Parasitic Resistance Effect on Four Switch Buck–Boost Converter for Wide Range Voltage Control

In this article, the effect of parasitic resistance on multimode operation of four-switch buck boost converter is first revealed. To meet the wide voltage range of distributed energy resource, the converter operates as a versatile circuit with buck, transition, and boost modes. At the boundary between buck and transition mode, the parasitic resistance will introduce voltage overshoot. In contrary, at the boundary between transition and boost mode, the parasitic resistance will lead to oscillation and instability. To solve the problem, the additional voltage overlap is artificially introduced to compensate the parasitic resistance. The expense of voltage overlap has been analyzed considering current stress and voltage overshoot. To suppress the voltage overshoot during mode switching, control compensation is proposed in the voltage control loop. The influence of parasitic resistance and the proposed compensation method has been tested through comparative simulations and experimental results, in verification of stable voltage regulation under wide output voltage range.