Interleaved MRI Gradient Drivers for Thermal Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Typical gradient driver configurations in MRI systems suffer from thermal instability and electrical losses, which decrease efficiency and complicate design, especially when delivering high-amplitude pulse sequences to gradient coils.
Innovation Solution
The use of interleaved multi-level gradient drivers, where each driver is configured to deliver less than the maximum current amplitude, allowing for concurrent or alternate operation to reduce electrical losses and improve thermal stability, with a 2-3 level or 2-2 level configuration using transformers for current balancing and switching semiconductors to manage pulse sequences effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a single gradient driver is used to deliver maximum amplitude current pulses, then the required pulse sequence amplitude is achieved, but thermal instability and electrical losses increase
Solution Approach 1:
The single gradient driver is divided into multiple interleaved drivers (first gradient driver and second gradient driver), each capable of delivering a portion of the total current amplitude. This segmentation allows the system to achieve the required maximum amplitude through combined output while reducing the current burden and thermal load on each individual driver, thereby minimizing electrical losses and improving efficiency.
2Power
If a single gradient driver is used to deliver maximum amplitude current pulses, then the required pulse sequence amplitude is achieved, but thermal stability deteriorates
Solution Approach 1:
The single gradient driver is divided into multiple interleaved drivers (first gradient driver and second gradient driver), each capable of delivering a portion of the total current amplitude. This segmentation allows the system to achieve the required maximum amplitude through combined output while reducing the current burden and thermal load on each individual driver, thereby minimizing electrical losses and improving efficiency.
3Loss of energy
If multiple interleaved gradient drivers are used, then electrical losses are reduced and thermal stability improves, but device complexity increases
Solution Approach 1:
Multiple interleaved gradient drivers are combined in a coordinated configuration where the first and second gradient drivers operate together to deliver the total required current amplitude. The drivers are electrically connected through a common load (gradient coil) and controlled by a controller that synchronizes their operation. This merging approach achieves reduced electrical losses and improved thermal stability while managing complexity through unified control and shared power supply infrastructure.
4Loss of energy
If multiple interleaved gradient drivers are used, then electrical losses are reduced and thermal stability improves, but design complexity increases
Solution Approach 1:
Multiple interleaved gradient drivers are combined in a coordinated configuration where the first and second gradient drivers operate together to deliver the total required current amplitude. The drivers are electrically connected through a common load (gradient coil) and controlled by a controller that synchronizes their operation. This merging approach achieves reduced electrical losses and improved thermal stability while managing complexity through unified control and shared power supply infrastructure.
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 configuration reduces electrical losses, enhances the precision and accuracy of pulse sequences, improves thermal stability, and simplifies the design of the gradient driver, leading to more efficient and reliable MRI system operation.
Implementation Method 1
The time-varying magnetic gradient fields may be produced by gradient coils in the MRI system which are driven by pulsed sequences of current having a large dynamic range
Implementation Method 2
MRI systems typically employ magnetic fields and pulses of radio frequency (RF) energy to generate images based on the gyromagnetic properties of tissues and structures within the body
Data Source
AI summary
Embodiments of the present disclosure include a magnetic resonant imaging (MRI) system including a gradient driver configured to deliver a pulse sequence to gradient coils in the MRI system. The gradient driver may be interleaved, and may include two or more interleaved drivers, such that a high amplitude pulse may be output by operating the two interleaved parts of the gradient driver while spreading the electrical loss and maintaining the thermal stability of the system. In one embodiment, each interleaved driver may be rated to output approximately half a maximum amplitude of a current utilized by the gradient coil, and only one interleaved driver may be in operation if only one interleaved driver is sufficient for delivering a necessary pulse to the coils. Further, the interleaved drivers may alternate in operation to maintain thermal stability in the switching semiconductors of the gradient driver.