Research On Rotor Design And Charge And Discharge Control Of High Power Flywheel Energy Storage System

China's power industry is developing rapidly,and thermal power units have moved toward large capacity and high parameters,and coal-fired power generation is still the main power supply for a long time to come.With the large-scale development of renewable energy,the country's adjustment of energy structure,and the implementation of policy documents,the thermal power industry faces severe challenges in the field of frequent,deep peaking and frequency modulation.As a physical energy storage technology,flywheel energy storage has the advantages of high energy storage density,large instantaneous power,short response time and long service life.Applying the flywheel energy storage technology to the frequency modulation operation,the unit can respond to the AGC command quickly and accurately under the condition of slow response speed and low climbing rate.The large-scale flywheel energy storage array can assist the thermal power unit to "cut the peak and fill the valley",and relieve the current rapid peaking and deep peaking pressure of the thermal power unit.This avoids a series of problems caused by peak shaving to a certain extent,improving the overall efficiency of the unit and the service life of the unit.This paper first introduces the working principle and key technology of flywheel energy storage.For the flywheel energy storage system applied in the field of peak regulation and frequency modulation of thermal power unit,the metal flywheel rotor is designed,and the finite element model of the flywheel rotor is established.The ANSYS finite element software is used to analyze the dynamic characteristics of the flywheel rotor,calculate the natural frequency,mode and vibration mode of the system,and determine the appropriate working speed for the charge and discharge control.Secondly,this paper studies the charging and discharging of energy storage system,introduces the working process of flywheel energy storage system and the control strategy of permanent magnet synchronous motor,and establishes the mathematical model of charging,discharging and grid-connection between permanent magnet synchronous bidirectional motor and full-power converter.The simulation of the charging and discharging is carried out.At the same time,in order to improve the control performance,the control strategy is optimized.The simulation results show that the control method designed in this paper can effectively complete the charging and discharging requirements of the flywheel energy storage system.