A miniaturized cost effective shared inductor based energy management system for ultra-low-voltage electromagnetic energy harvesters in battery powered applications

This paper presents a miniaturized and cost effective energy management system (EMS) for ultra-low-voltage electromagnetic energy harvesters (EMEHs) in battery powered applications. The EMS topology is based on utilizing a single inductor that is shared between positive and negative half cycles of the EMEH voltage and hence achieving system's cost and size reductions. Also, the EMS topology utilizes a smaller number of active components compared to existing solutions, used with ac harvesters, and hence allowing for further reduction in system's cost and simple implementation. The shared inductor is not only used by the power stage but also as a key part of the bias supply scheme. The EMS converts EMEH's ac voltage into a dc one in a single step and provides a maximum power point tracking (MPPT) feature to maximize the harvested energy. Experimental results show the effectiveness of the presented solution to provide MPPT for EMEH that has a damped voltage characteristics ranging from 1.2V to 10mV. The presented solution achieves 86.5% and 50% reductions in magnetics volume, which is the biggest contributor to the real estate of the EMS, compared to [1] and [2], respectively. Also, it can harvest more energy by 41.6% and 21.4% compared to [1] and [2], respectively, while reduces the BOM cost by 57.6% compared to [2].