Non-linear Inductor Resonant Circuit for CT High-Voltage Switching
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Solution Overview
Problem
Current high-voltage switching systems for computed tomography apparatuses are either costly or have low fault tolerance, making them unsuitable for reliable and cost-effective spectral imaging, particularly prone to issues like tube arcing.
Innovation Solution
A system utilizing a resonant circuit with a non-linear inductor and capacitor, which provides a square-like voltage waveform by reducing inductance as current increases, allowing for efficient and reliable high-voltage switching with reduced stress on the X-ray tube, achieved through a magnetic core that saturates at a predefined current level, enabling abrupt changes in current and voltage levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional high-voltage switching systems are used, then switching capability is achieved, but cost increases and fault tolerance decreases
Solution Approach 1:
The patent applies parameter changes by utilizing a non-linear inductor whose inductance value dynamically changes with current magnitude. At low currents, the inductor presents high impedance to limit current flow, while at high currents, the inductance drops to allow rapid current increase. This natural parameter change eliminates the need for complex switching electronics and enhances fault tolerance through inherent current limiting capability.
Solution Approach 2:
The resonant circuit with non-linear inductor provides self-service by automatically limiting inrush current and protecting against faults without external control. The non-linear inductance characteristic inherently prevents excessive current flow during switching transitions, and the resonant operation self-regulates the voltage waveform, eliminating the need for complex protection circuits or active control systems.
2Ease of manufacture
If conventional switching electronics are used, then kVp switching is achieved, but cost increases
Solution Approach 1:
The patent replaces complex electronic switching mechanisms with a passive resonant circuit containing a non-linear inductor and capacitor. This substitution eliminates expensive and fragile switching electronics while achieving the same kVp switching function through the natural resonant oscillation and non-linear inductance characteristics, improving both cost effectiveness and reliability.
Solution Approach 2:
The resonant circuit uses simple, inexpensive passive components (inductor and capacitor) instead of expensive electronic switching devices. These components are inherently more fault-tolerant and can withstand harsh high-voltage conditions without requiring complex protection circuits, making the system more cost-effective and reliable.
3Device complexity
If linear inductor is used in resonant circuit, then simple circuit design is achieved, but square-like voltage waveform cannot be generated
Solution Approach 1:
The non-linear inductor's inductance parameter changes dynamically with current magnitude, enabling the generation of a square-like voltage waveform. At low currents, high inductance limits current rise, creating flat voltage plateaus. At high currents, inductance drops abruptly, allowing rapid current change and voltage transitions. This parameter change mechanism achieves the desired waveform without complex circuitry.
4Productivity
If high current is applied to X-ray tube, then imaging speed improves, but stress on electrode increases
Solution Approach 1:
The non-linear inductor provides beforehand cushioning by limiting inrush current to the X-ray tube. During voltage transitions, the inductor's high inductance at low current automatically restricts current magnitude, preventing excessive stress on the electrode. This protective effect occurs naturally before any potential damage can occur, enabling faster imaging with reduced electrode stress.
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 system provides reliable and cost-effective high-voltage switching with reduced stress on the X-ray tube, ensuring consistent image quality and fault tolerance, while maintaining a "spectral always on" capability for computed tomography applications.
Implementation Method 1
achieved through a magnetic core that saturates at a predefined current level
Implementation Method 2
A first connection terminal of the capacitor is communicationally connected to a first connection terminal of the inductor for employing a resonant operation of a current through the inductor
Data Source
AI summary
The present invention relates to a system and a method for high-voltage switching for a computed tomography apparatus. The system comprises an oscillating circuit with a non-linear inductor and a capacitor. The inductor and the capacitor are connected in series, and the capacitor is connected to a high-voltage line of a high-voltage power supply. The inductor comprises an inductance that decreases with increasing current through the inductor, such that the inductance of the inductor significantly chances during a resonant operation of the oscillating circuit, thereby providing essentially a square voltage applied to the capacitor. The square voltage modulates the high-voltage of the high-voltage generator thus switching high-voltage levels applied to an electrode of a computed tomography system.