MRI Power Supply Frequency Offset to Reduce Heat and Interference
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Solution Overview
Problem
Existing MRI power source supply systems require multiple AC/DC conversion elements and linear regulators for different loads, leading to heat dissipation issues and interference with the magnetic field environment.
Innovation Solution
A power source supply system with an AC/DC conversion circuit and a switching power source for each load, where the switching frequency is set as a positive integer multiple offset from the Larmor frequency to avoid interference, using a transformer, AC/DC converter, filter, and branching elements like Y-cables or PCBA for efficient power distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple AC/DC conversion elements and linear regulators are used for different loads, then each load receives appropriate DC power, but heat dissipation problems occur and the structure becomes complex
Solution Approach 1:
The patent merges multiple AC/DC conversion functions into a single AC/DC conversion circuit that serves all loads. Instead of having separate AC/DC converters for each load, one conversion circuit converts AC power to DC power that is then distributed to multiple loads through switching power source elements, reducing structural complexity while maintaining reliable power supply.
Solution Approach 2:
The single AC/DC conversion circuit performs a universal function of converting AC power to DC power for multiple different loads. The switching power source elements then adapt this common DC output to meet the specific voltage requirements of each load, making the initial conversion stage universally applicable to all loads rather than requiring dedicated conversion circuits for each.
2Reliability
If linear regulators are used to maintain specified DC voltage, then voltage stability is achieved, but heat dissipation increases
Solution Approach 1:
The patent replaces linear regulators (which dissipate excess voltage as heat) with switching power source elements. These switching elements use electromagnetic induction and capacitive energy storage to efficiently convert voltage levels with minimal energy loss, substituting the linear regulation mechanism with a switching-based voltage conversion mechanism that dramatically reduces heat dissipation.
Solution Approach 2:
The switching power source elements change the operating parameters from continuous linear regulation to periodic switching operation. By switching the power transmission on and off at controlled frequencies and using pulse-width modulation, the system achieves precise voltage control while minimizing energy dissipation, as the switching elements operate in saturation/cutoff regions where power loss is minimal.
3Productivity
If switching power sources are used for each load, then power distribution efficiency improves, but interference with magnetic resonance imaging may occur
Solution Approach 1:
The patent carefully selects and adjusts the switching frequency parameter of the switching power source elements to avoid resonance with the MRI system's Larmor frequency. By changing the operating frequency parameter to a value that is not an integer multiple of the Larmor frequency, the system maintains efficient power distribution while eliminating electromagnetic interference that would otherwise disrupt the magnetic resonance imaging process.
Solution Approach 2:
The system incorporates frequency selection and adjustment mechanisms that respond to the MRI operating conditions. By monitoring or pre-determining the Larmor frequency and selecting switching frequencies that avoid integer multiples, the system provides feedback-based frequency optimization to prevent interference while maintaining power distribution efficiency.
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 a simple and efficient power supply to multiple MRI loads while minimizing interference with the magnetic resonance imaging process by selecting appropriate switching frequencies, ensuring reliable operation without heat dissipation issues.
Implementation Method 1
an AC/DC conversion circuit that converts a supplied AC current to a first DC current having a predetermined first voltage
Implementation Method 2
a switching power source, disposed in each of the loads that converts the first DC current to a second DC current having a second voltage
Implementation Method 3
the AC/DC conversion circuit has an AC/DC converter and a filter
Implementation Method 4
The switching frequency of the switching power source is set such that a positive integer frequency multiple thereof is offset from the Larmor frequency of the magnetic resonance imaging apparatus
Data Source
AI summary
A power source supply system for a magnetic resonance imaging (MRI) apparatus that has multiple loads operating in a magnetic field environment, has an AC/DC conversion circuit that converts a supplied AC current to a first DC current having a predetermined first voltage, a branching element that supplies the first DC current in separate paths respectively to the multiple loads, a switching power source, disposed in each of the loads that converts the first DC current to a second DC current having a second voltage capable of being supplied to the load, with a switching frequency of the switching power source being set such that a positive integer frequency multiple thereof is offset from the Larmor frequency of the MRI apparatus.