A bridgeless configured asymmetrical alternating current–direct current converter-based isolated single-stage electric vehicle battery charger with supply side power factor enhancement

Abstract

An approach is presented to employ two different types of converters in bridgeless configuration for supply side power factor enhancement of the system. The isolated single-stage electric vehicle battery charger uses two different converters in a bridgeless configuration to extract the advantages of both converters for supply-side power factor enhancement. For the negative and positive semi-cycles of the supply voltage, the power factor-enhanced asymmetrical alternating current–direct current converter utilises a fourth order single-ended primary-inductor converter and a second order buck-boost converter, respectively. The use of single-ended primary-inductor converter and buck-boost converter in bridgeless configuration reduces the net order of the system with respect to conventional bridgeless-single-ended primary-inductor converter schemes. The buck-boost converter also needs the supply-side filter to eradicate the unwanted harmonics in the supply current which increases the order of the system. The usage of both converters presents many benefits like input inductance of the single-ended primary-inductor converter can be utilised as a filtering element with a capacitor for the buck-boost converter. The anti-parallel diode conduction operation of both switches facilitates the elimination of extra reverse feed diodes (generally used in bridgeless schemes). The single-stage charger itself comes with the benefit of elimination of extra stages and thus the losses associated with it. The presented charger also witnesses the elimination of the rectifier due to usage of bridgeless configuration. The isolated single-stage electric vehicle battery charger is also garnished with electrical isolation which adds to the safety standard of the system. To attain power factor enhancement, the asymmetrical alternating current–direct current converter functions in discontinuous current conduction mode in the present work. The elimination of extra-stages (with respect to two stage charger), a filter, a rectifier, two extra reverse-feeding diodes, one voltage sensor, one current sensor (with respect to continuous current conduction mode), and electrical isolation not only makes the system compact and safer but also makes the system cheaper. Elaborated mathematical modelling and stability analysis of the presented alternating current–direct current converter using a pole-zero map and bode plot have been included in the article. The prototype and MATLAB/Simulink model of isolated single-stage electric vehicle battery charger system with discontinuous current conduction mode control has been built and results of both prototype and MATLAB/Simulink are deployed to verify isolated single-stage electric vehicle battery charger system's performance during dynamic and steady-state conditions.