Optimal control of multilevel boost converter via exact feedback linearization and decoupling

Multilevel boost converter is a multi-input multi-output nonlinear strongly coupled system. There is a coupling relationship between flying capacitor voltages and output voltage. In this paper, an optimal control method for n + 1-level boost converter based on exact feedback linearization and decoupling is proposed. The flying capacitor voltages and energy function are selected as the output functions to linearize and decouple the original system into n - 1 first-order subsystems and a second-order subsystem. Based on the optimal control theory, flying capacitor voltage balancing controllers are designed for n - 1 first-order subsystems, and an output voltage regulating controller is designed for the second-order subsystem. A five-level boost converter control system is verified by numerical simulation and a three-level boost converter control system is verified by experiment. Simulation and experimental results show that the proposed control strategy has better dynamic regulation performance and stronger robustness than PI decoupling control strategy based on small-signal model.