Ferrofluid Liquid Spring for Vibration Energy Harvesting
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Solution Overview
Problem
Existing vibration energy harvesters with rigid suspensions face challenges in capturing and converting lower-frequency vibrations due to higher resonant frequencies, leading to durability issues and inefficiencies, particularly in smaller devices.
Innovation Solution
A vibration energy harvester utilizing a ferrofluid liquid suspension within an enclosed chamber, which includes a magnetic array or coil array, to reduce resonant frequency and enhance durability by using a ferrofluid that becomes magnetized and acts as a mechanical spring, allowing for efficient conversion of kinetic energy into electrical energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a rigid suspension is used in vibration energy harvesters, then structural strength is improved, but resonant frequency increases and durability decreases
Solution Approach 1:
The patent replaces the traditional rigid mechanical suspension system with a ferrofluid-based magnetic suspension system. The ferrofluid, when magnetized, provides the necessary suspension force to hold the proof mass, eliminating contact mechanics and rigid structural supports that caused high resonant frequencies and failure points. This substitution of mechanical suspension with magnetic field-based suspension directly resolves the contradiction by providing both the needed structural support and the ability to achieve low resonant frequencies.
Solution Approach 2:
The patent changes the physical state and properties of the suspension medium from solid/rigid to liquid/ferrofluid. By using ferrofluid with controllable magnetic properties, the system can adjust its effective stiffness and damping characteristics. The ferrofluid's ability to be magnetized allows dynamic control of suspension properties, enabling the system to achieve low resonant frequencies while maintaining adequate support strength, thus resolving the contradiction between strength and durability.
2Strength
If a rigid suspension is used in vibration energy harvesters, then structural support is improved, but resonant frequency increases reducing efficiency for lower-frequency vibrations
Solution Approach 1:
The patent replaces rigid mechanical suspension with a ferrofluid-based magnetic suspension system. This substitution eliminates the high resonant frequency characteristic of rigid structures, allowing the energy harvester to efficiently capture and convert lower-frequency vibrations. The magnetic suspension provides structural support without the inertial constraints of rigid components, directly improving energy harvesting efficiency for lower-frequency applications.
Solution Approach 2:
The patent introduces dynamic control capabilities through the magnetized ferrofluid suspension. The magnetic field strength can be adjusted to dynamically tune the suspension stiffness and resonant frequency of the system. This dynamic adjustability allows the energy harvester to optimize its resonant frequency to match the operating vibration frequency, maximizing energy harvesting efficiency while maintaining adequate structural support.
3Ease of manufacture
If traditional fabrication processes are used for vibration energy harvesters, then manufacturing is simplified, but achieving low resonant frequency becomes difficult
Solution Approach 1:
The patent replaces complex mechanical suspension structures with a ferrofluid-based magnetic suspension system. This substitution simplifies the fabrication process by eliminating the need for precision-machined rigid suspension components and complex assembly procedures. Instead, the system uses a liquid ferrofluid that can be easily introduced into the device housing, significantly reducing manufacturing complexity while enabling low resonant frequency operation.
Solution Approach 2:
The patent employs a liquid-based (ferrofluid) suspension system analogous to hydraulic systems. The ferrofluid can be easily filled into the device through simple openings, and its properties can be adjusted by changing the magnetic field conditions rather than requiring precision mechanical adjustments. This approach greatly simplifies the fabrication process compared to traditional rigid mechanical suspension systems while achieving the desired low resonant frequency characteristics.
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
The ferrofluid liquid suspension enables a lower resonant frequency, increased durability, and improved energy conversion efficiency, allowing for effective capture and conversion of lower-frequency vibrations into electrical energy, suitable for smaller devices like smart watches.
Implementation Method 1
The ferrofluid liquid suspension may be a ferrofluid liquid suspension that becomes magnetized in the presence of a magnetic field and is attracted by a magnet
Implementation Method 2
the attractive forces of the ferrofluid liquid suspension counteracts each other when there is no applied acceleration
Implementation Method 3
The one or more copper coils and the multiple magnets are configured to generate the electrical energy from a relative movement between the one or more copper coils and the multiple magnets
Implementation Method 4
The ferrofluid liquid suspension may be configured to reduce a resonant frequency of the vibration energy harvester to 1-500 Hz
Data Source
AI summary
A vibration energy harvester includes a proof mass that is a magnetic array or a coil array. The magnetic array has multiple magnets. The coil array has one or more coils. The vibration energy harvester includes an enclosed chamber. The enclosed chamber has the other of the coil array or the magnetic array that is not the proof mass. The one or more copper coils and the multiple magnets are configured to generate the electrical energy from a relative movement between the one or more copper coils and the multiple magnets. The vibration energy harvester includes a liquid suspension that suspends the proof mass within the enclosed chamber.