Comparison of state-of-the-art voltage source converter topologies for medium voltage applications

This paper compares a two level voltage source converter (2L-VSC), a three-level neutral point clamped voltage source converter (3L-NPC VSC), a three-level flying capacitor voltage source converter (3L-FLC VSC) and a four-level flying capacitor voltage source converter (4L-FLC VSC) on the basis of state-of-the-art 6.5 kV, 3.3 kV and 2.5 kV IGBTs for a 2.3 kV medium voltage converter. The design of the power semiconductors, the installed switch power, converter losses, the semiconductor loss distribution, modulation strategies and the harmonic spectra are compared in detail.