Nonlinear MEMS Oscillator Stabilization Without External Power
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Solution Overview
Problem
Micromechanical oscillators are unreliable in low power consumption scenarios and lack the ability to maintain operation without an external power source, leading to amplitude and frequency loss when power is disrupted.
Innovation Solution
The use of nonlinear dynamics and energy exchange between coupled vibrational modes through an internal resonance condition allows the oscillator to maintain constant amplitude and frequency without an external power source, utilizing a phase-shifted voltage to drive the oscillator into a self-sustained motion where energy is transferred from a higher mode to a lower mode, stabilizing frequency oscillations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If an external power source is removed to reduce power consumption, then energy efficiency is improved, but the oscillator amplitude and frequency stability deteriorate
Solution Approach 1:
The oscillator system uses its own higher vibrational modes as an internal energy reservoir to sustain the fundamental mode oscillation without external power. The non-linear energy transfer mechanism allows the system to self-regulate and maintain stable frequency and amplitude using internally stored energy, making the oscillator autonomous and reliable even without external power sources.
2Duration of action of stationary object
If the oscillator operates without external power to extend duration of action, then operational autonomy is improved, but the oscillation amplitude decreases
Solution Approach 1:
The system pre-charges higher vibrational modes during powered operation, storing energy that will be needed later. When external power is removed, this pre-stored energy in higher modes is transferred to the fundamental mode to maintain oscillation amplitude, effectively extending the operational duration without external power while maintaining performance.
3Device complexity
If conventional oscillators are used in power-deprived environments, then device simplicity is maintained, but the oscillator becomes unreliable
Solution Approach 1:
The invention changes the operational parameters of the oscillator by driving it into a non-linear regime where higher vibrational modes are excited. This parameter change enables the system to exhibit qualitatively different behavior - specifically, the ability to transfer energy between modes to stabilize the fundamental oscillation, thereby improving reliability in power-deprived environments without adding external complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables continuous operation at a constant amplitude and frequency for a period of time after the external power source is removed, demonstrating improved frequency stability and reduced phase noise by harnessing the energy stored in higher vibrational modes.
Implementation Method 1
a first electrode in the resonator applies a periodic electrostatic force
Implementation Method 2
a second electrode in the resonator is used to transduce the motion of the resonator through a motional current
Implementation Method 3
amplifying a voltage, using an amplifier, from the oscillator
Implementation Method 4
phase shifting the amplified voltage
Implementation Method 5
the oscillator is at an internal resonance condition based at least on the amplitude of the phase shifted voltage, and wherein the internal resonance condition stabilizes frequency oscillations in the oscillator
Implementation Method 6
energy is transferred from the first mode to the second mode in the internal resonance condition, and wherein the transferred energy stabilizes the frequency oscillations in the oscillator
Data Source
AI summary
This invention comprises a nonlinear micro- and nano-mechanical resonator that can maintain frequency of operation and amplitude of operation for a period of time after all external power has been removed from the device. Utilizing specific nonlinear dynamics of the micromechanical resonator, mechanical energy at low frequencies can be input and stored in higher frequencies modes, thus using the multiple degrees of freedom of the resonator to extend its energy storage capacity. Furthermore, the energy stored in multiple vibrational modes can be used to maintain the resonator oscillating for a fixed period of time, even without an external power supply. This is the first demonstration of an “autonomous” frequency source that can maintain a constant frequency and vibrating amplitude when no external power is provided, making it ideal for applications requiring an oscillator in low power, or limited and intermittent power supplies.