---
_id: '48352'
abstract:
- lang: eng
  text: Star-connected cascaded H-bridge Converters require large DC-link capacitors
    to buffer the second-order harmonic voltage ripple. First, it is analytically
    proven that the DC-link voltage ripple is proportional to the apparent converter
    power and does not depend on the power factor for nominal operation with sinusoidal
    reference arm voltages and currents. A third-harmonic zero-sequence voltage injection
    with an optimal amplitude and phase angle transforms the 2nd harmonic to a 4th
    harmonic DC-link voltage ripple. This reduces the voltage ripple by exactly 50%
    for all power factors at steady-state at balanced conditions. However, this requires
    54% additional modules for unity power factor operation and even 100% for pure
    reactive power operation to account for the increased reference arm voltages due
    to the large amplitude of the optimal third-harmonic injection. If not enough
    modules are available, an adaptive discontinuous PWM is utilized to still minimize
    the voltage ripple for the given number of modules and power factor. With a very
    limited number of modules (modulation index is 1.15), the proposed method still
    reduces the DC-link voltage ripple by 24.4% for unity power factor operation.
    It requires the same number of modules as the commonly utilized 3rd harmonic injection
    with 1/6 of the grid voltage amplitude and achieves superior results. Simulations
    of a 10 kV/1 MVA system confirm the analysis.
author:
- first_name: Roland
  full_name: Unruh, Roland
  id: '34289'
  last_name: Unruh
- first_name: Joachim
  full_name: Böcker, Joachim
  id: '66'
  last_name: Böcker
  orcid: 0000-0002-8480-7295
- first_name: Frank
  full_name: Schafmeister, Frank
  id: '71291'
  last_name: Schafmeister
citation:
  ama: 'Unruh R, Böcker J, Schafmeister F. An Optimized Third-Harmonic Injection Reduces
    DC-Link Voltage Ripple in Cascaded H-Bridge Converters up to 50% for all Power
    Factors. In: <i>2023 25th European Conference on Power Electronics and Applications
    (EPE’23 ECCE Europe)</i>. IEEE; 2023. doi:<a href="https://doi.org/10.23919/epe23ecceeurope58414.2023.10264313">10.23919/epe23ecceeurope58414.2023.10264313</a>'
  apa: Unruh, R., Böcker, J., &#38; Schafmeister, F. (2023). An Optimized Third-Harmonic
    Injection Reduces DC-Link Voltage Ripple in Cascaded H-Bridge Converters up to
    50% for all Power Factors. <i>2023 25th European Conference on Power Electronics
    and Applications (EPE’23 ECCE Europe)</i>. 2023 25th European Conference on Power
    Electronics and Applications (EPE’23 ECCE Europe), Aalborg, Denmark. <a href="https://doi.org/10.23919/epe23ecceeurope58414.2023.10264313">https://doi.org/10.23919/epe23ecceeurope58414.2023.10264313</a>
  bibtex: '@inproceedings{Unruh_Böcker_Schafmeister_2023, title={An Optimized Third-Harmonic
    Injection Reduces DC-Link Voltage Ripple in Cascaded H-Bridge Converters up to
    50% for all Power Factors}, DOI={<a href="https://doi.org/10.23919/epe23ecceeurope58414.2023.10264313">10.23919/epe23ecceeurope58414.2023.10264313</a>},
    booktitle={2023 25th European Conference on Power Electronics and Applications
    (EPE’23 ECCE Europe)}, publisher={IEEE}, author={Unruh, Roland and Böcker, Joachim
    and Schafmeister, Frank}, year={2023} }'
  chicago: Unruh, Roland, Joachim Böcker, and Frank Schafmeister. “An Optimized Third-Harmonic
    Injection Reduces DC-Link Voltage Ripple in Cascaded H-Bridge Converters up to
    50% for All Power Factors.” In <i>2023 25th European Conference on Power Electronics
    and Applications (EPE’23 ECCE Europe)</i>. IEEE, 2023. <a href="https://doi.org/10.23919/epe23ecceeurope58414.2023.10264313">https://doi.org/10.23919/epe23ecceeurope58414.2023.10264313</a>.
  ieee: 'R. Unruh, J. Böcker, and F. Schafmeister, “An Optimized Third-Harmonic Injection
    Reduces DC-Link Voltage Ripple in Cascaded H-Bridge Converters up to 50% for all
    Power Factors,” presented at the 2023 25th European Conference on Power Electronics
    and Applications (EPE’23 ECCE Europe), Aalborg, Denmark, 2023, doi: <a href="https://doi.org/10.23919/epe23ecceeurope58414.2023.10264313">10.23919/epe23ecceeurope58414.2023.10264313</a>.'
  mla: Unruh, Roland, et al. “An Optimized Third-Harmonic Injection Reduces DC-Link
    Voltage Ripple in Cascaded H-Bridge Converters up to 50% for All Power Factors.”
    <i>2023 25th European Conference on Power Electronics and Applications (EPE’23
    ECCE Europe)</i>, IEEE, 2023, doi:<a href="https://doi.org/10.23919/epe23ecceeurope58414.2023.10264313">10.23919/epe23ecceeurope58414.2023.10264313</a>.
  short: 'R. Unruh, J. Böcker, F. Schafmeister, in: 2023 25th European Conference
    on Power Electronics and Applications (EPE’23 ECCE Europe), IEEE, 2023.'
conference:
  end_date: 2023-09-08
  location: Aalborg, Denmark
  name: 2023 25th European Conference on Power Electronics and Applications (EPE'23
    ECCE Europe)
  start_date: 2023-09-04
date_created: 2023-10-20T07:13:32Z
date_updated: 2023-10-20T10:01:02Z
department:
- _id: '52'
doi: 10.23919/epe23ecceeurope58414.2023.10264313
keyword:
- Cascaded H-Bridge
- Solid-State Transformer
- Capacitor voltage ripple
- Zero sequence voltage
- Third harmonic injection
language:
- iso: eng
main_file_link:
- url: https://ieeexplore.ieee.org/abstract/document/10264313
publication: 2023 25th European Conference on Power Electronics and Applications (EPE'23
  ECCE Europe)
publication_identifier:
  isbn:
  - 979-8-3503-1678-0
publication_status: published
publisher: IEEE
quality_controlled: '1'
status: public
title: An Optimized Third-Harmonic Injection Reduces DC-Link Voltage Ripple in Cascaded
  H-Bridge Converters up to 50% for all Power Factors
type: conference
user_id: '34289'
year: '2023'
...