An effect of coupling factor on the power output for electromagnetic vibration energy harvester †

Sensors are devices that measures a change in physical stimulus by converting it into an electronic signal which can be read by a designated instrument. To overcome the real-life challenges associated with powering a sensor using conventional batteries and chargers, this work focuses on formulating analytical framework for designing an ecofriendly, cheap, almost zero retrofit implication (except on damage) power module for sensors using an electromagnetic vibration energy harvester. This principle relies on the electromagnetic transduction whose harvested voltage/power is formulated from Faraday law of electromagnetic induction. An electromagnetic parameter that determines the degree of transduction is the coupling constant. The value of coupling constant must be accurately set during harvester design because it directly determines harvester damping ratio and the power available for the sensor. All parameters used to compute the coupling except the flux density are constant. In this work, we focus on formulating a set of analytical equations that could effectively determine the harvester’s optimum magnetic flux parameter to be used in computing the optimum coupling constant, the electromagnetic damping ratio, and the harvested power at resonant. This work concludes that the degree of coupling for the determined optimum flux density increases with an increased load resistance and hence larger harvested power is available to power the sensor.