A novel pendulum kinetic energy harvester based on magnetic coupling bistable buckling beam for low-power appliances in new energy buses

The rapid development of internet of things technology has created an urgent demand for wireless sensors. Although wireless sensors have the advantage of widespread use, their applications are limited by power supply. This manuscript proposes a novel magnetically coupled piezoelectric kinetic energy harvester (MPKEH) system to address this issue and enable wireless sensors to be self-powered. The proposed system included four parts: motion capture module, motion transformation module, energy transformation module, and power storage module. The motion capture module, a single-pendulum, is selected to convert the vehicle’s inertial energy into the mass ball kinetic energy. The motion transformation module, which includes a double-directional rectification mechanism and a mechanical speed-up mechanism, converts two-way rotations into one-way rotations and increases rotation speed. Piezoelectric material is frequently bent in the energy transformation module to generate alternating current (AC). The power storage module rectifies AC into direct current and stores the power in the super-capacitor, which supplies power to the electrical equipment. The velocity of the mass ball under five realistic bus driving cycles is obtained using multi-body dynamics software and Simulink. Experiments revealed that the average output power of the system could be as high as 2.4 W. Charging capacitors of 100 µF, 220 µF, 470 µF, and 1000 µF to 2 V using the MPKEH system takes 25 s, 49 s, 70 s, and 238 s, respectively. In the conducted experiments using the Liaocheng University campus bus, the maximum average power output reached 1.97 W. These results suggest that the MPKEH system can effectively self-supply energy for low-power appliances in new energy buses.