Auswahl der wissenschaftlichen Literatur zum Thema „Trackside energy harvesting“

This paper deals with an energy harvesting review and analysis of an ambient mechanical energy on a trackside during a passing of a train. Trains provide very high level of vibration and deformation which could be converted into useful electricity. Due to maintenance and safety reasons a rail trackside includes sensing systems and number of sensor nodes is increased for modern transportation. Recent development of modern communication and ultra-low power electronics allows to use energy harvesting systems as autonomous source of electrical energy for these trackside objects. Main aim of this paper is model-based design of proposed vibration energy harvesting systems inside sleeper and predict harvested power during the train passing. Measurements of passing train is used as input for simulation models and harvested power is calculated. This simulation of proposed energy harvesting device is very useful for future design.

Single-degree-of-freedom (SDOF) mechanical oscillators have been the most common type of generators used to harvest energy from mechanical vibrations. When the excitation is harmonic, optimal performance is achieved when the device is tuned so that its natural frequency coincides with the excitation frequency. In such a situation, the harvested energy is inversely proportional to the damping in the system, which is sought to be very low. However, very low damping means that there is a relatively long transient in the harvester response, both at the beginning and at the end of the excitation, which can have a considerable effect on the harvesting performance. This paper presents an investigation into the mechanical design of a linear resonant harvester to scavenge energy from time-limited harmonic excitations to determine an upper bound on the energy that can be harvested. It is shown that when the product of the number of excitation cycles and the harvester damping ratio is greater (less) than about 0.19, then more (less) energy can be harvested from the forced phase of vibration than from the free phase of vibration at the end of the period of excitation. The analytical expressions developed are validated numerically on a simple example and on a more practical example involving the harvesting of energy from trackside vibrations due to the passage of a train.

This thesis is dealing with creation of computation model of energy harvestors. Harvestors based on translational motion and planar motion were modeled. These models were created in MSC Adams. Proposed harvestors are tranforming mechanical vibrations into electrical energy by electromagnetical induction. To achieve better electrical output, harvestors were tuned to natural frequency suitable for chosen aplication. First proposed harvestor is meant for railway track. For validation of its usability in intended application, model of railway track section is also proposed. Force generated by passing train is used for excitation of the track model. Second harvestor is nonlinear electromechanical oscilator proposed for use on unanchored sea buoy (drifter). After retuning previously proposed concept of energy harvestor to natural frequency 1.6 Hz, computation model for simulation purposes was created. After the simulation of sinusoidal excitation, the excitation based on real sea data was simulated. When excited by regular sea, the peak electric power 9 W was achieved. When excited by irregular sea the peak electrical power of the generator was 7.5 mW.

This master thesis deal with analysis of possible alternative energy sources for health monitoring of railway trafic. Mainly focus on energy harvesting via SMART materials, specifically materials with piezoelectric and magnetostrictive properties. First theoretical background and real concepts are introduced, followed by material modelling and simulations. End of thesis cover parameter suggestion and SMART materials comparation and valorizations.

Abstract Railroad vibration energy harvester has been researched and developed to harness the energy from the vibration of railway track when the trains pass. The vibrational energy could be transformed into electrical energy using mechanical motion rectification (MMR) mechanism and then further be used to power trackside equipment including sensors and some smart electrical devices. In order to test the performance of the MMR railroad energy harvesting system, a series of infield tests were conducted with a self-developed distributed measurement system in Railroad Test Lab at Tongji University. A 10V peak voltage was achieved with 8 Ohms external resistive load at the train speed of 30 km/h, which was consistent with the result of in-lab bench tests. In addition, some experience of design and installation for the motioned based energy harvesting system was gained, which can provide some references for the future improvement of railroad energy harvesting systems.

Abstract This paper presents the design, modeling and bench testing of a smart railroad tie for energy harvesting from the motion of railway track. The system is intended for applications that require trackside power in remote locations, such as wayside electrical devices and safety equipment, signal lights, crossing gates, wireless communication, as well as rail health monitoring systems. The smart tie, which is designed to have similar dimensions to a conventional railroad tie, is installed in the same manner as a standard tie on the track. In particular, the mechanical energy harvesting module and its corresponding power management unit can be both embedded inside a composite, concrete or wooden tie, in order to shield the components from the harsh environment and protect the system against any potential theft or vandalism. Different from other railway track harvesters that typically harvest energy from bidirectional track deflections, the proposed smart tie only harvests the kinetic energy of the track when the wheels push it downwards, which resolves the preload and installation challenges of bidirectional harvesting and increases the overall system reliability. A nonlinear analytical model is developed to analyze the dynamic characteristic of the system and the simulation is conducted to predict the performance. Bench tests are subsequently carried out under both harmonic and recorded tie displacement inputs to validate the model and assess the harvesting performance. During the bench tests, the generator shaft was observed to start rotation at 0.1 mm vibration amplitude, indicating that the overall prototype has a relatively small backlash. In-lab test results indicate that an average power of 26.1–42.2W on 4 Ohms and 2 Ohms external loads were achieved under simulated tie movement recorded from a service track.

Abstract Rail transportation plays an important role in today’s economy by delivering a large quantity of goods and passengers to various locations throughout North America in an economic and efficient manner. Bearing failure is one of the leading causes of derailments that result in significant capital loss and in extreme cases tragic human loss. The two widely used bearing health monitoring systems are the Trackside Acoustic Detection System (TADS™) and the wayside Hot-Box Detector (HBD). These systems are reactive in nature and only give alerts when the bearings are nearing failure. To supplant that, a prototype wireless onboard condition monitoring system was developed by researchers at the University Transportation Center for Railway Safety (UTCRS). This onboard wireless system can detect bearing defects at their early stages of initiation so that proactive maintenance actions can be taken by the railroads and railcar owners. Due to the wireless nature of this system, a constant power supply is needed to ensure its continued operation. Currently, the prototype wireless system utilizes low-power circuitry that is powered by a rechargeable AA battery that can provide up to two years of operation depending on usage. Implementation of a suitable energy harvesting device can significantly increase the longevity of the batteries used in the wireless module, and in ideal operating conditions, generate consistent energy rendering the battery as a temporary energy storage device. The proposed energy harvesting device consists of thermoelectric generators, aluminum heat sinks, a switching boost convertor, and a battery management chip. This device was tested on a dynamic bearing test rig to assess the performance of the thermoelectric generators. To best simulate field operation conditions, the thermoelectric generators were placed on opposite sides of the bearing adapter; one exposed to direct forced convection while the other side is shielded by the adapter and experiences minimal convection. Thermoelectric generators were found to be an effective solution due to their ability to convert a temperature gradient into a usable voltage sufficient to charge the battery. The buck booster converter increases the voltage from the thermoelectric generators to 5-volts so that the battery management chip can regulate the voltage and efficiently charge the battery. This paper summarizes the performance of the thermoelectric modules under different operating conditions. The main goal of this project is to devise an energy harvesting device that allows the wireless module to be self-powered utilizing the heat generated from the bearing and the charge held by the battery as a hybrid power source.