AC-DC Boost Modelling for Magnetostrictive Energy Harvesting

The maximization of the output voltage is one of the most important aspects for those magnetostrictive Energy Harvesting applications where the excitation is such that the exploitable voltage ranges are much lower than the electronic standards 1.6, 3.3 and 5 V. On the other hand, a passive rectifier stage (diodes bridge), followed by a DC-DC Boost converter, involves power losses and consequently a reduced conversion efficiency. Then, a direct AC-DC Boost converter can be used. Several AC-DC techniques have been presented over the years for piezoelectric harvesters but very few or none for magnetostrictive ones. This paper presents the simulations of a combined model which couples a nonlinear model of a magnetostrictive Energy Harvesting device and the modelling of a direct AC-DC Boost converter. The simulations showed that the nonlinear modelling allows to consider a realistic voltage input for the AC-DC boost stage. Moreover, it has been found a linear dependence between the Duty Cycle and the Time Delay parameters, when the maximum output voltage is aimed.