A smart power converter module for buck applications operating at high input power factor

This paper proposes a single stage, single switch, isolated converter configuration using a hybrid combination of forward and flyback converters. The converter operates at a high input power factor with a regulated DC output voltage. It makes use of a novel control scheme combining the duty cycle and frequency control. Although frequency control is required, a continuous variable frequency control is not needed. The proposed configuration has the advantage of reduced peak current stresses on the devices and is specifically suited for 'buck' applications where low DC output voltages (e.g. 24 V, 48 V) are needed. The proposed configuration will be of specific interest to industries associated with battery charging and UPS systems. Keeping in view the wide industrial application it may have, the entire system is being integrated into a smart power module with the help of Advanced Power Technology-Europe (APTE). The theory of the proposed topology and the control scheme is discussed. Computer simulation results using PSPICE software are included. The details of the smart power module design and fabrication done at APTE, France, are presented as are the experimental results with a laboratory prototype.