Optimal Multivariable MMC Energy-Based Control for DC Voltage Regulation in HVDC Applications

The penetration of renewable energy resources is changing the way the power system is understood and operated. With an increasing number of power electronics devices integrated into the power system, the MMC is arising as one of the key technologies for HVDC applications. While several control strategies for MMCs have been proposed in the last years, designing controls for MMCs remains a challenging and non-trivial problem due to its large number of degrees of freedom. In this paper, a general multivariable control structure is proposed that generalizes and improves upon previously reported approaches. Moreover, to fully exploit the degrees of freedom offered by this control, a model-based tuning methodology is presented that extends results from optimal H2 structured control design to MMC applications. A case study using an HVDC link is used to illustrate and analyze the performance of the MMC of the proposed approach in different scenarios.