Power quality improvement in bridgeless AC–DC converter based multi-output switched mode power supply

Abstract

Computer power supplies are required to have multiple isolated regulated dc voltages with low ripple content and high input power factor at the utility interface. A dc–dc converter is used for obtaining these isolated multi-output dc voltages with excellent regulation. In this paper, a non-isolated ac–dc converter is proposed as the first stage converter to obtain a regulated dc output rather than using a simple uncontrolled diode bridge rectifier at the front end. A dc–dc converter is used at the second stage that has a high frequency transformer with multiple secondary windings to obtain different dc voltage levels at the output. The proposed bridgeless converter based power supply is designed using fundamental design equations, and different component values are calculated. Extensive simulations are carried out to demonstrate the improved performance of the proposed bridgeless converter based multi-output computer power supply at varying source voltages and load conditions. Experimental validation of the power supply is carried on a developed hardware prototype, and the test results are compared with the simulated performance for design verification.