Experimental Research On Small Wind Power Generator Grid-connection Control Based On Energy Storage

In China, clustered wind power generators are mainly connected to the grid in large scale and the wind farms are located in the western region of China that far from the eastern load center. Since the power cannot be consumed timely, the wind abandoned phenomenon is always happen. Also, when the clustered wind power cannot ride through the fault, they will trip off the grid in large scale adversely decreasing the power system stability. The small wind generators dispersedly connected to the grid in eastern load centers, are not only helpful to consume the power timely but also have less bad effect on power system stability due to their small capacity. In order to smooth the output power of the wind motor and improve the flexibility of the grid connected operation power, the energy storage system and the small wind power generator are combined to generate power. According to the distributed access method, the energy storage system takes the load side of the load side of the design into consideration and the energy storage device access location is designed in the DC side of the dual PWM converter. In order to reduce the capacity of small wind power converter and storage system and improve the economy, compared to the permanent magnet synchronous motor, this thesis chooses the doubly fed induction generator (Doubly Fed Induction Generator, DFIG) as the small wind turbine.First of all, the thesis designed a small wind power system based on energy storage. The selection and configuration of small wind power generator, PWM converters and the energy storage system is completed, and, at the same time, the microcomputer control system and control algorithm are suitably chosen. Secondly, this thesis designed the grid side PWM converter controlling experimental platform based on grid voltage oriented vector control, carried out the experimental work and verified the control strategy is effective that can maintain the DC voltage constant at the command value and guarantee the input characteristics with adjustable power factor; Thirdly, this thesis designed the rotor side PWM converter controlling experimental platform based on stator flux oriented vector control, carried out the experimental work for no-load grid connection by building up the doubly fed wind motor stator voltage; Fourthly, considering concrete case, this thesis carries out detailed analysis and summary on working mode of the small wind generators with applications of the battery energy storage device in sub-synchronous speed and super-synchronous speed. Finally, the theoretical analysis and summary of experimental research results of the full text has been done.