In this paper, different configurations of self-powered active rectifier circuits for energy harvesting in autonomous sensors are proposed. The circuits perform the conversion of the AC voltage provided by the mechano-electrical energy converter, and store the energy into multiple capacitors. The proposed Sequential Charging of Storage Capacitors (SCSC) technique has been developed to improve the energy extracted from converters with non-deterministic output voltage over a limited duration. Experimental results show that SCSC active rectifier circuits allow an increase of up to 147% of the stored energy versus passive rectifiers at same mechanical input.