HYBRID PIEZOELECTRIC-TRIBOELECTRIC ROTATIONAL ENERGY HARVESTER USING DYNAMIC COORDINATED MODULATION MECHANISM

The poor performance of energy harvesting under low speed excitation is the bottleneck that restricts the application of rotational energy harvesting. In this paper, a dynamic coordinated modulation mechanism is proposed to modulate the dynamic behavior of the system, which can make the device work effectively under low speed excitation and achieve an enhanced electrical performance of the rotational energy harvesting system. The coordinated modulation of centrifugal-softening-nonlinear-magnetic-force-geometric-boundary can not only increase the vibration displacement of the system and the deformation of the piezoelectric material under low speed excitation, but also modulate the maximum displacement of the system when the vibration displacement is too large, so as to make the vibration controllable and improve the reliability. Moreover, the geometric boundary can easily integrate the triboelectric nanogenerator to realize the coordinated power generation of piezoelectric and triboelectric in the process of vibration and impact, which can make effective use of space and enhance the electrical performance. Based on Hamiltonian principle, the electromechanical coupling equation of the system is established and verified by experiments. The experimental results show that the system can work effectively in the speed range of 0−250 r/min. The P-P voltage of piezoelectric unit and triboelectric nanogenerator are 132 V and 1128 V, and the total average power is 1426 μW at the speed of 250 r/min. The dynamic coordinated modulation mechanism proposed in this paper provides a new method to improve the dynamic and electrical performance of energy harvesting system, and shows potential application prospects in the self-powered internet of things.