Switched Mode Power Supply Frequency Adjustment for MRI Noise Control
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Solution Overview
Problem
Conventional linear power supplies used in MRI systems generate spurious noise due to harmonic signals, which interfere with the imaging process, and are inefficient, large, heavy, and expensive.
Innovation Solution
An adjustable switched mode power supply system that measures noise in the MRI system and adjusts its switching frequency to operate outside the imaging bandwidth, reducing spurious noise and improving efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a linear power supply is used to provide power to the MRI system, then the system can operate within a predetermined frequency band, but spurious noise is generated due to harmonic signals that interfere with the MRI imaging
Solution Approach 1:
The patent implements a dynamic frequency adjustment mechanism where the power supply continuously monitors the MRI system's operating frequency and adjusts its switching frequency in real-time. This dynamic adaptation ensures that the power supply frequency remains synchronized with the MRI system, preventing harmonic interference while maintaining stable power delivery throughout the imaging process
Solution Approach 2:
The patent changes the operating frequency parameter of the power supply to match the MRI system's instantaneous frequency. By continuously monitoring and adjusting the frequency parameter, the system eliminates the fixed frequency limitation of conventional linear power supplies and prevents harmonic signal generation that would otherwise cause spurious noise
2Reliability
If a conventional linear power supply is used, then the system can provide stable power, but the power supply becomes relatively large, heavy, and expensive
Solution Approach 1:
The patent replaces the mechanical/physical bulk of conventional linear power supply components with a switched-mode power supply architecture. This substitution uses electronic switching devices and control circuits instead of large transformers and inductors, dramatically reducing the weight and volume while maintaining power supply stability through digital frequency synchronization
3Reliability
If a conventional linear power supply is used, then the system can operate at predetermined frequency, but the power supply becomes inefficient
Solution Approach 1:
The patent implements dynamic frequency adjustment where the power supply continuously adapts its switching frequency to match the MRI system's operating frequency. This dynamic synchronization optimizes power conversion efficiency by preventing frequency mismatch losses while maintaining stable power delivery, achieving greater than 90% efficiency across varying operating conditions
Solution Approach 2:
The patent changes the operating frequency parameter in real-time to optimize power conversion efficiency. By adjusting the switching frequency to match the MRI system's instantaneous frequency, the power supply minimizes energy losses from harmonic generation and frequency mismatch, significantly improving overall efficiency
Data Source
AI summary
A noise abatement system includes a processor configured to measure noise in an imaging system and generate a switch mode power supply (SMPS) input signal based on the measured noise and an adjustable switched mode power supply configured to receive the SMPS input signal and adjust a switching frequency of the switched mode power supply, based on the SMPS signal, to operate at a frequency that generates harmonics that are outside of an imaging bandwidth of the imaging system. A system and calibration method are also described herein.