A power converting device is adapted for converting a DC voltage input from an external power source into an AC voltage output. The power converting device includes: a transformer having first and second windings each having opposite first and second ends; a clamp unit coupled to the external power source, and including a first switch coupled between a reference node and the second end of the first winding, and a series connection of a clamp capacitor and a second switch coupled across the first winding; and an inverting unit coupled to the first end of the second winding, and operable so as to output the AC voltage output based on an induced voltage across the second winding.