DC Distributed Power Systems - Analysis, Design and Control for a Renewable Energy System
Författare
Summary, in English
Present DC transmission systems are discussed and investigated in simulations. Then, different methods for load sharing and voltage control are discussed. Especially, the voltage droop control scheme is examined thoroughly. Since the droop control method does not require any high-speed communication between sources and loads, this is considered the most suitable for DC distributed power systems. The voltage feed back design of the controller also results in a specification of the DC bus capacitors (equivalents to DC link capacitors of single converters) needed for filtering. If the converters in the DC distribution system are equipped with capacitors selected from this design criterion and if the DC bus impedance is neglected, the source converters share the total load equally in per unit.
The same DC distribution bus configuration is studied in a wind power application. Especially the dynamic properties of load-source interactions are highlighted. They are interesting since the sources are considered weak for a distributed power system. This is illustrated with simulations where the power is fed from wind turbines only and constant power loads are controlled at the same time as the DC bus voltage level.
Personal safety and prevention of property damage are important factors of conventional AC power systems. A grounding scheme for the DC distribution system together with algorithms for detection of ground faults, are presented. The proposed method detects ground faults on both the AC and DC sides and is extended to cover short circuit faults with a minor work effort.
Experimental verifications follow the theoretical investigations introduced above. First, dynamic properties are studied and the behavior predicted from theoretical analysis and simulations is verified. Then, load sharing is investigated. Also in this investigation, the experimental results agree with the simulated.
Avdelning/ar
Publiceringsår
2002
Språk
Engelska
Fulltext
Dokumenttyp
Doktorsavhandling
Förlag
IEA-LTH, Box 118, SE-221 00 LUND, SWEDEN,
Ämne
- Other Electrical Engineering, Electronic Engineering, Information Engineering
Nyckelord
- Energiforskning
- fault detection
- load sharing
- wind power
- DC distributed power system
- voltage control
- Energy research
- Elektronik och elektroteknik
- VSC
- Electronics and Electrical technology
Status
Published
Handledare
ISBN/ISSN/Övrigt
- ISBN: 91-88934-25-X
- ISRN: LUTEDX/(TEIE-1033)/1-200/(2002)
Försvarsdatum
20 december 2002
Försvarstid
10:15
Försvarsplats
Room M:B of the M-building of Lund Institute of Technology, Lund University
Opponent
- Dushan Boroyevich (Professor)