An Universal Bidirectional Three-Port DC/DC/AC Converter With Isolated AC Port

A topology of versatile unsiversal three-port DC/DC/AC converter with isolated AC port is presented. The converter is based on LLC converter schematic that has been massively modified for providing bidirectional DC-to-AC conversion with galvanic isolation by high-frequency transformer. Besides, a bidirectional DC-DC conversion option is implemented on DC side. In overall, the proposed converter topology allows to combine a number of functions in one single device, i.e.: DC-AC converter for uninterruptible power supply; AC-DC converter for battery charging (or welding as an option); grid-tie inverter for renewable sources (PV panels); DC-DC converter for vehicle cranking or battery-powered welding. The converter is single stage, utilizing direct conversion principle, has no intermediate DC link. Moreover, the topology allows to implement “integrated magnetics” approach by using a transformer with a controlled leakage inductance