毕业设计

基于IGBT的150kHz大功率感应加热电源的研究与设计

摘要

本文以感应加热电源为研究对象，阐述了感应加热电源的基本原理及其发展趋势。对感应加热电源常用的两种拓扑结构——电流型逆变器和电压型逆变器做了比较分析，并分析了感应加热电源的各种调功方式。在对比几种功率调节方式的基础上，得出在整流侧调功有利于高频感应加热电源频率和功率的提高的结论，选择了不控整流加软斩波器调功的感应加热电源为研究对象。针对传统硬斩波调功方式感应加热电源功率损耗大的缺点，采用软斩波调功方式，设计了一种零电流开关准谐振变换器ZCS-QRCs(Zero-current-switching-Quasi-resonant)倍频式串联写真高频感应加热电源。介绍了该软斩波调功器的组成结构极其工作原理，通过仿真和实验的方法研究了该软斩波器的性能，从而得出该软斩波器非常适合大功率高频感应加热电源应用场合的结论。同时设计了功率闭环控制系统和PI功率调节器，将感应加热电源的功率控制问题转化为Buck斩波器的电压控制问题。

针对目前IGBT器件频率较低的实际情况，本文提出了一种新的逆变拓扑—通过IGBT的并联来实现倍频，从而在保证感应加热电源大功率的前提下提高了其工作频率，并在分析其工作原理的基础上进行了仿真，验证了理论分析的正确性，达到了预期的效果。另外，本文还设计了数字锁相环（DPLL），使逆变器始终保持在功率因数近似为1的状态下工作，实现电源的高效运行。最后，分析并设计了IGBT的缓冲吸收电路。

关键词：倍频，感应加热，大功率，DSP，软开关

ABSTRACT

This paper briefly introduced the basic principle and the development trend of induction heating technology. It introduced the two main topologies that are often used in induction heating power supply, and comparative analyzed was made between the current source invertand the voltage source inverter, and analyzed power regulating methods of induction heatinpower supply too. It can be concluded that power regulation in the commutate side in favor oenhancing the frequency and power level of high-frequency induction heating power suppl We chose uncontrolled rectifying circuit and Buck soft choppering power regulation methoas the subject investigated. As the conventional hard chopper has the disadvantage of higloss, we put forward a novel Zero-current switching quasi-resonant converter technologwhich used in series resonant induction heating power surce. It introduced the structure of thnovel chopper, and got its working principle by simulation method. At last it got thconclusion that this novel soft chopper is suitable for high power and high frequencinduction heating power supply. What’s more, it analyzed the principle of the invertedesigned the PI Power Regulator, and induction heating supply will power control probleinto a Buck chopper voltage control issues.

Because low frequency of IGBT devices, This paper presents a new inverter topology--through IGBT parallel to achieve multi-frequency, thereby, ensuring high-power induction heating power on the premise of increased frequency,analysis of its working principle, and isimulation, verification of the correctness of the theory, achieved the expected results. Iaddition, the design of a digital phase-locked loop(DPLL),the inverter always maintain in thpower factor approximation for a state work, and power efficient operation. Finally, thanalys is and design of the buffer IGBT snubber circuit.

KEY WORDS:Multi-frequency, Induction heating, High power, DSP, soft switch