New Single–Phase Three-Wire Interlinking Converter and Hybrid AC/LVDC Microgrid

Abstract

A hybrid microgrid (HMG) is comprised of both ac and dc subgrids interconnected via an interlinking converter (IC). Conventional single-phase ac/low voltage dc (LVdc) HMGs require four wires or buses, two buses for the ac subgrid as phase and neutral, and two buses for the dc subgrid as positive and negative. In this article, a new three-wire topology is proposed for single-phase ac/LVdc HMGs with a common neutral and negative bus. The proposed HMG topology benefits from two properly grounded subgrids and has some features, which help to reduce wiring costs, suppress leakage current, and improve dc and ac-side fault ride-through (FRT) by using a common ground strategy. For this purpose, a new three-wire single-phase ac/LVdc IC and its modulation method are also proposed. The proposed IC dc and ac-side FRT is investigated and compared with the conventional IC dc and ac-side FRT. To this aim, suitable models for the conventional single-phase and proposed ICs are derived. The models reveal the advantages of the proposed IC in the case of switches transients in fault conditions. The performance of the proposed IC and its control method in an HMG is proved through simulations in MATLAB/SIMULINK environment and by constructing an experimental setup.