Department of Electrical, Electronic and Computer Engineering, University of Pretoria, South Africa
Musasa, K., Department of Electrical, Electronic and Computer Engineering, University of Pretoria, South Africa; Gitau, M.N., Department of Electrical, Electronic and Computer Engineering, University of Pretoria, South Africa; Bansal, R.C., Department of Electrical, Electronic and Computer Engineering, University of Pretoria, South Africa
The use of a DC system in wind parks is becoming a more promising technology. Low weight and compact components in the offshore wind park are crucial to use due to strong wind perturbations out in the sea. A wind park with a DC collector is more compact than one using an AC collector. A DC collector employs power converters instead of a 50- or 60-Hz power transformer. For similar voltage/current ratings, the power converter is compact and of small weight compared to the power transformer. The full-bridge voltage source converter is commonly used as topology of the power converter resulting high power losses. This article proposes the use of cascade connection of a non-controlled full-bridge diode rectifier and a controlled DC-DC boost converter. The proposed topology differs from the conventional full-bridge voltage source converter by having a reduced number of operating switches. The power loss is reduced, thus improving the efficiency of the wind park. A DC collection grid consisting of series-parallel connections of wind energy conversion units (WECUs) is investigated. The impact caused to the wind park for a fault or a collapse of a given number of WECU is analyzed and mitigated. It is demonstrated that the use of large numbers of wind energy conversion units in a wind park improves the fault ride-through capabiliy. © 2015 Taylor & Francis Group, LLC.
DC transformers; Electric connectors; Electric load dispatching; Electric rectifiers; Energy conversion; Power converters; Power transformers; Pulse width modulation; Rectifying circuits; Topology; Voltage control; Wind power; DC collector; DC-DC boost converters; Off-shore wind parks; Pulse width modulation controllers; Signal modeling; DC-DC converters