| In the development of new energy technology,electric energy storage technology plays a crucial role,and has been a research hotspot for scholars at home and abroad.Among all kinds of energy storage technologies,flywheel energy storage has the advantages of high conversion efficiency,fast charging speed,long service life and friendly environment.At present,flywheel energy storage has been widely used in many fields,such as uninterruptible power supply,urban rail transit,new energy vehicles,aviation,power system,pulse power generation and so on.Flywheel energy storage system is mainly composed of flywheel motor and drive system.Homopolar induction motor(HIM)has low no-load loss and simple structure,which is suitable for the integrated design of flywheel and high-speed rotation.In this paper,the HIM is used as the flywheel energy storage motor,and the charging and discharging control strategy of flywheel energy storage are studied.Firstly,the basic structure and working principle of HIM are introduced.The stator and rotor structure of HIM are special.There are three-dimensional magnetic circuit and unipolar air-gap flux density.In order to facilitate the analysis,the lumped parameter model of HIM is established by referring to the theory of synchronous motor,and the analytical method is used to solve the model.On this basis,the Ansoft/Maxwell three-dimensional finite element model of the motor is built,and the parameters of air-gap flux density,inductance and backEMF are obtained by simulation.Then,the charging and discharging control strategy of flywheel energy storage HIM are studied.The rotor of HIM adopts solid steel structure,and high frequency current ripple will cause large rotor loss.Based on the analysis of the causes of current ripple,a PWM/PAM hybrid charging control strategy is adopted to reduce current ripple.In order to keep the output voltage stable,a discharge control strategy using the inductance of the motor to store energy and boost voltage is adopted.The motor parameters are calculated by Ansoft/Maxwell three-dimensional finite element simulation,and the results are imported into Matlab/Simulink.The precise mathematic model of the HIM is established by means of parameter query,and the charging and discharging of flywheel energy storage are simulated.Finally,the flywheel energy storage drive system is designed,and the hardware design and software design are introduced.The debugging of the driving system and the charging and discharging experiments of flywheel energy storage are completed.The experimental results are consistent with the simulation results,which verifies the feasibility of the control strategy. |
PDF Full Text Request