Research On High Frequency Induction Heating Power Supply Base On DPLL

Aiming at frequency tracking analog circuit deficiency in accuracy and rapidity and limitation in functions of the traditional induction heating power, the intelligent digital high frequency induction heating power with the high-performance MCU as the core will be studied and designed in this paper, which will track load's resonant frequency rapidly and accurately. Digital interactive system will be designed in the paper which realizes to informationize and intelligentize functions. As a result of communication interface circuit design, the power supply achieves online control in induction heating. We propose an improved PFM control mode and DPLL frequency tracking control strategy based on the digital hardware platform.In the base of theory analysis, the power supply system is designed. We select the series resonant half-bridge inverter. The digital control system with the PIC18F4520 as the core, and it improves the accuracy and static and dynamic characters of the system, achieves real-time online control due to communication interface circuit. Digital interactive system is designed in the paper which has informationize and intelligentize functions. Then the accuracy and process of induction heating become better. In the hardware, the power supply is parted to different circuits due to various functions. In the software, we use modular programming method to make clear control software and easy to maintain.Finally, this article based on the development of the induction heating power conduct the control experiment. We achieved the specification of scan frequency start method. The power supply could get nicer performance when Input Power was 5kW by improved PFM mode. The frequency tracking system could keep frequency tracking rapidly and accurately.