Unified power quality conditioner with shared legs and high-frequency transformer

This work proposes a three-phase unified power quality conditioner based on a nine-leg converter composed of three single-phase three-leg cells with shared legs and connecting the three DC-links by means of a DC-DC converter with a high-frequency transformer (HFT). Each DC-link is connected to a high frequency H-bridge and each H-bridge is connected to one winding of the transformer. The high-frequency transformer is responsible to balance the DC-links, providing the necessary power flow. Converter model is provided, as well as pulse-width modulation and control strategy. Simulations and experimental results are presented for validation purposes. The proposed converter is compared with a conventional solution in terms of harmonic distortion.