Nonlinearity has been successfully introduced into piezoelectric energy harvesting for power performance enhancement and bandwidth enlargement. While a great deal of emphasis has been placed by researchers on the structural design and broadband effect, this article is motivated to investigate the maximum power of a representative type of nonlinear piezoelectric energy harvesters, that is, monostable piezoelectric energy harvester. An equivalent circuit is proposed to analytically study and explain system behaviors. The effect of nonlinearity is modeled as a nonlinear stiffness element mechanically and a nonlinear capacitive element electrically. Facilitated by the equivalent circuit, closed-form solutions of power limit and critical electromechanical coupling, that is, minimum coupling to reach the power limit, of monostable piezoelectric energy harvesters are obtained, which are used for a clear explanation of the system behavior. Several important conclusions have been drawn from the analytical analysis and validated by numerical simulations. First, given the same level of external excitation, the monostable piezoelectric energy harvester and its linear counterpart are subjected to the same power limit. Second, while the critical coupling of linear piezoelectric energy harvesters depends on the mechanical damping ratio only, it also depends on the vibration excitation and magnetic field for monostable piezoelectric energy harvesters, which can be used to adjust the power performance of the system.

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单稳态压电能量采集器的等效阻抗和功率分析

非线性已成功地引入压电能量收集以增强功率性能和扩大带宽。虽然研究人员非常重视结构设计和宽带效应，但本文旨在研究具有代表性的非线性压电能量收集器，即单稳态压电能量收集器的最大功率。提出了一个等效电路来分析研究和解释系统行为。非线性的影响被建模为机械上的非线性刚度元件和电学上的非线性电容元件。在等效电路的推动下，功率极限和临界机电耦合的封闭形式解，即达到功率极限的最小耦合，获得了单稳态压电能量收集器，用于清晰解释系统行为。从分析分析中得出了几个重要的结论，并通过数值模拟进行了验证。首先，给定相同水平的外部激励，单稳态压电能量收集器及其线性对应物受到相同的功率限制。其次，虽然线性压电能量收集器的临界耦合仅取决于机械阻尼比，但它也取决于单稳态压电能量收集器的振动激励和磁场，可用于调整系统的功率性能。从分析分析中得出了几个重要的结论，并通过数值模拟进行了验证。首先，给定相同水平的外部激励，单稳态压电能量收集器及其线性对应物受到相同的功率限制。其次，虽然线性压电能量收集器的临界耦合仅取决于机械阻尼比，但它也取决于单稳态压电能量收集器的振动激励和磁场，可用于调整系统的功率性能。从分析分析中得出了几个重要的结论，并通过数值模拟进行了验证。首先，给定相同水平的外部激励，单稳态压电能量收集器及其线性对应物受到相同的功率限制。其次，虽然线性压电能量收集器的临界耦合仅取决于机械阻尼比，但它也取决于单稳态压电能量收集器的振动激励和磁场，可用于调整系统的功率性能。