Shielded Power Coupling Device for CT Scanner Inductive Transfer
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Solution Overview
Problem
Conventional power coupling devices for rotating systems, such as CT scanners, face issues with RF emission, electromagnetic interference, and limited flexibility in transferring power between multiple input and output voltages, while traditional slip-ring assemblies are unreliable and noisy, and existing inductive transformer solutions lack adequate shielding and adjustment options.
Innovation Solution
A shielded power coupling device with an inductive field generating and receiving element, separated by a core airgap, and a shell comprising fringe and non-fringe field mitigation elements made of conductive and dielectric materials to mitigate magnetic flux and reduce RF emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If inductive transformer is used to transfer power without slip-rings, then reliability is improved, but RF emission and electromagnetic interference increase
Solution Approach 1:
A magnetic core is introduced as an intermediary between the primary and secondary windings to confine and guide the magnetic flux. The core provides a low-reluctance path that keeps the magnetic field contained within the transformer structure, preventing RF emission while enabling reliable inductive power transfer.
Solution Approach 2:
The magnetic flux that would otherwise escape and cause RF emission is redirected through the magnetic core to serve a useful function. The core converts the harmful scattered flux into a controlled, contained magnetic field that efficiently transfers power from primary to secondary winding.
2Reliability
If inductive transformer is used to transfer power without slip-rings, then reliability is improved, but electromagnetic interference increases
Solution Approach 1:
The magnetic core acts as an intermediary that mediates the magnetic coupling between windings. It provides a controlled path for magnetic flux, preventing uncontrolled electromagnetic radiation and interference while maintaining the inductive power transfer function.
Solution Approach 2:
The magnetic core functions as a flexible magnetic circuit that adapts to the transformer geometry, providing continuous magnetic flux paths that contain the electromagnetic field and prevent interference with surrounding electronics.
3Power
If conventional inductive transformer is used, then power transfer is achieved, but flexibility in adjusting current and voltage is limited
Solution Approach 1:
The transformer design incorporates adjustable parameters such as variable turns ratios in the windings and adjustable airgap dimensions. These dynamic adjustments allow the transformer to adapt to different voltage and current requirements while maintaining efficient power transfer across varying operating conditions.
Solution Approach 2:
The transformer enables parameter changes by allowing adjustment of the airgap size between magnetic cores and varying the number of turns in windings. These parameter changes directly affect the transformation ratio, providing flexibility in output voltage and current while maintaining stable power transfer.
4Loss of energy
If magnetic flux is allowed to escape from core airgap, then power transfer efficiency is maintained, but RF emission increases
Solution Approach 1:
Additional magnetic core material is introduced as an intermediary to capture and redirect magnetic flux that would escape through the airgap. This intermediary core provides an alternative low-reluctance path that contains the flux within the transformer structure, preventing RF emission while maintaining coupling efficiency.
Solution Approach 2:
The design converts the potentially harmful escaped flux into a beneficial contained field by providing alternative magnetic paths through additional core material. The flux that would cause RF emission is redirected to strengthen the magnetic coupling between windings, improving efficiency while eliminating interference.
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 effectively reduces RF emission and electromagnetic interference, improves power transfer efficiency, and provides flexibility in adjusting current and voltage, while being more reliable and cost-effective than traditional methods.
Implementation Method 1
an inductive field generating element configured to convert electric power to an inductive coupling field
Implementation Method 2
an inductive field receiving element configured to convert the inductive coupling field to electric power
Implementation Method 3
The fringe field mitigation element comprises an electrically conductive material and is configured to mitigate magnetic flux generated by at least one of the inductive field generating element and the inductive field receiving element that escapes from at least one of the primary core and the secondary core near the core airgap
Data Source
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AI summary
One or more techniques and/or systems described herein provide a shielded power coupling device, such as may be used to transfer electric power from a stator portion of a computed tomography (CT) apparatus 100 to a rotor portion. The shielded power coupling device comprises a rotor portion 502 and a stator portion 504, separated by an airgap 506, respectively comprising one or more windings 508, 514 and a core 510, 516. The shielded power coupling device further comprises a fringe field mitigation element(s) (520) (e.g., an electrically conductive wire) that is configured to carry an induced current that creates a magnetic field that mitigates, or substantially cancels, magnetic flux generated by current in the windings 508, 514 that escapes from the core 510, 516 near the core airgap 506.