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Interconnection of Direct-Drive Wind Turbines Using a SeriesConnected DC Grid
Abstract:
This project presents a “distributed high-voltage dc (HVDC) converter” for offshore
wind farms. The proposed converter topology allows series interconnection of wind turbines
with the need of neither ac transformer nor offshore platform at the sending end. Each wind
turbine is equipped with a 5-MW permanent-magnet synchronous generator and an ac–dc–dc
converter. The converter topology is a diode rectifier (ac–dc) cascaded with a single-switch stepdown converter (dc–dc). The dc–dc stage allows the current to flow at all times in the dc link
while simultaneously regulating generator torque. The inverter station, located onshore,is a
thyristor-based converter that performs dc link current regulation. It also regulates the HVDC
link voltage through management inverter controls.
Existing method:
In this existing method many stages of power conversion, both ac–ac conversion via
multiple stages of transformers and ac–dc and dc–ac stages via high-cost VSC stations. Such
approaches also require construction of one or more offshore platforms, further increasing the
cost. On the wind turbine point of view, potential efficiency improvement resides in eliminating
the transformer installed in each unit [6]. New transmission configurations are also required to
minimize conversion losses and installation cost by reducing the number of conversion stages
and by eliminating the need for offshore platforms.
Proposed method:
The proposed converter topology allows series interconnection of wind turbines with the
need of neither ac transformer nor offshore platform at the sending end. Each wind turbine is
equipped with a 5-MW permanent-magnet synchronous generator and an ac–dc–dc converter.
The converter topology is a diode rectifier (ac–dc) cascaded with a single-switch step-down
Further Details Contact: A Vinay 9030333433, 08772261612
Email: [email protected] | www.takeoffprojects.com
converter (dc–dc). The dc–dc stage allows the current to flow at all times in the dc link while
simultaneously regulating generator torque. The inverter station, located onshore, is a thyristorbased converter that performs dc link current regulation. It also regulates the HVDC link voltage
through management inverter controls.
Block diagram:
Block diagram for wind turbines with the transmission line and the inverter
station.
This project developed in Matlab/simlink soft ware and the results have been studied.
Advantages:
1) Cost is reduced by minimiging the number of conversion stages.
2) Very easy to implement.
3) conversion losses are reduced.
Applications:
1) Communication systems.
2) Agricultural purpose.
3) Power grids.
Further Details Contact: A Vinay 9030333433, 08772261612
Email: [email protected] | www.takeoffprojects.com