Modeling of medium voltage power electronics converters utilizing advanced simulation tools

This paper addresses the steady-state and dynamic modeling of a three-level, neutral-point-clamped (NPC) voltage source converter (VSC) with active front-end (AFE) in a commercial 2.5 MW variable speed motor drive (VSD). The AFE of the modeled VSD adopts the selective harmonic elimination SHE-PWM technique with the optimization of inverter power capacity and power source quality for a wide-range VSD system. The modeling effectively captures the lineside behavior of the VSD driving an induction motor with a simplified model that only considers the AFE in detail. Numerical simulation in the PSCAD/EMTDC simulation package and experimental measurements of the existing physical setup are presented to validate the developed model. The VSC is used as an example to show the model development procedure that could be applied to other VSC and VSD applications. The off-grid operation with variable voltage source (VVS) based on power electronic converter is discussed as means to conduct model validation. Additionally, this paper will briefly discuss how the modeling approach can be used for dynamic parameter extraction.