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An impulsive noise filter applied in wireless control of wind turbines

de Almeida, L.A.L., Filho, A.J. Sguarezi, Capovilla, C.E., Casella, I.R.S., Costa, F.F.
Renewable energy 2016 v.86 pp. 347-353
generators (equipment), process control, renewable energy sources, wind turbines
This paper proposes a novel non-linear filter applied to wireless-transmitted reference signals in a deadbeat control strategy of a doubly-fed induction wind turbines. These signals are likely to be corrupted by spikes intrinsically imposed by the wireless channel. This impulsive noise is traditionally mitigated using classical error-correction schemes, and the proposed filter is an alternative that is simpler and has lower computational cost. The proposed technique, hereby designated as Functionally-Weighted Moving Average (FWMA) filter, is based on a non-conventional weighting of the signal samples, which is carried out by a rectangular function. The filter realization is as straight as any linear technique. The generator control scheme, which includes the filter, is embedded in a microprocessor locally placed at the generator site, where it acts on the reference signals at the receiving end of the channel. The performance of both the filter and the control system are verified by simulations that include the wind turbine dynamics and the communication channel. The proposed technique is compared with a morphological filter, previously suggested for the same purpose. The results endorse the FWMA filter efficacy to clean out impulsive interferences with minor delays.