Improved Control for Isolated Cycloconverter-type Dual Active Bridge DC/AC Converter

As isolated converters are incorporated in a larger number of applications such as photovoltaic generation or electric vehicle chargers, consumers are looking for cost efficient and compact solutions leading to a desire for large power density and high efficiency designs. Typical two-stage cascaded dual active bridge inverter designs contain a large capacitor bank for the DC bus limiting their power density, and the inclusion of two converters can lead to lower efficiency. Isolated single-stage converters offer the advantage of fewer active switches and reduced passive filters. This paper proposes a novel calculation to determine the lowest power loss operating conditions for a single-stage isolated DC/AC converter. A new control scheme that can operate the proposed converter at the minimum loss point for each discretized voltage of the output AC waveform is also suggested.