Department of Mechanical Engineering, Virginia Polytechnic Institute and State University, 151 Durham Hall, Mail Code 0238, Blacksburg, Virginia 24061, USA.
J Acoust Soc Am. 2012 Jul;132(1):162-72. doi: 10.1121/1.4725765.
Conversion of ambient vibrational energy into electric power has been the impetus of much modern research. The traditional analysis has focused on absolute electrical power output from the harvesting devices and efficiency defined as the convertibility of an infinite resource of vibration excitation into power. This perspective has limited extensibility when applying resonant harvesters to host resonant structures when the inertial influence of the harvester is more significant. Instead, this work pursues a fundamental understanding of the coupled dynamics of a main mass-spring-damper system to which an electromagnetic or piezoelectric mass-spring-damper is attached. The governing equations are derived, a metric of efficiency is presented, and analysis is undertaken. It is found that electromagnetic energy harvesting efficiency and maximum power output is limited by the strength of the coupling such that no split system resonances are induced for a given mass ratio. For piezoelectric harvesters, only the coupling strength and certain design requirements dictate maximum power and efficiency achievable. Since the harvesting circuitry must "follow" the split resonances as the piezoelectric harvesters become more massive, the optimum design of piezoelectric harvesters appears to be more involved than for electromagnetic devices.
将环境振动能量转换为电能一直是现代研究的动力。传统的分析主要集中在采集设备的绝对电功率输出和效率上，效率定义为将无限振动激励资源转换为电能的能力。当将共振采集器应用于具有更大惯性影响的主质量-弹簧-阻尼器结构时，这种观点在将共振采集器应用于具有更大惯性影响的主质量-弹簧-阻尼器结构时，其可扩展性有限。相反，这项工作旨在深入了解附加电磁或压电质量-弹簧-阻尼器的主质量-弹簧-阻尼器系统的耦合动力学。推导出控制方程，提出效率度量标准，并进行了分析。结果发现，电磁能量采集效率和最大功率输出受到耦合强度的限制，因此对于给定的质量比，不会产生分裂系统共振。对于压电采集器，只有耦合强度和某些设计要求决定了可实现的最大功率和效率。由于采集电路必须“跟随”分裂共振，因为压电采集器变得更重，因此与电磁设备相比，压电采集器的最佳设计似乎更加复杂。
