X-Ray Tube Power Regulation via Voltage Compensation
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Solution Overview
Problem
Portable x-ray units experience voltage drops during discharge, leading to distorted images due to unpredictable power line voltage fluctuations or battery degradation, resulting in insufficient kVp and mAs, which compromises image quality.
Innovation Solution
An automatic power regulation method that calculates and maintains a reference voltage (half of the supply voltage) to ensure maximum power delivery by adjusting the x-ray tube current based on real-time voltage measurements, using a microprocessor to dynamically control the filament current and exposure time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the x-ray unit operates at high power, then the image quality is improved, but voltage drops occur during discharge which distort the image
Solution Approach 1:
The system performs preliminary measurement of the power line voltage before the x-ray discharge occurs. Based on this pre-measurement, the controller calculates the expected voltage drop and automatically adjusts the filament current to compensate for the upcoming voltage drop, ensuring the x-ray tube receives the correct voltage during discharge without image distortion.
Solution Approach 2:
The system continuously monitors the actual power line voltage and uses this feedback to dynamically adjust the filament current. The controller compares the measured voltage with the required voltage for optimal image quality and modifies the filament current accordingly, creating a closed-loop control system that maintains image quality despite voltage fluctuations.
2Loss of energy
If the power line resistance is reduced, then voltage drops are minimized, but the system becomes more complex and less portable
Solution Approach 1:
The system automatically measures its own power line voltage and independently calculates the necessary compensation without requiring external intervention or complex external monitoring equipment. The built-in voltage sensor and controller work autonomously to compensate for voltage drops, eliminating the need for additional external devices or complex system architecture.
3Power
If the filament current is increased to compensate for voltage drops, then the maximum power is maintained, but the battery life is reduced
Solution Approach 1:
The system dynamically adjusts the filament current based on real-time voltage measurements and the specific discharge conditions. Rather than maintaining a constant high current that would deplete the battery rapidly, the controller modulates the filament current to match the actual power delivery capabilities of the battery at each moment, optimizing both power output and battery life.
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 method ensures consistent maximum power supply to x-ray units, maintaining image quality by compensating for voltage drops and internal resistance changes, thereby preventing the degradation of x-ray images.
Implementation Method 1
the actual values of the grid voltage and of the voltage drop are measured and the internal resistance values are calculated
Implementation Method 2
the peak value of the voltage applied, expressed as kVp, and on the other the product of the mA supplied and the exposure time
Data Source
AI summary
The objective of the method is operating an x-ray unit that supplies the maximum power at all times, for which the supply or input voltage at the x-ray tube must be half the power supply voltage ((Vbat)/2 or (Vline)/2), which will be termed the reference voltage (Vref); in case of a deviation from the reference voltage, the method modifies the current supplied, changing the exposure time so that the maximum power is delivered at all times. In short, it is based on a method that regulates the tube current as a function of the supply voltage (of the batteries or the grid).