新型MIT激励源和最佳激励线圈的设计与实现

Design and Implementation of a New Type Excitation Source And the Optimal Excitation Coil for MIT

为了提高磁感应断层成像(MIT)系统性能,设计高性能的脑磁感应断层成像(BMIT)激励源,选择最佳的激励线圈。设计输出可调的大功率激励源电路,用软件ICAP仿真输出正确波形,并制作实现电路。计算设计聚焦式和螺线管式激励线圈,通过磁场测试和神经细胞相位检测实验,得到最佳激励线圈。在一定工作频率下,激励源输出功率可调范围为0.035～31.4W,稳定输出电流峰值大于1A,频率稳定度达10-9,谐波失真小于-51dB。通过比较三种激励线圈磁场,得到圆形螺旋聚焦线圈对细胞相位检测最为有效。该激励源的输出功率可调范围大,频率稳定度高,谐波失真小。采用圆形螺旋聚焦线圈更有利于组织电导率信息的提取。

This research work was aimed to improve the performance of magnetic induction tomography （MIT） system by designing a high-performance excitation source and the optimal excitation coil. A new type excitation source with adjustable output was designed, and then the power circuit was simulated hy the software ICPA. Focused and solenoid coils were designed in accoradance with the design principle of coil, then the optimal excitation coil was proved by measuring the magnetic field distribution and the experimentation of phase detection using neuron cell models. At the stated excitation frequency, the parameters of the excitation source are output power 0. 035 W-31.4 W, steady output peak current over 1 A, frequency stability 10-9 , and THD amplitude less than -51 dB. When compared with other coils, the focused discal excitation coil is most effective for phase detection with the use of neuron cell models. The excitation source can produce the stated frequency sine wave with higher frequency stability, lower THD and wider adjustable output power. The phase difference between normal cell model and edema cell model was more significant by measurement using focused discal coil.