Capacitance Based Tunable Micromechanical Resonators

Adams, Scott G.; Bertsch, F.M.; Shaw, K.A.; Hartwell, P.G.; MacDonald, N.C.; Moon, Francis C.

doi:10.1109/sensor.1995.717233

Cited by 28 publications

(23 citation statements)

References 2 publications

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“…Adam [16] realized a tuning range from 7.7% to 146% of the central frequency of 25 kHz of a resonator with a single comb structure ( figure 13). The driving voltage ranged from 0 V to 50 V (figure 14).…”

Section: Electrostatic Methodsmentioning

confidence: 99%

Strategies for increasing the operating frequency range of vibration energy harvesters: a review

Zhu

Tudor

Beeby

2009

Meas. Sci. Technol.

578

352

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This review presents possible strategies to increase the operational frequency range of vibration-based micro-generators. Most vibration-based micro-generators are spring-mass-damper systems which generate maximum power when the resonant frequency of the generator matches the frequency of the ambient vibration. Any difference between these two frequencies can result in a significant decrease in generated power. This is a fundamental limitation of resonant vibration generators which restricts their capability in real applications. Possible solutions include the periodic tuning of the resonant frequency of the generator so that it matches the frequency of the ambient vibration at all times or widening the bandwidth of the generator. Periodic tuning can be achieved using mechanical or electrical methods. Bandwidth widening can be achieved using a generator array, a mechanical stopper, nonlinear (e.g. magnetic) springs or bi-stable structures. Tuning methods can be classified into intermittent tuning (power is consumed periodically to tune the device) and continuous tuning (the tuning mechanism is continuously powered). This review presents a comprehensive review of the principles and operating strategies for increasing the operating frequency range of vibration-based micro-generators presented in the literature to date. The advantages and disadvantages of each strategy are evaluated and conclusions are drawn regarding the relevant merits of each approach.

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Section: Electrostatic Methodsmentioning

confidence: 99%

Strategies for increasing the operating frequency range of vibration energy harvesters: a review

Zhu

Tudor

Beeby

2009

Meas. Sci. Technol.

578

352

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“…In this system, the tachogenerator contributes only an additional 2% in volume, 3% in mass and negligible cost over the two dc generators because it does not have to supply power. This means that the overhead of employing this technique is low compared to the ones reported in [4]- [6]. In this implementation, a PIC18F2431 microprocessor samples the tachogenerator EMF and the bridge current through a current transducer, and the microprocessor calculates a demand current for the bridge every 0.83 ms using (3).…”

Section: Prototype System Architecturementioning

confidence: 99%

“…1 is also possible, and the reason for this is explained below. Previous attempts in changing the resonant frequency of energy harvesters have involved modifying the mechanical properties of the resonant system, such as the spring constant, as reported in [4]- [6]. This is equivalent to changing the value of the primary-side inductor in the system model in Fig.…”

mentioning

confidence: 99%

“…1. In [4], Adams et al developed a technique to modify the spring stiffness using an electrostatic comb-drive actuator, and in [5], Ayala et al published results from a harvester with a contactless magnetic tuning mechanism, which modified the tensile strain in a cantilever thereby altering the spring stiffness. Challa et al demonstrated a different configuration of permanent magnets capable of increasing and decreasing the resonant frequency [6].…”

mentioning

confidence: 99%

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Tuning the Resonant Frequency and Damping of an Electromagnetic Energy Harvester Using Power Electronics

Mitcheson

Toh

Wong

et al. 2011

IEEE Trans. Circuits Syst. II

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Abstract-In order to maximize power density, the resonant frequency of an energy harvester should be equal to the source excitation frequency and the electrical damping set equal to the parasitic damping. These parameters should be adjustable during device operation because the excitation characteristics can change. This brief presents, for the first time, a power electronic interface that is capable of continual adjustment of the damping and the resonant frequency of an energy harvester by controlling real and reactive power exchange between the electrical and mechanical domains while storing the harvested energy in a battery. The advantages of this technique over previously proposed methods are the precise control over the tuning parameters of the electrical system and integrated rectification within the tuning interface. Experimental results verify the operation, and the prototype system presented can change the resonant frequency of the electro-mechanical system by ±10% and increase the damping by 45%. As the input excitation frequency was swept away from the un-modi?ed resonant frequency of the harvester, the use of the tuning mechanism was shown to increase real power generation by up to 25%. The prototype harvester is capable of generating 100 mW at an excitation frequency of 1.25 Hz.Index Terms-energy harvesting, pendulum energy harvester, impedance emulator, maximum power transfer.

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“…In the case when there is electromechanical coupling, the underlying question is: how does the conditioning circuit impact on the resonator of the MEMS device used in the harvester, and in turn affect the optimum parameter and converted power iii) Resonance frequency shift. It is known that a mechanical resonator experiences a modification of its resonance frequency, when interfaced with a capacitive transducer biased by a voltage source [16]. This phenomenon is well studied and described in literature.…”

Section: Introductionmentioning

confidence: 99%

Complete electromechanical analysis of electrostatic kinetic energy harvesters biased with a continuous conditioning circuit

O'Riordan

Galayko

Basset

et al. 2016

Sensors and Actuators A: Physical

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Capacitance Based Tunable Micromechanical Resonators

Cited by 28 publications

References 2 publications

Strategies for increasing the operating frequency range of vibration energy harvesters: a review

Strategies for increasing the operating frequency range of vibration energy harvesters: a review

Tuning the Resonant Frequency and Damping of an Electromagnetic Energy Harvester Using Power Electronics

Complete electromechanical analysis of electrostatic kinetic energy harvesters biased with a continuous conditioning circuit

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