Introduction to PLECS. Design Multilevel Inverter Modeling. Exploring the components within PLECS library, construct the Neutral Point Clamped Inverter as shown in the above figure. Replace the capacitors with ideal voltage sources (100 V for each source) and each load element as a 10 ohm resistor. The N or n is a ground point. Note that IGBTs are modeled in the above figure but any ideal switch (not considering device dynamics) will work just fine.