With the rapid development of renewable energy, data centers, and new energy vehicles, the power density of power electronic converters is continuously increasing. Higher power density requires more advanced thermal dissipation system designs. Consequently, designing an efficient cooling system is crucial for improving the power density of converters. Due to its simplicity and efficiency, the rectangular extruded-fin air cooling heat sink is the most common cooling system design for converters. With increasing power density, multiple power devices are often arranged along the airflow path in forced-air cooling systems. However, existing analytical thermal models for forced-air cooling systems typically focus only on the system’s maximum or average temperature, neglecting the temperature prediction of each individual device. In response, this paper proposes a novel distributed thermal resistance network model for rectangular extruded-fin air cooling heat sink. The model accounts for air temperature rise along the flow path and includes thermal coupling between heat sources, enabling accurate temperature estimation of individual devices. Furthermore, the proposed model is primarily based on analytical formulations, which ensures fast computation and makes it well-suited for rapid thermal evaluation and efficient optimization of cooling system designs. The accuracy of this thermal resistance network is verified through computational fluid dynamics (CFD) simulations and experiments, with an average prediction error of less than 6%, maximum error less than 14%. These results demonstrate that the model can accurately predicted temperature of multiple devices and assist in efficient thermal system design.

To address the need for dynamic and static parameter testing of IGBT modules, an integrated test platform was developed. In production-line applications, consistency differences in key parameters between the upper and lower bridge arms of manufactured modules were found to be difficult to quantify using a single metric. To overcome this limitation, a multi-parameter consistency evaluation method was proposed. Based on more than 400 sets of production-level measurements obtained from newly manufactured IGBT modules from the same batch, eight key parameters, including E_on, E_off, dv/dt, di/dt, V_CES, I_CES, V_GEth and I_GES, were selected to construct paired samples of the upper and lower bridge arms. A dimensionless consistency index (CI) was introduced to quantify relative deviations between bridge arms, and consistency characteristics were analyzed using raw-parameter boxplots, CI boxplots, and paired scatter plots in terms of distribution, discrepancy quantification, and sample-wise pairing. The results show that different parameters exhibit different levels of distributional difference and relative deviation between the two bridge arms under identical test conditions, and that the three analyses reveal mutually consistent trends. The proposed method provides an effective basis for within-batch quality assessment, bridge-arm matching, abnormal sample identification, and production process troubleshooting.