Study on the power generation performance of multi-mode piezoelectric–electromagnetic composite energy harvester based on rail vibration absorber

With the rapid development in rail transit industry in China, the energy supply of rail monitoring equipment has become a prominent problem, especially in some remote areas. The rail vibration caused by passing trains is a huge energy source. However, due to the characteristics of rail vibration (instantaneous, aperiodic and broadband excitation), the existing rail vibration energy harvesters can only collect rail vibration energy efficiently within a specific frequency range, the energy recovery efficiency is very low. In order to solve these problems, a multi-mode piezoelectric–electromagnetic composite energy harvester based on the rail vibration absorber has been presented in this paper. A model of the wheel–rail–vibration absorber system is established to simulate the rail vibration. In this model, the friction coupling between the wheel and rail has been considered. Under the same structural parameters and operating conditions, the predicted results of this model are consistent with the field-measured results. Base on this wheel–rail–vibration absorber model, numerical simulation analysis of the power generation performance of the composite energy harvester is carried out. The analysis results show that the output power of the multi-mode piezoelectric–electromagnetic composite energy harvester has a total of 6 peaks in the range of 0 to 600 Hz, with a maximum output power of 8.57 mW. Compared to existing vibration energy harvesters, the composite energy harvester has a wider energy harvesting frequency range and higher harvesting efficiency. The parameter analysis results show that the energy harvesting efficiency can be further improved by adjusting the structural parameters or the strain energy of the cantilever beam. This multi-mode piezoelectric–electromagnetic composite energy harvester is beneficial for improving the energy recovery efficiency of rail vibration. It effectively reduces the energy supply costs of the rail monitoring equipment.