Three-Quarter Bridge Converter Eliminates Dead Time Losses

A third switch is introduced as an intermediary component in the half-bridge architecture. This additional switch acts as a mediator during dead time periods, providing an alternative current path through the energy storage component rather than forcing current through the commutating diodes. The third switch is activated during the off-times of the primary and secondary switches, eliminating the need for diode conduction during these intervals and significantly reducing commutating diode conduction losses while preserving the simplicity of symmetrical drive control.

The third switch serves as a mediator that enables the system to achieve the benefits of asymmetrical drive (eliminating dead times and reducing commutating diode losses) while maintaining the waveform quality advantages of symmetrical drive. By introducing this intermediary component, the patent resolves the contradiction by providing a third current path that allows symmetrical switching control to be maintained while preventing the waveform degradation that would otherwise occur with asymmetrical drive approaches.

The patent segments the bridge architecture by adding a third switch that divides the current path into distinct segments. Instead of using a full-bridge configuration that requires differential load driving, the segmented approach uses the third switch to create separate current paths during dead time periods. This segmentation allows the load to be driven in a single-ended manner at lower common mode voltages while still eliminating dead time losses, as the third switch provides an alternative path for current during transition periods.