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Summary: This paper focuses on the steady‐state power distribution region of the modular multilevel converter (MMC) and the matching among its multiple constraints. First, an equivalent model of the steady‐state MMC is established, and its basic power distribution region is solved based on analysis. Second, the influence of the AC current constraint, the AC outlet voltage constraint, the modulation index constraint, the DC current constraint, and the DC voltage constraint on the power distribution region are studied through the phasor analysis method. The power distribution region under the multiple constraints is obtained, and the parameters matching principle among these constraints are studied. Finally, in PSCAD/EMTDC, the simulation results validate the correctness of the obtained power distribution region and the effectiveness of the parameters matching principle among the multiple constraints. [ABSTRACT FROM AUTHOR]

Summary: With the increase of the voltage as well as the capacity of the voltage source converter–based high voltage direct current (VSC‐HVDC) transmission system, it is difficult for the traditional modular multilevel converter (MMC) modeling method, which is based on the modeling of switching devices, to meet the demand for the simulation speed of the multiterminal transmission system. This paper proposed a computationally efficient modeling method of MMC by which the simulation speed is entirely unrelated to the number of the cascaded submodules. The paper is constructed as follows: The method for converting all the cascaded submodules in an arm into a single time‐variant capacitor was proposed first. Based on trapezoidal integration, the transient companion model of the equivalent time‐variant capacitor was studied. Then the efficient model of MMC is established based on arm equivalent time‐variant capacitor. Finally, the simulation accuracy and speed of the efficient model are verified in PSCAD/EMTDC. [ABSTRACT FROM AUTHOR]