Implementation of an Efficient Transformerless Single-Stage Single-Switch AC/DC Converter

A transformerless single-stage single-switch ac/dc converter is presented in this paper. The converter allows a portion of the input power to be processed once only, resulting in enhanced conversion efficiency. Additionally, due to the absence of a transformer, the size and manufacturing cost of the converter can be reduced. The intermediate bus voltage is well kept below 400 V while maintaining high power factor even at light load and high line-input conditions. Extended experimental results on a 100-W hardware prototype for universal input-voltage range (90-270 Vrms) are given to confirm the theoretical analysis and performance of the proposed converter.