Constant-power control method and device for full-load power generation working condition of wind turbine generator, and wind turbine generator

Abstract

The invention discloses a constant-power control method and device for the full-load power generation working condition of a wind turbine generator, and the wind turbine generator. The constant-power control method for the full-load power generation working condition of the wind turbine generator comprises the pitch variation operation step and the electromagnetic torque variation operation step. The pitch variation operation step includes that the electromagnetic torque difference of the generator is calculated according to the current rotating speed of the generator; the gain used by PI correction is determined according to a current blade pitch angle, and the PI correction is carried out on the electromagnetic torque difference of the generator to obtain a compensation value of the pitch angle; a given value of the pitch angle is added to the compensation value of the pitch angle, pitch variation operation is carried out on the basis of the pitch variation rate converted from a required value, obtained through addition, of the pitch angle. The electromagnetic torque variation operation step includes that electromagnetic torque variation operation is carried out on the basis of a required electromagnetic torque value which is obtained by dividing the rated power of the generator by the current rotating speed of the generator. According to the constant-power control method and device for the full-load power generation working condition of the wind turbine generator, under the full-load power generation working condition, the blade pitch angle is adjusted on the basis of pitch angle compensation, the rotating speed of the generator can be more stable, the electromagnetic torque variation operation is carried out on the basis of the pitch variation operation, power fluctuation of the generator is reduced, and constant-power control is achieved.

Description

technical field [0001] The invention relates to a constant power control method and device of a wind turbine based on pitch angle compensation under full engine conditions, and a wind turbine realized based on the device, belonging to the field of wind turbine generator speed and power control. Background technique [0002] At present, most of the wind turbines based on direct-drive permanent magnet technology or double-fed excitation technology adopt the control method of pitch and variable speed. Specifically, when the actual wind speed is below the rated wind speed, the rotational speed of the impeller is adjusted proportionally with the wind speed to maintain the optimal tip speed ratio, thereby obtaining more wind energy. Usually, the electromagnetic torque of the generator is controlled to control the speed of the generator to keep the blade pitch angle at the optimum pitch angle. The output demand value of the generator electromagnetic torque is proportional to the s...

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Problems solved by technology

Due to the small inertia of the converter, the electromagnetic torque of the generator responds quickly. Due to the large moment of inertia of the pitch actuator, the response of the impeller pitch is slow, so the torque difference of the generator (transmission shaft) rises quickly, and the acceleration of the impeller increase, that is to say, the generator speed is easy to rise

Then, if the generator speed is already in the critical overspeed state, the generator overspeed fault is prone to occur at this time, especially the floating wind turbine often has an overspeed fault

When the wind speed suddenly decreases, the impeller speed decreases, and the electromagnetic torque of the generator increases due to the constant power. Based on the above-mentioned principle that the inertia of the converter is small and the moment of inertia of the pitch actuator is large, the torque difference of the generator (transmission shaft) is Negative, the impeller produces negative acceleration, which causes the generator speed to drop, which can easily cause the wind turbine to suddenly jump from the full power state to the variable speed control stage, resulting in a large loss of generator power

[0004] In view of the fact that the generator speed and generator electromagnetic torque caused by constant power output under the above-mentioned full power condition are inversely proportional, and the change of generator electromagnetic torque has a negative damping effect on the generator speed, at present, when the PI correction control parameter is set , it is usually assumed that the electromagnetic torque of the generator is a constant value, and the change of the electromagnetic torque of the generator due to constant power is not considered, that is, the negative damping effect produced by the generator speed is ignored. However, it can be found from actual implementation that this approach will Make the wind turbine generator unstable and overspeed in the case of large turbulence or other extreme conditions

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