Multivariable Optimal Control of HVDC Transmission Links With Network Parameter Estimation for Weak Grids

Abstract

This paper features a model predictive control approach for high-voltage direct current lines (HVDC), where in particular the voltage source converter (VSC) HVDC configuration is investigated. The target is to develop a control method which, given the requested power and voltage values, yields an appropriate set of voltage references to be fed to the modulation scheme of the VSC. A parameter estimation scheme for the model employed in the model predictive control formulation is included. Since the chosen control approach directly encompasses the multivariable nature of the problem, no phase-locked loop is required for the purpose of dq frame alignment, facilitating tuning in the case of weak grids. The considered system is presented, the derived control procedure is described, and numerical simulations are illustrated showing the performance of the proposed approach.