一种基于调节缓冲电容的IGBT热管理方法

IGBT thermal management method based on snubber capacitor

针对结温波动加快绝缘栅双极型晶体管(IGBT)老化失效的问题,提出一种基于调节缓冲电容改变IGBT关断轨迹的热管理方法。依据IGBT寿命模型,通过关断轨迹调节关断损耗大小以平滑结温波动的方法能提高IGBT使用寿命。与现有的热管理方法相比,该方法具有对主电路影响小、实现简单等优点。首先,阐述热管理电路的工作原理,分析缓冲电路对IGBT关断损耗的影响。然后,建立IGBT损耗计算模型,归纳关断轨迹热管理调节能力的评估方法,以1.2 MW直驱风机系统为例,关断轨迹热管理可以平滑20%额定功率的负载变化造成的结温波动。最后,对该热管理方法进行小功率的实验验证。

Aiming at the problem that the junction temperature fluctuation accelerates the aging failure of the insulated gate bipolar transistor (IGBT) a thermal management method based on adjusting the snub ber capacitor to change the IGBT turn off trajectory is proposed. According to the IGBT life model the method of adjusting the turn off loss by turning off trace to smooth the junction temperature fluctuation can improve the service life of the IGBT. Compared with the existing methods this method has little influence on the main circuit and is easy to be implemented. The working principle of thermal management circuit was described and the effect of snubber circuit to the loss of IGBT was analyzed. IGBT loss calculation model was established and the evaluation method for the thermal management adjustment ability of the turn offtrajectorywassummarized. Taking1.2MW direct wind turbine systemas an example 20%load fluctuation can be smoothed by the thermal management. Finally the experiment verification is done in a low power inverter.