Observer Based Current Control of Dual Active Bridge Converter

A wide bandwidth current sensorless double loop control of dual active bridge (DAB) converter is presented in this paper. Conventional dual loop control requires measurement of the high switching frequency purely AC inductor current of DAB. High bandwidth current sensors and precise high speed sampling ADCs are necessary, which costs very high. This work proposes a state observer based design for the estimation of this current. After estimation, this observed state variable can be used as state feedback for the inner current loop to generate the phase shift duty ratio as control signal for closed loop operation.