A micro electromagnetic generator for vibration energy harvesting

Abstract

Vibration energy harvesting is receiving a considerable amount of interest as a means for powering wireless sensor nodes. This paper presents a small (component volume 0.1 cm 3 , practical volume 0.15 cm 3 ) electromagnetic generator utilizing discrete components and optimized for a low ambient vibration level based upon real application data. The generator uses four magnets arranged on an etched cantilever with a wound coil located within the moving magnetic field. Magnet size and coil properties were optimized, with the final device producing 46 µW in a resistive load of 4 k from just 0.59 m s −2 acceleration levels at its resonant frequency of 52 Hz. A voltage of 428 mVrms was obtained from the generator with a 2300 turn coil which has proved sufficient for subsequent rectification and voltage step-up circuitry. The generator delivers 30% of the power supplied from the environment to useful electrical power in the load. This generator compares very favourably with other demonstrated examples in the literature, both in terms of normalized power density and efficiency.

Enhancing the reliability of mobile robots control process via reverse validation

“…So far, it has been possible to determine the trajectory of the arm or the working tool of the mobile robot during the motion in space only by photogrammetric methods. 9 Ensuring higher accuracy is enabled by geodetic methods. However, they require the arm of the mobile robot to be at rest.…”

Comparison of energy harvesting systems for wireless sensor networks

“…A range of material combinations and magnet/coil configurations have been considered in research devices and a limited number of commercial units developed [80] . It has also been shown that an optimised device is capable of converting up to 30% of the total energy supplied into useful electrical energy [81] .…”

“…Beeby [51] presented tabulated results for a range of vibration based devices grouped according to the conversion method. The same group [81] presented a graphical comparison based on normalised power density (output power normalised for acceleration, Pout/A 2 ) but excluded the effect of frequency. Mitcheson et al [89] presented a comparison based on an estimate of efficiency which relied on assumptions about the input power supplied to the device.…”

Development of an Indoor Airflow Energy Harvesting System for Building Environment Monitoring

“…Theoretically, any kind of vibration source can be transformed into electric power [8]. There are three basic techniques for this kind of conversion: piezoelectric transducers-energy is induced by the deformation of piezoelectric materials, like PZT ceramics, PVDF films and piezoelectric composite fibers [9]; spring-mass electromagnetic transducers-energy is generated between a moving magnet and a coil based on Faraday's law [10][11][12]; and electrostatic transducers-energy is generated by charged vibrating capacitor electrodes [13,14].…”