Experimental investigation of an enhancement system to improve wind turbines power generation

Wind speeds, high or low, have a detrimental effect on the rated turbine’s rotational speed in wind energy systems. This study proposes an electromagnetic torque modulation enhancement system that consists of a brushless motor mounted on the turbine’s shaft to enhance the rotational speed by generating a magnetic field. This enhancement raises and lowers the rotational speed of the wind turbine blades as needed. For testing, a horizontal wind turbine consisting of a micro-generator connected to 820 mm rotor diameter was used, with a rated power of 8 W, and it was installed at 700 mm above ground. The enhancement system was evaluated under four different scenarios. Results showed that when the enhancement system decreased the rotational speed, it was able to recover a large portion of the energy that would have been curtailed in the case of cut-out speed and lost only 5.7% of the energy compared to 100% if the wind turbine was shut down due to overspeed. However, when the enhancement system increased the rotational speed or maintained it at a range of 500-750 RPM, it improved by 1%.