Research On Application Of 10kWh Flywheel Energy Storage Converter In Wind Farm

Wind power generation is characterized by intermittent,random and fluctuate,the large-scale wind power integration threats the dispatching and stability of power grid seriously.In order to improve the output power quality of wind farm,restrain the power fluctuation,and reduce the acceptance restrictions on wind power of power grid,the energy storage device can be used to suppress the output power fluctuation of wind farm.Making full use of advantages of flywheel energy storage,which features fast response,long service life,simple maintenance,high conversion efficiency,no pollution to the environment,etc.In this thesis,the control strategy of wind farm output power smoothing control strategy based on flywheel energy storage device is studied,and the control strategy of converter in the 10 k Wh flywheel energy storage device is reserched.The main work are as follows:(1)Research on technical characteristics,working principle and device structure of flywheel energy storage is studied in this thesis.Then the permanent magnet synchronous motor is selected as flywheel motor of flywheel energy storage device,and the vector control technology is adopted to control the flywheel motor of flywheel energy storage device,meanwhile,the mathematical model of flywheel energy storage devices is constructed.(2)Aiming at the problem that the outside disturbance is too large in the flywheel energy storage control and the change in the internal parameters of the motor,based on the sliding mode control,a flywheel motor current regulator is designed to replace the PID controller which in the motor side converter control system of flywheel energy storage device.The reference power of flywheel energy storage and the actual speed of flywheel motor are considered as the input of the controller,and the integral item and time variable item is introduced into the conventional sliding surface,according to the exponential reaching law the control law was designed,so that the control system has better robustness,better anti disturbance ability and dynamic response performance.(3)In order to overcome the main disadvantages of small capacity and low power,the battery is put in energy storage system,to cooperate stored energy with flywheel energy storage device.A wind power smoothing control strategy based on flywheel-battery unite energy storage is proposed subsequently.Using the lowpass filtering method to determine the power distribution of the flywheel and the battery,and a designed fuzzy controller used to correct the reference power of battery and flywheel in real time,so as to make more fully use of flywheel energy storage system,which features fast corresponding speed and long service life.The simulation model is built in simulation environment of the Matlab/Simulink,the simulation results show that the flywheel motor current regulator designed based on the sliding mode control,has better dynamic response ability and immunity,and can reduce the speed fluctuation of the flywheel motor,meanwhile,better stabilize the wind power fluctuation,prove the effectiveness of the design method.The wind farm output power smoothing control strategy based on flywheel-battery unite energy storage can not only stabilize the power fluctuation with high frequency,small amplitude,but also stabilize the power fluctuation with low frequency and large amplitude,which makes the smoothing effect of wind farm output power increase dramatically.Finally,the correctness of the control strategy proposed in this thesis is proved.