Improvement of Rf Signal Analysis for the Impedance Measurement Device in Hust Rf Negative Ion Source

作     者：Ai, Huangze Li, Dong Zuo, Chen Chen, Dezhi 

作者机构：State Key Laboratory of Advanced Electromagnetic Technology School of Electrical and Electronic Engineering Huazhong University of Science and Technology Hubei Wuhan430074 China 

出 版 物：《SSRN》 

年 卷 期：2024年

核心收录：

主　　题：Field programmable gate arrays (FPGA) 

摘      要：A high-power RF negative hydrogen ion source platform has been developed in Huazhong University of Science and Technology (HUST). An auto-tuning matching network is utilized to maximize the efficiency of RF power transmission. In order to provide the input impedance information for the auto-tuning system, a real-time impedance measurement device based on the voltage-current detection has been developed. This device employs FFT analysis and correction algorithm of double-spectrum-line interpolation based on rectangular window (DI-RW) to calculate the amplitude and phase of the RF voltage and current sampling signals. Due to the spectrum leakage and low spectrum line utilization of DI-RW, the error of impedance magnitude is around 3%, the error of impedance angle is within 2° in practice. For enhancing impedance analysis accuracy, the triple-spectrum-line interpolation based on Nuttall window (TI-NW) is adopted over the DI-RW, offering faster sidelobe attenuation and improving spectrum utilization. However, the parallel computing for multi-channel signals using TI-NW demands significant hardware resources. To mitigate resource consumption, a serial computation architecture for multi-harmonic analysis based on TI-NW is proposed. Using a signal generator to simulate V-I sampling signals, the test results of the upgraded impedance measurement device have been given, which proves the higher accuracy compared with DI-RW. © 2024, The Authors. All rights reserved.