An independent AC-DC converter operating on buck and buck-boost topology for low power harvesting

Independent powered devices harvest the ambient energies by micro generators and can perform their Operations without any continuous external power supply. Many types of micro-generators, used in the self-powered devices, are reported in the literature for harvesting different forms of ambient energies. Minimum voltage generators requires higher efficiency which can be obtained by direct conversion of low ac input voltage to required high voltage dc output at higher efficiency.ac-dc bridge converters may not be of practical use for operation of micro generators. This paper presents a novel ac-dc converter topology for low power harvesting where a boost converter is operated in positive half cycle and a buck-boost converter is operated in negative half cycle. For independent operation a self-starting circuit is proposed and power parameters and duty cycle are used to operate and control the converter where detailed loss calculation of converter is carried out. Experimental results are also presented along with simulation Design guidelines are presented for selecting the converter component and control parameters.