Analysis of Alternative Baseplate-to-Heatsink Grounding Schemes in 10 kV SiC MOSFET Modules with Series-Connected Devices
Analysis of Alternative Baseplate-to-Heatsink Grounding Schemes in 10 kV SiC MOSFET Modules with Series-Connected Devices
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DOI：
10.1109/apec42165.2021.9487470
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发表时间：
2021-06
期刊：
影响因子：
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通讯作者：
L. Ravi;Xiang Lin;Yue Xu;D. Dong;R. Burgos
中科院分区：
文献类型：
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作者：
L. Ravi;Xiang Lin;Yue Xu;D. Dong;R. Burgos
在这项工作中，基板到MOSFET的电气连接方案进行了分析，Wolfspeed 10 kV XHV-9 SiC MOSFET半桥功率模块串联配置作为一个等效的“20 kV开关”。虽然模块中两个器件的额定击穿电压可以共同支持高达20 kV的直流输入电压，但模块内部的电场需要进一步考虑，以降低封装电场应力。由于SiC MOSFET的dv/dt开关速度较高（> 50 V/ns），底板连接不正确时，模块基板可能会出现峰峰值高达直流总线电压的双极性PWM电压，并出现快速极性反转。采用有限元分析方法研究了模块封装中假定存在内部缺陷的两种基板连接方案。实验结果表明，双极性激励在整个基板的结果在部分绝缘击穿，而单极激励相同的峰值在额定条件下产生可靠的操作。此外，一个测试试样与内部空隙被用来调查双极电压激励的局部放电签名和调查结果的报告。
In this work, baseplate-to-heatsink electrical connection schemes are analyzed for the Wolfspeed 10 kV XHV-9 SiC MOSFET half bridge power module in series-connected configuration for use as an equivalent "20 kV switch". Although the breakdown voltage rating of the two devices in the module can together support dc input voltages up to 20 kV, the electric field inside the module needs further consideration to reduce package electric field stress. With improper baseplate connection, the module substrate can potentially see bipolar PWM voltages with a peak to peak value up to the dc bus voltage with fast polarity reversal due to the high dv/dt switching speeds of the SiC MOSFET (> 50 V/ns). The module package is studied using finite-element analysis for two baseplate connection schemes with assumed internal defects in the module package. Experimental results show that a bipolar excitation across the substrate results in partial insulation breakdowns while a unipolar excitation of the same peak value yields reliable operation at the rated conditions. Further, a test coupon with an internal void is used to investigate the effect of bipolar voltage excitation on the partial discharge signature and the findings are reported.