A Wide Range Four-Switch DC/DC Converter Based on Switched-Inductor Units

Non-isolated buck-boost DC/DC converters play a key role in many applications such as DC microgrids and electric vehicles. To achieve wider output voltage gain range and higher conversion efficiency, a new four-switch buck-boost converter based on switched-inductor (SL) unit is proposed in this paper. It could effectively extend the output voltage gain range and reduce the current stress of the switches. Through the analysis of three steady-state modes namely buck mode, boost mode and buck-boost mode, a new control method based on gain judgement is designed, which realizes smooth switching among the three modes based on the dual-modulation-wave single-carrier-wave modulation strategy. Experiments are conducted which verified the wide gain range and high efficiency as well as the effectiveness of the proposed three-mode switching control strategy.