Hybrid Four-wire Three-Level Inverter Equipped with Model Predictive Control for UPS Applications

In this paper, a new hybrid four-wire three-level three-phase converter (HFTLTPC) for uninterruptible power supply (UPS) applications is presented to feed unbalanced and nonlinear loads. The proposed HFTLTPC shows the same functionalities with less semiconductors compared to other three level converters. The HFTLTPC with having enough active switching vectors is able to precisely track the reference; however, the selection of the best switching vector in terms of reference tracking is a challenging issue. This paper proposes a finite set model predictive control (FCS-MPC) for the HFTLTPC, which control the inverter with higher bandwidth as well as minimum switching frequency. Control hardware in the loop (CHiL) results verify the proposed model and control structure performance.