Superconducting Magnet Eddy-Current Braking for High-Speed Trains
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Solution Overview
Problem
High-speed trains face challenges with conventional braking systems, particularly at high speeds, due to reduced wheel-rail friction coefficients in adverse conditions, leading to increased wear and limited braking performance, and existing eddy-current braking systems have limitations in energy consumption, size, and weight.
Innovation Solution
A superconducting magnet for eddy-current braking with a specially designed container structure, including a coil box, thermal shield, and Dewar, immersed in liquid helium, surrounded by liquid nitrogen, and equipped with tie rod assemblies and heat insulating blocks to manage vibrations and heat loss, providing a lightweight and low-energy solution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If electromagnetic eddy-current braking uses conventional magnets with iron cores and windings, then braking force can be adjusted by changing excitation current, but the system has large electric power consumption and high coil temperature
Solution Approach 1:
The patent changes the fundamental parameter of magnetic field generation from resistive electromagnetic induction to superconducting current flow. By using superconducting coils that operate at cryogenic temperatures with zero electrical resistance, the system achieves adjustable braking force through current control while eliminating the large power consumption associated with conventional resistive windings.
Solution Approach 2:
The patent employs composite material structures including superconducting wires embedded in epoxy resin, combined with liquid helium cooling systems and thermal insulation layers. This composite approach enables the magnet to simultaneously achieve high magnetic field strength, low energy consumption, and effective thermal management.
2Force
If electromagnetic eddy-current braking uses conventional magnets, then braking force can be adjusted, but the system has large size and weight
Solution Approach 1:
The patent changes the magnetic field generation mechanism to superconducting operation, which produces higher magnetic flux density for the same current. This parameter change allows the magnet to generate equivalent or superior braking force with reduced coil mass and smaller overall dimensions compared to conventional resistive electromagnets.
3Weight of moving object
If superconducting magnet is used for eddy-current braking, then weight and size are reduced with increased magnetic flux density, but the magnet requires special structure to withstand inertial impacts at high speed
Solution Approach 1:
The patent incorporates shock-absorbing support structures and flexible mounting mechanisms designed beforehand to cushion inertial impacts during high-speed operation. These pre-installed protective elements absorb mechanical stresses without compromising the superconducting magnet's performance or requiring complex active control systems.
Solution Approach 2:
The patent uses flexible support structures and thin-film thermal insulation layers that can accommodate mechanical vibrations and inertial forces while maintaining the cryogenic environment. These flexible elements reduce structural complexity compared to rigid, over-engineered solutions.
4Force
If adhesion braking is used for high-speed trains, then braking is effective at lower speeds, but wheel-rail friction coefficient drops sharply above 300 km/h causing sliding
Solution Approach 1:
The patent replaces the mechanical adhesion-based braking system with an eddy-current braking system that uses electromagnetic induction. This substitution eliminates dependence on wheel-rail friction, allowing reliable braking force generation at high speeds where adhesion braking becomes ineffective due to reduced friction coefficients.
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 superconducting magnet reduces energy consumption, increases magnetic flux density, and enhances braking force while withstanding inertial impacts, offering improved performance and durability compared to conventional electromagnet eddy-current brakes.
Implementation Method 1
a superconducting coil is provided in the coil box, and is immersed in the liquid helium
Implementation Method 2
Eddy-current braking is independent of wheel-rail adhesion. The combination of the eddy-current braking and the existing wheel-rail adhesion braking can greatly increase braking forces of the trains
Implementation Method 3
the coil box is filled with liquid helium, and a liquid helium inlet and a liquid helium outlet are provided on the coil box; the thermal shield has a high vacuum environment therein; a plurality of liquid nitrogen pipelines surround an outer wall of the thermal shield
Data Source
AI summary
A superconducting magnet for eddy-current braking for a high-speed train. The superconducting magnet is fixed at a bottom of a bogie of the high-speed train through a connecting mechanism, and an air gap is formed between the superconducting magnet and a top of a guide rail below the bogie. The superconducting magnet after being excited generates an eddy-current effect with the guide rail of the high-speed train, so as to generate a braking force opposite to a traveling direction of the train, thereby braking the high-speed train. A liquid-level meter is provided on the superconducting magnet to detect a position of a cooling agent liquid level in real time. The superconducting magnet withstands vibration impact through elastic tie rod assemblies when the high-speed train is under operation, showing good adaptability.