No abstract

In this study, cosimulation with Q3D and Simplorer were adopted to design a single-phase power stack with equal output current on three paralleled IGBT modules in high power application, therefore, the derating of total current will be reduced, which can improve the current utilization and power density of power stack. The performance of the designed stack was verified using a double-pulse test (DPT). The circuit used in the DPT regarded the power stack output current as static current, which is a critical index to evaluate current sharing. The static current sharing among the IGBT modules was mainly dependent on the stray inductance of the DC busbar, IGBT modules, and phase output bar (POB), which is used to connect the IGBT modules to load, in parallel paths of the power stack. Cosimulation was performed to determine the stray inductance of the IGBT modules, DC busbar and POB, and a constant-current-slope method was used to verify the inductance. Subsequently, design the shapes of DC busbar and POB for attaining maximum ratio of imbalanced current (MRIC) of the three IGBT modules is within 3% under 200% (2400A) rated current. The cosimulation results indicated that the MRIC of the current paths in power stack were 0.8%. Finally, three IGBT modules and a gate driver were used to construct power stack with 1000V DC link. The experimental results obtained by DPT indicated that the MRIC was 0.9% under 200% rated current, demonstrating the effectiveness of the proposed stray inductance design method.

This paper analyzes the impact of R&D locational choices that manufacturing firms in Taiwan take under the differentiation of locational advantages between Vietnam and Taiwan as well as improves some points which are incompletely focused in the same study on Taiwanese firms, the cross-strait, and overweighing case-studies in the past. The empirical evidences bring that the impact of variables to locational distribution of Taiwanese manufacturing firms across the strait is many: locational advantages, the type of R&D unit, the scale of the market, political conditions, industrial clusters, knowledge flows and R&D investments. Except for the negative relationship between the scale of market/type of R&D unit and R&D locational choices, the rest variables have the positive relationship with R&D locational choices, which means that, barring that the scale of market in Taiwan is so small that Taiwanese firms choose to set up R&D spots in Vietnam, other variables in Taiwan are more attractive than those in Vietnam; Taiwan possesses in negligible energies of regional creativity.