Design of Asynchronous Microgrid Power Conditioning System with Gen-3 10 kV SiC MOSFETs for MV Grid Interconnection

Asynchronous Microgrid Power Conditioning Systems (AMPCS) play a pivotal role as essential power electronic converters, enabling the seamless interconnection of asynchronous grids. The asynchronous configuration offers advantages over synchronous interconnection regarding fault clearance time, islanding operation, and disturbance propagation. Currently, the asynchronous interconnection of medium voltage microgrids relies on AC-DC and DC-AC power converters, incorporating galvanic isolation provided by power frequency transformers connected to the grids. Typically implemented with 3.3kV - 6.5kV silicon IGBTs, these converters form the basis of the existing setup. This paper introduces a novel approach utilizing a Three-phase, Three-Level Neutral Point Clamped (3L-NPC) converter, enabled by series-connected 10 kV SiC MOSFETs and 10 kV SiC JBS Diodes, serving as a foundational element for realizing AMPCS in medium voltage interconnections. This AMPCS configuration involves two grid-connected converters interfaced by a bidirectional isolated DC-DC converter, ensuring a continuous energy flow. The paper comprehensively explores system-level control and operation for AMPCS, including the dc-link stability analysis, the sensor sampling analysis, and the protection overview. It delves into the operational intricacies and challenges of medium voltage AMPCS and concludes with the system-level demonstration with experimental results.