Stray capacitance is not taken into account..124 Figure IV-6 LEPG with a small drop of water in the channel..132 Figure IV-7 Process flow a. Hz and Rl 4 MOhm..144 Figure IV-19 Diagram showing all connections through LEPG ..145 Figure IV-20 Voltage waveforms with resistors connected through V3-V4, V1-.
Introduction
Scope of thesis
First, a device is constructed that uses torque to change the overlapping area of the charged capacitor structure. This paper shows 2.5 mW of power produced from a 2 cm diameter rotary generator at 12 kRPM and 10 μw for a 0.1 cm3 linear shaking generator at 60 Hz.
Second, a mechanical vibration force is used to shake a solid capacitor structure containing an air gap and liquid that can flow in and out of the air gap, thereby changing the strength of an electric field within the charged capacitor structure. Design and fabrication of different versions of the device are presented, as well as the experimental results.
Electricity
Notable advances in human understanding of electricity began in the 18th century, around the time Benjamin Franklin used lightning, which is simply the discharge of triboelectrically generated charge in clouds. The work of Ampere, Maxwell, and others led to well-understood laws of electricity that were used to develop electromagnetic current generators (electrostatic current generators already existed).
When a motor is operated at 60 Hz, it will inevitably produce vibration at this driving frequency and multiples of the driving frequency.
A form of alternative energy that is not renewable is nuclear fission, as the source of this energy, radioactive elements, change in a physical way that cannot be reversed in a human lifetime.
In contrast, solar cells used in calculators and watches provide energy by converting an external energy source, the sun or indoor lighting, into electrical power. Other small devices can produce electrical energy from kinetic energy from an external source, such as human movement.
Energy Harvesting
Assuming that the ambient energy is relatively constant, Figure I-2 clearly shows the benefits of energy harvesting over time. Energy harvesting is the act of converting wasted environmental energy into usable electrical energy.
The advantages of using stored chemical energy are that the available power is well known and the power density is much higher than the energy recovery solution, as shown in Table I-4. The differences between power density and energy density drive the development of chemical cells towards longer lifetimes and energy harvesters towards greater power transfer.
![Table I-4. Survey of power sources [9, 10]](https://thumb-ap.123doks.com/thumbv2/123dok/11361697.0/32.918.135.664.127.461/table-i-4-survey-power-sources-9-10.webp)
Zl Maximum internal displacement The moving element inside the generator has limited movement relative to the structural frame of the generator. This figure of merit is proportional to the efficiency of the device divided by the volume.
This magnet causes alternating magnetic fields to impinge on the generator coil, which produces a low-voltage alternating current. Using only the magnet and coil as the generator volume, the volume is approximately 1cc.
The packaged, 2-terminal version of this current generator shown in Figure I-8 is approximately 30 cubic centimeters, weighs 50 grams, and delivers 4mW at 100Hz (see Figure I-9 for power curve) and an acceleration of 0.4g.
![Figure I-8 Perpetuum’s 2-terminal power generator package [16].](https://thumb-ap.123doks.com/thumbv2/123dok/11361697.0/43.918.227.588.97.417/figure-8-perpetuum-terminal-power-generator-package-16.webp)
Although piezoelectric materials and transducers are well researched, new piezoelectric generators have recently been introduced in the literature, such as the piezoelectric windmill presented by Priya et al. The torque on the shaft causes the connected plugs to bend the piezoelectric bimorphs, resulting in an electrical polarization of the bimorphs that can be used as electricity.
So NLEH =73,000cc-1, which is most likely a large exaggeration because the total mass and volume of the device were not explicitly stated. Furthermore, the power required to operate the circuit is not specified, which is most likely much greater than the power produced.
This power generator is reported to produce 0.3μJ per cycle at 1Hz, 250μm displacement and a mass of 0.5g. The following was reported for the variable gap generator shown in Figure I-14: generated power = 116μW/cc, mass assumed to be silicon density times driving mass.
Displacement Current Power Generators
But somehow the bottom plate of the capacitor sends the same current back through the circuit. According to Gauss's law, any charge q on the top plate will create an electric field in the capacitor.
