PROJECT TITLE :

LCL Filter Design and Inductor Current Ripple Analysis for a Three-Level NPC Grid Interface Converter

ABSTRACT:

The harmonic filter for a 3-level neutral-purpose-clamped (NPC) grid interface converter is meant during this paper with smart filtering performance and little component size. LCL topology is chosen because of the attenuation and size tradeoff. The planning of the inverter-facet inductor L1 is emphasized due to its cost. A detailed inductor current ripple analysis is given based on the space vector modulation. The analysis derives the inductor volt-second and the most current ripple equation in line cycle. It conjointly reveals the switching cycle current ripple distribution over a line cycle, with the consideration of power factor. The overall system loss is calculated with different ripple current. Inductor L1 is set by the loss and size tradeoff. Additionally the capacitor- and grid-facet inductor L2 is designed based mostly on attenuation requirement. Different damping circuits for LCL filter are compared and investigated well. The filter design is verified by each simulation and 200-kVA 3-level NPC converter hardware.