RF Amplifier Power Supply Switching for MRI Peak Power Modes
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing RF amplifiers in MRI systems are optimized for a single operation mode, making it inefficient to rapidly switch between different peak power requirements, particularly in applications like amide proton transfer (APT) weighted imaging where rapid mode switching is necessary.
Innovation Solution
A RF transmit system with at least two power supply devices and a DC switch that can quickly switch the voltage supplied to the amplifier based on sensor data, allowing operation at high and low peak powers with high efficiency, using a solid-state switch for fast switching and a capacitor bank to compensate for voltage drops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single power supply device is used for the RF amplifier, then the device complexity is reduced, but the adaptability to different operation modes (high power and low power) deteriorates
Solution Approach 1:
The power supply system is segmented into multiple independent power supply devices (first power supply device for high power mode, second power supply device for low power mode), each optimized for specific operation conditions. This segmentation allows the system to select the most appropriate power supply for each operation mode, improving adaptability while managing complexity through modular design
Solution Approach 2:
The power supply system is designed with multi-functionality by incorporating multiple power supply devices that can serve different operation modes. The system universally handles both high power and low power requirements through a unified architecture that includes switching mechanisms and control logic, allowing a single system to perform multiple functions
2Power
If the drain voltage is increased to achieve high peak power (16 kW), then the power output is improved, but the power efficiency deteriorates
Solution Approach 1:
The system dynamically adjusts the drain voltage based on the required power output level. For high peak power applications (16 kW), the voltage is increased to achieve the necessary power output. For continuous low power applications (500 W), the voltage is reduced to maintain high efficiency. This dynamic adaptation resolves the contradiction between power output and efficiency by matching voltage levels to operational requirements
Solution Approach 2:
The system changes the operating parameters (drain voltage Vds) according to the operation mode. By switching between different voltage parameters (higher voltage for high power mode, lower voltage for low power mode), the system achieves both high peak power capability and high efficiency at low power levels, eliminating the fixed trade-off between power and efficiency
3Loss of energy
If the drain voltage is decreased to improve power efficiency at low power (500 W), then the power efficiency is improved, but the peak power output capability deteriorates
Solution Approach 1:
The system dynamically adapts the drain voltage based on real-time power requirements. When low power output (500 W) is needed, the system operates at lower voltage to maintain efficiency above 20%. When high peak power (16 kW) is required, the system switches to higher voltage operation. This dynamic behavior allows the system to optimize efficiency at low power while maintaining peak power capability when needed
4Adaptability or versatility
If multiple power supply devices are introduced to support different operation modes, then the adaptability is improved, but the device complexity increases
Solution Approach 1:
A switching mechanism acts as an intermediary between multiple power supply devices and the RF amplifier. This intermediary component manages the complexity by providing a unified interface and automated selection logic, allowing multiple power supplies to work together seamlessly without proportionally increasing system complexity. The switch rapidly connects the appropriate power supply based on operation mode requirements
Data Source
AI summary
The present invention is directed to a RF transmit system (1) for a magnetic resonance examination system where it is intended to provide a solution for the problem of rapidly switching between operation modes of different peak power requirements at good power efficiencies. For this purpose the RF transmit system (1) comprises at least one RF channel (14) wherein the RF channel (14) has an RF amplifier (3), at least two power supply devices (4, 5) wherein each of the power supply devices (4, 5) is configured to supply a voltage to the amplifier (3). The RF transmit system (1) further comprises a DC switch (8) configured to switch the voltage supplied to the amplifier (3) between the power supply devices (4, 5) and a controller (2) configured to switch the voltage based on sensor data.