The main elements of the electret current generator are the electret, metal plates, and a mechanism to change the electric field on the plates. The electret material in the generator stores a fixed amount of charge Q, creating a mirror charge on the capacitor plates.
This would mean that it would also have a narrow frequency of interest and likely perform poorly as a microphone.
The voltage of the two plates will change over time in proportion to the permittivity of the air gap, and this is used to drive an external circuit.
Physical Scaling
Since λ has units of length, λ is called the "characteristic dimension". If the characteristic dimension is greater than a certain amount, the physics of motion will apply. A device can be said to be a microdevice if the operating principles require it to have a characteristic dimension less than 100x10-6 meters.
The terms "MEMS device" and "micro device" are used interchangeably to describe devices that exploit the physics of the micro world. Since MEMS is a process- and materials-driven field, the process-scale-based definition is as valid as the physical-interaction-based definition, and the term is widely used.
Funding
Photostructurable glass ceramic material will be used to fabricate highly efficient 3D (non-extruded form) turbines with high. Numerical simulations of the pulsating flow-thermal-reacting fields will be used for system and component optimization.
Electrets
- Electret Classification
- a. Heterocharge Electrets
- b. Homocharge Electrets
- Charging Methods
- a. Triboelectric
- b. Back Lighted Thyratron for Electron Beam Implantation
- Measurement Techniques
- a. Charge Density
- a.i. Error in Depth of Charge
- a.ii. Lateral Resolution of Charge
- b. Depth Sounding Techniques
- Uniformity
- a. Floating Metal Layer Electret
- a.i. Floating Metal Layer Process
- Conclusions
Electron implantation with the BLT produces a Gaussian distribution over the surface of the electret, as in Figure II-7, which is not desirable to provide a uniform electret. The liquid metal layer provides a reference voltage and therefore an electric field non-uniformity of less than 1% of the surface seen in.
Variable Area Rotational Electret Power Generator
Introduction
Theoretical Development
QTeflon( )t is the charge implanted in the Teflon and residing only in the capacitor configuration defined by the overlapping area of the top and bottom plates. From Figure III-3, n is the number of poles, r is the radius of the generator, and t is the time.
Design and Fabrication
Choosing a different dielectric, such as oxide material, may allow more charge to be stored, but the charge life will be significantly shortened.
To neglect the fringe field, the smallest dimension within 90% of the active area of the generator must be ten times the gap distance. Since 90% of the effective area of the r=5 mm generator is outside r=1.58 mm, the shortest dimension w (see Figure III-5) is 1.2 mm using the number of poles, n=4, and the cosine law.
To prevent the rotor and stator from making physical contact with each other, a gap distance must be maintained by some mechanism. When assembled, the rotor and stator must face each other with the normal to the surfaces antiparallel.
Fluorinert FC-40 has similar electrical properties to Fluorinert FC-75, but FC-40 has a kinematic viscosity 2.75 times higher than FC-75. The major disadvantage of FC-40 is its higher boiling point, which means higher temperatures and longer baking times are required to remove all solvent from the thicker Teflon film.
The rotor must be mounted with its normal plane aligned with the long axis of the rotating shaft or else the rotor and stator planes cannot be parallel during rotation. Finally, a small piece of teflon is removed with a razor blade from one corner of the stator for electrical connection with silver and a wire.
The process in Figure III-10 begins by using standard lithography to determine the location of the trenches in the photoresist mask. As can be seen in Figure III-11, the thick layer of Teflon AF is cracked after step 3, which is the result of a large volume change, as about 94% of the liquid evaporates and only 6% remains behind.
Therefore, small, deep trenches can be etched into the silicon substrate prior to the cavity etch in step 1, providing greater opportunities for the reflowed Teflon to mechanically lock onto the substrate. The final improvement to this process was to perform an extended, isotropic etch of these small deep voids to provide a locking structure that the Teflon could hold on the substrate.
While machining the rotors and stators, the design requirement was changed so that the radius of the rotors and stators was 10 mm. This could allow for greater energy production and better aligns with the DARPA grant design requirements discussed in section I.6.
Experimental Results
After the rotor and stator are parallel, the stator is backed by about 100μm (~120 degrees rotation) so that the motor can be started. The stator is then moved closer to the spinning rotor in four ~25μm increments, corresponding to 30 degree increments.
