A Novel Flyback-Based Input PFC Stage for Electronic Ballasts in Lighting Applications

This paper proposes an electronic driver for public lighting systems. The input stage is based on the integration of two flyback converters with different polarities, in order to avoid the use of the input diode bridge rectifying stage. The output stage is a boost converter with an output current control. The proposed circuit is introduced and analyzed, and a design example for a 50-W light-emitting diode lamp is presented. The most relevant simulation and experimental results are also shown, in order to validate the idea. A comparison in terms of efficiency for the input stage is carried out between the proposed topology and the conventional flyback converter, showing an efficiency enhancement in the proposed converter. However, the most important advantage of the proposed converter is outlined in the final part of this paper. This advantage comes from the avoidance of the input diode bridge, thus enabling the bidirectional power flow at the input stage. Therefore, the topology can be used to deliver energy into the power grid. In recent lighting applications, the use of micro renewable generators in lighting points has made the use of special electronics to handle the energy flows in the ballast necessary. The present topology is an alternative to standard bidirectional input stages.