三参数电磁能量收集装置机电耦合性能研究

Analyzing the characteristics of electromechanical coupling of a three-parameter energy harvester

以电磁能量收集装置作为研究对象,考虑装置机械振动部分结构形式的差异,分别建立三参数和两参数电磁能量收集装置的系统模型。通过引入无量化参数,以单频简谐激励作为环境载荷给出两类能量收集装置的位移响应和电流响应的解析表达式。分别考虑电路部分和机械振动部分各主要设计参数进行影响因素分析,对比研究了两类能量收集装置的机电耦合性能。为了更直观比较不同类型能量收集装置的能量转化性能,将输入到电路外部负载的平均电功率作为考核指标。结果表明:改变机械阻尼比和三参数系统的刚度比,可显著提升能量收集装置的机电耦合性能和能量转化特性。同时,三参数系统输入电路外部负载的平均电功率也大于两参数装置。仅改变电路部分的参数,对两类能量收集装置的影响相同;但是,通过同时调整机械阻尼比和三参数系统刚度比可增强三参数能量收集装置的能量转化效率。

Two systematic models of a three-parameter and a two-parameter electromagnetic energy harvesters are presented in this paper via taking into account of the influences due to the difference of mechanical vibration components. By introducing some non dimensional parameters into the systematic equations, the analytical expressions of the displacement response, the current response for the magnet and the electric circuit of the energy harvesters are respectively derived under single frequency harmonic excitation. Investigations first consider the effects of the designing variables from the electrical component and the mechanical component, respectively, on the characteristics of the electromechanical coupling for the harvesters are studied. For comparing the performance of the two types of the energy harvesters to convert the ambient excitation into electrical energy, the expression of the non-dimensional average power which delivered into an electrical load is obtained and is used as a key evaluating index. The calculating results show that the electromagnetic coupling performance and the energy converting efficiency are improved dramatically by changing the mechanical damping efficiency and the stiffness ratio for the three parameter system. Meanwhile, the average power of the three parameter harvester, which delivered into the external electrical load, is greater than the two-parameter one. In addition, the influences on the energy harvesters can be omitted when only changing the parameters of the electrical component. However, the energy converting efficiency will be strengthened when the effects of me chanical damping and the stiffness ratio of the three-parameter system are also considered at the same time.