| The proposal of the dual-carbon goal has brought opportunities for the development of wind power and solar power generation.However,there are many problems in new energy power generation.The most important problem to be solved is intermittent and unstable.This problem has always restricted the development of wind power and solar power generation.By introducing energy storage technology,large-scale new energy power plants can be connected to the grid,which plays an important role in improving the efficiency and security of the power system.Flywheel energy storage has many advantages,such as high energy conversion efficiency,fast response,high energy storage density,long service life,environmental protection,low charge and discharge cycle cost,and is widely used in power grid peak shaving and frequency modulation.The temperature of the flywheel energy storage system has a great impact on its performance.Therefore,it is important to study and analyze the temperature of the flywheel energy storage system.The main heat-generating components of flywheel energy storage system are motor,bearing and rotor.In this paper,the thermal management of a flywheel energy storage system with power of 200kW and 400kW is studied and analyzed when it operates under rated conditions.Through analysis,it is known that the bearing loss is mainly friction loss,and its main influencing factors are load and speed,etc.The rotor loss is mainly friction loss with thin air,and its influencing factors are rotor structure,rotational speed,vacuum degree and clearance,etc.The motor loss is mainly winding loss,iron core loss and eddy current loss,and its influencing factors are current,frequency,material properties and magnetic induction strength etc.The flywheel energy storage system studied in this paper adopts asynchronous motor,the flywheel rotor is restrained by permanent magnetic bearings in the axial direction,and mechanical bearings in the radial direction.After calculation and simulation analysis,the bearing loss power is 1085.37W,the wind friction loss power is 71.34W,the stator loss power of 200kW flywheel energy storage system motor is 23555.98W,the rotor eddy current loss is2.67×10-5 W/m3,the stator loss power of 400kW flywheel energy storage system motor is 93433.34W,the eddy current loss is 9.55×105 W/m3.This paper designs a cooling scheme for the 200kW and 400kW flywheel energy storage system,determines the cooling pipe arrangement,pipe diameter,coolant type and flow rate,and simulates the flywheel energy storage system using ANSYS Fluent software,and obtains the temperature distribution of each component of the flywheel energy storage system.The results show that the temperature of each component is within the allowable temperature,and the cooling system can meet the heat dissipation requirements of the system.In this paper,the temperature distribution of flywheel energy storage system with different flow channel arrangement,different coolant and different cooling pipe diameters is calculated.Through comparative analysis,it is concluded that the system temperature is lower when the flow channel is arranged spirally than when the flow channel is arranged in-line.When the cooling medium is SSR,the system temperature is lower than when the cooling medium is water.When the pipe diameter is 10mm,the system temperature is lower than when the pipe diameter is 20mm.Aiming at the problems existing in the in-line arrangement,this paper improves the cooling scheme by changing the coolant flow path.The results show that the temperature of the optimized cooling scheme is lower than that before optimization.The 400kW flywheel energy storage system generates more heat,and the previous cooling scheme cannot meet the heat dissipation of the system.Therefore,increase the coolant flow rate to strengthen the heat transfer,and the simulation results show that increasing the flow rate can meet the heat dissipation of the high-power system. |
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