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A master's thesis from Aalborg University
Book cover


Impact of Turbine Converter Control on Wind Farm with DC Collection Grid

Term

4. term

Publication year

2018

Submitted on

Pages

94

Abstract

This thesis presents a control strategy for a DC/DC resonant converter for offshore WT application. The main objective is to obtain fast and accurate power tracking. The control architecture is based on a feedforward developed by linearization of the power to frequency equations. The method used contains an algorithm that obtains the right switching frequency from a look-up table in order to follow the reference power. Results obtained by simulation on a lossless 10MW converter show a good performance on the whole operating range during power and output voltage steps. Moreover, the controller is able to reject output voltage harmonics and has a proper set-point tracking bandwidth. The validation of the control structure is performed on a 10kW and 5kV output voltage laboratory setup. Experimental results reflect a favorable matching but arise further issues such as: proper MV measurement, non-idealities and output choke impact. Furthermore, the need of a low gain compensator in parallel is necessary to avoid steady-state error when the resolution of the feedforward is reduced.