Research On Active Power Fluctuation Suppression Of Grid-connected Wind Power System Based On Flywheel Energy Storage

Wind power grid-connected is the most important approach to utilize wind energy. However, the power wind turbine output to the grid tends to have greater fluctuation because of wind’s volatility and intermittent characteristics. Large power fluctuation will bring many adverse effects on the frequency and voltage of power grid, then affecting the stability and security of the power system. Therefore, it is necessary to take some measures to suppress output power fluctuation in the operation of wind turbine.This thesis presents a method using flywheel energy storage device to suppress the fluctuation of the wind turbine’s output power, it first introduces the characteristics of flywheel energy storage technology, working principle and main composition structure, as well as 10 kWh flywheel drive motor mathematical model and the vector control method of id = 0.Then this thesis gives an analysis about the allocation method of flywheel energy storage device in wind power. In order to study the inhibitory effect of flywheel energy storage device on the output power fluctuation of wind turbine generator, the wind turbine model and 1.5MW double fed wind power generator model, as well as grid model are established to constitute a whole system with 10 kwh flywheel device model, then the control strategy of grid side converter and flywheel rotor side converter are studied. Finally the simulate results show the doubly fed wind generator output power fluctuation can be well controlled by flywheel energy storage system compared with the simulate results without flywheel energy device.In view of the disadvantage of rotating speed exceeds the limit existing in the traditional control strategy, a special optimum control method based on fuzzy reasoning is proposed in the thesis, then the rotational speed and compensation power of flywheel device are used as input control signal of the fuzzy reasoning, make the flywheel speed and compensation power more closely, this method enhances the dynamic response ability of flywheel device, reduces the overcharge, discharge rate of flywheel motor as well as probability of rotating speed exceeds the limit.