On Exploiting Active Redundancy of a Modular Multilevel Converter to Balance Reliability and Operational Flexibility

Jaesik Kang, Heejin Kim, Hong Ju Jung, Dong Su Lee, Chan Ki Kim, H. Alan Mantooth, Kyeon Hur

Research output: Contribution to journalArticle

Abstract

This paper presents a practical strategy for utilizing the submodule (SM) redundancy of a modular multilevel converter (MMC) for its fault tolerance. This strategy provides a systematic framework for balancing the tradeoff between two conventional methods for using the active redundancy and, thus, achieves operational flexibility. One of the existing methods improves SM reliability owing to less voltage stress on the SM components by employing all of the SMs to form the ac or dc voltages (voltage-sharing mode). The other avoids transients by keeping the average SM voltage constant at the cost of slightly increased stress on the SM components (fixed-level mode), which, however, can be controlled to provide the grid-adaptive operation by reserving the energy of the SMs not in service. We, thus, develop a new redundancy management scheme by integrating these two methods and exploiting their technical benefits to meet the PQ requirements and MMC control performance. This research provides a theoretical basis and a technical guide to determining the number of SMs, which can further increase the voltage steps as per the MMC and grid conditions. This paper also connects the remaining PQ capability of the MMC at a particular operating point with the SM redundancy concept by defining a potential redundancy, especially useful when the physical redundancy is exhausted. The theoretical findings and efficacy of the proposed strategy are validated through PSCAD/EMTDC time-domain simulations followed by experiments using a nine-level single-phase MMC system.

Original languageEnglish
Article number8379464
Pages (from-to)2234-2243
Number of pages10
JournalIEEE Transactions on Power Electronics
Volume34
Issue number3
DOIs
Publication statusPublished - 2019 Mar

Fingerprint

Redundancy
Electric potential
Fault tolerance
Experiments

All Science Journal Classification (ASJC) codes

  • Electrical and Electronic Engineering

Cite this

Kang, Jaesik ; Kim, Heejin ; Jung, Hong Ju ; Lee, Dong Su ; Kim, Chan Ki ; Mantooth, H. Alan ; Hur, Kyeon. / On Exploiting Active Redundancy of a Modular Multilevel Converter to Balance Reliability and Operational Flexibility. In: IEEE Transactions on Power Electronics. 2019 ; Vol. 34, No. 3. pp. 2234-2243.
@article{bc9a1e24d6b1466385d1bd4315b85ea5,
title = "On Exploiting Active Redundancy of a Modular Multilevel Converter to Balance Reliability and Operational Flexibility",
abstract = "This paper presents a practical strategy for utilizing the submodule (SM) redundancy of a modular multilevel converter (MMC) for its fault tolerance. This strategy provides a systematic framework for balancing the tradeoff between two conventional methods for using the active redundancy and, thus, achieves operational flexibility. One of the existing methods improves SM reliability owing to less voltage stress on the SM components by employing all of the SMs to form the ac or dc voltages (voltage-sharing mode). The other avoids transients by keeping the average SM voltage constant at the cost of slightly increased stress on the SM components (fixed-level mode), which, however, can be controlled to provide the grid-adaptive operation by reserving the energy of the SMs not in service. We, thus, develop a new redundancy management scheme by integrating these two methods and exploiting their technical benefits to meet the PQ requirements and MMC control performance. This research provides a theoretical basis and a technical guide to determining the number of SMs, which can further increase the voltage steps as per the MMC and grid conditions. This paper also connects the remaining PQ capability of the MMC at a particular operating point with the SM redundancy concept by defining a potential redundancy, especially useful when the physical redundancy is exhausted. The theoretical findings and efficacy of the proposed strategy are validated through PSCAD/EMTDC time-domain simulations followed by experiments using a nine-level single-phase MMC system.",
author = "Jaesik Kang and Heejin Kim and Jung, {Hong Ju} and Lee, {Dong Su} and Kim, {Chan Ki} and Mantooth, {H. Alan} and Kyeon Hur",
year = "2019",
month = "3",
doi = "10.1109/TPEL.2018.2846406",
language = "English",
volume = "34",
pages = "2234--2243",
journal = "IEEE Transactions on Power Electronics",
issn = "0885-8993",
publisher = "Institute of Electrical and Electronics Engineers Inc.",
number = "3",

}

On Exploiting Active Redundancy of a Modular Multilevel Converter to Balance Reliability and Operational Flexibility. / Kang, Jaesik; Kim, Heejin; Jung, Hong Ju; Lee, Dong Su; Kim, Chan Ki; Mantooth, H. Alan; Hur, Kyeon.

