Pages 103-
In small wind turbines, the load torque is often considered to be proportional to the square of the rotational speed. The load torque gain, as a proportional constant, includes the reference air density and other constant parameters. A constant gain assumes there is no variation in the air density. In a real situation, the air density is a function of time due to the variation of the atmospheric pressure, temperature, and humidity. Because of this air density variation, an operating condition based on a constant gain may not be maintained. We examine the effect of air density variation on the operating tip-speed ratio, which is a quantity characterizing the operating condition. The effects of air density variation on both the operating tip-speed ratio and power of a wind turbine are calculated using the modeled differential equation.
