The Effect of Electrothermal Nonuniformities on Parallel Connected SiC Power Devices Under Unclamped and Clamped Inductive Switching
The Effect of Electrothermal Nonuniformities on Parallel Connected SiC Power Devices Under Unclamped and Clamped Inductive Switching
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DOI：
10.1109/tpel.2015.2477831
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发表时间：
2016-06
影响因子：
6.7
通讯作者：
Ji Hu;O. Alatise;J. González;R. Bonyadi;L. Ran;P. Mawby
中科院分区：
文献类型：
--
作者：
Ji Hu;O. Alatise;J. González;R. Bonyadi;L. Ran;P. Mawby
并联连接的器件的电容特性的不均匀性降低了整体可靠性，因为功率在器件之间不是相等地耗散的。此外，不均匀的运行退化率会引起系统的波动，从而加速故障的发展。采用仿真和实验相结合的方法，定量和定性地研究了非箝位电感开关（UIS）条件下并联功率器件的导通电阻变化对器件可靠性的影响。这一点尤其适用于SiC，因为小芯片面积意味着器件通常并联连接以获得更高的电流能力。测量和模拟表明，在UIS下，增加初始结温和并联器件之间的开关速率的变化，可将总可持续雪崩电流减少10%。可以看出，具有较低结温和较低开关速率的器件失效。测量结果还表明，对于给定的结温和开关速率的变化，最大可持续雪崩能量随着雪崩持续时间的增加而增加，这意味着与高能量（低电流和高电感）脉冲相比，高功率（高电流和低电感）UIS脉冲的雪崩变化的影响更为关键。这些结果对状态监测和可靠性分析具有重要意义。
Nonuniformities in the electrothermal characteristics of parallel connected devices reduce overall reliability since power is not equally dissipated between the devices. Furthermore, a nonuniform rate of operational degradation induces electrothermal variations thereby accelerating the development of failure. This paper uses simulations and experiments to quantitatively and qualitatively investigate the impact of electrothermal variations on the reliability of parallel connected power devices under unclamped inductive switching (UIS) conditions. This is especially pertinent to SiC where small die areas mean devices are often connected in parallel for higher current capability. Measurements and simulations show that increasing the variation in the initial junction temperatures and switching rates between parallel connected devices under UIS reduces the total sustainable avalanche current by 10%. It is seen that the device with the lower junction temperature and lower switching rate fails. The measurements also show that the maximum sustainable avalanche energy for a given variation in junction temperature and switching rate increases with the avalanche duration, meaning that the effect of electrothermal variation is more critical with high power (high current and low inductor) UIS pulses compared with high energy (low current and high inductance) pulses. These results are important for condition monitoring and reliability analysis.