Nonlinear control of modular multilevel converters

To dealing with the multivariable, nonlinear and strong coupled characteristics of modular multilevel converters (MMC), a sliding mode variable structure control strategy based on feedback linearization is proposed. Firstly, the nonlinear state function model of the MMC is built and transformed into a linearized and decoupled model by utilizing output-redefined feedback linearization method in order to implement decoupling control. On the basis of the linearized model, a sliding mode variable structure controller is designed. The simulation results show that the proposed control strategy has favorable steady-state and dynamic performance. It also has good robustness against system parameter deviations. © 2020, Editorial Board of Acta Energiae Solaris Sinica. All right reserved.