scholarly journals Electromagnetic Vibration Energy Harvesting for Railway Applications

2018 ◽  
Vol 148 ◽  
pp. 12004 ◽  
Author(s):  
S. Bradai ◽  
S. Naifar ◽  
C. Viehweger ◽  
O. Kanoun

Safe localization of trains via GPS and wireless sensors is essential for railway traffic supervision. Especially for freight trains and because normally no power source is available on the wagons, special solutions for energy supply have to be developed based on energy harvesting techniques. Since vibration is available in this case, it provides an interesting source of energy. Nevertheless, in order to have an efficient design of the harvesting system, the existing vibration needs to be investigated. In this paper, we focus on the characterization of vibration parameters in railway application. We propose an electromagnetic vibration converter especially developed to this application. Vibration profiles from a train traveling between two German cities were measured using a data acquisition system installed on the train’s wagon. Results show that the measured profiles present multiple frequency signals in the range of 10 to 50 Hz and an acceleration of up to 2 g. A prototype for a vibration converter is designed taking into account the real vibration parameters, robustness and integrability requirements. It is based on a moving coil attached to a mechanical spring. For the experimental emulation of the train vibrations, a shaker is used as an external artificial vibration source controlled by a laser sensor in feedback. A maximum voltage of 1.7 V peak to peak which corresponds to a maximum of 10 mW output power where the applied excitation frequency is close to the resonant frequency of the converter which corresponds to 27 Hz.

2015 ◽  
Vol 14 (01n02) ◽  
pp. 1460017
Author(s):  
Hongyu Si ◽  
Jinlu Dong ◽  
Lei Chen ◽  
Laizhi Sun ◽  
Xiaodong Zhang ◽  
...  

The resonance between piezoelectric vibrator and the vibration source is the key to maximize the ambient vibration energy harvesting by using piezoelectric generator. In this paper, the factors that influence the output power of a single piezoelectric vibrator are analyzed. The effect of geometry size (length, thickness, width of piezoelectric chip and thickness of metal shim) of a single cantilever piezoelectric vibrator to the output power is analyzed and simulated with the help of MATLAB (matrix laboratory). The curves that output power varies with geometry size are obtained when the displacement and load at the free end are constant. Then the paper points out multi-resonant frequency piezoelectric power generation, including cantilever multi-resonant frequency piezoelectric power generation and disc type multi-resonant frequency piezoelectric generation. Multi-resonant frequency of cantilever piezoelectric power generation can be realized by placing different quality mass at the free end, while disc type multi-resonant frequency piezoelectric generation can be realized through series and parallel connection of piezoelectric vibrator.


Author(s):  
Brennan E. Yamamoto ◽  
A. Zachary Trimble

As the required power for wireless, low-power sensor systems continues to decrease, the feasibility of a fully self-sustaining, onboard power supply, has increased interest in the field of vibration energy harvesting — where ambient kinetic energy is scavenged from the surrounding environment. Current literature has produced a number of harvesting techniques and transduction methods; however, they are all fundamentally similar in that, the harmonic excitation frequency must fall within the resonant bandwidth frequency of the harvesting mechanism to maintain acceptable energy output. The purpose of this research is to investigate the potential for natural frequency tuning by means of passive electrical components, that is, using an imposed electrical inductance to adjust the equivalent stiffness, and resulting resonant frequency of a vibration energy harvester. In past literature, it was concluded that an “active” frequency tuning mechanism would be infeasible, as the power required by an equivalent “stiffening transducer” would require more power to maintain the system at resonance, than the system would actually produce as a result of maintaining resonance, i.e., a net energy loss (Roundy and Zhang 2005). It is believed that the model used in this conclusion can be improved by directly modeling changes in system stiffness as an equivalent mechanical spring, instead of an external inertial loading. Due to the conservative nature of the harmonic spring, the compliance of a harvesting mechanism can be theoretically altered without energy losses, whether the actuation is applied using “active” or “passive” means. This revised model departs from the traditional, base excitation model in most vibration energy harvesting systems, and includes additional stiffness, and damping elements, representative of induced mechanical spring, and related losses. We can validate the feasibility of this technique, if it can be shown that the natural frequency of an energy harvester can be altered, and still maintain energy output similar to its “untuned” natural frequency. If feasible, this tuning method would provide a viable alternative to other bandwidth-increasing techniques in literature, e.g., wideband harvesting, bandwidth normalizing, high-damping, etc. In this research, a change in natural frequency of the experimental energy harvesting system of 0.5 Hz was demonstrated, indicating that adjusting the natural frequency of a vibration energy harvesting system is possible; however, there are many new challenges associated with the revised energy harvesting model, related to the new introduced losses to the system, as well as impedance matching between the mechanical and electrical domains. Further research is required to better quantitatively characterize the relationship between natural frequency shift, and imposed electrical inductance.


2020 ◽  
Vol 10 (7) ◽  
pp. 2484 ◽  
Author(s):  
Marcin Kulik ◽  
Mariusz Jagieła ◽  
Marian Łukaniszyn

The coreless microgenerators implemented in electromagnetic vibration energy harvesting devices usually suffer from power deficiency. This can be noticeably improved by optimizing the distribution of separate turns within the armature winding. The purposeful optimization routine developed in this work is based on numerical identification of the turns that contribute most to the electromotive force and the elimination of those with the least contribution in order to reduce the internal impedance of the winding. The associated mixed integer nonlinear programming problem is solved comparatively using three approaches employing surrogate models based on kriging. The results show very good performance of the strategy based on a sequentially refined kriging in terms of the ability to accurately localize extremum and reduction of the algorithm execution time. As a result of optimization, the output power of the system increased by some 300 percent with respect to the initial configuration.


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