Hybrid modulation strategy for eliminating low-frequency NP voltage oscillations in NPC using redistribution of NTV duty ratios

Neutral point (NP) clamped (NPC) inverters produce low-frequency NP voltage oscillations when modulated with nearest three-vector (NTV) methods for certain loading conditions. Non-NTV modulations can address these oscillations at the expense of increased switching frequency, output voltage distortio...

Full description

Saved in:
Bibliographic Details
Published in:IET power electronics Vol. 10; no. 12; pp. 1504 - 1517
Main Authors: Narendrababu, A, Agarwal, Pramod
Format: Journal Article
Language:English
Published: The Institution of Engineering and Technology 01.10.2017
Subjects:
complex algorithms
generalised algorithm
hybrid modulation strategies
hybrid modulation strategy
hybrid NTV‐SSTV modulation strategy
invertors
low‐frequency NP voltage oscillation elimination
neutral point clamped NPC inverters
NP voltage oscillations
NTV duty ratio redistribution
Research Article
selected three‐vector modulation
STV modulation
vectors
NTV duty ratio redistribution
generalised algorithm
low-frequency NP voltage oscillation elimination
hybrid modulation strategies
STV modulation
selected three-vector modulation
hybrid modulation strategy
NP voltage oscillations
invertors
vectors
hybrid NTV-SSTV modulation strategy
neutral point clamped NPC inverters
complex algorithms
ISSN:1755-4535, 1755-4543
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Neutral point (NP) clamped (NPC) inverters produce low-frequency NP voltage oscillations when modulated with nearest three-vector (NTV) methods for certain loading conditions. Non-NTV modulations can address these oscillations at the expense of increased switching frequency, output voltage distortion and complexity. This study presents a new generalised algorithm to implement hybrid modulation strategies which can also eliminate NP voltage oscillations using a combination of the aforementioned methods. The proposed algorithm avoids abrupt changeover between the two modulations and ensures minimum contribution of non-NTV operation and hence its drawbacks. Moreover, the algorithm is computationally efficient compared with its counterparts, since it only uses redistributed NTV duty ratios to generate NTV and non-NTV modulations instead of using two separate complex algorithms which result in increased computational burden. A non-NTV method called selected three-vector (STV) modulation is chosen to perform the detailed analysis of above proposed algorithm for hybrid NTV–STV modulation. Additionally, a simplified STV (SSTV) is derived to develop a new hybrid NTV–SSTV modulation strategy which further reduces losses and complexity compared with the hybrid NTV–STV modulation, without affecting the performance of NPC. The proposed algorithm and the derived hybrid modulation strategy are validated using simulation and experimental results.
ISSN:1755-4535
1755-4543
DOI:10.1049/iet-pel.2016.0511