单逆变桥同步双频感应加热电源的数字化逆变控制

发布时间：2018-06-28 05:02

本文选题：感应加热 + 同步双频　；参考：《清华大学》2015年硕士论文

【摘要】：感应加热是利用电磁感应原理,使得金属工件在通以交流的感应线圈中产生涡流从而自身表面发热升温,达到对工件加热的目的。感应加热技术自20世纪初应用于工业生产以来,以其低能耗、高效率、清洁程度好、自动化程度高等优点在我国的各个行业里得到了广泛的应用。随着电力半导体器件、电路拓扑结构以及微处理器技术的迅速发展,感应加热技术不断向大容量、高效率和智能化方向发展,目前工业领域中广泛应用的感应加热装置多采用模拟控制,由于其系统具有可靠性低、拓展性弱的缺点,因此具有较高可靠性的全数字式控制方式成为感应加热领域一个重要的研究方向,为此本文在单逆变桥双频感应加热结构的电源基础上,研究了其数字化逆变的控制策略和方法。本文首先介绍了感应加热的基本原理和应用领域,阐述了感应加热电源的发展现状和未来的发展方向,并分析了单逆变桥双频感应加热结构的工作原理和工作特性,确定了本文研究同步双频感应加热数字化逆变控制的内容和目的。针对传统模拟电路控制的缺点,本文设计了基于FPGA的全数字化逆变控制方式,确立了以数字锁相环和数字SPWM为核心的逆变主控制电路,详细分析了数字锁相环的构成及各个模块的设计方式和原理,研究了正弦脉冲调制中数字波形发生器、比较器和死区时延的设计原理,最终形成了在复合谐振电路基础上进行双频频率跟踪的控制策略。在理论分析的基础上,文中应用Verilog HDL软件语言在Quartus II仿真平台上对数字锁相环和数字SPWM进行了底层模块设计与仿真验证,通过仿真波形验证了锁相环和SPWM设计方法的正确性。同时,在现有的MOSFET高频感应加热电源样机实验平台上,搭建了同步双频感应加热的开环电路和闭环电路,分析和讨论了实验结果,验证了数字化逆变控制的可行性。最后,从理论研究、仿真分析、实验验证三个方面对单逆变桥同步双频感应加热电源的数字化逆变控制策略进行了总结和讨论,针对数字化逆变控制模块设计中存在的逆变工作频率跟踪精度不够的问题进行了说明,也对未来研究中可改进的方面进行了探讨。
[Abstract]:Induction heating is based on the principle of electromagnetic induction, which makes metal workpiece produce eddy current in the inductive coil with alternating current, thus heating up the surface of the metal workpiece to achieve the purpose of heating the workpiece. Since its application in industrial production in the early 20th century, induction heating technology has been widely used in various industries in China because of its advantages of low energy consumption, high efficiency, good degree of cleanliness and high degree of automation. With the rapid development of power semiconductor devices, circuit topology and microprocessor technology, induction heating technology continues to develop in the direction of large capacity, high efficiency and intelligence. At present, the induction heating devices widely used in the industrial field mostly adopt analog control. Because of its low reliability and weak expansibility, Therefore, full digital control with high reliability has become an important research direction in the field of induction heating. The control strategy and method of digital inverter are studied. In this paper, the basic principle and application field of induction heating are introduced, the present situation and future development direction of induction heating power supply are described, and the working principle and characteristics of single-inverter bridge dual-frequency induction heating structure are analyzed. The content and purpose of digital inverter control of synchronous dual frequency induction heating are determined in this paper. Aiming at the shortcoming of the traditional analog circuit control, this paper designs the full-digital inverter control mode based on FPGA, and establishes the main inverter control circuit with digital phase-locked loop and digital SPWM as the core. The structure of digital phase-locked loop (DPLL) and the design methods and principles of each module are analyzed in detail. The design principles of digital waveform generator, comparator and dead-time delay in sinusoidal pulse modulation are studied. Finally, the control strategy of dual frequency tracking based on compound resonant circuit is formed. On the basis of theoretical analysis, the digital phase-locked loop and digital SPWM are designed and verified by using Verilog HDL on Quartus II simulation platform. The correctness of the design method of phase-locked loop and SPWM is verified by simulation waveform. At the same time, the open loop circuit and closed loop circuit of synchronous dual frequency induction heating are built on the experimental platform of MOSFET high frequency induction heating power supply. The experimental results are analyzed and discussed, and the feasibility of digital inverter control is verified. Finally, the digital inverter control strategy of synchronous dual-frequency induction heating power supply with single inverter bridge is summarized and discussed from three aspects: theoretical research, simulation analysis and experimental verification. In this paper, the problem that the tracking accuracy of the inverter working frequency is not enough in the design of the digital inverter control module is explained, and the improvement aspects in the future research are also discussed.
【学位授予单位】：清华大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM464

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