The Research On Control Strategy Of Flywheel Energy Storage System In Wind Farm

With the gradually new energy power generation technology’s development and maturity, at the present stage, wind power generation system occupies a considerable proportion in power system. Nevertheless, wind belongs to the typical intermittent energy, and its production has a certain degree of randomness. So the controllability of wind power generation system is generally weaker than the controllability of traditional power generation systems, which will seriously affect the power system’s safety operation. The large-scale application of wind power system is faced with severe challenge.The development of energy storage technology provides the possibility of solving these problems. If to add the energy storage equipment for wind power system, according to the needs of the reality, it is helpful to improve the stability and controllability of wind power generation system. To add energy storage equipment in the power system also becomes a basic requirement for future smart grid’s construction.With its many advantages, flywheel energy storage system(FESS) can play a vital role in enhancing the wind power generation system’s operation reliability and efficiency This paper takes the direct-drive permanent magnet synchronous wind power generator as the research object, and proposes a kind of FESS’s coordinate control strategy used in wind farm.Firstly, for the control for flywheel energy storage unit, this paper designs the charge-discharge control strategy, and based on speed-current double closed loop control, puts forward an improved neuron adaptive PID controller. It is used to control the flywheel motor’s operation to realize the charge and discharge process. Then according to the classical Lyapunov stability theory, a kind of method to prove the algorithm’s stability is put forward and digital simulations prove its feasibility and effectiveness.Secondly, contrary to general FESS’s research, except for every wind generator equipped with a flywheel energy storage unit, this paper also proposes to parallel a flywheel energy storage matrix system(FESMS) at the exit of wind farm. The FESMS consists of multiple flywheel energy storage units with same parameters configuration and parallel to each other. For FESMS, its grid topology is designed. And in accordance with the master-slave control mode, the charge and discharge control strategy between FESMS and wind farm and security control strategy are designed. The FESMS’s power allocations for charge-discharge and security control strategies are performed by the main controller, and the local controllers perform to control the operation of the flywheel energy storage unit according to master controller’ command. With the cooperation of the FESS, at the period of wind speed fluctuation, wind farm still transmits relatively smooth active power to the grid.Finally, through analyzing the problem of low voltage failure, the charging and discharging strategy for power grid failure status is designed. On the basis of without affecting the utilization rate of wind and avoiding the waste of energy, FESS can improve the direct-drive permanent magnet generator’s ability of low voltage ride through.The research of this paper provides reference for the development of flywheel energy storage technology and provide the direction and thinking for the application with wind farm and FESS.