High efficient rectifiers

In all electronic equipment the power supply plays an important role even though the power supply typically has nothing to do with the primary function of the equipment. From the manufacturers point of view, the power supply is a necessity but since it has nothing to do with the primary function of the equipment, little focus is directed towards this unit.

As a result of the introduction of the new European norm EN61000-3-2, focus has been directed towards the implementation of the off-line power supplies. This norm limits the low frequency harmonic current content in the line current. The most commonly used ac/dc power supply configuration (bridge-rectifier + filter capacitor) is affected by the new norm, forcing the manufacturers to pay attention to the way that the ac/dc conversion is performed.

Solutions like the PFC boost converter in a Two-Stage configuration that complies with the regulations have been known long time before the implementation of EN61000-3-2, but since the regulations accommodate some distortion of the line current, many new PFC approaches that take advantage of this have been proposed during the last decade.

Two of the dominating PFC approaches are referred to as the Single-Stage approach and the Reduced Power Processing approach. This thesis is a fundamental study of the performance of these dominating PFC approaches consisting of the Single-Stage approach, the Reduced Power Processing approach and the Two-Stage approach.

All of the PFC approaches basically consists of a reconfiguration of the basic dc/dc converter topologies and by characterizing the stress on these individual converters it is shown that the well known, well proven Two-Stage approach is the superior approach with regard to the component stress and thereby the conversion efficiency.

As a result of this work with characterizing and comparing the different PFC approaches, a new family of PFC converters have emerged.