A volumetric evaluation is presented, which compares the physical dimensions of all major contributing passive components in three-phase pulse width-modulated (PWM) active front-end AC-DC converters. Previous work was mainly focused on the comparison between topologies with up to three voltage levels. The proposed evaluation, in contrast, considers the component volumes in multilevel converters with up to five voltage levels and compares them to the basic industrial two-level solution. Therefore, the impact of the switching frequency and modulation technique on the volume is carefully studied for all major passive components, including the electromagnetic interference (EMI) input filter, boost inductors, dc-link capacitors and occasionally flying capacitors. For the modulation technique, two common modulators are implemented: continuous space vector pulse width modulation (SVPWM) and 60° discontinuous pulse width modulation (DPWM). The results presented for an 11 kW, 800 V active power factor correction (PFC) application indicate that the increased complexity of multilevel converters may not always be justified. Three-level converters, however, offer great benefits while the complexity of both the power system and the system control remains at a reasonable level.
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