Arc-Shaped Magnetic Core Harvesting for HVDC Saturation Avoidance
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Solution Overview
Problem
Traditional magnetic energy harvesting methods for high voltage direct current (HVDC) transmission lines are ineffective due to core saturation from strong DC fields, and existing solar and wind collectors are unstable, hindering the deployment of self-powered sensors.
Innovation Solution
A non-invasive harmonic magnetic field energy harvesting device using an arc-shaped magnetic core and flux collectors, which avoids saturation by employing a non-closed structure with lower permeability, enabling energy harvesting through electromagnetic induction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If traditional magnetic energy harvesters based on current transformers are used, then magnetic field energy can be harvested in AC transmission lines, but the magnetic core experiences deep saturation due to strong DC fields in HVDC transmission lines, rendering them unable to harvest energy
Solution Approach 1:
The magnetic core is segmented into multiple independent magnetic path segments. This segmentation prevents the formation of a closed magnetic loop, thereby eliminating the strong demagnetizing field that causes saturation in traditional closed-core transformers when exposed to DC fields. Each segment independently channels magnetic flux without creating cumulative saturation effects.
Solution Approach 2:
Air gaps are introduced as intermediary elements between magnetic path segments. These air gaps act as magnetic flux mediators that prevent direct magnetic coupling between segments, reducing the overall magnetic flux density in the core material and preventing saturation while still allowing harmonic magnetic field energy to be coupled to the secondary winding.
2Use of energy by moving object
If solar and wind energy collectors are used, then energy can be harvested, but output power is unstable due to susceptibility to weather conditions
Solution Approach 1:
The energy harvesting device utilizes the harmonic magnetic fields already present in the HVDC transmission line as its energy source. These harmonic fields are naturally generated by the switching operations in the rectification and inversion stages of the HVDC system, eliminating the need for external weather-dependent sources like solar or wind. The system essentially harvests waste electromagnetic energy from the transmission infrastructure itself, providing stable, weather-independent power output.
3Reliability
If a non-closed arc-shaped magnetic core is used, then core saturation is avoided, but the effective permeability is lower compared to closed toroidal magnetic cores
Solution Approach 1:
The magnetic core is divided into multiple arc-shaped segments that are spatially separated. This segmentation inherently creates a non-closed magnetic path structure, preventing saturation while maintaining reasonable permeability through the distributed magnetic paths. The segmented design is simpler than attempting to design a complex closed core with saturation prevention features.
Solution Approach 2:
The magnetic flux path is extended into the spatial dimension by using arc-shaped segments arranged in a specific geometric configuration. This dimensional approach allows the magnetic field to travel through air paths between segments, effectively reducing the magnetic coupling that leads to saturation while maintaining functional permeability through the extended flux path geometry.
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
Effectively harvests harmonic magnetic field energy without core saturation, providing stable power output unaffected by weather conditions.
Implementation Method 1
the alternating magnetic field generated by the harmonic current will generate an induced voltage in the coil based on electromagnetic induction, thereby enabling energy harvesting
Data Source
AI summary
The present disclosure proposes a non-invasive harmonic magnetic field energy harvesting device for a high voltage direct current (HVDC) transmission line, and the device includes an arc-shaped magnetic core and flux collectors; the arc-shaped magnetic core is located at the center of the device and the flux collectors are located at both ends of the arc-shaped magnetic core, and the device is placed near the transmission line without being snapped onto the transmission line. The designed arc-shaped magnetic core is a non-closed arc-shaped magnetic core with relatively low effective permeability, which can effectively prevent saturation of the magnetic core caused by a strong direct current. When the magnetic core is unsaturated, the alternating magnetic field generated by the harmonic current will generate an induced voltage in the coil based on electromagnetic induction, thereby enabling energy harvesting.