Improving ruggedness of rectifiers under power line disturbances

The industry trend towards high power factor equipment with low harmonic distortion and low start-up or inrush current increases the power quality of the AC utility. There are still potential problems for equipment connected directly to the AC utility. Power line disturbances from the AC utility can affect the electric components in a disruptive or destructive manner. Under severe lightning and heavy power line disturbances, both ferroresonant and switchmode rectifiers require proper protection of the semiconductors to prevent any failure of those components. The paper presents the required protection schemes used in common designs. The paper also presents a different curve of tolerance against line disturbances.