In: IEEE Transactions on Power Electronics, Vol. 34, No. 3, 8379464, 03.2019, p. 2234-2243.

Research output: Contribution to journalArticle

TY - JOUR

T1 - On Exploiting Active Redundancy of a Modular Multilevel Converter to Balance Reliability and Operational Flexibility

AU - Kang, Jaesik

AU - Kim, Heejin

AU - Jung, Hong Ju

AU - Lee, Dong Su

AU - Kim, Chan Ki

AU - Mantooth, H. Alan

AU - Hur, Kyeon

PY - 2019/3

Y1 - 2019/3

N2 - This paper presents a practical strategy for utilizing the submodule (SM) redundancy of a modular multilevel converter (MMC) for its fault tolerance. This strategy provides a systematic framework for balancing the tradeoff between two conventional methods for using the active redundancy and, thus, achieves operational flexibility. One of the existing methods improves SM reliability owing to less voltage stress on the SM components by employing all of the SMs to form the ac or dc voltages (voltage-sharing mode). The other avoids transients by keeping the average SM voltage constant at the cost of slightly increased stress on the SM components (fixed-level mode), which, however, can be controlled to provide the grid-adaptive operation by reserving the energy of the SMs not in service. We, thus, develop a new redundancy management scheme by integrating these two methods and exploiting their technical benefits to meet the PQ requirements and MMC control performance. This research provides a theoretical basis and a technical guide to determining the number of SMs, which can further increase the voltage steps as per the MMC and grid conditions. This paper also connects the remaining PQ capability of the MMC at a particular operating point with the SM redundancy concept by defining a potential redundancy, especially useful when the physical redundancy is exhausted. The theoretical findings and efficacy of the proposed strategy are validated through PSCAD/EMTDC time-domain simulations followed by experiments using a nine-level single-phase MMC system.

AB - This paper presents a practical strategy for utilizing the submodule (SM) redundancy of a modular multilevel converter (MMC) for its fault tolerance. This strategy provides a systematic framework for balancing the tradeoff between two conventional methods for using the active redundancy and, thus, achieves operational flexibility. One of the existing methods improves SM reliability owing to less voltage stress on the SM components by employing all of the SMs to form the ac or dc voltages (voltage-sharing mode). The other avoids transients by keeping the average SM voltage constant at the cost of slightly increased stress on the SM components (fixed-level mode), which, however, can be controlled to provide the grid-adaptive operation by reserving the energy of the SMs not in service. We, thus, develop a new redundancy management scheme by integrating these two methods and exploiting their technical benefits to meet the PQ requirements and MMC control performance. This research provides a theoretical basis and a technical guide to determining the number of SMs, which can further increase the voltage steps as per the MMC and grid conditions. This paper also connects the remaining PQ capability of the MMC at a particular operating point with the SM redundancy concept by defining a potential redundancy, especially useful when the physical redundancy is exhausted. The theoretical findings and efficacy of the proposed strategy are validated through PSCAD/EMTDC time-domain simulations followed by experiments using a nine-level single-phase MMC system.

UR - http://www.scopus.com/inward/record.url?scp=85048480231&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85048480231&partnerID=8YFLogxK

U2 - 10.1109/TPEL.2018.2846406

DO - 10.1109/TPEL.2018.2846406

M3 - Article

AN - SCOPUS:85048480231

VL - 34

SP - 2234

EP - 2243

JO - IEEE Transactions on Power Electronics

JF - IEEE Transactions on Power Electronics

SN - 0885-8993

IS - 3

M1 - 8379464

ER -