Abstract

Modern AC-DC power supplies utilize power factor correction in order to minimize the harmonics in the input current drawn from the utility. The Boost topology is the most popular topology for power factor correction today but it has some disadvantages like very high EMI due to reverse recovery of the boost diode and high switching losses caused by hard switching of the boost switch. Many variations of the original boost topology have been suggested to overcome these problems. The Zero Voltage Transition Boost converter is one such solution. In such a converter an auxiliary resonant circuit is employed which is activated only when the boost switch is turning on or off. This auxiliary circuit allows the boost switch to turn on and off under zero voltage conditions thus reducing the switching losses. However the auxiliary circuit might be very complex and conduction losses in it might offset the expected rise in efficiency. In this thesis a soft-switching boost power converter is proposed and analyzed. This converter reduces the EMI and increases the efficiency because the auxiliary circuit is itself soft-switching and has low conduction losses due to creative placement of the resonant capacitors. Characteristic curves are generated for the proposed converter which not only give valuable insight on the behavior of the converter but also aid in designing the converter. The feasibility of the proposed converter is examined by means of results obtained from an experimental prototype.