Sliding-mode observer based sensor-less control of a small wind energy conversion system

Small wind turbines are becoming an attractive solution for household applications. These micro generation units can be used as standalone applications or grid connected applications. However to get the full potential benefits of these wind turbines, systems should be low cost and reliable. Introducing the wind speed and rotor speed sensors at the generator shaft may reduce the reliability of small wind turbines. In this study, a grid connected sensor-less 5 kW small wind energy conversion system has been studied. The maximum power point tracking method of the wind turbine is totally independent from wind speed and rotor speed measurements. Optimum rotor speed and actual rotor speed are estimated using output current and voltage of the generator. To estimate the optimum rotor speed of the wind turbine, power signal feedback method has been used. Moreover, a sliding-mode observer is designed to estimate the rotor speed. Performance of the sliding-mode observer system has been compared with the measured rotor speed based wind energy conversion system. The simulation results show the effectiveness of the proposed sensor-less control system for the system under consideration.