Method and device for controlling optimal tip speed ratio under variable air density

Abstract

The invention provides an optimum tip speed ratio control method and device under variable air densities. The method comprises the steps of obtaining the actual air density of the position where a wind generating set is located, calculating the target rotating speed of the wind generating set under the actual air density at a transition area between an area II and an area III, obtaining the rotating speed and torque control reference value corresponding to the optimum tip speed ratio of the wind generating set under the actual air density, and using the target rotating speed, the rotating speed and torque control reference value and the measured rotating speed of wind wheels of the wind generating set as input to carry out optimum tip speed ratio rotating speed and torque control over the wind generating set so as to adjust the rotating speed of the wind wheels of the wind generating set, enable the optimum tip speed ratio sections of the wind generating set under the actual air density and under standard air density to be identical, and further avoid the problems that the optimum tip speed ratio control area is reduced due to changes of air density, the wind-power utilization coefficient is lowered, and the output power of the wind generating set is lowered.

Description

technical field [0001] The invention relates to the technical field of control of wind power generating sets, and more specifically relates to a control method and device for optimal blade tip speed ratio under variable air density. Background technique [0002] Existing commercial variable speed variable pitch wind turbines usually adopt figure 1 The speed and torque control principle shown in the figure controls the torque of the wind turbine, which divides the working area of ​​the wind turbine into four control areas, among which, area Ⅰ is the constant speed control, and area Ⅱ is the maximum wind energy capture control , area Ⅲ is constant speed control, area Ⅳ is constant power control. In the existing torque control, the focus is on zone II control, that is, in the design speed range of the wind turbine ω 1 ~ ω 3 within, to maintain the operating state of the wind turbine as figure 2 The maximum wind energy utilization coefficient point C shown p (λ opt ,β 0 ...

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Problems solved by technology

combine figure 2 The analysis shows that when the peak speed ratio decreases rapidly, the corresponding wind energy utilization coefficient also decreases rapidly, so that the wind energy absorption in area III decreases, and the output power of wind turbines decreases significantly, as shown in image 3 shown in the shaded part

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