| The flywheel battery is a modern energy storage device that integrates machinery,electricity and magnetism with the advantages of high efficiency,high energy density and long life cycle and a series of superior performances.It also has a wide range of application prospects in electric vehicles,power systems,new energy generation and aerospace.In view of the disadvantages of complex structure,high loss and low speed for the traditional flywheel battery,a novel flywheel battery based on HEBSRM was presented supported by the National Natural Science Foundation of China(51307077,51377074 and 51707082).The HEBSRM is used to realize four-degree-of-freedom radial suspension force.The AUPMB unloads the flywheel’s weight and the AHMB assists in overcoming the axial dynamic load,so as to achieve the five-degree-of-freedom suspension force.The new flywheel battery not only greatly reduces the copper loss,but also improves the critical speed,integration and reliability.Thus,it is conducive to the further development and promotion for the flywheel battery and significant research significance and application value.The main results are as follows:(1)A novel HEBSRM was proposed aiming at the disadvantages of nonlinearity and strong coupling for the traditional BSRM.The use of permanent magnet reduces the turns of the winding and improves the efficiency.The implementation of the four-degree-of-freedom suspension force shortens the axial length of the flywheel battery and makes it more compact and stable.The structure and working principle of the HEBSRM were introduced in detail.The mathematical model of the suspension force was deduced and the calculation method of the basic dimension was given.The single variable method was used to analyze the influence on the average torque,the torque ripple,the average suspension force and the suspension force ripple among the rotor yoke,the rotor pole arc,the torque pole arc,the suspension pole arc and the thickness of the permanent magnet,so as to determine the optimal parameters.Ansoft Maxwell 3D was used to analyze the characteristics of magnetic density,torque,suspension force and coupling based on the optimal parameters.The rationality of the structure was verified.(2)In view of the uncontrollability when the permanent magnet is excited separately or the high loss when the coil is excited separately,the AHMB mixed with the excitation of the permanent magnet and the coil was selected.Then it described in detail the structure and working principle of the AHMB.The mathematical model of the axial suspension force was validated by finite element analysis.(3)The gravity of the flywheel rotor is a constant static load.The use of the unloading bearing greatly reduces the power consumption of the AHMB and improves the operation efficiency.The way of magnetization of the permanent magnet was analyzed and axially magnetized AUPMB was selected.The mathematical model of the unloading force was deduced and the maximum unloading force was obtained by finite element analysis which verified the rationality of the mathematical model and the structure.(4)For the needs of high-speed operation,a digital control system based on TMS320F28335 and EPM570 was built.It mainly includes controller,the power converter of winding of suspension system,the power converter of winding of torque system,drive circuit,detection circuit of rotor displacement and position and detection circuit of current.As a conclusion,it summarized the work carried out in this paper and put forward the content need to be studied in the next step. |
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