Design of wideband vibration-based electromagnetic generator by means of dual-resonator

This paper describes the design of a wideband electromagnetic energy harvester that utilizes a novel dual-resonator method to improve the operational frequency range of the vibration-based generator. The device consists of two separate resonator systems (coil and magnet), which each comply with their respective resonance frequencies. This is because both resonators are designed in such a way that both magnet and coil components will oscillate at an additive phase angle, and hence create greater relative motion between the two dominating resonance frequencies, which realizes the wideband generator. Each resonator system consists of a distinctive cantilever beam, one attached with four magnets and steel keepers, the other attached with a copper coil and stainless steel holder as the free end mass. Both cantilevers are clamped and fitted to a common base that is subjected to a vibration source. Basic analytical models are derived and a numerical model is implemented in MATLAB-Simulink. Electromagnetic, structural modal and static mechanical analysis for the design of the prototype are completed using ANSYS finite element tools. For a 0.8 m s−2 acceleration, the open-loop voltage obtained from the experiment shows a good correlation with those from the simulation. Peak induced voltage is measured to be 259.5Vrms as compared to 240.9Vrms from the simulator at 21.3 Hz, which implies an error range of 7.7%. The results also indicate that there is a maximum of 58.22% improvement in the induced voltage within the intermediate region which occurs at the intersection point between the output response plots of two single resonator generators

Magneto-Mechanical Transmitters for Ultra-Low Frequency Near-field Communication

Electromagnetic signals in the ultra-low frequency (ULF) range below 3 kHz are well suited for underwater and underground wireless communication thanks to low signal attenuation and high penetration depth. However, it is challenging to design ULF transmitters that are simultaneously compact and energy efficient using traditional approaches, e.g., using coils or dipole antennas. Recent works have considered magneto-mechanical alternatives, in which ULF magnetic fields are generated using the motion of permanent magnets, since they enable extremely compact ULF transmitters that can operate with low energy consumption and are suitable for human-portable applications. Here we explore the design and operating principles of resonant magneto-mechanical transmitters (MMT) that operate over frequencies spanning a few 10's of Hz up to 1 kHz. We experimentally demonstrate two types of MMT designs using both single-rotor and multi-rotor architectures. We study the nonlinear electro-mechanical dynamics of MMTs using point dipole approximation and magneto-static simulations. We further experimentally explore techniques to control the operation frequency and demonstrate amplitude modulation up to 10 bits-per-second.Comment: 10 pages, 9 figure

Pendulum Energy Harvester with Amplifier

This paper presents a new principle of inductive vibration power harvester. Harvester is a pendulum that uses energy capacitor which is the mass. The mass is connected to the pendulum via a gearbox to achieve greater movement of the pendulum that generates an electromagnetic voltage. The harvester is developed at a very low frequency (1-10 Hz) which uses the rectified magnetic fluxes. Magnets are statically placed in the harvester case, and relative motion is carried out by the coil. Magnets are static, and the coil moves due to the weight ratio of magnets which the steel leads of the magnetic flux and the coil itself. This paper is focused on a harvester with a mechanical amplifier with the proposed technique is brings the plow harvester access with an auxiliary force. The experimental results indicate that the optimal results of the harvester with an accumulator for the resonant zone are 3.75 Hz, 7 Hz, and 10 Hz

Harvesting EM Energy to Produce Electrical power

The desire to transfer power wirelessly is not a new phenomenon in today’s world. The idea has been driven by the need to diversify the traditional methods of using wires to transfer energy from one point to another. Wireless power transfer also plays a very important role in such a way that electronic devices such as cell phones and laptops could be charged wirelessly. The advancement in technology, the influx of electronic devices and the cost of cables is an alarm to influence the work on wireless power transfer. Wireless power transfer is mostly dependant on the property of magnetic induction. By selecting a specific resonant frequency of an induction circuit, energy can be transferred wirelessly from one circuit to another of the same resonating frequency. The result of this project shows that very little power can be transferred wirelessly using electromagnetic induction. However, improvements can be made to the circuits to obtain better results in the future

Magnetic docking stations for remotely powered light emitting diodes

Light emitting diodes (LEDs) are efficient light sources which due to low power consumption often are considered for demonstrations of wireless energy transmission. It is often not only necessary to power these light sources wirelessly, but also to ensure that they conveniently dock at the correct position as effortlessly as possible without the need for chemical adhesives or mechanical attachment. In the current work a passive magnetic docking system which aids attachment of wirelessly powered LEDs is proposed. The system utilizes electromagnetic induction of nearby coils to power the LED. The spatial range of the magnetostatic interactions is controlled by the specific magnet arrangement used, such that the light is turned on either before or after docking is initiated. The constant and time-varying magnetic fields occupy the same volume, thus allowing the presenter to demonstrate the difference between magnetostatic interactions locking the LED in place and electromagnetic induction turning the LED on. It is demonstrated that the proposed system works well for light signaling in salt water, and may find use in wireless underwater communication.acceptedVersio

Advanced Energy Harvesting Technologies

Energy harvesting is the conversion of unused or wasted energy in the ambient environment into useful electrical energy. It can be used to power small electronic systems such as wireless sensors and is beginning to enable the widespread and maintenance-free deployment of Internet of Things (IoT) technology. This Special Issue is a collection of the latest developments in both fundamental research and system-level integration. This Special Issue features two review papers, covering two of the hottest research topics in the area of energy harvesting: 3D-printed energy harvesting and triboelectric nanogenerators (TENGs). These papers provide a comprehensive survey of their respective research area, highlight the advantages of the technologies and point out challenges in future development. They are must-read papers for those who are active in these areas. This Special Issue also includes ten research papers covering a wide range of energy-harvesting techniques, including electromagnetic and piezoelectric wideband vibration, wind, current-carrying conductors, thermoelectric and solar energy harvesting, etc. Not only are the foundations of these novel energy-harvesting techniques investigated, but the numerical models, power-conditioning circuitry and real-world applications of these novel energy harvesting techniques are also presented

Human movement energy harvesting : a non-linear electromagnetic approach

Energy harvesting is one of the methods that currently engage actively in energy “recycling”. Of the many energy sources that carry the potential to have energy harvested and recycled, humans are seen as a potential source of energy. High amounts of energy are wasted from daily activities that humans do, if only a portion of the wasted energy can be harvested and reused with the aim of improving the quality of life of the user.To do that, the accelerations of selected movements are recorded from sensors attached to four different locations of the body. Human movements operate on a low and wide frequency scale, nonlinear energy harvesting techniques is seen as a suitable technique to be applied. Nonlinear energy harvesting techniques are expected to increase the bandwidth of operation of the energy harvester. The electromagnetic method of transduction is also selected (using two opposing magnets) to be paired with the nonlinear energy harvesting techniques to evaluate the potential of energy harvesting from human movements. The pick-up coil to be used will be placed at a novel location within the energy harvester prototype.Through simulations and experiments, frequency responses obtained did show an increase in bandwidth which agrees with literature from nonlinear energy harvesting techniques. Phase portraits are also used to provide a more in depth understanding on the movements from the cantilever under linear and nonlinear dynamics. Result comparisons were made between the simulation model and the experimental prototype to verify the agreement between the two.Additionally, results obtained also showed that the resonant frequency of the system was reduced when operating under the nonlinear regime. These attribute favour energy harvesting though human movements.Finally, the novel placement of the pick-up coil within the nonlinear electromagnetic energy harvester had the desired effect. Similar power outputs were achieved even though the separation distances between the two opposing magnets were varied