Rotary Transformer With Electromagnetic Shield For High-Speed Power Transfer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for transferring electrical power to high-speed rotating rotors face challenges such as limited power transfer, reliability issues, and dynamic mechanical problems due to the use of slip rings and heavy ferrite materials, which require frequent maintenance and can cause wear and instability.
Innovation Solution
A high-power rotary transformer design that includes a stationary primary coil and an electromagnetic shield on the rotor, using an alternating current with a frequency of at least one kilohertz to induce a voltage in a secondary coil connected to the load, while isolating the rotor from eddy current heating, thus avoiding undesirable torque and mechanical instability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If slip rings and brushes are used to transfer power to the rotor, then power delivery can be controlled independently of rotor speed, but the brushes experience wear and have limited service life
Solution Approach 1:
The patent replaces the mechanical slip ring and brush contact system with a magnetic coupling system. The stator generates a rotating magnetic field that induces current in the rotor windings without physical contact, eliminating brush wear while maintaining the ability to control power delivery independently of rotor speed through electronic control of the stator frequency and amplitude.
Solution Approach 2:
The patent introduces a magnetic field as an intermediary between the stator and rotor. The stator creates a magnetic field that couples power to the rotor through electromagnetic induction, serving as a non-contact mediator that transfers energy without the mechanical contact and wear associated with slip rings and brushes.
2Loss of energy
If ferrite materials are used in the rotor for low frequency power transfer, then power coupling efficiency is improved, but the rotor becomes heavy and causes dynamic mechanical problems at high speed
Solution Approach 1:
The patent changes the operating frequency parameter from low frequency (50/60 Hz) to high frequency (at least 1 kHz). This frequency change eliminates the need for heavy ferrite materials in the rotor while maintaining efficient power coupling, as the high-frequency magnetic field achieves effective coupling without requiring high-coercivity materials that would add excessive weight and cause dynamic balance problems.
3Power
If electromagnetic induction is used for power transfer, then power can be transferred to the rotor, but the rotor speed changes when electrical load changes
Solution Approach 1:
The patent incorporates feedback control where the stator frequency and amplitude are adjusted based on the desired rotor speed and load conditions. By monitoring rotor speed and electrical load, the control system modifies the stator magnetic field parameters to maintain constant rotor speed despite changes in electrical load, enabling independent control of power delivery and speed.
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
Enables efficient and maintenance-free power transfer to high-speed rotating members without introducing dynamic balance problems, allowing for reliable operation and reduced wear, and eliminates the need for heavy ferrite structures by using high-frequency alternating current.
Implementation Method 1
the application of an alternating current having a frequency of at least one (1) kilohertz to the primary produces an alternating electromagnetic field having flux lines in the secondary in the secondary oriented generally parallel to the axis of rotation. The alternation of the electromagnetic field induces a voltage in the secondary that generates an electric current to the load.
Implementation Method 2
The shield isolates the rotor from the alternating electromagnetic field to prevent eddy current heating of the rotor.
Data Source
AI summary
A rotary transformer for coupling electrical power at a high level into a rotor operable at a high rotational speed without the introduction of undesirable electromagnetic torque and problems of dynamic mechanical instability comprises a stationary primary mounted in surrounding relationship with respect to the rotor, an electromagnetic shield having an exterior surface thereon mounted to the rotor, and a secondary mounted on the exterior surface of the shield. The secondary is connected in an electrical circuit with the load such that the application of an alternating current having a frequency of at least one (1) kilohertz to the primary produces an alternating electromagnetic field having flux lines in the secondary in the secondary oriented generally parallel to the axis of rotation. The alternation of the electromagnetic field induces a voltage in the secondary that generates an electric current to the load. The shield isolates the rotor from the alternating electromagnetic field to prevent eddy current heating of the rotor.