Harnessing energy from spring suspension systems with a compressive-mode high-power-density piezoelectric transducer

Abstract In this paper, we present a compressive-mode high-power-density piezoelectric transducer for harvesting vibration energy from spring suspension systems. This device is comprised of a piezoelectric stack and a force amplifier. The piezoelectric stack is mainly composed of multiple PZT-5H piezoelectric units. The force amplifier strengthens the force on the piezoelectric stack to increase the generated energy. We propose an electromechanical conversion relation for the transducer. In this paper, we studied the output capabilities of a prototype though a series of experiments. The experimental results verify the proposed relation and show that the prototype can reach an average output power of 13.63 mW at the resonant frequency of 46.3 Hz under the 0.3 g harmonic excitation with the 1.975 kΩ matched impedance. The prototype has an excellent charge performance with microfarad level capacitors. For instance, the prototype charged a 1000 μF capacitor to saturation (7.5 V) within 18.1 s. The maximum 420 LED diodes were successfully lit by the prototype. Furthermore, the prototype charged a 3 V, 25 mAh lithium battery by 0.017 V in 300 s. This research can be of great significance for piezoelectric energy harvesting and powering wireless sensors in spring suspension systems.