Performance investigation of piezoelectric-mechanical electromagnetic compound vibration energy harvester for electric tractor

The electric tractor belongs to off-road vehicle and often travels on the rugged ground generally featured as the Class-D Road which leads to large vibration. Currently, this kind of vibration energy has not been effectively recovered and utilized which results in energy waste. To address this problem, a novel piezoelectric-mechanical electromagnetic compound vibration energy harvester (P-MECVEH) was proposed. Then, the 10 DOF nonlinear dynamic model of the P-MECVEH was established, and its energy nonlinear dynamic characteristics were revealed numerically through the global bifurcation, phase orbit, Poincaré map and FFT spectrum. The results showed that the energy output response of the P-MECVEH presented a high-energy period-2 state within the ranges of the excitation frequency f∈ [2.475, 2.850 Hz] and amplitude Am∈ [0.00644, 0.01000 m]. Finally, the reliability of the established dynamic model was verified through comparative analysis between the prototype experimental and theoretical results, and it was shown that the prototype generated a maximum output voltage of 38 V and a peak power of 14.44 W at a load resistance of 100 Ω under the excitation frequency of 2.42 Hz and amplitude of 0.002 m, which indicates that the P-MECVEH has the potential in vibration energy recovery and utilization for electric tractors.