Improvement of DC Short-Circuit Fault Ride Through Capabilities Based on Hybrid Modulated Model Predictive Control for Hybrid MMC-HVDC

In this article, the hybrid modulated model predictive control (HM<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>PC) method for the hybrid modular multilevel converter (hybrid-MMC) in high voltage direct current (HVDC) applications is introduced to improve the fault ride-through (FRT) capabilities on the direct current side (DCS). For the studied system, compared to conventional PI-based control method under DC short-circuit fault (DC-SCF) conditions, the proposed HM<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>PC demonstrates faster dynamics, lower dc and arm over-currents (reduced by 62% and 47%, respectively), moderate voltage fluctuations in submodule capacitors, and lower fault clearing (FC) time (reduced by 48%). While HM<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>PC shares the advantage of rapid dynamic response with model predictive control (MPC) techniques during fault conditions, it offers additional benefits over direct (DMPC) and indirect MPC (IMPC) methods, such as reduced computational complexity, independence from the converter's number of levels, and the elimination of the need for weighting factor tuning. As a result, the proposed method combines fast dynamic performance in DC-SCF conditions with ease of implementation on digital standard platforms. To validate the proposed method under DC-SCF conditions, simulations are conducted based on real high-power HVDC applications and MTDC grids in MATLAB/simulink. For comparing and experimental validation, the proposed HM<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>PC, IMPC, and conventional PI-based methods have been implemented on a five-level (5L) hybrid-MMC setup based on ZYNQ module hardware in DC-SCF conditions, and the results confirm the claims.