The Active Power Predictive Control Research Of Direct-drive Permanent Magnet Synchronous For Wind Turbines

Wind power as a kind of clean and pollution-free renewable energy, has the development and utilization of natural value. In recent years, the use of wind power has gradually penetrated into the grid, but the intermittent, volatility, and the load characteristics of wind power will impact on the power grid safe and economic operation of power balance and frequency stability, and the effect will be more remarkable with the increase of wind power in power grid permeability. With the increase of wind power capacity and improvement of grid specifications, seeking a kind of wind turbines active power control strategy to ensure efficiently and smoothly running, is the emphasis and difficulty in wind power research scholars.This paper selects permanent magnet direct drive wind turbines as the research object, introduces the advanced control theory of model predictive control technique, and puts forward two kinds of wind turbines active power model predictive control method, in order to smooth the generator active power.Firstly, this paper introduces the parts of the wind turbines, analyzes the principle and operation characteristics of the parts, gives a mathematical model of each part, and sets up a simulation model for the wind power system in the Matlab/Simulink simulation platform. Considering the randomicity of wind energy and strongly nonlinear of direct-drive permanent magnet wind power system, this paper makes the model units piecewise local linearization, puts forward the range of wind speed of multi-model predictive control strategy to achieve the best power tracking at low wind speed, the smooth transition of the output power near the rated wind speed, achieve the smooth control of the output power at high wind speed period.Secondly, in the process of multi-model predictive controller designing, unreasonable local linearization, or frequent switching between piecewise model near every block is likely to lead to poor control precision. Aiming at this problem, this paper proposes a kind of permanent magnet direct drive wind turbines based on Hammerstein model predictive control strategy, and through the study of the model identification of a large number of experimental data obtained Hammerstein model of permanent magnet direct drive wind turbines, effectively improves the permanent magnet direct drive wind turbines active power predictive control precision.Finally, this paper carries out the simulation study against the 2MW permanent magnet direct drive wind turbines power predictive controller. The results show that compared with traditional PI control strategy, the proposed model predictive control strategy can greatly reduce the power fluctuation, and effectively smoothly control the output of the generator speed and active power.