Inverse decoupling sliding mode control for multilevel buck converters in low-power applications

Multilevel buck converters are gradually gaining attention in low-power applications. To realize the decoupling of the flying capacitor voltage and the output voltage, this paper proposes an inverse decoupling sliding mode control approach. A nonlinear mathematical model of the multilevel buck converters is built. The reversibility of the model is analyzed based on the inverse system theory, and linearization and decoupling are achieved. In addition, multiple pseudo-linear subsystems are obtained. Then sliding mode controllers are designed to control the linear subsystems. Furthermore, the global asymptotic stability of the control system is verified using the Lyapunov theory, and the robustness of the closed-loop system is demonstrated. Simulation and experimental results show that the proposed approach provides a better dynamic response when compared with existing methods.