Research And Development Of Control System For Permanent Magnet Direct Drive Wind Turbine Based On Variable Speed Constant-frequency

Wind power system is a kind of new clean energy which is rapid developmentin the world. The control system is an important part of wind power generationsystem. Because the wind speed changes quickly, and the operation environment isbad, the control system requires high speed, high precision and high reliability.Because of the technical difficulties, the control system is not mature in china. Withthe rapid development of wind power industry, the control system has become thekey factor restricting the localization of wind turbine. In order to meet the needs ofdevelopment of wind power generation system, the control system of permanentmagnet direct drive wind turbine is research and development in this thesis.The control strategy of large-scale wind turbine are analyzed and studieddeeply based on the1.5MW permanent magnet direct drive wind turbine. Afterresearching the actual operation and working principle of the wind powercontrol system working condition, the control strategy for direct drive permanentmagnet wind turbine is proposed, that is variable-speed variable-pitch constantfrequency control. Then the functional requirements and technical indi-cators ofcontrol system is made clear, and the DCS solutions is formulated according to thespecific technical requirements of wind power system in the actual operation.The variable-speed constant frequency control strategy is proposed accordingto the characteristics of wind power system such as high wind speed change rate andpoor operating condition etc，joining actual operation features of the permanentmagnetism direct-drive wind turbine. Variable speed operation can maximizethe utilization rate of wind energy. When the control strategy is defined, the maincontrol system is designed and developed， including the development of thesoftware and hardware, the development of the auxiliary control devices as wellas the design of the safety protection of the generator wind turbine.The piecewise PID variable-pitch control strategy is proposed, joining the fieldoperating working conditions. It can improve the efficiency of power generation,and ensure the safe and stable operation of the turbine. Using the piecewise PIDcontrol algorithm, the generator wind turbine realizes constant speed and constantpower by adjusting the pitch angle at high wind speed region. According to thevariable-pitch control strategy, the variable-pitch system is designed and developed,including the selection and configuration of hardware and the programming ofsoftware.After the control system being design and development, the prototype enteredthe commissioning and trail operation stage. Through the grid debugging, the hardware and software of control system are improved and optimized, the controlsystem to achieve the safe and stable running, and the control parameters meet thedesign requirements.