A quasi-closed-loop control strategy for efficiency-oriented DC–DC converters under mixed steady-state and transient conditions

This paper proposes a quasi-closed-loop control strategy for DC-DC converters to achieve improved power efficiency while maintaining dynamic response. The proposed approach allows the converter to operate in open-loop mode under steady-state conditions to reduce control-induced losses and activates closed-loop voltage or current regulation only when significant disturbances or overcurrent events occur. Taking a boost converter as a case study, the dual-mode switching logic between open-loop and closed-loop operation is developed, and the coordination mechanism between voltage and current closed-loop modes is investigated. An internal state update method for the digital controller is designed to ensure smooth mode transitions without voltage or current discontinuities. The hardware prototype and experimental platform are established to validate the proposed strategy. Experimental results under various load-switching conditions demonstrate reduced voltage and current overshoot, faster error convergence, and improved steady-state efficiency. Efficiency comparison results further confirm the effectiveness of the proposed quasi-closed-loop control strategy. • Analytical formulation of loss which is introduced by close-loop regulation. • Proposition of control algorithm which combines open loop and close loop regulation. • Incremental optomization of control algorithm for enhanced dynamic response.