Single-stage dual active bridge (DAB) DC/AC converter has many degrees of control freedom

and the parameters such as transformer turn ratio

leakage inductance and switching frequency are coupled with each other

which leads to multiple constraints in converter efficiency optimization. In this paper

the constraint relations among transformer turn ratio

leakage inductance and zero-voltage switching (ZVS) range

root mean square (RMS) value of leakage inductance current and current stress of leakage inductance are analyzed. Efficiency-sensitive factor is extracted as the feature parameter to represent system efficiency. In order to achieve the optimized hardware parameters

the influence mechanism of efficiency-sensitive factor on system efficiency is studied

which can provide theoretical guidance for efficiency optimization. Finally

a 450 W DAB-DC/AC prototype is built and the proposed theory is verified by simulation and experiments.