Impedance-based stability analysis of the DC transformer back-to-back system

The DC transformer(DCT), which has been regarded as the core power electronics equipment, has gained increasing importance in the modern DC power distribution system. This paper presents a systematic design and stability analysis of the DCT back-to-back system, which consist of two DCT working as voltage source and current source respectively. The DCT average model including the current limiting inductor is proposed in this paper. In addition, the stability of the back-to-back system is analyzed according to the Nyquist criterion. At last, the effectiveness of the proposed system model is validated by the simulation and experiment results.