考虑老化影响的SSPC功率管热模型自适应在线修正方法

Adaptive Online Update Method for Thermal Model of SSPC Power Device Considering Aging Effects

固态功率控制器SSPC(solid-state power controller)中功率管的结温监测对SSPC的可靠性有至关重要的作用,热模型法因其无需直接接触测量且方法简单而被广泛使用。然而,功率芯片的老化会导致热路径的退化,器件的结壳热阻抗增加,使实际结温远远超过热网络模型的估计值,导致对器件健康状态的乐观估计。焊料层疲劳失效被认为是SSPC功率管老化失效的主要原因之一。因此,在SSPC的寿命周期中实时监测器件的老化状态,并对功率管的热模型进行自适应在线修正,通过测量不受焊料层退化影响的热敏参数来计算热阻作为更新依据,将热阻信息关联焊料层老化状态来更新热模型。所提方法可在不影响SSPC正常工作的前提下,实时修正热模型,实验结果验证了方法的有效性。

The junction temperature monitoring of power devices in a solid-state power controller(SSPC)plays a vital role in the SSPC reliability.The thermal model method is widely used owing to its contactless measurement and simplicity.However,the aging of the power chip will lead to the degradation of the thermal path,and the junction-to-case thermal resistance of the device will increase.As a result,the actual junction temperature may far exceed the value estimated by the thermal network model,leading to an optimistic estimation of the device’s state-of-health.The failure of the solder layer is considered to be one of the main reasons for the aging failure of SSPC power devices.In this paper,the device’s aging state is monitored in real time during the life of SSPC,and the thermal model of the power device is adaptively updated online.The thermal impedance taken as an update basis is calculated by measuring the temperature-sensitive electrical parameters which are not affected by the degradation of the solder layer,and the thermal impedance information is associated with the aging state of the solder layer to update the thermal model.Using the proposed method,the thermal model can be updated in real time without affecting the normal operation of SSPC,and experimental results verified the effectiveness of this method.