Research On Control Strategy Of Flywheel Energy Storage High Speed Permanent Magnet Synchronous Motor

Energy storage technology can dramatically increase the amount of wind,solar,and other renewable energy that is absorbed into the grid while simultaneously resolving the unpredictability and volatility issues brought on by the extensive grid connection of new energy systems;Energy storage technology can also help China’s power system’s supply and demand imbalance and increase the system’s flexibility.In the areas of rail transit braking energy recovery,new energy grid connection,and uninterruptible power supply,there are numerous application scenarios for flywheel energy storage technology,a type of energy storage device with high energy conversion efficiency,high service life,and is environmentally friendly and pollution-free.The main element of a flywheel energy storage system is a high-speed permanent magnet synchronous motor,which impacts the system’s performance,safety,and dependability.This paper focuses on the flywheel energy storage high-speed permanent magnet synchronous motor drive system,and puts forward the corresponding control strategy for the charging and discharging mode of the FESS.The main research contents are as follows:(1)First,the flywheel energy storage system’s structure and function are described.The system’s integrated motor is chosen to be a high-speed permanent magnet synchronous motor,and the flywheel system’s power electronic component is chosen to be a three-phase bridge complete control circuit.and develop the flywheel system mathematical model.(2)The flywheel energy storage system’s charging control is investigated.A composite control method that combines constant maximum torque in the low speed range and constant power in the high speed range is used to realize the fast charging of the flywheel system.This method is based on the vector control strategy of permanent magnet synchronous motor.The finite element motor model is built in Maxwell software.The speed-current double closed-loop control circuit model is built in MATLAB/Simulink,and the feedforward decoupling module and anti-integral saturation design are added.Simplorer is used to build the main circuit model and run the joint simulation.The outcomes of the simulation demonstrate how successful the composite control method is.(3)This paper analyzes the limitation of the traditional FESS discharge control strategy,which only aims at the DC terminal voltage for voltage stabilization control.When the flywheel speed fluctuates in a large range,the motor terminal voltage also fluctuates,resulting in difficulties in power device selection and voltage stabilization control.Based on the constant flux control method,a dual-port stabilized flux control strategy is proposed to control not only the DC terminal voltage but also the generator terminal voltage.The simulation model is built and verified.The simulation results show that the proposed two-terminal stabilized voltage control strategy has good performance when the speed drops in a large range.(4)Because the flywheel system works in the vacuum chamber,it is not conducive to heat dissipation.The purpose of the high-speed motor test platform is to investigate the temperature rise properties of the high-speed motor.The resistance-capacitance load is used to assess the motor’s temperature rise in order to circumvent the issue that the armature reaction brought on by a weak magnetic field cannot be loaded.The experimental results show that the temperature rise of the oil-cooled high-speed motor meets the design requirements under the working conditions of long time,large current and high speed.