Piezoelectric vibration harvesters with strong electromechanical coupling coefficients have recently been combined with nonlinear electrical techniques capable of tuning their resonant frequency as a solution to provide energy to wireless sensor nodes from wideband vibrations. To be fully competitive, this approach requires piezoelectric generators with strong global electromechanical coupling coefficients k². However, the presence of non-linear dielectric and piezoelectric losses in piezoelectric materials significantly reduces the power harvested when strongly coupled materials are used. This paper presents a non-linear model that allows for a better consideration of losses for such piezoelectric harvesters. An experimental validation is performed with a strongly coupled cantilever based on a PMN-PT material (k² = 16 %). The results reveal the importance of considering non-linear dielectric losses. Indeed, we show thanks to the model that neglecting these losses can induce an 18 % overestimation of the harvested power for the presented prototype driven at 0.5 m/s² amplitude ambient acceleration.

具有强机电耦合系数的压电振动采集器最近与能够调整其谐振频率的非线性电气技术相结合，作为从宽带振动向无线传感器节点提供能量的解决方案。为了充分竞争，这种方法需要具有强大全局机电耦合系数 k ^{2 的}压电发电机. 然而，当使用强耦合材料时，压电材料中非线性介电和压电损耗的存在显着降低了收集的功率。本文提出了一种非线性模型，可以更好地考虑此类压电采集器的损耗。使用基于 PMN-PT 材料 (k ²  = 16 %)的强耦合悬臂进行实验验证。结果揭示了考虑非线性介电损耗的重要性。实际上，由于模型，我们表明忽略这些损失会导致对以 0.5 m/s ²振幅环境加速度驱动的所呈现原型的收集功率高估 18% 。