Power Electronic Converters in Low-Voltage Direct Current Distribution – Analysis and Implementation
Nuutinen, Pasi (2015-12-18)
Väitöskirja
Nuutinen, Pasi
18.12.2015
Lappeenranta University of Technology
Acta Universitatis Lappeenrantaensis
Julkaisun pysyvä osoite on
https://urn.fi/URN:ISBN:978-952-265-891-3
https://urn.fi/URN:ISBN:978-952-265-891-3
Tiivistelmä
Over the recent years, smart grids have received great public attention. Many proposed
functionalities rely on power electronics, which play a key role in the smart grid, together
with the communication network. However, “smartness” is not the driver that alone motivates
the research towards distribution networks based on power electronics; the network
vulnerability to natural hazards has resulted in tightening requirements for the supply security,
set both by electricity end-users and authorities. Because of the favorable price
development and advancements in the field, direct current (DC) distribution has become
an attractive alternative for distribution networks.
In this doctoral dissertation, power electronic converters for a low-voltage DC (LVDC)
distribution system are investigated. These include the rectifier located at the beginning
of the LVDC network and the customer-end inverter (CEI) on the customer premises. Rectifier
topologies are introduced, and according to the LVDC system requirements, topologies
are chosen for the analysis. Similarly, suitable CEI topologies are addressed and selected
for study. Application of power electronics into electricity distribution poses some
new challenges. Because the electricity end-user is supplied with the CEI, it is responsible
for the end-user voltage quality, but it also has to be able to supply adequate current in all
operating conditions, including a short-circuit, to ensure the electrical safety. Supplying
short-circuit current with power electronics requires additional measures, and therefore,
the short-circuit behavior is described and methods to overcome the high-current supply
to the fault are proposed. Power electronic converters also produce common-mode (CM)
and radio-frequency (RF) electromagnetic interferences (EMI), which are not present in
AC distribution. Hence, their magnitudes are investigated.
To enable comprehensive research on the LVDC distribution field, a research site was
built into a public low-voltage distribution network. The implementation was a joint task
by the LVDC research team of Lappeenranta University of Technology and a power company
Suur-Savon S¨ahk¨o Oy. Now, the measurements could be conducted in an actual
environment. This is important especially for the EMI studies. The main results of the work concern the short-circuit operation of the CEI and the EMI issues. The applicability
of the power electronic converters to electricity distribution is demonstrated, and suggestions
for future research are proposed.
functionalities rely on power electronics, which play a key role in the smart grid, together
with the communication network. However, “smartness” is not the driver that alone motivates
the research towards distribution networks based on power electronics; the network
vulnerability to natural hazards has resulted in tightening requirements for the supply security,
set both by electricity end-users and authorities. Because of the favorable price
development and advancements in the field, direct current (DC) distribution has become
an attractive alternative for distribution networks.
In this doctoral dissertation, power electronic converters for a low-voltage DC (LVDC)
distribution system are investigated. These include the rectifier located at the beginning
of the LVDC network and the customer-end inverter (CEI) on the customer premises. Rectifier
topologies are introduced, and according to the LVDC system requirements, topologies
are chosen for the analysis. Similarly, suitable CEI topologies are addressed and selected
for study. Application of power electronics into electricity distribution poses some
new challenges. Because the electricity end-user is supplied with the CEI, it is responsible
for the end-user voltage quality, but it also has to be able to supply adequate current in all
operating conditions, including a short-circuit, to ensure the electrical safety. Supplying
short-circuit current with power electronics requires additional measures, and therefore,
the short-circuit behavior is described and methods to overcome the high-current supply
to the fault are proposed. Power electronic converters also produce common-mode (CM)
and radio-frequency (RF) electromagnetic interferences (EMI), which are not present in
AC distribution. Hence, their magnitudes are investigated.
To enable comprehensive research on the LVDC distribution field, a research site was
built into a public low-voltage distribution network. The implementation was a joint task
by the LVDC research team of Lappeenranta University of Technology and a power company
Suur-Savon S¨ahk¨o Oy. Now, the measurements could be conducted in an actual
environment. This is important especially for the EMI studies. The main results of the work concern the short-circuit operation of the CEI and the EMI issues. The applicability
of the power electronic converters to electricity distribution is demonstrated, and suggestions
for future research are proposed.
Kokoelmat
- Väitöskirjat [1029]