New Method to Achieve AC Harmonic Elimination and Energy Storage Integration for 12-Pulse Diode Rectifiers

The 12-pulse rectifier is often used to supply high-power industrial loads. Its ability to effectively and cheaply mitigate the harmonics on the ac side has ensured its dominance in the industry even as active front ends become cheaper and more reliable. Despite its many benefits, the 12-pulse rectifier is not able to reduce the ac-side harmonics to a level acceptable by the pertinent IEEE standards without additional filtering. In this paper, we outline a novel method to profile the rectifier output current to be triangular which results in low ac-side harmonics. The novelty in the proposed approach is that we exploit the dc-side filter design to minimize the volt-amperes (VA) rating of the current source used to profile the dc-side rectifier current. Additional benefits of the proposed method include lower VA rating of the dc filter, simple integration of dc energy storage, and effective ac harmonic control even when the initial rectifier current is discontinuous.