Design and investigation of a magnetic coupling piezoelectric inertial energy harvesting system for low-power wireless sensors in intercity buses†

As Internet of Things technology rapidly advances, the issue of self-powering in wireless sensors has garnered significant attention. During the operation of new energy buses, a considerable amount of inertial energy is frequently converted into other forms. This paper presents a magnetic coupling piezoelectric inertial energy harvesting system (MPIHS) designed to supply or store power for low-power wireless sensors by effectively recovering inertial energy generated during the operation of buses. The system consists of an energy collection module, motion transmission module, energy transduction module, and a power reservoir module. Part of the lost inertial energy is translated into the rotor's kinetic energy, enabling unidirectional output and a speed increase. The mechanical energy is transformed into electrical energy via the piezoelectric effect, while a dedicated adjustment circuit is designed to effectively store the electrical energy generated. According to the actual historical working condition data of the bus, the MPIHS's maximum output power has been determined to be 7.1 mW. The charging times for capacitor voltages of 100 μF, 220 μF, 330 μF, 470 μF, and 680 μF to reach 2 V are 9 s, 22 s, 30 s, 40 s, and 54 s, respectively. In the feasibility test, the MPIHS demonstrates the capability to illuminate 96 LED bulbs. Additionally, the temperature and humidity sensor functions effectively. These results suggest the practicality and potential applications of the MPIHS as a power source or supplemental power supply for low-power electrical appliances in vehicles.