A hybrid kinetic energy harvester for applications in electric driverless buses

Abstract

Electric driverless buses are an important part of future urban transportation. There is a large amount of inertial kinetic energy wasted during the driving of electric driverless buses. Harvesting environmental energy to realize self-powered applications has attracted research attention. This paper presents a hybrid kinetic energy harvester (KEH) based on uneven turntable for applications in electric driverless buses. The KEH consists of three main components: energy input module, energy conversion module and energy management module. The energy input module includes a harvesting mechanism and an excitation amplification mechanism, which harvests the omnidirectional inertial kinetic energy by rotating uneven turntable under acceleration and amplifies the excitation input through gear train and magnet array. In the energy conversion module, kinetic energy is converted into electrical energy through the hybrid energy harvesting mechanism of electromagnetic and piezoelectric, due to the rotation of the electromagnetic motor (EM) and the oscillation of the piezoelectric beam (PB). The energy management module stores electricity in capacitors for low-power applications. The component of gravitational acceleration during deflection is utilized in the experiment to simulate the acceleration environment. Experimental data shows that the average output power of the KEH can reach 8.31 mW at 8 m/s2 acceleration. The hybrid energy harvesting (KEH) can achieve a higher charging voltage of 3.72 V with a 220 μF capacitor, which has 481 % increase compared with a single electromagnetic energy harvesting (EM) and 11 % increase compared with a single piezoelectric energy harvesting (PB). A total of 54 LED lights can be lit by the KEH, verifying the great potential of the KEH to achieve self-powered applications in electric driverless buses.