| Compared with traditional battery energy storage system,flywheel energy storage system has many advantages as a new type of energy storage,such as higher energy storage density,higher specific power and power density,lower risk of overcharge or over-discharge,wide range of operation temperature,very long life cycle and environmental friendliness and broad application prospects.As the energy storage flywheel prototype design for the research background,this research focused on energy storage flywheel rotor-active magnetic bearing system to provide a reference for the development of the prototype system,the main contents are as follows:Based on the design requirements of energy storage flywheel system,the support system layout plan was determined,the dynamic model of energy storage flywheel system rigid rotor system and the electromagnetic force model were established to analyze variation trend of the bearing characteristics of the AMB with the variation of control parameters.Considering the influence of controller,by the analysis the variation trend of the equivalent stiffness and equivalent damping with the variation of control parameters was gained.On this basis,the influence of the controller parameters on whirl frequency of the system was obtained;the qualitative research of the characteristics of electromagnetic bearings supporting was completed preliminarily to provide the basis for the energy storage flywheel system rotor dynamics analysis.The logical structure of dynamics model for the electromagnetic bearing-flexible rotor of the flywheel energy storage system has been analyzed to establish the model of the flexible rotor with the finite element method.The model has been used to calculate the natural frequency of the system free vibration,first six vibration mode maps,and to analyze the impact of gyroscopic effect,bearings damping,axial force and moment on its free vibration characteristics.The results were used to verify the correctness of the dynamics model.Because of the external excitations in the actual operation,including mass imbalance,basic incentives,as well as the system damping,the unbalance response to external incentives were expected based on the flexible rotor model.Simulation analysis show that the quality of response amplitude imbalance is larger at the lower bearing,of the response amplitude of the lower bearing is relatively small,to provide reference for rotor balancing.The dynamic characteristics of the rotor system to speed through the critical speed was studied,the simulation results show that the vibration can be suppressed by controlling the magnetic bearing stiffness and damping.The relationship between the first three order critical speed distribution and the electromagnetic bearing characteristics was analyzed to obtain the critical speed range.Based on the analysis,the PID control strategy with variable parameter based on speed was proposed,and the rules of the changed parameters was given.According to the constraint optimization problems of the structure for the bearing-rotor system,the dynamic sensitivity to the second order critical speed of the structural parameters-of rotor system was calculated to select the design variables,including the lengths of the bearing unit,height and diameter of the flywheel.The second order critical speed was set as the optimization goal with the constraints of the energy storage for the system.The hybrid algorithm of genetic algorithm and simulated annealing method was used to finish the structure optimization.The optimized structure parameters can effectively avoid the critical speed and the optimized structure parameters can provide a design reference for flywheel energy storage system.The virtual prototype model of rotor system was built with UG,ANSYS,ADAMS and MATLAB software.Combined with the design of the PID controller,the co-simulation of flywheel rotor system was gained to verify the feasibility of the variable parameter controller and provide a good platform for the virtual experiments. |
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