నైరూప్య

A New Single Phase Single Stage Three Level Power Factor Correction Ac/Dc Converter

D.Swarna Rekha, P.Anjappa, V.Ramesh

AC-DC power electronic converters are widely used for electrical power conversion in many industrial applications such as for telecom equipment, information technology equipment, electric vehicles, space power systems and power systems based on renewable energy resources. Conventional AC-DC converters generally have two conversion stages, an AC-DC front-end stage that operates with some sort of power factor correction to ensure good power quality at the input, and a DC-DC conversion stage that takes the DC output of the front-end converter and converts it to the desired output DC voltage. Due to the cost of having two separate and independent converters, there has been considerable research on so-called single-stage converters. Converters that can simultaneously perform AC-DC and DC-DC conversion with only a single converter stage. Elimination of one of these stages reduces the cost, weight, size, complexity and increase the overall reliability of this converter. The main focus of this thesis is on development of new and improved AC-DC singlestage converter that is based on multilevel circuit structures (topologies) and principles instead of conventional two-level the drawbacks of previous proposed converters are reviewed. A variety of new power electronic converters including new single-phase and a new DC-DC converter are then proposed. A new three-level single-stage power factor- corrected ACDC converter is presented. The proposed circuit integrates the operation of a boost power factor correction converter and a three-level DC/DC converter into one converter. The Proposed converter does not have the problem of high component stress due to high rising intermediate bus voltages that other single-stage converters have because of its three-level structure. It can operate over a wider load range with significantly less output inductor current ripple; moreover, its input current has little distortion. In the thesis, the operation of the new converter is explained in detail and analyzed, its steadystate characteristics are determined, and its design is discussed.