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在稳压式变极性焊接电源的输出电流极性变换过程中,加载在绝缘栅双极型晶体管(IGBT)上的瞬间脉冲功率损耗可能会使IGBT结温发生突变,可能超过最高结温允许值,进而影响其安全工作。该文利用热-电等效的局部网络模型,导出了在电源给定输出电流和再燃弧电压等参数条件下的IGBT最高结温计算公式,并将计算结果与仿真结果进行对比,证明了导出公式的正确性。分析了主要运行参数对IGBT最高结温的影响,获得了在选定IGBT型号时将其结温控制在安全范围的约束条件,为变极性焊接电源二次逆变电路设计时合理选择IGBT器件和优化运行参数提供了参考。
In the process of changing the polarity of the output current of the regulated variable polarity welding power supply, the instantaneous pulse power loss loaded on the insulated gate bipolar transistor (IGBT) may cause the IGBT junction temperature to change suddenly and may exceed the maximum junction temperature allowance Value, thus affecting its safety work. In this paper, the calculation formula of the maximum junction temperature of IGBT under the condition of given output current of power supply and arcing voltage is deduced by using the thermoelectric-equivalent local network model, and the calculation results are compared with the simulation results. The correctness of the formula. The influence of the main operating parameters on the maximum junction temperature of the IGBT is analyzed. The constraints of controlling the junction temperature in the safe range of the selected IGBT model are obtained. The IGBT devices are selected reasonably for the design of the secondary inverter circuit with variable polarity. And to optimize the operating parameters provide a reference.