A Novel direct AC/DC converter for efficient low voltage energy harvesting

In this paper, a direct ac-to-dc power converter is proposed for efficient energy harvesting from the low voltage inertial microgenerators. The conventional power converters use diode bridge rectifiers and condition the microgenerator outputs in two stages. Hence, they are inefficient and may not be a feasible option for very low voltage microgenerators. Moreover, they are not conducive for optimum energy harvesting. The proposed converter avoids the use of bridge rectifiers, and directly converts the ac input to the required dc output. This converter uses a boost converter and a buck-boost converter to process the positive and negative half cycles of the ac input voltage, respectively. Furthermore, using this converter, maximum energy harvesting can be implemented effectively. Analysis of the converter is carried out. Based on the analysis, two schemes are proposed to control the converter. Simulation results are presented to validate the proposed converter topology and control scheme. Experimental results are also presented for verification.