Predictive Power Control of Modular Multilevel Converter for Wind Energy Integration via HVDC

The modular multilevel converter-based highvoltage direct current (MMC-HVDC) transmission technology has become a promising solution for integrating offshore wind energy. In the MMC-HVDC wind energy integration system, the grid-side MMC (GSMMC) is in charge of transferring active and reactive power and guaranteeing power quality to fulfill grid codes. For the GSMMC with multiple nonlinear control objectives, model predictive control (MPC) is an effective control alternative. In order to avoid the inherent heavy computation, generally, three independent MPC controllers are designed to regulate the three-phase currents of the MMC, respectively. Therefore, the predictive power control cannot be realized in such three-phase independent control structure, resulting in the design of extra PI-based power controllers and poor power control performance. Aiming at these challenges, this paper proposes a direct model predictive power control (DMPPC) solution to simultaneously control power, circulating currents and capacitor voltages for the GSMMC, which is realized within a three-phase centralized MPC controller. Finally, a comparative study with the simulation results verify that the proposed DMPPC method shows better steady-state and dynamic performance than the PI-MPC.