Power performance enhancement of vortex-induced vibration wind turbines using a semi-active control approach


Bladeless wind turbines based on vortex-induced vibration usually consist of a cylindrical body mounted on a flexible support. An inherent feature of this kind of turbines is that the power generation is considerable only in a narrow wind speed band, when the frequency of shedding vortices is close to the structural natural frequency. The present study proposes a novel semi-active approach for tuning the turbine response to widen the effective power generation region. Based on numerical modeling of aeroelasticity interaction phenomenon, a parametric analysis is done and the effective parameters on the turbine performance are highlighted. The proposed tuning technique then works to maintain the effective parameters at the optimum value from the power generation point of view. To realize this, a supporting mechanism is suggested that can change the elastic member length and consequently structural natural frequency. However, to avoid phenomenon attenuation due to power extraction process, a second level of tuning the structure damping ratio is added. Results of numeric simulations showed that, compared to previous work, the proposed approach has considerably broadened the effective wind speed range. The conversion efficiency is greater than or equal 15% over a wind speed range of 3.3–6 m/s.

Publication Title

Energy Sources, Part A: Recovery, Utilization and Environmental Effects