An Improved Indirect Model Predictive Control Approach for Modular Multilevel Converter

The computational complexity is one of the major issues in the implementation of direct model predictive control (D-MPC) for modular multilevel converters (MMC). The computational complexity is significantly reduced by combining the conventional voltage balancing approach with the MPC. This approach is referred as indirect model predictive control (I-MPC). The D-MPC and I-MPC approaches have higher voltage harmonic distortion and current ripple. In this paper, an improved indirect model predictive control (II-MPC) is proposed to overcome the drawbacks of D-MPC and I-MPC approaches. To implement the II-MPC strategy, a detailed three-phase MMC model is presented. The simulation studies are conducted on a three-phase half-bridge based MMC to validate the dynamic and steady-state performance of II-MPC strategy.