Abstract
Three-level neutral-point clamped inverter (3LNPCI) is a widely popular topology in the realm of multi-level inverters. The low frequency third-harmonic neutral-point (NP) current in a 3L-NPCI and the corresponding NP-voltage oscillations on the DC-side are known characteristics of the 3L-inverter. In this paper, a quantitative analysis is presented for characterizing the DC-side third-harmonic phenomena observed in 3LNPCI. Departing from the traditional space-vector perspective, an alternate formulation based on time-domain functions and Fourier-series is adopted, and an analytical expression for the 3rd harmonic NP-current is derived as a function of inverter modulation index and load power factor-this is applicable for all conventional carrier-based PWM techniques employed on 3LNPCIs. The corresponding NP-voltage variation on the DC-side and its translation onto the AC-side as low-frequency harmonic distortions in the inverter output voltage are analytically quantified. Based on this, a model-based observer is designed to mitigate the AC side distortions through accurate estimation of the disturbance variables and feed-forward cancellation. Experimental results along with a full-order switched model simulation of a three-phase 3L-NPCI system validate the theoretical analysis and mitigation technique proposed in this paper.
| Original language | English (US) |
|---|---|
| Title of host publication | 2021 IEEE Energy Conversion Congress and Exposition, ECCE 2021 - Proceedings |
| Publisher | Institute of Electrical and Electronics Engineers Inc. |
| Pages | 3563-3570 |
| Number of pages | 8 |
| ISBN (Electronic) | 9781728151359 |
| DOIs | |
| State | Published - 2021 |
| Event | 13th IEEE Energy Conversion Congress and Exposition, ECCE 2021 - Virtual, Online, Canada Duration: Oct 10 2021 → Oct 14 2021 |
Publication series
| Name | 2021 IEEE Energy Conversion Congress and Exposition, ECCE 2021 - Proceedings |
|---|
Conference
| Conference | 13th IEEE Energy Conversion Congress and Exposition, ECCE 2021 |
|---|---|
| Country/Territory | Canada |
| City | Virtual, Online |
| Period | 10/10/21 → 10/14/21 |
Bibliographical note
Funding Information:This material is based upon work supported by the U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy (EERE) under Solar Energy Technologies Office (SETO) Agreement Number EE0009025.
Publisher Copyright:
© 2021 IEEE.