Energy concept-based nonlinear stabilization and control for Modular Multilevel Converters for voltage oscillation reduction

The Interconnection and Damping Assignment Passivity-Based Control (IDAPBC) is applied phase-independently to the Modular Multilevel Converter (MMC) in order to overcome “dqo”-based control problems. In addition, an equilibrium point estimator is proposed to determine the time-varying equilibrium state of the MMC needed as input for the non-linear controller. This control strategy provides global robust stabilization of the MMC against variations on both its AC and DC sides. The control + estimator strategy combines both the state-space and energy dynamics models of the MMC.