磁悬浮式双自由度轨道车辆轴箱振动能量采集器研究

Double-degree-of-freedom magnetic levitation vibration energy har⁃vester of the axle box for a railway vehicle

提出了一种适合采集轨道车辆轴箱振动能量的磁悬浮式双自由度振动能量采集器。基于单自由度磁悬浮振动能量采集器的基本原理,设计磁悬浮式双自由度振动能量采集器的基本构型。利用磁偶极子模型,推导了圆柱磁铁的磁力方程,建立了磁悬浮式双自由度能量采集系统的动力学方程。考虑到系统具有的强非线性特点,利用龙格⁃库塔方法,得到了系统的幅频响应曲线。根据轨道车辆轴箱实测时间历程和频率分布特点,设计了磁悬浮式双自由度振动能量采集器的核心参数。对比分析单自由度振动能量采集器和双自由度振动能量采集器的频率响应特性。研究结果表明:非线性双自由度振动能量采集器可以有效拓宽俘能装置的工作带宽,进而提高能量采集功率。在简谐振动激励下,双自由度振动能量采集器比单自由度振动能量采集器的输出功率增加了约1.1倍,且工作带宽可以拓宽约2.7倍;在实测的轨道车辆轴箱振动激励下,双自由度振动能量采集器在一站间可采集到31.5 mJ能量,峰值感应电流为14.6 mA,峰值输出功率为9.4 mW。

A double-degree-of-freedom magnetic levitation vibration energy harvester is proposed for collecting the vibration energy of the rail vehicle axle box.Based on the basic principle of single-degree-of-freedom magnetic levitation vibration energy harvester,the basic configuration of double-degree-of-freedom magnetic levitation vibration energy harvester is designed.Based on the mag-netic dipole model,the magnetic force equation of the cylindrical magnet is derived,and the dynamic equation of double-degree-of-freedom magnetic levitation energy harvester system is established.Considering the strong nonlinear characteristics of the system,the amplitude-frequency response curve of the system is obtained through Runge-Kutta method.According to the measured time history and frequency distribution characteristics of the rail vehicle axle box,the core parameters of the double-degree-of-freedom magnetic levitation vibration energy harvester are designed.Frequency response characteristics are compared between the single-de-gree-of-freedom and the double-degree-of-freedom vibration energy harvesters.The results show that the nonlinear double-degree-of-freedom vibration energy harvester can effectively broaden the working bandwidth of the energy harvesting device,and then im-prove the energy collection power.Under simple harmonic vibration excitation,the output power of the double-degree-of-freedom vibration energy harvester is about 1.1 times higher than that of the single-degree-of-freedom vibration energy harvester.Besides,the working bandwidth can also be broadened by about 2.7 times.Under the measured rail vehicle axle box vibration excitation,the double-degree-of-freedom vibration energy harvester can collect 31.5 mJ energy in a station interval.The corresponding peak in-duced current is 14.6 mA,and the peak output power is 9.4 mW.