Research On IGBT Half-bridge Resonant Inverter

Induction heating power supply, power electronics and power semiconductor devices are closely related. Induction heating power supply has been widely used in melting, casting, welding and other production areas currently. As the topology of the inverter part of the advantages of the induction heating, IGBT half-bridge series resonant inverter has easy to control, small size and good economic returns, and it deserves great attention in the induction heating field.Firstly, this paper describes the principle of the induction heating, characteristics and development status native and abroad, then the core of the induction heating technology-the series resonant inverter has been studied.Secondly, the seried resondent inverter is researched. Based on the analysis of main circuits and working principles of the full-bridge series resonant inverter and two kinds of half-bridge seried resonant inverters, the circuit models of the two kinds of half-bridge seried resonant inverters are created. Through the comparison of the structual characterestics, advantages and disanvantages among the full-bridge series resonant inverter and two kinds of half-bridge seried resonant inverters, the full-bridge series resonant inverter deserve the advantages of simple and cost-effective.Thirdly, based on the research of the existing power control methods, the control circuit using PFM combined with the minimum angle is designed. On the one hand, the control circuit can achieve FM transfer function; on the other hand, it can prevent the half-bridge series resonant inverter strayed into the capacitive work area and to ensure the half-bridge series resonant inverter working reliably in emotional state while the declining frequency closed to the load resonant frequency.Finally, the FM PLL control circuit models of the two half-bridge resonant inverters are built and simulated. Based on this, a prototype35KW/1KHz of induction heating power supply is designed. The prototype is tested in different load operating frequencies. The test results verify the correctness and feasibility of the FM phase lock control method.