Research And Design Of Control System Of 2MW Variable Speed Constant Frequency Wind Turbine

Environment and energy are urgent problems to be solved in the survival and development of humans.The use of renewable,green energy has great significance for the mitigation of the problems in recent years,in which the wind power has drawn great attention for its outstanding advantages,and has become a technology in new energy area as tremendous scholars'research hotspot.This paper introduces the research status of wind power technology at home and abroad, analyses two kinds of the most widely applied wind power generators. Advantages of wind power generator with variable speed and constant frequency, such as high utilization ratio of wind power and stable power output,are described.This paper introduces the structure of the megawatt wind power generator with variable speed and constant frequency, describes the functions of the constituent parts.This paper also studies the principle of doubly-fed induction generator in detail,including the control of stator voltage, rotating speed and power of the motors and so on.This paper analyses the maximum wind energy capture principle when the wind speed is below the rated value.This paper adopts a method which has combined the wind speed detection and Hill-Climbing Control Algorithm to realize the maximum power point tracking. The adopted method is proved to be effective and precise.This paper researches the Hill-Climbing Control Algorithm applied to yaw control system, analyses the control parameters of the algorithm.The software design of the maximum wind energy and yaw control are completed.The control system of a 2WM wind power generator with variable speed and constant frequency is analysed and designed in this paper. The control system has a master-slave structure in which the main controller of generator is the core.The connections between main controller and slave controller, as well as the connection between slave controllers,are all realized via CAN bus,it ensures the real-time and stability of the transmission of control signal,status value and detection value.The designed main controller of the generators based on FPGA embedded system has integrated the 32-bit processor, the CAN bus controller and a Gigabit Ethernet MAC controller. The testing units are also designed to complete the measurement of the temperature, wind speed and wind direction.The excitation controller has adopted two DSP processor to control the line side PWM converter and the rotor side PWM controller respectively. The IGBT driver IC produced by Concept Company is used in the design, which has functions such as hardware short circuit protection and over current protection. Based on the advantages of the IGBT driver IC, the IGBT alarm circuit is designed in which the software protection is added to improve the safety of the power module. Various values, including the voltage, current and rotating speed of the motor, is detected by the detective units of the excitation controller and uploaded to the main controller of the generators. To effectively control the rotating speed, the active power and the reactive power of DFIG, The grid-voltage oriented vector control is applied to line side PWM converter and rotor side PWM controller on the basis of the stability of the DC bus voltage. The vector control method and the flow chart of the DSP controllers are analysed, and the corresponding software design is also completed.This paper designs a system of active yaw control. Yaw motor is controled by H bridge, so the optimal yaw of wind trubine is detemined.