An isolated soft switching buck boost converter utilizing two transformers and embedded bidirectional switches on secondary side for wide voltage applications
A dual phase shift controlled isolated buck boost converter is presented for wide input or output voltage range applications. Two transformers and a voltage doubler rectifier with embedded bidirectional switch are employed. The primary windings of the two transformers are in series and the secondary windings are in parallel. With optimized dual phase shift modulation strategies, zero voltage switching (ZVS) is achieved for both the primary and secondary side power MOSFETs in a wide load range. The reverse recovery problem of rectifying diodes is eliminated as well. Leakage inductances of the transformers are utilized for power transferring. The voltage stresses of primary side and secondary side power MOSFETs are clamped to the input voltage and half of the output voltage, respectively. Besides, the converter can operate in the buck, balance and boost modes to achieve a wide voltage range. The operational principles are analyzed and experimental results of a 1 kW 100 kHz prototype are provided to verify the effectiveness of the presented converter.
2016 IEEE Applied Power Electronics Conference and Exposition (APEC)