Novel Dual Output AC/DC Power Supply Using Switched Transformer Forward Converter with Active Front End Power Factor Correction

The paper proposes a dual DC output switched transformer based power supply with Active Front-End Power Factor Correction (PFC) working on single phase AC. The proposed topology combines two converters (Boost and Forward) which is realized through a simplified magnetics and control stage, resulting in reduction in component count and footprint. The switched turns ratio transformer is incorporated into the topology to minimize the power loss in the secondary Zener Regulator. The principle of operation, design calculations and simulation results are presented for the 230V and 120V AC line voltage operations.

I. Introduction

The increased use of power electronic converters has resulted in deteriorated power quality because of the enhanced THD of the AC mains current. Deteriorated mains power draw can degrade the network components and overload the distribution network while increasing transmitted and radiated EMI levels. IEC standards IEC60601-1 and IEC60601-2 require the inclusion of a power front-end PFC stage in all electrical appliances rated less than 1kW once when operating from the 115V/230V, 50Hz/60Hz mains. Figure 1 describes the simplest PFC solution is implemented using a Boost Inductor post the rectifier and before the capacitor. Figure 1:

Boost PFC Converter