基于状态反馈线性化的IGBT外部热管理

External Thermal Management of IGBT Based on State Feedback Linearization

绝缘栅双极型晶体管(IGBT)的热管理技术能降低其运行时的结温波动,提高器件的可靠性。针对IGBT外部热管理系统中的非线性成分,建立系统的仿射非线性模型。通过引入状态反馈线性化方法对其进行线性化,弥补目前IGBT热管理控制系统设计中缺乏精确数学模型的缺陷。基于线性二次型调节器(LQR)设计一种闭环控制方法,通过调节外部散热条件以平滑IGBT运行时由于负载波动导致的低频结温波动。基于Buck电路进行实验,实验证明,所提算法对负载电流在额定值的60%~100%范围内波动时,能够降低约60%的结温波动,提高IGBT约69倍的寿命。最后,基于小电流注入法在线测量结温,验证了基于模型计算结温的准确性。

Thermal management technology for insulated gate bipolar transistor(IGBT)can reduce junction temperature fluctuations during operation and improve the reliability of devices.In view of the nonlinear characteristics of the IGBT external thermal management system,an affine non-linear model of the system was established.The state feedback linearization method was introduced to linearize the system,which makes up for the current lack of accurate mathematical models in the design of IGBT thermal management control systems.Based on a linear quadratic regulator(LQR),a closed-loop control method was designed to smooth the low-frequency junction temperature fluctuations caused by load fluctuations during IGBT operation by adjusting external cooling conditions.The experimental verification based on the Buck circuit shows that the proposed algorithm can reduce the junction temperature fluctuation by about 60% and increase the life of the IGBT by about 69 times when the load current fluctuates within the range of 60%~100% of the rated value.Finally,the junction temperature was measured online based on the small current injection method,which verified the accuracy of the junction temperature calculation by the proposed model.