Simplified four-level inverter-based dynamic voltage restorer with single DC power source

This paper proposes a simplified four-level (S4L) inverter based dynamic voltage restorer (DVR). In the proposed configuration, the dual buck stage can output full, two thirds, and one third of dc link voltage. Including the zero voltage provided by the two-level inverter, the output of the proposed inverter can be four levels. With the same switching frequency, the S4L inverter based DVR achieves better performance than the existing two-level and three-level inverters based DVRs. Moreover, compared with the existing four-level inverter based DVRs, it requires less active switches/diodes and only requires a single DC power source. The experimental results are provided for the validation of the proposed system.