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Modulation Strategy for Three-level Neutral-Point- Clamped Converter Achieving Clamping Diodes Loss Control
10/09/2022TYPE: PAPER - CONFERENCE
Authors: Lin, Xiang; Dong, Dong
Source: ECCE 2022
ABSTRACT
For the medium voltage (MV) three-level (3L)neutral-point-clamped (NPC) converter, minimizing the clampingdiodes volume are desired to reduce the cost and footprint of theconverter, not to mention the simplification of the laminated busstructure.In the traditional 3L modulation methods, theconduction losses of clamping diodes change significantly underdifferent operation conditions, e.g. power rating and powerfactors. Therefore, the selection of diodes needs to cover the worstscenario. In this paper, to help reduce clamping diodes cost andvolume, a new modulation strategy is proposed to control thelosses of the clamping diodes by operating the 3L NPC converterin the combination of 3L modulation and quasi-2-level (Q2L)modulation. The detailed modulation strategy is introduced in thispaper. The total device loss comparison of the proposedmodulation strategy, Q2L modulation, and 3L modulation is thenpresented. To verify the proposed modulation strategy, 3L NPCphase leg with 10 kV SiC MOSFET is tested, and the proposedmodulation strategy is verified.
