Zhang Long, Shao Hang, Zhang Jiaxiang, Liu Deping, Aw Kean C, Su Yufeng
School of Mechanical and Power Engineering, Zhengzhou University, Zhengzhou 450001, China.
Department of Mechanical and Mechatronics Engineering, University of Auckland, Auckland 1010, New Zealand.
Micromachines (Basel). 2023 Jul 4;14(7):1374. doi: 10.3390/mi14071374.
This paper presents an improved solution for the airflow energy harvester based on the push-pull diamagnetic levitation structure. A four-notch rotor is adopted to eliminate the offset of the floating rotor and substantially increase the energy conversion rate. The new rotor is a centrally symmetrical-shaped magnet, which ensures that it is not subjected to cyclically varying unbalanced radial forces, thus avoiding the rotor's offset. Considering the output voltage and power of several types of rotors, the four-notch rotor was found to be optimal. Furthermore, with the four-notch rotor, the overall average increase in axial magnetic spring stiffness is 9.666% and the average increase in maximum monostable levitation space is 1.67%, but the horizontal recovery force is reduced by 3.97%. The experimental results show that at an airflow rate of 3000 sccm, the peak voltage and rotation speed of the four-notch rotor are 2.709 V and 21,367 rpm, respectively, which are 40.80% and 5.99% higher compared to the three-notch rotor. The experimental results were consistent with the analytical simulation. Based on the improvement, the energy conversion factor of the airflow energy harvester increased to 0.127 mV/rpm, the output power increased to 138.47 mW and the energy conversion rate increased to 58.14%, while the trend of the levitation characteristics also matched the simulation results. In summary, the solution proposed in this paper significantly improves the performance of the airflow energy harvester.
本文提出了一种基于推挽式抗磁悬浮结构的气流能量采集器的改进方案。采用四槽转子来消除浮动转子的偏移，并大幅提高能量转换率。新型转子是中心对称形状的磁体，这确保了它不会受到周期性变化的不平衡径向力的作用，从而避免了转子的偏移。考虑到几种类型转子的输出电压和功率，发现四槽转子是最优的。此外，采用四槽转子时，轴向磁弹簧刚度的总体平均增加量为9.666%，最大单稳态悬浮空间的平均增加量为1.67%，但水平恢复力降低了3.97%。实验结果表明，在气流速率为3000 sccm时，四槽转子的峰值电压和转速分别为2.709 V和21367 rpm，与三槽转子相比分别高出40.80%和5.99%。实验结果与分析模拟结果一致。基于这一改进，气流能量采集器的能量转换因子提高到0.127 mV/rpm，输出功率提高到138.47 mW，能量转换率提高到58.14%，同时悬浮特性的趋势也与模拟结果相符。综上所述，本文提出的方案显著提高了气流能量采集器的性能。
