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The Research of Control System for Digital Design RF Generator

Author: ShiBaoSong
Tutor: JinXing
School: China University of Geosciences
Course: Mechanical and Electronic Engineering
Keywords: Digital ICP RF power CLASS-DE PWM
CLC: TM83
Type: Master's thesis
Year: 2009
Downloads: 215
Quote: 1
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Abstract

Inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS) is a new element analysis techniques can be fast at the same time detect the periodic table on almost all the elements to become recognized as the most powerful element analysis means widely used in the field of environmental, food, pharmaceutical, geological and polymer materials. In the commercial ICP-AES/MS instrument, inductively coupled plasma is by far the most commonly used in vitro source. RF power is used to ignite and maintain the inductively coupled plasma discharge excitation means is a core member of the inductively coupled plasma source. Involved in this thesis, the RF power frequency 27.12MHz, all the semiconductor electronic components made. In order to improve the efficiency of the RF power, the use of the digital drive mode, its main power amplifier parts - high frequency high power MOS transistor operating in the switch state can be more effective to generate plasma. The content of this thesis is the digital RF power control system, the text is divided into six parts: the first part, first introduced the source and purpose of the thesis topics and research status of ICP with RF power and the development of trends are described, and finally clear the main research content. The second part describes the digital RF power of design thinking and the composition of the control system. First of all, the digital RF power applications - ICP spectrum analyzer overview. Then, the formation process of the inductively coupled plasma discharge is described. Then, inductively coupled plasma RF power requirements from the start, it excited and self-excited RF power performance, and thus clear the the excited RF power performance advantages. On this basis, it the excited RF power circuit structural characteristics are described. Finally, it stimulated digital RF power of design thinking and the ideological guidance of clear digital RF power control system components. Part III details the design and commissioning of the core part of the control system - Digital RF Power driver stage. RF PWM (Pulse-Width Modulation) clock signal generation and transmission circuit and the drive signal power amplifier circuit has been described in accordance with the order of signal transmission, respectively. The radio frequency PWM clock signal generating circuit design points, followed by a choice of main points of the quartz crystal oscillator clock signal shaping circuit, PWM modulation circuit, self-locking circuit and PWM clock signal output circuit. Designed gate drive power amplifier circuit high power MOS gates gate drive signal for digital RF power amplifier circuit part of the drive signal. Part IV, respectively, of the power control method of digital RF power, working condition monitoring and control system software development made presentations. In the power control section, made a presentation method of the amount of RF power Chau, then set the RF output power control method is explained, and highlights the role of the matching network. In software development, focusing ICP ignition with the power to maintain workflow. Part V describes the electromagnetic compatibility of digital RF power control system. The sixth part of the completion of the process and results of the papers pointed out that the lack of prospect. This thesis, the design of digital RF power control system of the performance targets were achieved satisfactory results, and laid the foundation for high-performance all solid ICP source successfully developed its innovative point is that: the first digital RF the power of design thinking, CLASS-DE power amplifier is successfully applied to the ICP RF power development. Second, the use of direct digital drive, high-power MOS pipe work in the state of the switch, and to set and adjust the PWM modulation of the RF output power. Third, the important operating parameters of the RF power can control microcontroller unit real-time acquisition, analysis, and through the micro-controller to set the protection parameters, the RF power in a timely manner to protect the monitoring parameters abnormal to improve the reliability of the RF power, and convenience of system debugging.

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