基于负荷特性的车用SiC逆变器寿命评估

Mission Profile Oriented Lifetime Assessment of SiC Inverter for Electric Vehicle Application

电动汽车的运行环境恶劣,对可靠性要求高,电力电子器件的故障率较高,急需评估车用逆变器的寿命特性。针对标准的和实际的车用工况,基于车辆动力学模型,采用功率器件的电–热协同分析方法,文中研究车用SiC逆变器的寿命评估方法。首先,基于电动汽车的工况与路况特征、电动汽车的动力学模型、车用电机的数学模型、电机的控制策略,给出了车用逆变器的负荷特性。其次,基于功率器件的损耗模型,分析车用逆变器的损耗特性。然后,基于功率模块的电–热耦合模型、寿命模型和累计损伤理论,构建车用SiC逆变器寿命的评估方法。最后,基于电动汽车的不同工况和路况,详细分析工况、路况、汽车质量对SiC逆变器寿命的影响规律,为SiC功率模块和车用逆变器的设计,提供基础理论和技术途径。

Due to the harsh mission of the electric vehicle,the inverter of the powertrain for electric vehicle applications requires high reliability.However,the power electronic device performs a very high failure rate.It is urgent to assess the lifetime characteristics of the inverter for the electric vehicle.Focusing on the standard drive cycle and actual drive cycle,the lifetime of the SiC inverter for electric vehicle is insightfully characterized,combining the dynamical model of the electric vehicle and the electro-thermal model of the power device.Firstly,based on the drive cycle and road profile of the mission of the electric vehicle,taking the vehicle kinetics,mathematical model of motor and its control strategy into account,the mission profile of the SiC inverter is created.Secondly,concerning the power loss model of the power device,the dissipation characteristics of the inverter are derived.Then,from the multi-physics perspective,a synthetic model is proposed to assess the lifetime of the SiC inverter,including the electro-thermal model coupling,the lifetime model,and the cumulative damage model of the power module.Finally,considering the influences of the drive cycle,road profile,heat dissipation,vehicle mass,and inverter specification of the vehicle,the lifetime of the inverter is comprehensively assessed.The created models,proposed methodologies,and observed mechanisms might enhance the design and control of the SiC power module and powertrain of the electric vehicle.