Sequentially-excited multi-oscillator piezoelectric rotary energy harvester for charging capacity enhancement

Energy harvesting technology can provide a power solution for IoT sensors. In this paper, a sequentially-excited multi-oscillator piezoelectric rotary energy harvester (SEMPREH) is proposed. A theoretical model of the piezoelectric oscillator was established, and a magnetic simulation analysis was performed. The results show that for the same exciting magnet arrangement (A) and rotation speed, the voltages when the exciting and excited magnets in attraction are higher than in repulsion. The waveforms are denser and have a higher charging capacity with A₄ compared to A₁ (simultaneous excitation). The optimum combination is attraction and A₄ with a maximum peak-to-peak open-circuit voltage of 23.2 V at 200 RPM, and the maximum average power at the same speed is 1.11 mW (at 30 kΩ). The SEMPREH assembled with the wind turbine can light up the LED board at 4.13 m/s. It has the potential to power microelectromechanical systems such as IoT sensors.