Vibrational Energy Generator with Dual-Frequency Magnetic Core
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Solution Overview
Problem
Existing electromechanical generators face challenges in achieving high mass, high Q factor, and high magnetic coupling for efficient conversion of mechanical vibrational energy into electrical energy over a wide bandwidth, particularly for powering wireless sensors where vibration frequency is unknown or variable.
Innovation Solution
The design incorporates a metallic magnetic core assembly with flat springs at opposed ends, maximizing moving mass and magnetic coupling by minimizing flux leakage, and includes a vibrating electrical coil assembly with different natural resonant frequencies to enhance electromagnetic coupling across a broad range of frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the mass of the spring-mass combination is increased to generate higher electrical power, then the output power is improved, but the device size and complexity increase
Solution Approach 1:
The patent employs a magnetic core made of ferromagnetic material combined with a coil assembly, creating a composite structure that maximizes magnetic coupling while maintaining manageable mass. The magnetic core and coil work together as an integrated electromechanical system that converts vibrational energy to electrical energy with high efficiency, resolving the contradiction between needing high power output and maintaining acceptable device mass.
Solution Approach 2:
The patent optimizes multiple parameters simultaneously: magnetic coupling factor, quality factor Q, and mass of the spring-mass combination. By carefully tuning these parameters together rather than maximizing mass alone, the system achieves high power output over a wide bandwidth without excessive weight. The magnetic coupling factor is enhanced through precise geometric design of the core and coil arrangement.
2Power
If the quality factor Q is increased to improve power output at resonant frequency, then the electrical power is improved, but the bandwidth over which power is generated decreases
Solution Approach 1:
The patent employs a dual-frequency approach where the magnetic core assembly and coil assembly are designed to vibrate at different natural resonant frequencies. This dynamic configuration allows the system to maintain high electromagnetic coupling across a broad range of input vibrational frequencies, effectively widening the operational bandwidth while preserving high power output capability.
Solution Approach 2:
The system optimizes the quality factor Q and magnetic coupling factor simultaneously through precise design of the magnetic core geometry, coil winding configuration, and spring-mass parameters. This coordinated parameter optimization enables high power generation across wide bandwidth rather than at a single resonant frequency, resolving the contradiction between peak power and operational versatility.
3Power
If the magnetic coupling factor is increased to improve power generation efficiency, then the electrical power output is improved, but the device complexity increases
Solution Approach 1:
The patent integrates the magnetic core and coil into a unified composite assembly where ferromagnetic material is strategically positioned to maximize magnetic flux linkage with the coil windings. This composite structure achieves high magnetic coupling factor through material selection and geometric arrangement rather than through complex mechanical linkages or control systems, thereby improving power output without excessive complexity.
Solution Approach 2:
The magnetic core is designed with specific geometric features at critical locations to concentrate magnetic flux where it most effectively couples with the coil. By optimizing the local quality of magnetic material distribution and coil winding density in key regions, the system achieves high overall magnetic coupling factor without requiring complex structures throughout the entire device.
4Loss of energy
If clearance is minimized between the moving magnetic core assembly and housing to reduce eddy current losses, then energy efficiency is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent optimizes the clearance parameter between the magnetic core assembly and housing to achieve an optimal balance: sufficiently small to minimize eddy current losses and improve energy efficiency, but large enough to accommodate reasonable manufacturing tolerances. This parameter optimization, combined with precise magnetic circuit design, reduces energy losses without imposing excessive precision requirements that would complicate manufacturing.
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 configuration results in a high electrical output over varying vibrational frequencies, increasing the device's operational bandwidth and power generation efficiency, making it suitable for diverse energy harvesting applications without the need for batteries or power cables.
Implementation Method 1
an electromechanical generator for converting mechanical vibrational energy into electrical energy... when the system vibrates, a coil cuts through the flux formed by a magnetic core
Implementation Method 2
flat springs at opposed ends of the magnetic core assembly and of the electrical coil assembly
Implementation Method 3
almost all the magnetic flux gets channeled through the coil
Implementation Method 4
the electromagnetic coupling between the coil and the magnetic flux can be maximized over a broad range of vibrational frequencies
Data Source
Figure 1~4
Figure 2~3
AI summary
An electromechanical generator for converting mechanical vibrational energy into electrical energy, the electromechanical generator comprising a housing, an electrically conductive coil assembly movably mounted in the housing, the coil assembly having radially inner and outer sides, and upper and lower edges, thereof, a mount for the coil assembly extending inwardly of the radially inner side for mounting the coil assembly for linear vibrational motion along an axis about, a first biasing device mounted between the housing and the mount to bias the electrically conductive coil assembly in opposed directions along the axis towards a central coil position, a magnetic core assembly movably mounted in the housing for linear vibrational motion along the axis, and a second biasing device mounted between the housing and the magnetic core assembly to bias the magnetic core assembly in opposed directions along the axis towards a central magnet position, wherein the magnetic core assembly encloses the electrically conductive coil assembly on the radially outer side and on the upper and lower edges, and on a part of the radially inner side, the magnetic core assembly having a gap on a radially inner portion thereof through which the mount extends, and the radially inner portion including two opposed magnets spaced along the axis.