF piezoelectric nanogenerator generates voltage, current, and power density of up to 1.49 V, 10.5 nA, and 4.4 nW/cm2, respectively, under a force of 50 N. Our results show the promising future of FFbased piezoelectric devices in self-powered and wearable electronics application. / Diphenylalanine peptide (Phe-Phe eller FF) är ett mycket lovande biomaterial i den framtida bärbara elektronikapplikationen på grund av dess självmontering till nanorör och nanorband med hög piezoelektrisk koefficient som är jämförbar med traditionella oorganiska piezoelektriska material. För att effektivt skörda piezoelektrisk respons krävs inriktning och enkelriktad polarisering av FFnanorör. De flesta tidigare arbeten visar att det huvudsakligen finns två metoder för att uppnå inriktning och enkelriktad polarisering. De är epitaxiell tillväxt och menisk-driven dopp-beläggning. Men de har fortfarande vissa nackdelar som låg produktivitet eller svåra förhållanden. I detta arbete använder vi bläckstråleutskriftsteknik för att utveckla en skalbar, programmerbar och mönsterdesignbar process för tillverkning av FF-nanorör. De flesta tidigare verk använder giftigt lösningsmedel 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) för att lösa upp FF-peptid. I vårt arbete innehåller bläcket endast hållbara och miljövänliga lösningsmedel som ättiksyra och etylenglykol. I bläckstråleutskriftsprocessen kan mönster tryckas perfekt på substratet av grafen och etylcellulosa. Riktningen och längden på FF nanoband är kontrollerbara. Justerade FF-nanoband kan observeras i de utskrivna enheterna. Ortorhombisk kristallstruktur kännetecknas av SEM och XRD. Den piezoelektriska prestandan hos enheten med justerade FF-nanoband är mycket högre än de slumpmässiga FF-baserade enheterna. FF piezoelektriska nanogeneratorn genererar spänning, ström och effekttäthet på upp till 1,49 V, 10,5 nA respektive 4,4 nW/cm2 med en kraft på 50 N. Våra resultat visar den lovande framtiden för FF-baserade piezoelektriska enheter i sig själv -driven och bärbar elektronikapplikation.