A Decentralized Control Strategy with Output Voltage Deviation-Correction for Input-Series-Output-Parallel DC Transformer Based on Dual-Active-Bridge

DC transformers with dual-active-bridge (DAB) as units are widely used in DC distribution network. Usually it adopts input-series-output-parallel (ISOP) structure. This paper presents a decentralized control strategy with output voltage deviation-correction for this configuration. Under decentralized control, each DAB unit is self-contained and no central controller is needed. It improves the system stability, flexibility and reduces the cost. However, the existing decentralized control strategy will cause a deviation between the output voltage and the reference. With the proposed control strategy, decentralized control is achieved and the deviation of the output voltage is almost eliminated. Even if the transmission power of the system changes, the output voltage will not deviate from the reference value. And the operation principle of decentralized control is also introduced. The design method of output voltage deviation-correction is included. Finally, the simulation results verify the effectiveness of the proposed control strategy.