Flux feedback mechanism for realizing enhanced flux density in an electromagnetic vibration energy harvester

This work focus on improving the efficiency of the transducer that could harvest and convert ambient vibration into electrical energy by using a coupled coil-magnet transducer model. During vibration, the electrical energy is induced in the coil by electromagnetic induction, such energy could successfully power sensor nodes and micro devices. Since the degree of the flux filed of the permanent magnet determined the extent of coupling and the voltage/power induced in the coil during vibration, this work focus on how to realize an improved flux field in the coil using a flux feedback mechanism in the magnet geometry. While noting that the flux density in the model without feedback increase by approximate 4.00 % for every 0.50 mm increase in the thickness of the flux converging steel, the model with feedback shows that for equivalent increase in the feedback thickness, a higher flux density is measure at the center coil slot position, however, the flux depleted with increasing feedback thickness at the sided coil slot position on the model with feedback. If the slotted coils are connected in series over equivalent R
l
, when zero flux leakage is realized in both conventional and flux feedback model, the harvested power on the feedback model improved by 57.36 % and 9.94 % at = w
s‒con
= 0.20, w
s
= 1.00 mm and w
s
= 2.00 mm respectively relative to conventional model at w
s‒con
= 0.00 mm and w
s
= 5.00 mm.