Bridgeless AC-DC buck-boost converter with switched capacitor for low power applications

AC-DC converters are mostly used as power supplies for microelectronic systems, battery chargers, wind energy applications, electric appliances in household and dc motor drives. Switched-capacitor (SC) network based converters can be good solution to the challenges of 21st century having high voltage conversion ratio and low EMI emissions. The application of this type of converters is in microprocessor based systems where the line voltage requires a steep step down to 3V or even less in order to drive integrated circuits (ICs). In this paper, a new high step down bridgeless single switch AC-DC converter with switched capacitor is proposed. The absence of transformer as well as bridge rectifier reduce the components count, size and cost of the converter. Unlike the existing converters, this proposed buck-boost converter is able to achieve simple control structure with single switch, high efficiency, low total harmonic distortion (THD) and high input power factor.