Research On Maximum Wind Energy Capture Control Of DFIG Based On Speed Sensorless

Doubly-fed induction generator(DFIG) is currently the most mainstream motor in Chinese wind power. It not only has the excitation characteristics of the synchronous motor, but also has a speed characteristic of asynchronous motors, and by its control ways and advantages of flexible connection, which widely used in wind power generation system. In most applications, the system requirements are very strict for operation of the motor, so controller is essential for DFIG. Based on the observer of speed sensorless control, which can eliminates the speed measuring device, reduces the cost of system and the affection of external interference, and it has become a hot topic. In this paper, taking DFIG as the research object, designed several speed sensor terminal sliding mode control schemes as follow:The fuzzy terminal sliding mode control for DFIG maximal wind energy capture based on fuzzy adaptive observer is designed. And aiming at the mathematical model of DFIG in two-phase synchronous rotating coordinate system, a fuzzy adaptive observer is designed. The problem is solved, in which the effect of observation is influenced by the fixed gain used in proportion and integration adaptive law. The observer can observe rotor speed of the DFIG at real time, and then the speed measuring device can be saved. In order to improve the robustness and control precision of the system, the speed controller is designed according to the principle of maximum wind energy capture. A method of fuzzy terminal sliding mode is used to control the decoupled rotor model of DFIG, which can restrain the system chattering phenomenon effectively, realize tracking without steady-state error in a limited period and ensure the accuracy of the observation.The terminal sliding mode optimization control for maximal wind energy capture of DFIG with speed sensorless is designed. And considering the mathematical model of the rotor flux oriented under two-phase synchronous rotating coordinate system as two subsystems, the backstepping terminal sliding mode controllers are designed for them respectively to realize maximal wind energy capture. The observer of DFIG speed and flux is designed by nonsingular terminal sliding mode, moreover, and high-order terminal sliding mode surface is used to suppress chattering effectively. The simulation results show that the designed observer and controller can realize no static error tracking and have the characteristics of quick response, good robustness and high stability accuracy.The terminal sliding mode optimization control for maximal wind energy capture of DFIG with speed sensorless based on intelligent optimization algorithm is designed. For this system, the backstepping terminal sliding mode controller is designed to achieve maximum wind energy capture. Tracking-differentiator(TD) is used to arrange the reference input signal, which can solve the problem of large initial error. The extended state observer(ESO) is established to estimate flux linkage and motor speed in the meantime. The ripples of flux linkage and torque have been reduced, and the control with speed sensorless has been realized. In addition, the ESO is used to observe and compensate the disturbing terms such as coupling in current equations, which can make the design of backstepping terminal sliding mode controller simple. Because there are many parameters in the controller and observer, and they are very difficult to set, the firefly optimization algorithm(FA) is used to optimize these parameters.