新型半桥式IGBT逆变中频感应加热电源

New Half-bridge IGBT Inverter Power Supply for Intermediate Frequency Induction Heating

由于全桥晶闸管并联逆变电源的输出电压高,感应圈长,噪声大,受工作频率限制,加热中小锻件的效率低。为此,研制了一种新型半桥式IGBT逆变中频感应加热电源。该电源的半桥式逆变电路由一对二极管及反向并联的IGBT模块构成。控制回路由启动、频率跟踪、驱动信号、缺水保护电路组成。该回路可产生频率跟踪炉体的脉冲信号,通过三角波发生器连接电压比较器,经二极管互锁再驱动模块,使线路结构简单。文中分析了电源主回路和控制电路的结构及工作原理。主电路的仿真和试验结果表明,电源输出电压仅200V左右,工作频率可达1kHz,功率因数接近于1,提高了电热效率。

In the full-bridge thyristor shunt-wound inversion power supply,the efficiency of heating smaller forgings limited by the working frequency is low because of the high output voltage,the long induction coil, and the great noise.In order to solve these problems,we develop a new kind of half-bridge IGBT inverter for middle frequency induction heating power supply.The half-bridge inversion circuit is consisted of a pair of diodes and reverse shunt-wounded IGBT module. The controlling loop includes start-up circuit,frequency tracking circuit,driving signal circuit, and water lack protecting circuit.The loop can generate frequency tracking pulse signals of the furnace.The signals go through a triangle wave generator and interlocked by diodes then drive the module.Thus makes the loop＇s structure simple.In this paper,the structure and working principle of the main circuit and controlling circuit are analyzed.The results of the main circuit simulation and experiment indicate that the new power supply＇s output voltage is about 200V,it＇s working frequency may reach 10kHz, and it＇s power factor close to unit.The galvanothermy efficiency of the electrical sources improved.