Multi-Core Electromagnetic Harvester Reducing Wire Resistance
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Solution Overview
Problem
Existing electromagnetic vibration energy harvesters are inefficient for small vibration amplitudes and suffer from high power loss due to wire resistivity and uneven magnetic flux distribution, particularly in devices with single core configurations.
Innovation Solution
A multi-core electromagnetic energy harvester design where a magnet is suspended to vibrate close to multiple coils arranged around a ferromagnetic disc, with upper and lower ferromagnetic bars confining magnetic flux, reducing wire resistance and enhancing magnetic flux distribution, and a spring-less configuration using a hinge and seismic mass for vibration-induced alternating voltage generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single core configuration is used, then the device structure is simple, but power loss due to wire resistivity is high
Solution Approach 1:
The patent divides the single core into multiple cores (at least two cores) arranged around the magnet. This segmentation allows the magnetic flux to be distributed across multiple parallel magnetic circuits, effectively reducing the equivalent wire resistance and power loss. Each core carries a portion of the total magnetic flux, similar to how parallel resistors reduce total resistance.
2Device complexity
If a single core configuration is used, then the device structure is simple, but magnetic flux distribution is uneven
Solution Approach 1:
By segmenting the magnetic circuit into multiple cores surrounding the magnet, the magnetic flux is evenly distributed across all cores. This symmetric arrangement ensures that each core experiences similar flux conditions, improving the uniformity and stability of magnetic flux distribution throughout the device.
Solution Approach 2:
The patent transitions from a single-core linear arrangement to a multi-core radial or circumferential arrangement around the magnet. This dimensional change from one-dimensional to two-dimensional or three-dimensional configuration optimizes the magnetic flux path and distribution, allowing more uniform flux density across all magnetic circuits.
3Adaptability or versatility
If small vibration amplitudes are used, then the device is suitable for body movements, but the magnetic flux reversal efficiency is reduced
Solution Approach 1:
The patent utilizes the natural vibration and movement of the human body as the driving force. The magnet is suspended to allow it to vibrate and move relative to the multi-core structure during body movements. This mechanical vibration approach enables the device to effectively convert small-amplitude body movements into useful electromagnetic energy through the relative motion between the magnet and multiple cores.
Solution Approach 2:
The patent employs a composite structure combining a suspended magnet with multiple ferromagnetic cores arranged in a specific geometric configuration. This composite design enhances the magnetic flux reversal efficiency by creating multiple magnetic circuits that work in parallel, compensating for the lower amplitude of vibrations from body movements and maintaining effective energy generation.
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 multi-core design achieves a 50% reduction in power loss due to wire resistance and increases average magnetic flux by 56%, while the spring-less configuration prevents mechanical damage from large impacts and maintains efficiency without the need for stoppers.
Implementation Method 1
According to Lentz and Faraday's laws, such movement induces electromotive force between the coil wires that may be harvested to power devices
Implementation Method 2
a ferromagnetic core (113) winded by coil (114)
Data Source
AI summary
An electromagnetic energy harvester for converting vibrations of a body to electricity that includes a coil with two ends that is wound along a longitudinal axis of a ferromagnetic core, a magnet, and a suspending device that its first end is designed to be fixed to the body and its second end is designed to be fixed to the magnet. The first end of the core is design to be at close proximity to the magnet and the longitudinal axis of the core is designed to be substantially aligned vertically to the magnetic axis of the magnet. The vibrations of the body can cause a relative alternating movement between the core and the magnet that can create alternating voltage between the ends of the coil.