Analysis and control of a three-level power energy storage system with dual active bridge DC-DC converter

The energy storage system plays an important role in the distributed network, and the three-level converter has a smaller du/dt of output voltage compared with the two-level converter. This paper focus on the modeling and voltage balance control of a three-level energy storage system with dual active bridge dc-dc converter. The small signal model of the dual active bridge is proposed, which enables the output voltage and current to be controlled simultaneously. Besides, an improved voltage balancing technique for a three-level converter is presented, which makes a good tradeoff between the dc-link capacitor ripple voltage attenuation and the power device switching action reduction. Finally the system is tested by MATLAB/SIMULINK, and the experimental results are presented.