High-Frequency Power Distribution Unit for CT Systems
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Solution Overview
Problem
Traditional power distribution units (PDUs) in computed tomography (CT) systems are large, expensive, and consume power even when the system is not in use, leading to reliability issues and inefficiencies due to the use of mechanical contactors and large transformers.
Innovation Solution
A high-frequency power distribution unit (HFPDU) is introduced, featuring a three-phase rectifier, inverter, and isolation transformer to convert DC current to AC, providing power to the CT system with reduced transformer size and energy consumption by using a high-frequency transformer and active front-end circuitry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a large transformer operating at line frequency is used in the PDU, then power can be supplied to the CT system, but the transformer size and cost increase significantly
Solution Approach 1:
The patent changes the operating frequency parameter from line frequency (50/60 Hz) to high frequency (20-50 kHz). This parameter change allows the transformer to be much smaller in size while still providing the required power output, as transformer size is inversely proportional to operating frequency.
Solution Approach 2:
The patent replaces the traditional mechanical transformer-based power conversion system with an electronic system using inverters and high-frequency switching. This substitution eliminates the need for large line-frequency transformers and mechanical contactors, achieving both size reduction and improved reliability.
2Stability of the object's composition
If a large capacitor is used to minimize voltage droop, then voltage stability is improved, but inrush current increases requiring mechanical contactors
Solution Approach 1:
The patent replaces mechanical contactors with solid-state electronic switching devices (inverters and switches). This substitution eliminates mechanical wear and reliability issues while providing precise control over capacitor charging and inrush current limitation through electronic control circuits.
Solution Approach 2:
The patent employs feedback control through the inverter circuitry to monitor and regulate voltage levels. This feedback mechanism allows the system to maintain voltage stability without requiring oversized capacitors, as the electronic control can dynamically adjust to voltage variations and prevent droop.
3Ease of operation
If the transformer remains energized continuously, then power availability is ensured, but energy consumption increases by 500 W or more
Solution Approach 1:
The patent implements periodic action by using high-frequency switching (20-50 kHz) instead of continuous operation. The inverter switches the transformer on and off rapidly, maintaining power availability through controlled periodic energization while dramatically reducing average power consumption compared to continuous transformer operation.
Solution Approach 2:
The patent introduces dynamics by replacing the static, continuously-energized transformer system with a dynamic switched-mode power supply. The inverter dynamically controls the transformer energization based on load requirements, enabling the system to maintain power availability while consuming minimal energy during idle periods.
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 HFPDU reduces the size of the isolation transformer, enhances power efficiency, and minimizes energy consumption during idle periods, improving reliability and reducing costs while maintaining tight output voltage regulation and galvanic isolation.
Implementation Method 1
a three-phase rectifier coupled to the input bus and configured to output a DC current to an inverter
Implementation Method 2
the inverter configured to convert the DC current to an AC current
Implementation Method 3
output the AC current to a primary winding of an isolation transformer, and the isolation transformer having a secondary output
Data Source
AI summary
A CT system includes an x-ray source, a high-voltage power supply (HVPS) coupled to the x-ray source, and a high-frequency power distribution unit (HFPDU) having an input bus that is coupleable to a three-phase source, and having an output bus. The HFPDU includes a three-phase rectifier coupled to the input bus and configured to output a DC current to an inverter, the inverter configured to convert the DC current to an AC current, and output the AC current to a primary winding of an isolation transformer, and the isolation transformer having a secondary output to an isolation transformer, that is coupled to a full bridge rectifier, to produce DC current to the output bus and to DC bus loads of the CT system.