| With the rapid development of power electronic technology,the application of power electronic devices in various industries is becoming more and more extensive.In many applications,reliability problems of power electronic devices are also exposed.Power semiconductor devices are one of the most important components in power electronic devices,and they are components with high failure rates.Therefore,the overall reliability of power electronic devices is closely related to the reliability of power devices,and it is of great practical significance to study how to improve the reliability of power devices.Thermal management technology of power semiconductor device aims to smooth low-frequency junction temperature fluctuations and improve device reliability.It is an interdisciplinary subject of thermodynamics and power electronics technology.In recent years,more and more researchers have begun to pay attention to this field.Most of the research focuses on the junction temperature adjustment method based on device loss,but other aspects are relatively less involved.In this paper,an insulated gate bipolar transistor(IGBT)power module in a wire-bond package is taken as the research object.Based on the IGBT life model,a method for optimizing the dynamic adjustment performance of a heat sink is studied,and the external thermal management of the IGBT is established.The linearization model is proposed and the thermal management control strategy is designed.The main work done in this article is as follows:First,the failure mechanism and reliability model of the IGBT module are analyzed,and it is found that the junction temperature fluctuation is one of the important factors affecting the life of the IGBT module.The external thermal management technology of the power module can reduce the junction temperature fluctuation,which has great significance for improving the expected life of the IGBT.Considering online junction temperature measurement of IGBT is of great difficulties,the junction temperature is estimated based on the IGBT loss model and a simplified RC thermal network model.Based on a special circuit topology and switching transistors control timing,an IGBT junction temperature online measurement method is proposed to verify the accuracy of the junction temperature calculation result.Secondly,according to the current design of power device heat sinks,it is difficult to meet the requirements of IGBT external thermal management for heat sinks.Based on the numerical calculation method,an optimization method of forced air cooling heat sinks is proposed.Different from the traditional heat sink design,the proposed method focuses on how to increase the adjustment range of the ambient thermal resistance of the heat sink and improve the dynamic response speed instead of considering only increasing the heat dissipation capacity.Based on the finite element analysis tool,the accuracy of the numerical calculation method was verified.Based on the optimization method,an optimization scheme for the dynamic adjustment performance of the radiator is obtained.Finally,the modeling method of the external thermal management system of IGBT module is studied.State space equations were written for the system’s RC thermal network.For the nonlinear components contained in the model,an accurate linearization method based on state feedback was introduced for the first time to the IGBT external thermal management modeling,which verified the conditions under which the original system can be linearized The state feedback matrix is derived to eliminate the linearization of the original system.Then a heat sink control algorithm for IGBT thermal management is designed based on the linear quadratic regulator(LQR).The proposed method has certain universality and is applicable to any converter device with adjustable heat dissipation power,so that the design of the thermal management algorithm no longer depends on experience,so that the design of the thermal management system has a model basis and theoretical support,while improving The design efficiency of the junction temperature closed-loop control parameters is discussed. |
