The thermal design constraint of power electronic converters under the specific power loss and heat sink is mainly determined by the maximum permissible junction temperature of the power devices. As the power density and switching frequency increase, transient electro-thermal models become more and more important for the thermal management system design of the power electronic converters. In traction inverters, the junction temperature has huge variation because the fundamental frequency and phase currents vary significantly during the load cycles. Thus, the junction temperature estimation becomes extremely important for the reliability of traction inverters.
In this thesis, the transient electro-thermal analysis of a traction inverter considering the inter-dependency of the power losses and junction temperature in an iterative process is implemented. Considering the impact of circuit stray parameters on the switching loss, the temperature dependent power loss model is built based on the datasheet values and the measured switching losses. A state-of-the-art thermal model of the entire inverter including the power modules and the heat sink is developed considering the thermal coupling effects of multiple power devices. By using transient thermal simulation, the linearity of the heat transfer process of the entire traction inverter is verified. The impact of the material thermal properties on the thermal impedance is also presented. In addition, the accuracy of the combination of the thermal subsystem models is verified with simulation. The developed transient electro-thermal model is then used to simulate the junction temperature profiles of the inverter under different operating conditions. Finally, the developed model is experimentally verified. By considering the thermal impedance of the thermal grease layer, the simulation results match with the experimental results very well.
The proposed electro-thermal model can provide important information for the thermal management system design, package optimization, long-term reliability analysis, and maximum rating characterization of the traction inverters. / Thesis / Master of Applied Science (MASc)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/16521 |
| Date | 06 1900 |
| Creators | Yang, Kai |
| Contributors | Emadi, Ali, Mechanical Engineering |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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