Ferrite Core Overcurrent Detection Using Magnetic Saturation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing technologies face challenges in quickly and robustly detecting overcurrents in DC and alternating voltage networks, particularly in low-voltage areas, due to high short-circuit currents and the need for non-invasive measurement methods that avoid additional losses or delays.
Innovation Solution
The proposed overcurrent limitation unit and detection unit utilizes a ferrite core brought into saturation by permanent magnets, allowing for non-invasive detection of overcurrents through a detection coil galvanically separated from the network coil. This design enables automatic, fast detection and control of a circuit breaker to switch off the electrical network current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If non-invasive measurement methods are used to detect overcurrents, then additional losses are avoided, but detection delay increases due to required interference immunity
Solution Approach 1:
The ferrite core is pre-saturated by permanent magnets before fault occurrence. This preliminary magnetic saturation creates a baseline state where any sudden change in magnetic flux (indicating overcurrent) can be immediately detected by the detection coil, eliminating detection delay while maintaining non-invasive measurement benefits
Solution Approach 2:
The invention changes the magnetic parameter of the ferrite core from unsaturated to saturated state using permanent magnets. This parameter change enables the detection coil to sense overcurrent conditions through magnetic flux changes without requiring complex signal processing or interference immunity measures, thus avoiding both additional losses and detection delay
2Reliability
If inductances are added to limit current rise, then component protection is improved, but switching time increases and energy dissipation increases
Solution Approach 1:
The ferrite core acts as an intermediary magnetic element that provides rapid overcurrent detection and triggering of protective devices. This mediator enables fast protection response without requiring large inductances that would slow down switching, thus protecting components while maintaining fast switching times
Solution Approach 2:
The invention replaces mechanical/current-based current limiting (using inductances) with a magnetic field-based detection system. The detection coil senses magnetic flux changes caused by overcurrent and triggers protection, substituting the need for large inductances and reducing both switching time and energy dissipation
3Adaptability or versatility
If additional circuit blocks are added for combined detection and current limitation, then functionality is improved, but device complexity and installation space increase
Solution Approach 1:
The invention merges the detection function (detection coil) and the current limitation function (ferrite core with permanent magnets) into a single integrated unit. The same magnetic circuit serves both detection and protection purposes, eliminating the need for separate circuit blocks and reducing device complexity while maintaining combined functionality
Solution Approach 2:
The ferrite core with permanent magnets serves multiple functions simultaneously: it provides magnetic saturation for current limitation and enables magnetic flux detection for overcurrent sensing. This multi-functional design reduces the number of components needed while achieving both detection and protection capabilities
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 solution allows for immediate, non-invasive detection of overcurrents without additional losses, enabling swift action to limit the rise of short-circuit currents and protect components, while also reducing the need for additional recording blocks and minimizing installation space and costs.
Implementation Method 1
a magnetic flux induced by the at least one permanent magnet runs counter to a magnetic flux induced by the mains coil
Implementation Method 2
a ferrite core (10), which is brought into a saturated range with regard to its magnetic conductivity by arranging at least one permanent magnet (20) in order to effect a magnetic non-conductivity of the ferrite core (10)
Implementation Method 3
a detection coil (40), which is galvanically isolated from the mains coil (30), is wound around a portion of the ferrite core (10) and is designed to detect a transition from the saturated region of the ferrite core (10) to an unsaturated region of the ferrite core (10)
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
Described is an overcurrent limiting and detection unit comprising: a ferrite core, the magnetic conductivity of which is saturated by the arrangement of at least one permanent magnet in order to effect magnetic non-conductivity of the ferrite core; a mains coil wound around a portion of the ferrite core and configured to carry an electrical mains current during operation of the overcurrent limiting and detection unit, wherein the at least one permanent magnet is arranged on the ferrite core such that a magnetic flux generated by the at least one permanent magnet opposes a magnetic flux generated by the mains coil during operation of the overcurrent limiting and detection unit; and furthermore, a detection coil, galvanically isolated from the mains coil, is wound around a portion of the ferrite core.which is configured to detect a transition from the saturated region of the ferrite core to an unsaturated region of the ferrite core during a fault operation of the overcurrent limiting and detection unit by detecting a detection voltage at the detection coil, wherein the overcurrent limiting and detection unit is configured to control a circuit breaker upon detection of the detection voltage in order to interrupt the electrical mains current through the mains coil. Furthermore, a method for manufacturing and a method for operating an overcurrent limiting and detection unit are described.