Modelling and Control of Brushless Doubly Fed Machine (BDFM)
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Date
2018-06-18
Journal Title
Journal ISSN
Volume Title
Publisher
University 20 August 1955 – Skikda
Abstract
The Brushless Doubly Fed Machine (BDFM) continues to attract increasing interest
for applications in wind power generation systems and variable speed motor drives
where, robustness and low servicing costs are much desirable. As has been mentioned by various studies, the main disadvantage of this machine is its control which
is relatively complex with respect to the Doubly Fed Induction Machine (DFIM).
This difficulty is mainly due to the lack of a mathematical model connecting the
inputs of the machine (control winding) to its outputs (power winding). To solve
this problem, a new model that describes the input-output relationships of the machine is proposed. This dissertation adopts a transfer function approach to derive
a mathematical model of the BDFM as a Multiple-Input Multiple-Output (MIMO)
dynamic system. The proposed model is used to carry out a stability analysis of
a benchmark machine under unbalanced grid voltage conditions and parameters
variation. The stability study is done in an extremely wide speed range, and valid
for both motor and generator operation modes. In addition to the stability investigation, the mathematical model is used to synthesise appropriate controllers for
the BDFM as generator connected to the grid. The validity of the proposed model
has been verified by experimentation, and the effectiveness of the control scheme
has been validated by simulations