Full-Digital Soft-Switching Control Method for Four-Switch Buck-Boost Converter With Wide Voltage and Load Ranges

A full-digital pulsewidth modulation (PWM) plus phase shift control method is proposed in this article for zero-voltage-switching (ZVS) of the four-switch buck-boost (FSBB) converter. Based on the quadrilateral inductor current modulation, the ZVS can be realized in wide voltage and load ranges. The proposed control method can be digitally implemented without any additional hardware, which eliminates the zero-crossing detection (ZCD) circuits. In addition, effective judgment methods have been proposed for the multisolution problem of the duty cycle in digital control, which can achieve stable operation. Finally, the experimental results verify the effectiveness and correction of the proposed full-digital soft-switching control method for the FSBB converter.