A Simplified Virtual Space Vector Modulation Strategy for Four-level T-Type NNPC Converter

The four-level T-Type nested neutral-point clamped (T-NNPC) converter is a recently proposed topology of voltage converters. In this paper, a strategy of controlling the flying capacitor voltage based on space virtual vector modulation is proposed. Compared with other four-level inverters, the T-NNPC inverter has fewer components. In order to alleviate the calculation burden of conventional dwell-time calculation, a simple but effective 60-degree coordinate system algorithm is proposed.