基于dsPIC的串联谐振式中频感应加热电源研究

发布时间：2018-11-21 10:19

【摘要】：随着电力电子技术的发展,感应加热在工业领域得到了广泛应用。同时,对感应加热电源的可靠性和效率要求也在不断提高,数字化控制是提高感应加热电源性能的重要手段。本文以dsPIC为控制核心,对串联谐振式中频感应加热电源的数字化控制进行了研究。本文介绍了感应加热的基本原理、应用及其优点、发展现状及趋势,在分析和比较了几种常用感应加热电源主电路结构和控制方案的基础上,确定了串联谐振式中频感应加热电源的系统结构,其中整流电路采用三相不控整流方式,逆变电路采用单相全桥逆变结构。研究了串联谐振负载工作特性、移相PWM调功特性及逆变电路工作方式和过程,对频率跟踪技术中的锁相环工作原理和相位差测量方法进行了说明,分析了电源启动的常用实现方法。分析了常规的数字PID控制在感应加热电源系统中的应用缺陷,基于模糊控制原理,采用了FUZZY-DPLL和FUZZY-PI两种复合控制策略。在实现频率跟踪时,依据所测相位差并利用FUZZY-DPLL分段复合控制进行频率修正和相位修正,其中相位差通过dsPIC的输入捕捉模块配合快速傅里叶变换得到。在实现功率调节时,依据移相PWM调功原理,利用FUZZY-PI分段复合控制进行移相角计算,并在数字PI控制中使用模糊自适应PID整定控制来调节控制参数。另外,依据负载电流检测值和DDS技术,采用扫频程序解决了电源启动问题。最后,基于dsPIC33EP32MC202对所研究的串联谐振式中频感应加热电源进行了硬件设计和软件设计,并依据设计内容搭建了仿真模型和实验平台,对实现系统频率跟踪和功率调节等关键问题的控制策略进行了调试和分析。仿真与实验结果证明了控制系统设计的合理性与可行性,为今后感应加热电源进一步的数字化研究奠定了良好基础。
[Abstract]:With the development of power electronic technology, induction heating has been widely used in industry. At the same time, the requirement of reliability and efficiency of induction heating power supply is also increasing. Digital control is an important means to improve the performance of induction heating power supply. In this paper, the digital control of series resonant intermediate frequency induction heating power supply is studied with dsPIC as the control core. This paper introduces the basic principle, application and advantages of induction heating, its development status and trend. Based on the analysis and comparison of the main circuit structure and control scheme of several kinds of common induction heating power supply, The system structure of series resonant intermediate frequency induction heating power supply is determined. The rectifier circuit adopts three-phase non-controlled rectifier and the inverter circuit adopts single-phase full-bridge inverter structure. The working characteristics of series resonant load, phase-shifted PWM power modulation and the working mode and process of inverter circuit are studied. The working principle of phase-locked loop and the method of phase difference measurement in frequency tracking technology are explained. The common realization methods of power source startup are analyzed. The defects of conventional digital PID control in induction heating power supply system are analyzed. Based on the fuzzy control principle, two kinds of compound control strategies, FUZZY-DPLL and FUZZY-PI, are adopted. In the realization of frequency tracking, frequency and phase correction are carried out according to the measured phase difference and the FUZZY-DPLL piecewise composite control. The phase difference is obtained by the input capture module of dsPIC and the fast Fourier transform (FFT). In the realization of power regulation, according to the principle of phase-shifted PWM power regulation, the phase shift angle is calculated by using the FUZZY-PI piecewise composite control, and the fuzzy adaptive PID tuning control is used in the digital PI control to adjust the control parameters. In addition, according to the load current detection value and DDS technology, the power source startup problem is solved by frequency sweep program. Finally, the hardware design and software design of the series resonant intermediate frequency induction heating power supply are carried out based on dsPIC33EP32MC202, and the simulation model and experimental platform are built according to the design content. The control strategy for the key problems such as system frequency tracking and power regulation is debugged and analyzed. The simulation and experimental results show that the design of the control system is reasonable and feasible, which lays a good foundation for the further digital research of the induction heating power supply in the future.
【学位授予单位】：兰州理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM924.01;TM46

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