Electrodynamic Energy Harvesting Research Articles

An electrodynamic energy harvester with a 3D printed magnet and optimized topology

Abstract An electrodynamic energy harvester is proposed for scavenging the electromagnetic energy in the vicinity of a power transmission line. To improve the efficiency and to maximize the distortion power factor of the energy harvester, the permanent magnet in the energy harvester is especially designed by the finite element method to optimize the topology and subsequently fabricated by additive manufacturing. An isotropic polymer-bonded NdFeB material is used for the fused-deposition modeling 3D printing process. Tensile tests of the printed magnetic parts show proper mechanical properties for harsh environments. Compared to a non-optimized magnet, the distortion power factor can be increased by 55%. The power and power density under the resonance condition of the fabricated harvester can reach 93 mW and 2.6 mW/cm3, respectively. The advantages of such an optimized energy harvester include being a fast and affordable manufacturing technique, an enhanced distortion power factor, and high output power. The properties of the energy harvester show that it has great potential for many self-powered applications such as wireless sensor networks and Internet of things.

The Study of an Electric Circuit of Force-Based Electrodynamic Energy Harvesting Device

The energy harvesting became more popular as the need for small energy sources was growing. Among different types of energy harvesting (electromagnetic, piezoelectric, magnetostrictive, light, heat) the first one is the oldest and still popular. The common studies focused on optimizing the electro-mechanical design. This paper is focusing on the study of the electric circuit, with the main goal of finding some optimum rules. The results could be used for designing the coil of the sensor and the external electrical circuit.

Nonlinear analysis of an electrodynamic broadband energy harvester

In order to maximize energy from ambient vibration sources, wide band harvesters working at a range of frequencies are important. This paper presents an electrodynamic energy harvester model working for a frequency band from 25 Hz to 45 Hz. The developed converter consists of a magnetic spring formed by one moving magnet placed between two fixed magnets. A ring magnet is placed around the moving magnet leading to additional nonlinear stiffness to increase the power output. A comparison to a basic configuration electrodynamic converter was carried out by finite element analysis to show that a significant increase in power output was realized. Simulation results have been confirmed by experimental investigations under harmonic excitations. Based on the experimental time series, we have examined the frequency spectrum and phase portraits to identify the dynamic response of the system. In conclusion, the generator is able to harvest 1.5 times more energy than the simple generator for the bandwidth of 20 Hz with the resonant frequency of 35 Hz and the excitation amplitude of 2 mm.

Electrodynamic energy harvester for electrical transformer’s temperature monitoring system

The development of an electrodynamic energy harvester (EDEH) for operating a wireless temperature monitoring system for electrical transformer is reported in this work. Analytical modeling, fabrication and characterization of EDEH prototype are performed. The developed EDEH consists of a mild steel core, a wound copper coil and Teflon housing. COMSOL Multiphysics software is used to optimize the design of the harvester. The split-cylindrical design of the developed EDEH permitted the harvester to be wrapped around the output power cable of the electrical transformer without shutting-off the power or disconnecting the power cable. From the electrical transformer, at current levels of 27, 72 and 155 A in the main power line, the energy harvester produced maximum RMS load voltages of 0.356, 1.09 and 2.58 V respectively, when connected to 100 Ω load resistance. However, at matching impedance of 24 Ω (resistance of the coil), the EDEH produced the maximum power levels of 2.99, 19.66 and 112.03 mW for a cable currents of 27, 72 and 155 A respectively. The simulation results of the devised analytical model of the harvester are in good agreement with the experimental results. Moreover, at a cable current of 93 A, when the harvester is connected to the rectifying circuit, the optimum impedance shifted to 185 Ω and the maximum power of 19 mW is generated at that load. The reduction in power generation is attributed to the power consumption of the rectifying circuit. When the rectified DC voltage is used to charge a 3.8 V, Nickel–Cadmium (Ni–Cd) rechargeable battery, it took 3 h to completely charge the battery from 1 to 3.85 V. With the charged battery a wireless temperature sensor node is successfully operated for monitoring the temperature of the electrical transformer.

Harvesting Energy from the Counterbalancing (Weaving) Movement in Bicycle Riding

Bicycles are known to be rich source of kinetic energy, some of which is available for harvesting during speedy and balanced maneuvers by the user. A conventional dynamo attached to the rim can generate a large amount of output power at an expense of extra energy input from the user. However, when applying energy conversion technology to human powered equipments, it is important to minimize the increase in extra muscular activity and to maximize the efficiency of human movements. This study proposes a novel energy harvesting methodology that utilizes lateral oscillation of bicycle frame (weaving) caused by user weight shifting movements in order to increase the pedaling force in uphill riding or during quick speed-up. Based on the 3D motion analysis, we designed and implemented the prototype of an electro-dynamic energy harvester that can be mounted on the bicycle's handlebar to collect energy from the side-to-side movement. The harvester was found to generate substantial electric output power of 6.6 mW from normal road riding. It was able to generate power even during uphill riding which has never been shown with other approaches. Moreover, harvesting of energy from weaving motion seems to increase the economy of cycling by helping efficient usage of human power.