Analysis of the design space of single-stage and two-stage LC output filters of switched-mode AC power sources

This paper proposes a systematic approach to design the output filter of a 10 kW, low-voltage 400 Vll,rms, fouroutput phase, hard-switched AC source based on the Three-Level Neutral Point Clamped Voltage Source Converter topology. Given specifications of the AC source, such as the voltage quality, the control performance or the conducted EMI at the output of the source, are translated into corresponding families of curves in the parameter space of the output filter. The area/volume enclosed by these curves represents the design space of the output filter in which all tuples (Lf, Cf), e.g. for a single-stage LC-filter, fulfill every single AC source specification. From all possible filter parameters in the design space, the set of parameters resulting in the smallest filter volume, the lowest filter weight, the highest filter efficiency and/or the lowest filter costs can be selected.