Abstract

Partial power converters (PPCs) have been widely studied for DC-DC conversion due to their ability to process only a fraction of the total power, resulting in high-efficiency solutions. However, conventional PPCs typically rely on high-frequency transformers, increasing their size, weight and cost, and limiting their efficiency. To address this issue, transformerless AC-link PPCs have recently been proposed, replacing the transformer with an impedance network, enabling further improvements in terms of power density and efficiency. This paper proposes a generalization of the transformerless AC-link PPCs to N-phase configurations, which is particularly attractive for high-power applications. To validate the concept, a three-phase transformerless AC-link PPC is implemented and analyzed in comparison with the two-phase alternative. Simulation results demonstrate an extended operating range and improved efficiency in particular at high power levels, showing the interest of the proposed multiphase approach for scaling transformerless AC-link PPCs to high-power applications.