Design of modular multilevel converter Hardware-in-Loop Platform based on RT-lab

Modular multilevel converter (MMC) as a new converter topology has been widely used in the field of the high voltage direct current transmission (HVDC) and flexible alternating current transmission system (FACTS). This paper established a MMC Hardware-in-Loop (MMC-HIL) Platform based on RT-LAB. This platform contains a monitor computer, the OP5600 object machine, a modular multilevel converter, digital and analog interfaces and the protection system. Design principles and implementation schemes for the proposed platform are all introduced. And the control strategy for MMC is also analyzed in this paper, including stratified balance control strategy of sub-module capacitor voltage and circulating current suppressing control strategy based on proportional resonant (PR) regulator. The experimental results validate the effectiveness of the proposed strategy. They show that this MMC-HIL platform based on RT-LAB provides a convenient way for control strategy developing.