Research And Design Of High Frequency Induction Heating Power Supply Based On PDM

Compared with the traditional heating methods, induction heating power supply is more advanced in its high efficiency, energy saving, environmental protection, safety, fast heating speed and easy control, etc. Now it has been widely used in multiple areas of national economy, such as metallurgical industry, machinery manufacturing, food industry and medicine industry, etc. This research is mainly focused on high frequency induction heating power supply based on power density modulation(PDM). Firstly, combined with the latest domestic and international development status and trend, this paper expounds the basic principle and development trend induction heating power supply.Then we make a comparison between two kinds of resonant modes(Series resonant mode and parallel resonant mode). Because of the high frequency and frequent start, we decided to use the series resonant circuit as the inverter topology. Then this paper introduces the principle of all kinds power regulating method of series resonant circuit. Via comparison, Combined with the actual needs of of the project, we select power density modulation(PDM) as the power regulation mode.In this paper, the series resonant inverter topology working state was analyzed in detail. Through Comparison and analysis, we find that the optimum working state which have the minimum Loss are inductive and resistive states. According to the need of design, the selection of each main components of the main circuit are given. Also, the detailed calculation and production process of matching transformer, current transformer and other components are given. In this project, we select SG3525 chip and realize the synchronization and frequency tracking through the synchronous port of SG3525. Then the sweep circuit, the protection circuit and drive circuit are designed.This research project applied soft switching mode to regulate the power so that we can reduce the switching loss when the system working at hard switching. By setting the dead time reasonable, the power MOSFETs can work at Zero Voltage Switching state. In this paper, according to the analysis of waveform of the MOSFETs, we designed a ZVS-QRCs(Zero-Voltage-Switching-Quasi-resonant) resonant inverter.In this paper, the last part showed the principle diagram of main control circuit and drive circuit. After verified by simulation and experiment, combined with the part of the experimental debugging waveform, each part of the PDM high frequency induction heating power supply can achieve the desired design target. We realized the Zero Voltage Switching which can decrease the switching loss and improve the system efficiency significantly.