Line-Frequency Rotary Transformer for CT Gantry Power
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Solution Overview
Problem
Computed tomography (CT) systems face challenges in reducing weight and manufacturing cost, particularly due to the inefficiencies and maintenance requirements of contact slip rings and high-frequency rotary transformers, which introduce complexity and particulate contamination.
Innovation Solution
A line-frequency rotary transformer is designed with a primary and secondary core configuration, utilizing an air gap to reduce magnetizing inductance and incorporating series and shunt capacitances to manage leakage inductance, allowing for efficient power transmission to X-ray sources and detectors with reduced weight and complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If contact slip rings are used to transmit power from stator to gantry, then power transmission is achieved, but mechanical wear and particulate contamination occur
Solution Approach 1:
The patent replaces the mechanical contact slip ring system with a non-contacting rotary transformer that uses electromagnetic induction. The primary winding on the stator and secondary winding on the rotating gantry create magnetic coupling through an air gap, eliminating mechanical contact and thus preventing wear and particulate contamination while maintaining reliable power transmission.
2Reliability
If high-frequency rotary transformer is used for power transmission, then power transmission is achieved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent changes the operating frequency parameter from high-frequency to line-frequency (50/60 Hz), which simplifies the transformer design and reduces manufacturing cost. The line-frequency operation allows for larger core cross-sections and simpler winding configurations, reducing device complexity while maintaining reliable power transmission for the CT gantry application.
3Power
If rotary transformer with air gap is used, then magnetizing inductance is reduced, but leakage inductance increases
Solution Approach 1:
The patent optimizes the air gap dimension and core geometry parameters to achieve a balance between magnetizing inductance and leakage inductance. By carefully selecting the air gap size and core cross-sectional area, the transformer achieves sufficient magnetizing inductance for efficient power transmission while minimizing leakage inductance effects and associated energy losses.
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 improves power quality, reduces maintenance costs, and decreases the need for additional conversion components, resulting in a lighter and less costly CT system with acceptable voltage regulation and reduced operational losses.
Implementation Method 1
The rotary transformer utilizes alternating magnetic fields to couple the stator to the gantry for power transmission
Implementation Method 2
The primary side is configured to receive the line-frequency AC input power and induce the line-frequency AC output power at the secondary side
Data Source
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AI summary
A line-frequency rotary transformer is provided, including a primary core and a secondary core. The primary core is magnetically couplable to the secondary core. The primary core includes a first plurality of E-core steel laminates arranged in a first ring couplable to a stator. The primary core includes a primary winding disposed within the first ring and configured to transmit line-frequency AC power. The secondary core includes a second plurality of E-core steel laminates arranged in a second ring couplable to a gantry. The gantry is rotatably couplable to the stator. The secondary core includes a secondary winding disposed within the second ring and is configured to receive a line-frequency AC power induced in the secondary winding through the primary core and the secondary core by the primary winding.