An Improved Quadrangle Control Strategy for Four-Switch Buck-Boost Converters With Load Current Feedforward

The insufficient dynamic response of Four-Switch Buck-Boost (FSBB) converters in 48V data center power systems is addressed in this study through the proposal of a load current feedforward dynamic control strategy. A small-signal model of the FSBB converter is established, and a voltage single-loop control architecture without current inner loops is designed. Compensation is achieved through the direct injection of load current derivative signals, resulting in a significant enhancement of control bandwidth. Simulation results demonstrate that, at a switching frequency of 500 kHz, the transient response time during load step changes is reduced by 33% compared to conventional PI control, while output voltage variation is decreased by more than 50%. The effectiveness of the proposed methodology is thereby validated.