| 英文摘要 | Induction heating for pipeline water is a technology that heats the tube wall and water by eddy current, it’s widely used in industrial production for the sake of high efficiency, cleanliness and other advantages. With the development of microelectronics and digital signal processing technology, induction heating technology is developing in the direction of intelligent and digital control. DSP with high-speed operation ability and abundant peripheral resources, has made some advanced control strategies applied into practice. Using DSP to study the key technologies of induction heating can make the heating system more reliable and realize real-time control, it has important research significance and application value in the field of induction heating. In this paper, taking the key technologies of induction heating as the core research work, we mainly studied the problems which include PLL frequency-tracking, phase-shift PWM power regulation, the design of hardware and software based on DSP and so on. The main content of this paper is as follows: 1. In this paper, we introduced the basic principle of induction heating and the research status at home and abroad. By analyzing and comparing several power circuits of the induction heating power supply, we determined the power circuit for this paper, and the RLC series resonant circuit was analyzed. 2. We described the two key technologies of induction heating—PLL and power regulation, established the mathematical model of digital PLL and analyzed the working principle of phase-shift PWM power regulation. The system was simulated with the SIMULINK toolbox in MATLAB and the simulation data are presented. 3. We determined the scheme of the hardware system and designed the power circuit and control circuit. The power circuit uses IGBT full bridge inverter. We designed the sampling circuit, the phase detection circuit. Using DSP TMS320F28335 as the core processor, we designed IGBT driving circuit, protection circuit, human-machine interface circuit and so on. 4. On the basis of the hardware platform, we wrote the control program. Using 훍C/OS II embedded real-time operating system as the basic framework in CCS, we developed programs for digital PLL, phase-shift PWM power regulation, closed-loop power control, fault protection, human-machine interface and so on, the key parts are introduced and the program flow charts are given. 5. Finally, the induction heating system was debugged in low power condition ... |
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