Pendulum type magnetically coupled rotary piezoelectric energy harvester

This research proposes a rotary motion-based non-contact pendulum piezoelectric energy harvester (P-PEH). The working region of the piezoelectric vibrator can be maintained in a magnetically coupled system at all times by means of a motion conversion mechanism. The combination of the motion conversion mechanism and the magnetic coupling system not only reduces the loss of the piezoelectric material, but also improves the output performance of the piezoelectric vibrator. The paper investigates the effects of the excitation distance L, the radius of the base circle R, and the number of excitation magnets N on the output performance of the P-PEH. When the input speed of 600 rpm, L = 10 mm, R = 21 mm, and N = 1, the peak-to-peak voltage (Vpp) is 58.75 V. At this parameter, the output power of the device with an external 20 kΩ load is 0.0187 W. The viability of P-PEH was finally demonstrated through several application testing. P-PEH can easily light up 63 LEDs while its output energy can keep the temperature and humidity sensor in use. In summary, P-PEH can effectively collect external rotational energy for power storage and supply, and supply electricity to wireless sensor networks and microelectronic devices with further studies.