DC Switch Arc Extinction Using Segmented Permanent Magnets
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Solution Overview
Problem
Existing DC circuit interrupters struggle to effectively extinguish arcs at air gaps, especially in high-voltage and high-current photovoltaic applications, and are limited in interrupting DC power of both polarities due to the orientation of contacts and conductors, leading to inefficient arc extinction and polarity-specific operation.
Innovation Solution
Incorporating a pair of magnetic field elements, such as permanent magnets, oriented parallel to the pivot axis with their north poles aligned, to generate Lorentz forces that extinguish arcs at air gaps, allowing for optimized arc extinction in both polarity directions by positioning magnets at each air gap to apply forces perpendicular to the arc, ensuring effective interruption of DC power regardless of polarity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single magnetic field element is used to extinguish arcs, then arc extinction is optimized for one polarity, but the device cannot effectively interrupt DC power of opposite polarity
Solution Approach 1:
The magnetic field generation is segmented into two separate magnetic field elements (first and second magnetic field elements) positioned at opposite air gaps. Each magnetic field element is optimized to generate magnetic flux in a specific direction to extinguish arcs for one polarity, enabling the device to handle both polarities effectively while maintaining reliable arc extinction performance.
2Ease of operation
If the shaft is rotated to create air gaps for circuit interruption, then the circuit can be opened, but arcs form at the air gaps that are difficult to extinguish in high voltage and current applications
Solution Approach 1:
The invention converts the harmful arc phenomenon into a beneficial effect by utilizing the magnetic field generated by the magnetic field elements. The magnetic flux interacts with the arc current to produce Lorentz forces that drive the arc away from the contact surfaces and facilitate its extinction, thereby transforming the harmful arc into a controllable and extinguishable phenomenon.
Solution Approach 2:
The magnetic field elements serve as intermediaries between the mechanical switching action and the arc extinction process. By introducing magnetic flux as an intermediary field, the device enables controlled arc behavior and extinction without directly interfering with the mechanical shaft rotation and air gap formation.
3Power
If high voltage and current are used in photovoltaic applications, then more solar arrays can be connected, but arc extinction becomes increasingly difficult
Solution Approach 1:
The magnetic field elements are strategically positioned at specific locations (opposite air gaps) where arcs are most likely to form. Each magnetic field element creates a localized magnetic flux that is optimized to extinguish arcs in its specific region, providing targeted arc extinction capability that scales with the overall power handling capacity of the device.
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 solution enables rapid and efficient extinction of arcs across all air gaps, enhancing the DC switch apparatus's ability to interrupt direct current in either direction, thereby improving current interruption capability and expanding its applicability to both polarities.
Implementation Method 1
a pair of magnetic field elements in the form of permanent magnets or other magnets to apply Lorentz forces to the arcs
Data Source
AI summary
An improved arc extinction apparatus that can be used in an improved DC switch apparatus includes a pair of magnetic field elements in the exemplary form of permanent magnets to apply Lorentz forces to the arcs. The magnetic fields are arranged in the vicinity of the air gaps that form between the ends of a pivoting conductor and a pair of contacts such that the system is optimized to extinguish an arc at one air gap when current is flowing through the conductor in a first direction and is further optimized to extinguish an arc at the other air gap when current is flowing in an opposite direction through the conductor. This is accomplished by providing a magnet at each air gap of the circuit, with the magnetic fields being oriented parallel with the pivot axis and having their north poles pointed in the same direction.