Back-to-back geometrical configuration of two parallel-connected double-sided cooling modules for parasitic inductance reduction

This paper proposes a structure with two parallel-connected double-sided cooling SiC-MOSFET power modules with back-to-back geometrical configuration. This arrangement effectively reduces parasitic inductance by making the currents flowing through the two parallel connected modules be in opposite direction and generating negative magnetic coupling between two current loops. The inductance analysis by simulation showed that the parasitic inductance of the proposed structure with the reverse order arrangement was 23 % lower than that of a conventional structure, which has the same order arrangement. Reduction in the parasitic inductance was experimentally eval-uated by using fabricated mock-up of modules based on the proposed concept. The measured inductance exhibited a good agreement with simulation results. Actual power modules based on the proposed concept were also fabricated using bare dies of SiC-MOSFETs. Turn-off switchings were demonstrated with the fabricated power modules with different current levels. The demonstration exhibited approximately 10% reduction in surge voltage in comparison to that by the conventional structure.