Semiconductor Losses of PWM Buck DC-AC Converter Operated as Dynamic Power Supply

This paper presents a method for calculating the semiconductor losses in asynchronous and synchronous PWM buck converters when operated as a fixed-VI, fixed-RL, variable-VO dynamic power supply. Equations are derived for MOSFET switching and conduction losses in both circuits, as well as diode conduction and forward-voltage losses. This work also compares the two topologies from the perspective of semiconductor losses to determine which circuit is inherently more efficient. The low-side MOSFET of the synchronous converter is shown via analysis and simulation to contribute the most significant power loss, thus demonstrating the asynchronous dc-ac converter topology is generally more efficient if designs are otherwise comparable.