电感耦合等离子体(ICP)光谱仪是一种应用范围很广的元素分析仪, 主要用于元素定性与定量的分析。ICP光源是光谱仪的核心部件, 它在光谱仪中扮演着至关重要的角色。目前主流的ICP光源有两种: 自激式和他激式, 各自具有优缺点。他激式光源电路复杂、 体积庞大、 阻抗匹配速度较慢、 最大输出功率有限。设计了一种基于镀金工艺的高功率MOSFET和变频实现阻抗匹配的自激式ICP光源, 该光源采用射频放大和阻抗匹配一体化的设计, 把从负载线圈采样的频率信号 f₁以及功率放大电路放大后的频率相位 f₀进行相位比较, 再根据两者相位差的变化, 进而控制频率的变化, 实现阻抗匹配; 设计上采用了镀金工艺的金属化硅N通道型高功率的MOSFET实现功率放大, 具有更大的功率密度、 更小的体积, 最大输出功率超过2 400 W。对研制的ICP光源进行了电学静态测试, 给出了鉴相器、 压控振荡器以及功率的输出特性, 验证了各电路在相应工作状态下的性能表现; 同时结合光谱仪进行了包含Ba、 Na和Li元素标准溶液的测试, 获得了目标元素的光谱信号; 另外, 对获得的光谱信号进行了处理, 使用了基于EEMD特征增强的方法对目标元素光谱信号进行有效增强, 信号的线性决定系数(R²)从0.97降至0.99, 相对标准偏差(RSD)从6.47%降至1.07%, 增强了信号的准确性和可用性。本文所研制的自激式ICP光源, 通过射频放大和阻抗匹配一体化设计缩小了体积, 变频技术使阻抗匹配速度从毫秒级提升到纳秒级, 镀金工艺的MOSFET技术使最大输出功率从原来的1 800 W增加到2 400 W, 为ICP光源的进一步优化和应用奠定了基础, 具有重要的科学研究和工程实践意义。

The inductively coupled plasma (ICP) spectrometer is a widely used elemental analyzer, mainly for qualitative and quantitative elements analysis. The ICP source is the core component of the spectrometer, playing a crucial role. By exciting the target elemental atoms in the sample, the ICP source generates corresponding characteristic spectra, which are then analyzed and measured by the spectrometer, achieving rapid and accurate detection of target elements in the sample. Currently, there are two mainstream types of ICP sources: self-excited and external-excited, each with its advantages and disadvantages. The external-excited ICP source generally consists of Radio Frequency (RF) amplification and impedance matching. The two are designed separately, with a complex circuit and a relatively large volume. The impedance matching uses a mechanical capacitance matching method, with response times in milliseconds or even seconds, resulting in slow matching speeds. At the same time, the design mostly employs Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFET) with low power amplification, and the maximum output power is limited. This paper presents a self-excited ICP source based on a gold-metalized silicon n-channel RF power transistor and variable frequency impedance matching. The ICP source uses an integrated design of RF amplification and impedance matching, comparing the phase difference between the frequency signal f₁ sampled from the load coil and the amplified frequency phase f₀, and controlling the frequency change based on the phase difference to achieve impedance matching. The design uses gold plating technology to amplify power with high-power silicon n-channel RF power transistor, providing greater power density and smaller volume, with a maximum output power exceeding 2 400 W.The paper conducted electrical static tests on the developed ICP source, providing the characteristics of the Phase Detector(PD), Voltage-Controlled Oscillator(VCO), and power output, verifying the performance of each section under corresponding working conditions. Additionally, tests were carried out with standard solutions containing Ba, Na, and Li elements using the spectrometer, obtaining an ICP spectrogram of the target elements. Furthermore, the obtained ICP spectrograms were processed using the Ensemble Empirical Mode Decomposition (EEMD) method to enhance the spectral signals of the target elements effectively. The R² coefficient of determination (R²) of the signal is increased from 0.97 to 0.99, and the relative RSD Standard Deviation (RSD) is increased from 6.47% to 1.07%, enhancing the signal’s accuracy and usability. The self-excited ICP source developed in this paper has been reduced in size through the integrated design of RF amplification and impedance matching. The frequency conversion technology has improved the impedance matching speed from the millisecond level to the nanosecond level, and the MOSFET technology of gold plating technology has increased the maximum output power from 1 800 to 2 400 W, which has laid a foundation for further optimization and application of ICP source and has important scientific research and engineering practice significance.