부산대학교 도서관

Occurrence of high frequency emission due to increasing use of power electronic based equipment challenges the functioning of equipment, e.g., malfunctions of equipment, audible noise or performance/lifetime degradation of dc-link capacitor. When subjected to a high frequency voltage distortion, an ac–dc converter draws intermittent current of the same frequency, this is referred to as “intermittent conduction.” In this article, a link between intermittent conduction and dc-link capacitor current has, for the first time, been constituted through a mathematical expression. Based on this, a model that can quantify the impacts on dc-link capacitor and calculate maximum allowed voltage in the frequency range of 2–150 kHz, so called “supraharmonics (SHs),” has been proposed for avoiding degradations. Besides modeling, a testing technique is implemented where maximum allowed voltage can be identified for an equipment under test. The result shows that dc-link capacitor's stress can be managed under the SHs if maximum SH voltages are respected. The proposed model gives a better understanding of SH impacts on dc-link capacitor and the mechanisms behind. This article has been limited to equipment that draws input current lower than 16 A as they exhibit more nonlinear characteristic and longer zero crossing, which results in intermittent conduction.