MRI Coil Control Device Using DC-DC Switching Converter
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Solution Overview
Problem
Conventional MRI coil control circuits experience high energy losses, leading to overheating and increased system complexity and costs due to the use of two power supplies and a water-cooling system, resulting in a low signal-to-noise ratio and non-uniform image quality.
Innovation Solution
A coil control device utilizing a DC-DC switching converter with a buck and buck-boost circuit, controlled by a feedback system to provide constant current or voltage, reducing energy waste and eliminating the need for a water-cooling system by integrating the power supply into a single unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional coil control circuit with two power supplies and diode is used, then the coil can be controlled, but high energy losses occur leading to overheating and low efficiency
Solution Approach 1:
The patent merges two separate power supplies (positive and negative voltage sources) into a single DC power supply by introducing a voltage inversion circuit. This consolidation reduces energy losses associated with multiple power supplies while maintaining the necessary bipolar voltage control for the coil. The merging principle directly addresses the energy efficiency problem while the integrated design manages the complexity through functional integration.
Solution Approach 2:
The patent replaces the conventional diode-based current sinking mechanism with an active switching circuit using MOSFETs and operational amplifiers. This substitution eliminates the significant voltage drop and energy dissipation inherent in diode operation, achieving much lower energy losses (reducing efficiency loss from 93.5% to minimal levels) while providing more precise control capability.
2Temperature
If a water-cooling system is added to handle heat from energy losses, then overheating is prevented, but system complexity and costs increase
Solution Approach 1:
The patent converts the harmful heat generation problem into a benefit by designing a control circuit that inherently minimizes energy dissipation through active switching rather than passive diode operation. By using MOSFETs with low on-resistance and implementing intelligent current control, the system generates minimal heat that does not require external cooling, thus eliminating the need for complex water-cooling systems while maintaining reliable thermal management.
3Device complexity
If a conventional control circuit with diode is used, then simple circuit design is achieved, but energy loss rate reaches 93.5% which is unacceptable
Solution Approach 1:
The patent substitutes the passive diode component with an active electronic control system comprising MOSFETs, operational amplifiers, and feedback circuits. This replacement transforms the circuit from a simple but inefficient design to a more complex yet highly efficient active control system that achieves minimal energy loss through intelligent switching and feedback regulation, directly resolving the 93.5% energy loss problem.
Solution Approach 2:
The patent implements feedback control mechanisms using operational amplifiers that continuously monitor the voltage and current across the coil and adjust the switching signals accordingly. This feedback system ensures precise control of the coil current while minimizing energy dissipation by optimizing the switching timing and duration, thereby achieving high efficiency without sacrificing control precision.
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 solution significantly reduces energy loss, simplifies the system, and maintains high signal-to-noise ratio and uniform image quality without the need for a water-cooling system, thereby saving energy and reducing costs.
Implementation Method 1
A coil control device is provided that includes a DC-DC switching converter... The DC-DC switching converter includes a buck circuit and a buck-boost circuit
Implementation Method 2
Magnetic resonance imaging (MRI) is a technique using magnetic resonance phenomena for imaging... nuclei containing a single proton has a spinning movement similar to a small magnet... When an external magnetic field is applied, these small magnets will be rearranged according to the magnetic force lines
Data Source
AI summary
A coil control device of a magnetic resonance imaging system includes a DC-DC switching converter and a controller. The DC-DC switching converter is configured for switching and converting a DC power supply to a DC current or a DC voltage. An input end of the DC-DC switching converter is connected in parallel to the DC power supply. The controller is configured to control the DC-DC switching converter to switch and provide the DC current or the DC voltage. In some embodiments of the coil control device described herein, two power supplies (e.g., +15 V and −32 V) may be reduced to one power supply (e.g., +15 V), thereby saving energy and foregoing a water-cooling system.