A power converter device includes a power element module, a conductor, and a magnetic-conductive assembly. The power element module includes at least two electrodes and a power semiconductor unit. Voltage among these electrodes is AC voltage. The power semiconductor unit includes at least one pure die, and the pure die includes plural surfaces. The surface which occupies the most area of the pure die is the pure die surface. The conductor is coupled to the power element module. A current loop forms between the power element module and the conductor. A magnetic loop forms in the magnetic-conductive assembly. The magnetic-conductive assembly includes a chamber. The current loop passes through the chamber and intersects the magnetic loop to form inductance which the current loop needs. A part of the power element module is disposed in the chamber.