The Impedance-Based Stability Analysis of the Single-Phase Solid State Transformer

The whole stability analysis of the single-phase solid state transformer (SST) is proposed in this paper. Firstly, the different SST concepts has been researched in literature and technical aspects. Meanwhile, plenty of inherent characteristics can potentially limit the application of the SST in microgrid, e.g. low-frequency oscillation and harmonic oscillation. As a result, the stability analysis of the SST in detail is discussed in this paper. First and foremost, the typical structure of the SST and its each subsystem controller are studied. Further, the stability analysis of the each subsystem is provided via closed-loop transfer function, respectively. In the end, the whole stability analysis based on Z+Z type cascade system impedance analysis is studied. The impedance-based stability analysis method of the single-phase SST can be validated through relative simulation results.