A multi-cell unified power quality conditioner that operates with asymmetrical DC links voltages for minimum THD

A multi-cell Unified Power Quality Conditioner that operates with different DC link voltages is presented. Unlike what the literature reports, the DC link voltage levels are chosen to minimize the THO of the resulting AC voltage delivered by the topology for a given switching frequency. The benefits are fixed switching frequency, minimum passive component size, and high quality waveforms. In this work, the DC link voltage values are achieved at the cell level by generating a quasi-square voltage waveform where the amplitude is regulated and the firing angles optimized off-line. The formulation is generalized for _c, cells that can generate an AC voltage waveform out of 2n_c, +1 possible levels. Preliminary results evidence than with a waveform of 9 levels and 400 [Hz] commutation frequency an 8,83 % THD Is obtained.