It is for this reason that power measurements were never taken from this installation. However, the axial output is not specified because it is highly dependent on the load.
Due to increased interest in the liquid electret generator, this testbed was not tested. Furthermore, this testbed is not suitable for a final device design, as it is expensive, large and cannot reach the desired speeds.
The other parameters used in the theoretical values match the measured values of the generator, which are n=4, r=4mm, σ=-2.8x10-4Coulomb/m2, KTeflon=1.93, d=9μm. The noise in the experimental graphs is directly attributable to stator-to-rotor collision.
For the graph above (Figure III-26), a similar trend is seen to Figure III-24, where the power output decreases at higher RPM. Additional testing will need to be performed to separate the gap distance effect from any other competing effect that may reduce power output.
Conclusions
On the bright side, it is now possible to extract the kernel of the results from the 32-pole electricity generator with data taken from a Seiko watch, and find that a large gain can be made by switching out the Seiko electromagnetic electricity generator for a rotary electret. electrical power generator as shown in Figure III-27. By exploiting micromachining techniques, an electrostatic electricity generator has been produced that produces more power output than commercial miniature electromagnetic electricity generators.
Liquid Rotor Electret Power Generator
Introduction
Using silicone oil to prevent electrowetting would allow the use of water, but it is not clear what effect this would have on the required fixed charge, as it is also used to reduce charge build-up in electrowetting devices. The simplicity of this device makes it possible to generate power without the use of control circuits, which would consume power.
Theory
As a side note, it is obvious that equation (IV.14) reduces to the familiar RC tank circuit when the capacitors are kept constant by setting α( )t =const. By setting some values for the capacitances, the voltage can be solved numerically and then find the power generated by .
At this point, mercury provides a test case to demonstrate the equivalence of variable permittivity current generators using mercury and variable area or variable distance current generators.
Design and Fabrication
At this point it is also necessary to realize that the maximum current (Equation (IV.18)) flowing through the external circuit is proportional to the implanted charge. Decrease 10x d Decrease decreases peak-to-. dead space 1mm-5mm Allowable volume, target. frequency Optimal length decreases with increasing frequency f. frequency) Increase 120 Hz Wall strength and sealing.
In this case, the water in the channel would vibrate until it triboelectrically charged the Teflon.
The top electrode plate is then glued to the spacer to complete the device (Figure IV-9). Clear epoxy bonds the top plate to the bottom plate and prevents mercury from escaping.
To fill half of the chamber in the lower electrode plate, either liquid drops of mercury or a pile of steel beads are used [64]. The top electrode plate is then placed in the spacer to complete the device (Figure IV-11).
Experimental Details
This is because the beads used in the tests are originally sold as sandblasting media, which is many orders of magnitude cheaper than buying individual bearing balls. It is expected that mercury can generate higher power in Figure IV-13 because it can completely occupy the gap in the LEPG and completely evacuate it, while the motion of the beads prevents them from moving perfectly in unison.
Careful examination of Figure IV-19 reveals that the V1-V2 and V3-V4 signals are inverted and inverted in time. What this suggests is that neighboring electrodes have significant influence on each other and that the system needs further modeling where all four electrodes are considered to be part of the same system.
Conclusions
Conclusions and Future Work
Rotary Electret Power Generator
The REPG is essentially a low current generator, with current that is proportional to the area of the generator. This is due to the increase in current at higher speeds (Equation (III.10), which causes a lower internal resistance (Z) of the generator.
Liquid Rotor Electret Power Generator
After load matching experiments are performed, the LEPG should be scaled in parallel to the 3rd dimension by stacking 2-dimensional arrays. Once a LEPG generator system is proven sufficiently reliable, efficiency tests must be performed to characterize how much of the mechanical energy is absorbed in the generator and how much of the absorbed energy is converted to electrical energy.
Palov, "Theoretical investigation of total secondary electron yield for Teflon," Japanese Journal of Applied Physics Part 1-Regular Proceedings Short Notes & Review Papers, 37(7), p. ,” Japanese Journal of Applied Physics Part 1 - Regular Papers Short Notes and Review Papers, 31 (3), p.
Brief history of electricity [1-4]