摘要
匀场放大器是一种应用于磁共振设备上,对局部高阶磁场进行补偿的高精度电流放大器。随着磁共振设备往高场方向发展,局部高阶磁场的畸变使磁共振成像的伪影变得越来越严重,市场上已有的匀场放大器由于其响应速度过慢,不能对这种伪影进行有效的抑制,而受到了局限。为了改善其在高场应用中的性能,该设计以TI公司的具有高分辨率PWM模块的TMS320F2808 DSP作为主控芯片,设计了一个数字动态匀场放大器,并采用模糊自整定PI作为控制器算法。实验结果表明该动态匀场放大器,具有响应速度快和稳态精度高的特点,能满足高场应用的要求。
Shim amplifier is a component in magnetic resonance devices.It is actually a high precision current amplifier used to compensate the local magnetic field.With the development of high-field magnetic resonance equipment,static shim amplifiers has been limited because of its slow response speed.In order to improve its performance in high-field application,this design uses TI＇s DSP provided with high-resolution PWM module to design a digital dynamic Shim amplifiers,and using fuzzy self-tuning PI as the control algorithm.Simulation and experimental results show that the dynamic shim amplifier,with high response speed and high accurate steady state,can meet the high field applications.
出处
《自动化与仪表》
北大核心
2011年第2期45-49,共5页
Automation & Instrumentation
