A Novel Deadbeat Sliding Mode Predictive Control for T-Type Three-Phase Four-Leg Three-Level Voltage-Source Inverters

This article proposes a novel deadbeat sliding mode predictive control (DB-SMPC) strategy for T-type three-phase four-leg three-level voltage source inverters (3P-4L-3L-VSIs). Developed in the αβγ frame, the control strategy integrates the advantages of traditional sliding mode control (SMC) and deadbeat predictive control (DBPC), offering enhanced robustness, stability, and superior dynamic and steady-state performance. It outperforms traditional SMC and DBPC in terms of voltage regulation and dynamic response under varying load conditions. This strategy also reduces system chattering, ensures a fixed switching frequency, thereby simplifying the design of LC-filters. The four-leg inverter topology effectively addresses unbalanced and nonlinear loads. When integrated with the proposed DB-SMPC strategy, it enables robust system performance under such conditions. In addition, it significantly reduces total harmonic distortion (THD) for nonlinear loads and improves the dynamic and steady-state performance of balancing neutral-point voltage under unbalanced load conditions. Experimental results verify the effectiveness of the proposed strategy.