A model predictive method for efficient power ramp rate control of wind turbines

A model predictive method is proposed to control the power ramp rate of a wind turbine system integrated with ultracapacitors as its high power, short-term, energy storage. In this method, it is assumed that the wind turbine output power can be predicted within a predefined horizon time interval. The proposed method involves two steps. First, the total stored energy required to maintain a preset power ramp rate during the prediction horizon time is calculated. Should the value of the calculated energy exceed the storage capacity, the power ramp rate is incremented gradually until the storage system can supply the required energy. Next, the prediction horizon is shifted forward by a desirable time interval and the previous step is repeated. It is shown that the expansion of the prediction time interval decreases the average power ramp, enhancing the efficiency of the proposed method.