Gradient Amplifier Power Supply Voltage Prediction
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Solution Overview
Problem
Magnetic resonance imaging (MRI) gradient amplifiers experience significant power losses due to conduction and switching losses, leading to increased operational costs and heat generation, necessitating a more efficient power supply system.
Innovation Solution
A method and system that predicts the gradient voltage required to drive the gradient coil based on a gradient coil model derived from historical data, calculates a voltage set point for the power supply, and provides electrical power accordingly, reducing the magnitude of power input.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If gradient amplifiers use switching devices (MOSFETs/IGBTs) to generate gradient signals, then the gradient amplifier can drive the gradient coil to produce magnetic field gradients, but conduction loss and switching loss occur, increasing power consumption and heat generation
Solution Approach 1:
The system pre-calculates the required gradient voltage waveform based on the selected imaging sequence and coil parameters before the scan begins. This preliminary calculation allows the power supply to be optimized in advance, determining the exact voltage requirements without needing to over-provision for worst-case scenarios, thereby reducing conduction losses in the gradient amplifier switches.
Solution Approach 2:
The system dynamically adjusts the power supply voltage setpoint during the scan based on real-time requirements. By continuously monitoring the gradient waveform requirements and adjusting the power supply output accordingly, the system avoids maintaining excessive voltage levels that would increase conduction losses, while still meeting the dynamic demands of different imaging sequences.
2Reliability
If the power supply provides larger magnitude power to compensate for losses, then the gradient amplifier can maintain required output, but operational costs increase and heat generation increases
Solution Approach 1:
The system incorporates feedback mechanisms where the actual gradient coil performance and power consumption are monitored during operation. This feedback is used to refine the voltage setpoint calculations and adjust power supply parameters in real-time, ensuring that the system operates at optimal efficiency points while maintaining reliable gradient coil driving capability across different imaging conditions.
Solution Approach 2:
The system changes key operating parameters such as the power supply voltage setpoint, switching frequencies, and current limits based on the specific imaging sequence and gradient coil requirements. By optimizing these parameters for each scan type rather than using fixed conservative values, the system reduces unnecessary power consumption and heat generation while maintaining gradient coil performance.
3Loss of energy
If the system uses historical data and gradient coil models to predict gradient voltage, then power supply can be optimized, but system complexity increases due to modeling and calculation requirements
Solution Approach 1:
The gradient coil model and voltage waveform calculations are performed in advance during system setup and sequence planning, before the actual scan begins. This preliminary modeling phase captures the complex calculations offline, allowing the real-time control system to simply execute pre-determined voltage waveforms, thereby reducing the real-time computational burden and perceived system complexity.
Solution Approach 2:
The patent introduces an intermediary computational layer that acts as a bridge between the imaging sequence requirements and the power supply control. This intermediary model translates high-level imaging parameters into specific gradient voltage waveforms, shielding the user from the underlying complexity while enabling optimized power supply control through automated calculations based on historical data and coil characteristics.
Data Source
AI summary
A method for supplying electrical power to a gradient amplifier that drives a gradient coil for a magnetic resonance imaging system is provided. The method includes predicting a gradient voltage required to drive the gradient coil for a scan based at least in part on a gradient coil model. The method further includes calculating a voltage set point for a power supply based at least in part on the predicted gradient voltage. The method further includes providing electrical power to the gradient amplifier via the power supply based at least in part on the calculated voltage set point. The gradient coil model is based at least in part on historical data acquired prior to the scan.