Design of a piezoelectric-electromagnetic hybrid energy harvester and power collection for railway monitoring

In order to enhance the efficiency of vibration energy harvesting from the railway, a piezoelectric-electromagnetic hybrid energy harvester (P-EHEH) is proposed and the power collection system is studied to couple with the harvester outputs. Both the piezoelectric transducer and the magnetic transducer are composed in the P-EHEH to harvest the vibration energy of the railway when the base structure is excited by the trains passing through. The P-EHEH has been accurately modeled and experimentally verified. The results show that at the excitation displacement amplitude of 4 mm @20 Hz, the maximum output power reaches 280 mW. When the P-EHEH charges a capacitor of 470 μF, the maximum voltage of the capacitor is augmented by 45% (from 9 V to 13 V) compared with a single electromagnetic energy harvester (EEH), and the charging time is reduced by 47% (from 75 s to 40 s) compared with a piezoelectric energy harvester (PEH). It is concluded that the P-EHEH proposed in this paper can effectively harvest the vibration energy of the railway and provide a power supply for monitoring devices in the wireless sensing system.