A Suitable Load Control Method for Constant Tip Speed Ratio Operation of Stand-Alone Wind Turbine-Generator Systems

Abstract

A suitable load control method for constant tip speed ratio operation of a stand-alone system using a vertical axis wind turbine with self-starting capability is discussed. The system with a straight-wing-type turbine is mainly operated at a constant tip speed ratio. Two types of load control methods are considered: Method-1, where the load torque is controlled in proportion to the square of the rotational speed, and Method-2, which adopts feedback control of the rotational speed in response to the measured wind speed. In this second report on a suitable load control method, the influence of the measurement error of the inflow wind speed is particularly focused on. The computational results obtained using the dynamic simulation model show that Method-1, which is not affected by the measurement error and has a fine smoothing effect of the output fluctuation, is the more suitable load control method.