Design and experimental study of piezoelectric energy harvester from driving motor system of electric vehicle based on high-low excitation frequency profiles

There is a lot of wasted vibration induced from the driving motor system of an electric vehicle. Due to this, the vibration characteristics of the driving motor are performed, and the acceleration vibration responses are measured and analyzed. This investigation will explore an opportunity in vibration energy harvesting technology of a vehicle drive motor. Based on the vibration characteristics of the drive motor, two rectangular piezoelectric energy harvester (PEH) beams and two optimized T-shaped PEH beams with 15 Hz and 250 Hz of frequencies are designed, and the electro-mechanical characteristics and stress distribution of the PEHs are simulated using finite element method. The optimized T-shape PEHs are selected and fabricated for the experimental validation, and the result proves that the output performance of T-shape PEHs is reliable and can be used for further research. The voltage outputs of the optimized PEHs under different test points and similar steady-state operation are measured, with the maximum output voltage of 15 V determined from the motor casing. The voltage outputs under cyclic operational conditions load are also obtained, which indicates that the operation of driving motor generates an abundance of high and low-frequency vibration energy, with the maximum voltage up to 144 V. The optimized PEHs can efficiently convert the high and low-frequency vibration energy of the drive motor. This provides a practical method for supplying electrical energy to electronic devices and offers new insights for the vibration energy harvesting technology in automobiles.