A Conceptually New Approach for Regulated DC to DC Converters Employing Transistor Switches and Pulsewidth Control

A new regulated dc to dc converter circuit gains several advantages over conventional approaches by separating the pulsewidth control function from the inverter. The distinguishing feature of the new circuit is the relocation of the principal filter inductor from the rectifier output to the inverter input. This departure from the conventional use of a shunt capacitor at the inverter input yields a number of fundamental improvements. These include the following: substantially reduced inverter switching losses, elimination of transistor switch-through and transformer saturation problems, greatly reduced peak reverse voltages on rectifier diodes, and simple means for limiting the peak output voltage and the peak current in all of the semiconductor components under transient conditions. These advantages are of major significance for high-power converters employing a high switching frequency(e.g., 1.8 KW and 20 kHz).