Self-powered solution of synchronous current inversion and energy extraction (SCIEE) for electromagnetic energy harvesting enhancement

Self-powered and self-start issues are essential for the standalone applications of switched-mode interface circuits for micro-generators. This paper introduces a self-powered and self-starting solution for small-scale electromagnetic energy harvesters. The self-start solution uses a passive voltage multiplier and an energy buffer-release circuit to kickstart the circuit during cold start-up. Introducing an energy buffer-release mechanism in the start-up process reduces the required voltage amplitude for cold-start. The energy buffer-release circuit features low power dissipation and adjustable thresholds. The operation principle of the proposed energy buffer-release circuit is elaborated. The voltage thresholds are theoretically derived and experimentally validated. In experiments, the proposed start-up circuit is applied to the synchronized current inversion and energy extraction (SCIEE) circuit, which enhances the harvested power of a low-voltage electromagnetic energy harvester. Experiments show that it can start at a relatively small input voltage amplitude, as small as 1.35 V. The total power consumption of the start-up and control circuits accounts for 8.8 % of the harvested power at 14 V load voltage. The energy buffer-release circuit only dissipates around 46 μW.