Study Of Speed-sensorless Control For Doubly-fed Wind Turbine

In the research of wind power generation technology, variable speed constant frequency doubly-fed wind power generation(DFIG) technology is the current mainstream. In the traditional doubly-fed wind power system, speed sensor brings not only the additional cost of installation and maintenance, but also the unreliability of the system. Therefore, the research on speed sensor-less control algorithm is a hot research field in recent years and is of great significance.At first, this paper analyzes the present situation of wind power generation technology in China and abroad, chooses the variable speed constant frequency doubly-fed wind power generator as the research object, and investigates the speed sensor-less vector control theory. A design of inner electric current ring based on the inverse system is presented to overcome the deficiency of dynamic robusthess with the change of system parameters under the traditional stator voltage oriented sector control system.Then several methods of speed identification in speed sensor-less technology, focusing on the specific analysis of advantages and disadvantages of the algorithm of model reference adaptive system (MRAS) for speed estimation based on rotor flux, is studied. A novel scheme of speed sensor-less vector control system for DFIG based on MRAS is presented binding MRAS and the stator voltage oriented vector control.Furthermore, the simulation model of speed sensor-less vector control system for DFIG based on MRAS is built with simulation software Matlb/Simulink. The wind turbine module, the doubly-fed wind generator module, the grid-side Pulse Width Modulation. (PWM) converter module, the rotor-side PWM converter module, the Space Vector Pulse Width Modulation (SVPWM) module and the speed module is designed and combined. The correctness and feasibility of this scheme have been verified through the analysis of simulation results.Finally, taking the TI Company’s latest TMS320F28335DSP chip as the core of the control system and combining the stator voltage vector control theory, the DFIG control system is controlled by SVPWM signal. The hardware and software of the control system is built through the MRAS and the stator voltage and current and rotor current which is easily detected. The validity and efficiency of the system is verified through the results of experiments.