RT Journal Article
T1 Band-Limited Three-Level Modulation for Balancing Capacitor Voltages in Neutral-Point-Clamped Converters
A1 Beniwal, Neha
A1 Townsend, Christopher David
A1 Farivar, Glen Ghias
A1 Pou, Josep
A1 Ceballos, Salvador
A1 Tafti, Hossein Dehghani
AB In this article, a band-limited three-level modulation scheme is proposed for a three-phase neutral-point-clamped (NPC) converter with an aim to balance the average capacitor voltages under all operating conditions. When conventional carrier-based pulsewidth modulation is applied, the amplitude of neutral point (NP)-voltage ripple tends to increase under linear imbalances, while the NP voltage can shift, leading to instability in the presence of nonlinear loads. A previously proposed three-level modulation scheme was able to eliminate all low-frequency capacitor voltage ripple by switching a phase between three levels in each switching period. This approach significantly increased the switching loss. The proposed modulation scheme limits the increase in switching loss by employing two operational bands, one fixed band applied to the capacitor voltages and another variable band applied to the phase currents. If the instantaneous capacitor voltages exceed the voltage band, then an appropriate phase-leg is switched in three levels to guarantee that the capacitor voltages cannot diverge further. If the instantaneous capacitor voltages reside within the voltage band, a variable current band is used to regulate switching in three voltage levels in order to obtain lower switching losses as compared to the conventional three-level modulation scheme. Therefore, the proposed modulation scheme presents a tradeoff between switching losses and capacitor voltage ripple. The experimental results are obtained under different loading conditions for validating the performance of the proposed modulation scheme.
SN 0885-8993
YR 2020
FD 2020-09-01
LK https://hdl.handle.net/11556/4277
UL https://hdl.handle.net/11556/4277
LA eng
NO Beniwal , N , Townsend , C D , Farivar , G G , Pou , J , Ceballos , S & Tafti , H D 2020 , ' Band-Limited Three-Level Modulation for Balancing Capacitor Voltages in Neutral-Point-Clamped Converters ' , IEEE Transactions on Power Electronics , vol. 35 , no. 9 , 8970239 , pp. 9739-9754 . https://doi.org/10.1109/TPEL.2020.2969452
NO Publisher Copyright: © 1986-2012 IEEE.
NO Manuscript received August 26, 2019; revised December 13, 2019; accepted January 21, 2020. Date of publication January 27, 2020; date of current version May 1, 2020. This work was supported in part by the Singapore Ministry of Education Academic Research Fund Tier 1 under Grant 2017-T1-001-213 (RG 90/17) and in part by the Basque Government within the Research program ELKARTEK under Project ENSOL (KK-2018/00040). This article was presented in part at the IEEE Energy Conversion Congress and Exposition (ECCE), Baltimore, MD, USA, October 2019, under the title “Balancing Average Capacitor Voltages in Neutral-Point-Clamped Converters Using Band-Limited Three-Level Modulation” [26]. Recommended for publication by Associate Editor B. P. McGrath. (Corresponding author: Neha Beniwal.) N. Beniwal is with the Energy Research Institute at NTU (ERI@N), Interdisciplinary Graduate School, Nanyang Technological University, Singapore 639798, Singapore (e-mail: nsingh341@gmail.com).
DS TECNALIA Publications
RD 28 jul 2024