Magnetic-Blow Contactor Structure for 10 kA Short-Circuit Switching
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Solution Overview
Problem
High-voltage DC contactors in new energy vehicles face challenges in withstanding surge currents and maintaining stable operation during abnormal conditions, leading to unpredictable failures and incorrect operations due to limited current carrying capacity and structural defects in existing contactor designs.
Innovation Solution
A contactor design featuring an insulation outer housing, static and movable terminals, magnetic conductors, and an elastic member, where the distance between magnetic conductors varies with current flow to manage electromagnetic forces, and magnetic blowing magnets to extinguish electric arcs, enhancing the contactor's ability to handle high currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the contact structure is improved to increase the ability to withstand short circuit current, then the current withstanding capacity is improved, but the ability to cut off current and turn on current decreases
Solution Approach 1:
The contactor is divided into multiple functional modules: a contact assembly with movable and static contacts for current switching, a magnetic blowing assembly with first and second magnetic conductors for arc extinguishing, and an elastic member for providing restoring force. This segmentation allows each module to be optimized independently - the contact assembly for switching performance and the magnetic blowing assembly for withstanding short circuit currents.
Solution Approach 2:
The magnetic blowing assembly acts as an intermediary mechanism between the contacts and the arc. When short circuit current flows, the magnetic conductors generate a magnetic field that blows the arc away from the contacts, protecting them from direct current stress while allowing the contacts to maintain their switching function.
2Reliability
If magnetic conductors are added to withstand high currents, then the current carrying capacity is improved, but the device complexity increases
Solution Approach 1:
The magnetic conductors serve multiple functions: they generate the magnetic field for arc blowing during normal operation, provide structural support for the contact assembly, and act as flux conduits to concentrate and direct the magnetic field during short circuit conditions. This multi-functionality reduces the need for separate components.
Solution Approach 2:
The magnetic blowing assembly is integrated with the contact assembly, where the first magnetic conductor is fixed to the movable terminal and the second magnetic conductor is supported in the static bracket. This merging of functions into a compact structure increases current carrying capacity without proportionally increasing overall device complexity.
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 design improves the contactor's ability to withstand short circuit currents up to 10 kA, maintaining stable connection and disconnection operations while effectively extinguishing electric arcs, thus ensuring reliable performance under high-voltage conditions.
Implementation Method 1
magnetic blowing magnets to extinguish electric arcs
Implementation Method 2
an elastic member
Implementation Method 3
a strong electric repulsion force (including Lorentz force and Holm force) will be generated
Data Source
AI summary
A contactor comprises an insulation outer housing, a pair of static terminals, a movable terminal, a first magnetic conductor, a static bracket, a second magnetic conductor and an elastic member. The pair of static terminals are arranged in the insulation outer housing and are stationary relative to the insulation outer housing. The movable terminal is also arranged in the insulation outer housing and is movable between a closed position in contact with the static terminal and an opened position separated from the static terminal. The first magnetic conductor is fixed to the movable terminal to move synchronously with the movable terminal. The static bracket is arranged within the insulation outer housing and is stationary relative to the insulation outer housing. The second magnetic conductor is floatably supported in the static bracket by the elastic member.