Modular multilevel converter modeling for power system studies

This paper presents two modular multilevel converter model versions that could be used for power system studies, with slow dynamics. Additionally, the interfacing of the presented models with the control systems is been demonstrated when both models are used to simulate an HVDC converter station that operates in an inversion mode. The presented models have been validated against a detail modular converter model with 16 cells per arm (the same power rating and control systems). It is shown that the presented models are able to match the results obtained from a detail switch model of the modular converter. This includes active and reactive power manipulation, and voltage and current waveforms. Further results that illustrate the potential use of a modular converter dq model in small signal stability are also presented. This paper also presented detailed design of the current controller, taking into account the internal parameters of the modular converter.