数字化频率跟踪感应加热电源的研制

发布时间：2019-01-27 09:16

【摘要】：传统的加热方式是采用电阻一体化线圈来加热物体，这种加热方式具有能耗高、热效率低、寿命短、工作环境差等缺点，而感应加热技术比起传统的加热方式优点不言而喻。但如今在使用感应加热方式来加热物体时，随着温度的升高，其负载线圈电感值随之改变，所以感应电源不能在其最佳工作点上工作，最后使电源失去谐振开关的工作方式，同时频率跟踪和功率控制不能很好的结合，使快速性和准确性不佳。如今感应电源加热工艺控制落后，不具备与上位机进行通讯和监测的能力，不能进行在线控制和不能及时反映故障原因等。鉴于此，本文研制一套以高性能MCU为核心的数字化频率跟踪感应加热电源，基于数控思想，搭建数字化人机交互系统，使电源可以在线调节电参数，修改电源功率，运用高精度频率跟踪控制策略，实时跟踪负载频率，从而保证了电源的工作效率。同时设计了上位机通讯电路以及开发基于Qt平台上位机监控软件，方便对其实时观察和控制。本文以IGBT作为逆变功率开关管，设计选择串联谐振逆变拓扑结构，搭建了中小功率感应加热电源。研制了频率跟踪控制系统采用PIC18F4520和CD4046为基本组成的数字和模拟相结合的闭环控制，研制并运用了改进型PFM功率控制策略，改善了电源加热精度和工艺效果，使感应加热电源工作在弱感性模式下，从而提高了电源的可靠性。同时还增加了负载检测、过流保护、过压保护、过热保护、驱动、死区生成电路、人机交互等功能电路。在软件设计方面，采用模块化的编程方法，，使得控制软件条理清晰，便于维护和升级。最后，基于所设计的感应加热电源试验平台，验证了改进的PFM功率控制方式可以获得良好的控制效果，频率跟踪控制系统达到了快速、准确跟踪频率的要求，人机交互功能较好实现电源的在线控制。
[Abstract]:The traditional heating method is to use the resistance integrated coil to heat the object. This heating method has the disadvantages of high energy consumption, low thermal efficiency, short life, poor working environment, etc. The advantages of induction heating technology are self-evident compared with the traditional heating method. But now when using induction heating to heat objects, the inductance of the load coil changes with the increase of temperature, so the inductance of the induction power cannot work at its best working point, and finally the power source loses its resonant switch. At the same time, frequency tracking and power control can not be well combined, which makes the speed and accuracy poor. Nowadays, the heating process control of induction power supply is backward, and it does not have the ability to communicate and monitor with the upper computer, can not carry on the on-line control and can not reflect the fault cause in time, and so on. In view of this, a digital frequency tracking induction heating power supply based on high performance MCU is developed in this paper. Based on the idea of numerical control, a digital man-machine interactive system is built to make the power source adjust the electrical parameters and modify the power supply on line. The high precision frequency tracking control strategy is used to track the load frequency in real time, thus ensuring the efficiency of power supply. At the same time, the communication circuit of the host computer and the monitor software based on Qt platform are designed, which is convenient for real-time observation and control. In this paper, IGBT is used as the inverter power switch, the series resonant inverter topology is designed and the medium and small power induction heating power supply is built. A frequency tracking control system is developed, which combines digital and analog control with PIC18F4520 and CD4046. The improved PFM power control strategy is developed and applied to improve the heating accuracy and technological effect of the power supply. It makes the induction heating power working in the weak inductive mode, thus improving the reliability of the power supply. At the same time, load detection, overcurrent protection, overvoltage protection, overheating protection, drive, dead-zone generation circuit, man-machine interaction and other functional circuits are added. In software design, modular programming method is used to make the control software clear, easy to maintain and upgrade. Finally, based on the designed test platform of induction heating power supply, it is verified that the improved PFM power control method can obtain good control effect, and the frequency tracking control system achieves the requirement of fast and accurate tracking frequency. The function of man-machine interaction is better to realize the online control of power supply.
【学位授予单位】：哈尔滨理工大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TM919;TP368.1

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