Direct Power Control Of Grid-connected Doubly-fed Wind Induction Generator

This paper describes the status and trends of the development of wind power industry at home and abroad, doubly-fed induction wind turbine control technology is currently the most widely used in wind power industry, the research status of the technology are discussed in detail. Selected on the basis of a doubly-fed induction generator control, power grid control as the main research content.First introduced the principle of doubly-fed induction generator variable speed constant frequency generation, and doubly-fed induction generator mathematical model and its coordinate transformation relationship are built in the stationary coordinate system, the coordinate system and the synchronous rotating coordinate system. It provides the theoretical foundation for this research.Followed by the introduction of a doubly-fed induction generator no-load and load net and island grid three common grid, determine the no-load and network for the research focus of this article, the design of the rotor side of the stator flux orientation current transformer no-load and network control algorithm, and introduced the principle of SVPWM and specific method, simulation studies using Matlab/Simulink to build simulation models. Studies have shown that the doubly-fed induction generator stator voltage can be completed in four cycles, the grid voltage tracking, the entire dynamic response of the process there is no overshoot, and the net impact of current small doubly-fed induction generator sets smooth grid.Again derived in accordance with the mathematical model of the doubly-fed induction generator vector control and direct power grid control strategy, both active and reactive power decoupling control, the vector control system is complex, vulnerable to the impact of motor parameters will result in instability of the control system, and direct power control dynamic response fast, is not sensitive to the motor parameters, but difficult to resolve quickly and overshoot contradiction. In this paper, the direct power control based on the introduction of TD tracking differentiator, instead of the traditional PI,a non-linear combination of the direct power and direct power-based nonlinear PID control algorithm software simulation comparative study. Simulation results show that based on the power of the nonlinear PID control for a wide range of parameters, has a good robustness can be achieved quickly without overshoot control, and the mutual influence of the dynamic process of active and reactive power can be reduced.Doubly-fed motor rotation is driven fan motor simulation to build experimental platform. Doubly fed induction generator control hardware system and software process design and structure are introduced, and gives the experimental results based on doubly-fed induction generator in MS320F2812grid and power conditioning.