A High-Performance Multicell Topology Based on Single-Phase Power Cells for Three-Phase Systems Operating Under Unbalanced AC Mains and Asymmetrical Loads

This paper presents a multicell converter topology composed of N single-phase power cells per phase and a multipulse power transformer. The topology achieves high-power-quality waveforms in three-phase applications under the presence of severe unbalanced ac mains. Moreover, the power cells are properly arranged in order to achieve high-performance ac supply current waveforms under asymmetrical loads. The configuration is based on single-phase power cells that feature a pulsewidth-modulation rectifier in order to achieve an overall unitary displacement power factor and a controlled dc-link voltage at the power-cell level. The configuration is implemented, and different experimental tests are performed where unbalance and distortion indexes are computed.