Paralleled Gradient Power Amplifier Control for Low Circulating Current
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Solution Overview
Problem
Existing magnetic resonance (MR) systems with gradient power amplifiers (GPAs) face challenges in reducing circulating currents and achieving low cost, small volume, and enhanced dynamic response performance due to the need for high-inductance couplers, which increase system size and cost while reducing control bandwidth.
Innovation Solution
A GPA system with a controller that determines control parameters for paralleled GPAs based on total and average current parameters, using algorithms like PI, prediction, or pole assignment, and optionally employs a low-inductance coupler for current sharing control, eliminating the need for large high-inductance couplers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If high-inductance couplers are used to reduce circulating currents, then circulating currents are reduced, but system volume and cost increase
Solution Approach 1:
The patent changes the inductance parameter of the coupler from high to low values. By using low-inductance couplers instead of high-inductance couplers, the system achieves effective circulating current reduction while significantly decreasing the volume of the coupler and overall system.
Solution Approach 2:
The patent implements a feedback control mechanism where the controller monitors the circulating currents and dynamically adjusts control parameters of the GPAs. This active feedback approach replaces the passive high-inductance coupler solution, enabling circulating current suppression without requiring large-volume components.
2Object-generated harmful factors
If high-inductance couplers are used to reduce circulating currents, then circulating currents are reduced, but system cost increases
Solution Approach 1:
The patent changes the inductance parameter from high to low, which directly reduces the cost of couplers. Low-inductance couplers are cheaper to manufacture and acquire compared to high-inductance couplers, thereby reducing overall system cost while maintaining circulating current suppression performance through control algorithms.
Solution Approach 2:
The patent substitutes the mechanical/passive high-inductance coupler solution with an active control system using low-inductance couplers combined with controller algorithms. This substitution reduces reliance on expensive passive components and leverages cost-effective active control to achieve the same circulating current reduction goal.
3Object-generated harmful factors
If high-inductance couplers are used to reduce circulating currents, then circulating currents are reduced, but control bandwidth decreases
Solution Approach 1:
The patent changes the inductance parameter from high to low, which directly improves control bandwidth. Low-inductance couplers have smaller time constants and faster response characteristics compared to high-inductance couplers, enabling the system to maintain high control bandwidth while effectively suppressing circulating currents through active control.
Data Source
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AI summary
Gradient power amplifier (GPA) systems and methods are provided. A GPA system may include a plurality of paralleled GPAs; and at least one controller operably coupled to the plurality of paralleled GPAs. The at least one controller may be configured to perform operations including: obtaining a total current parameter of the plurality of paralleled GPAs; determining, based on the total current parameter and a target current parameter, a first difference value; and determining, based on the first difference value, a first control parameter of a first GPA of the plurality of paralleled GPAs, wherein the first control parameter is configured to control an output current of the first GPA.