面向铁氧体裂纹检测的感应加热电源研制

Development of an induction heating power supply for detecting ferrite surface cracks

针对常规感应加热电源对铁氧体加热时存在加热均匀性差和负载回路谐振频率漂移的问题,提出了一种全桥逆变拓扑结构的串联谐振式数字感应加热电源.基于负载串联谐振回路换流时电压和电流的相位差特性,通过PSPICE软件分析了阻性、感性和容性三种换流状态,仿真结果表明,串联谐振回路工作于弱感性状态,可以保证电路安全可靠运行;基于电磁耦合原理,对比分析了原边补偿和副边补偿两类负载匹配变压器,通过匹配负载等效电阻实现电源系统最大能效输出;采用Fuzzy-PI频率跟踪技术实现负载谐振频率实时跟踪.最后,将研制的数字感应加热电源成功地应用于铁氧体裂纹检测实验.

Aiming at the problems of the non-uniform heating distribution and the resonanted frequency drifting of load in ferrite heating using the conventional induction heating power, a series resonant digital induction heating power with a full bridge inverter structure was proposed. Based on the characteristics of phase difference between voltage and current during the commutation of series resonant circuits, the resistive, inductive and capacitive states were simulated with PSPICE. The result show that the circuit operated reliably when the series resonant circuit ran in the weakly inductive state. Based on the principle of electromagnetic coupling, primary compensation and secondary compensation load matching transformers were analyzed~ and the latter was applied to the power supply by matching the load equivalent resistance to realize maximized energy efficiency output. The Fuzzy-PI frequency tracking technology was applied to the power supply to realize real-time frequency tracking. Finally, the digital induction heating power was successfully used for the ferrite crack detection experiment.