Phase Locking Control Strategy For Ultra-high Frequency Induction Heating

With the development of power electronic devices and power electronic technology, high-frequency has become the trend of induction heating. Based on this point, paper does some research about the phase lock control strategy for ultra-high frequency hybrid full-bridge inverter.Hybrid full-bridge inverter with good switching characteristics is very suit for ultra-high frequency induction heating, since when works properly, it can realize Zero-Voltage switching turn on, Zero-Current switching turn on and nearly Zero-Voltage switching turn off. But the circuit’s load voltage has a small zero-voltage platform which makes difficulty for phase locking. This paper has researched on hybrid full-bridge inverter, proposes a novel ultra-high frequency induction heating phase locking strategy, using the passive integrator to detect the phase of load voltage, with the XOR gate phase lock strategy, be able to achieve phase lock function accurately and quickly.Chapterl introduces the history and basic knowledge of induction heating especially analyses the development situation of ultra-frequency induction heating.At last introduces the topic and content of this paper.Chapter2analyses the working principle of hybrid full-bridge inverter,especially about the reason of why there is the small zero-platform,and what’s the relationship between it and the working frequency.Chapter3bases on the chapter2,finds out the the relationship between the drive voltage phase and load voltage phase,proposes using the passive integrator to detect the phase of load voltage,and give the design method in details.Chapter4pays attention on the design of experimental prototype. Introduces the phase lock circuit in details,and gives the experimental result.Chatpter5makes summary and prospect to this paper.