Study on an elastic lever system for electromagnetic energy harvesting from rail vibration

Energy harvesting from rail vibration is a promising approach to solve the power supply problem in remote and off-grid areas. The major issue of current energy harvesting techniques and devices is the limited power generating capacity. In this paper, the authors put forward an elastic lever system to enhance the performance of an electromagnetic energy harvester. A vehicle-track coupling dynamics model is established to simulate the service condition of the energy harvester. The Power Amplification Factor (PAF), which is defined as the ratio between the output power with and without a lever system, is introduced to quantify the Enhanced Energy Harvester (EEH). It is found that the PAF can be greater than n2 with a leverage ratio of n. Simulation shows that the output power can be magnified by 430 times with an elastic lever system with a leverage ratio of 10. The amplification effect of the output power comes from two aspects, one is the magnifying effect of leverage itself and the other is the resonance effect. Additionally, it is found that a single EEH will increase the wheel-rail contact force slightly, which indicates the EEH is impractical for use as an approach for rail vibration reduction. Nevertheless, it will not have a significant negative effect on rail vibration

Magnetic field energy harvesting from the traction return current in rail tracks

This is the final version. Available from Elsevier via the DOI in this record. Alternating magnetic fields generated by AC traction return currents in rail tracks are an untapped energy source that can be scavenged by a magnetic field energy harvester (MFEH) to power wireless condition monitoring sensors. This paper reports the first comprehensive study on the design, optimisation and experimental testing of such MFEH. The magnetic core has been specially designed with two flux collectors partially enclosing the rail track to increase the power output. An electromagnetic-circuit coupled finite element model (FEM) has been developed to optimise the design under the influence of eddy current loss in the rail track, which has not been investigated before. The simulation reveals that an optimal design should trade off the effective permeability against the eddy current loss, instead of purely maximising the effective permeability as in previous studies. The effects of the various design parameters on the performance of the MFEH have been investigated to obtain an optimised design. An optimised design has been prototyped and tested under a section of current-carrying rail track. The experimental results showed good agreements with simulations. Experimental results show that nonlinear magnetization and magnetic saturation has negatively affected the power generation but the effect can be minimised by increasing the load resistance. The MFEH has produced average power of 5.05, 3.5 and 1.6 W, when placed at 48, 95, 190 mm from the rail track carrying 520 A at 50 Hz, respectively. The power generated has a significant potential for powering wireless sensors for a range of railway monitoring applications.Engineering and Physical Sciences Research Council (EPSRC

Kinetic Electromagnetic Energy Harvester for Railway Applications-Development and Test with Wireless Sensor

This paper deals with a development and lab testing of energy harvesting technology for autonomous sensing in railway applications. Moving trains are subjected to high levels of vibrations and rail deformations that could be converted via energy harvesting into useful electricity. Modern maintenance solutions of a rail trackside typically consist of a large number of integrated sensing systems, which greatly benefit from autonomous source of energy. Although the amount of energy provided by conventional energy harvesting devices is usually only around several milliwatts, it is sufficient as a source of electrical power for low power sensing devices. The main aim of this paper is to design and test a kinetic electromagnetic energy harvesting system that could use energy from a passing train to deliver sufficient electrical power for sensing nodes. Measured mechanical vibrations of regional and express trains were used in laboratory testing of the developed energy harvesting device with an integrated resistive load and wireless transmission system, and based on these tests the proposed technology shows a high potential for railway applications

Vibration Energy Harvesting for Wireless Sensors

Kinetic energy harvesters are a viable means of supplying low-power autonomous electronic systems for the remote sensing of operations. In this Special Issue, through twelve diverse contributions, some of the contemporary challenges, solutions and insights around the outlined issues are captured describing a variety of energy harvesting sources, as well as the need to create numerical and experimental evidence based around them. The breadth and interdisciplinarity of the sector are clearly observed, providing the basis for the development of new sensors, methods of measurement, and importantly, for their potential applications in a wide range of technical sectors