Rotary Transformer Non-Contact Power Transfer for CT Gantry
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Solution Overview
Problem
Current medical computed tomography (CT) systems face challenges in increasing rotational speed and power requirements while maintaining safety and efficiency, particularly in high-voltage power generation, which can lead to increased space needs and potential safety hazards.
Innovation Solution
A non-contact power transfer system utilizing a rotary transformer with a split configuration, isolation and summing transformers, and modular power inverter stages to deliver high-frequency, high-power energy without physical contacts, allowing for efficient power regulation and control, and reducing leakage currents and static charge buildup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If traditional high voltage power supply and slip ring system is used, then power can be transferred to rotating x-ray tube, but the system requires large disc space for tube cooling and high voltage power supply, and creates safety hazards with physical contacts
Solution Approach 1:
The patent replaces the mechanical slip ring contact system with a non-contact magnetic coupling system. The stationary inverter generates high-frequency power that couples magnetically to the rotating assembly through a stationary transformer and rotary transformer, eliminating the need for physical sliding contacts and reducing space requirements on the rotating gantry.
Solution Approach 2:
The patent introduces magnetic coupling fields as an intermediary between the stationary power source and rotating load. The stationary inverter and rotary transformer create a magnetic field that transfers power without direct physical contact, serving as a mediator that eliminates the need for large physical power supply components on the rotating side.
2Speed
If rotational speed is increased for real-time cardiac imaging, then imaging speed improves, but the requirements for high voltage response and peak power increase, requiring more space for cooling and power supply
Solution Approach 1:
The patent replaces the mechanical power transmission system with a magnetic coupling system that can respond instantaneously to changing power demands. The stationary inverter with resonant circuits provides high-frequency power that couples through the magnetic field to the rotating assembly, enabling high-speed rotation without increasing the physical space for power supply and cooling on the rotating gantry.
Solution Approach 2:
The patent changes the operating parameters by using high-frequency resonant power conversion instead of traditional low-frequency power supply. The stationary inverter operates at high frequency with series resonant circuits that limit frequency content and reduce common-mode components, enabling efficient power transfer at high rotational speeds without requiring proportionally larger power supply components.
3Power
If slip ring is used to transfer power, then power can be supplied to rotating components, but frequency content and common-mode components increase causing power losses
Solution Approach 1:
The patent eliminates the slip ring mechanical contact system entirely and replaces it with a non-contact magnetic coupling system. The stationary inverter generates high-frequency power that couples through the magnetic field to the rotary transformer on the rotating assembly, completely eliminating the power losses associated with slip ring contacts while maintaining efficient power transfer.
Solution Approach 2:
The patent changes the power transfer mechanism from low-frequency contact-based transfer to high-frequency magnetic coupling. The series resonant circuits in the stationary inverter limit frequency content and reduce common-mode components, enabling power transfer at optimized frequencies that minimize losses while the magnetic coupling eliminates the lossy slip ring interface.
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 enables safe and efficient high-speed power transfer, reducing the need for large power supplies on the rotating gantry, enhancing safety, and improving the operational efficiency of CT systems by eliminating the need for physical contacts and minimizing space requirements.
Implementation Method 1
a rotary transformer that couples power between a stationary side and a rotating side
Implementation Method 2
The isolation transformer configured to receive a sum of the one or more outputs of the power inverter system and to drive the primary winding of the rotary transformer
Data Source
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AI summary
A device for isolating one or more outputs of a power inverter system from a primary winding of a rotary transformer adapted to couple power between at least one stationary element and at least one rotational element, wherein the power inverter system is configured to provide input power to the primary winding of the rotary transformer, comprises an isolation transformer configured to receive a sum of the one or more outputs of the power inverter system and to drive the primary winding of the rotary transformer.