Research on single stage combined uninterruptible AC-DC converters with high power factor

A circuit structure and circuit topologies family of single stage combined uninterruptible AC-DC converters with high power factor based on boost-flyback converter are proposed. The converter which is constituted of a full bridge rectifier and a boost-flyback converter with power factor correction, uninterruptible power supply and fast output voltage regulation, can transfer one AC voltage into desired output DC voltage. The three operational modes (normal operating mode, back-up operating mode, charging operating mode ) , steady principle, control strategy ,and design criterion of key circuit parameters are investigated. The test results are given. The converter has the advantages of single stage power conversion, uninterruptible power supply, high line power factor, high frequency electrical isolation between battery and line or load, fast regulation speed of the output voltage, small size, lower weight , low cost. The converter can be used application field in the telecom, computer industry and so on.