Magnetic Shielding for Synchronous Machine Excitation
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Solution Overview
Problem
Existing synchronous machines with superconducting windings face issues with magnetic field interference from stator and rotor stray fields, which can saturate ferromagnetic materials and render electronics inoperable, especially when using contact-based energy transmission methods.
Innovation Solution
An internal exciter device with non-contact energy transmission and magnetic shielding using magnetically conductive materials like ferrites or soft magnetic composites, which can be arranged as a housing or individual elements, to minimize interference and protect sensitive electronics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If contactless energy transmission with inductive coupling is used, then magnetic field interference is reduced, but ferromagnetic materials still become saturated due to high magnetic flux density
Solution Approach 1:
The patent introduces an intermediary substance (magnetic shielding material or air gap) between the source of magnetic flux and the ferromagnetic components to mediate the magnetic field interaction. This intermediary reduces the magnetic flux density reaching the ferromagnetic materials, preventing saturation while allowing contactless energy transmission to function.
Solution Approach 2:
The patent extracts or removes ferromagnetic materials from the excitation device design, replacing them with non-magnetic alternatives that do not suffer from saturation. This extraction eliminates the harmful effect of magnetic saturation while maintaining the necessary magnetic coupling for contactless energy transmission.
2Loss of energy
If excitation device is installed close to magnet wheel inductance, then losses on supply lines are minimized, but magnetic field interference with electronics increases
Solution Approach 1:
The patent places magnetic shielding materials as intermediaries between the excitation device and sensitive electronics. This allows the excitation device to remain close to the magnet wheel inductance for minimal supply line losses, while the shielding intermediary protects the electronics from magnetic field interference.
Solution Approach 2:
The patent applies magnetic shielding selectively in specific local areas where electronics are located, rather than throughout the entire machine. This local application of shielding provides protection where needed while minimizing the impact on the overall magnetic field distribution and maintaining efficient energy transmission.
3Object-affected harmful factors
If shields made of magnetic material are used, then magnetic field shielding is improved, but eddy current losses increase due to high conductivity
Solution Approach 1:
The patent employs composite shielding structures that combine magnetic materials with non-magnetic, low-conductivity materials. This composite approach provides effective magnetic field shielding through the magnetic material while the low-conductivity component minimizes eddy current losses, achieving both shielding effectiveness and energy efficiency.
Solution Approach 2:
The patent uses different materials with different properties in different parts of the shielding structure. Magnetic materials are used where field redirection is needed, while low-conductivity materials are used where eddy current suppression is critical, optimizing both shielding performance and energy efficiency in different local regions.
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 effectively weakens interfering magnetic fields, allowing for reliable non-contact energy transmission and magnetic core utilization, ensuring the functioning of sensitive electronics and reducing losses in superconducting machines.
Implementation Method 1
the interfering extraneous fields of the stator and rotor windings are suitably weakened
Implementation Method 2
magnetic shielding using magnetically conductive materials like ferrites or soft magnetic composites
Implementation Method 3
magnetic shielding using magnetically conductive materials like ferrites or soft magnetic composites
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
The invention relates to a synchronous machine which comprises a magnet wheel and a stator winding which are necessary for an excitation device. It is also necessary to transfer energy to a magnet wheel inductivity, preferably, energy to a super-conductive coil, by means of an excitation device. Protection (30, 30') for protecting against the magnetic field produced by the current in the winding head is also necessary. According to the invention, the protection (30, 30') is in the form of a specific system which is used to reduce the corruptions of the interfering fields of stator and rotor windings (6, 10).