The integration of energy dissipation units into the Modular Multilevel Converter (MMC) enables surplus power dissipation without the need for additional energy dissipation devices outside the converter valve, thereby reducing the cost of the surplus power fault ride-through (FRT) solution. The existing topology integrates energy dissipation units in all submodules (SMs) of the MMC, increasing the difficulty of modification. To address this issue, this paper proposes a single-phase integrated configuration of energy dissipation units, in which only the SMs in the outermost phase unit of the converter valve need to be modified. This configuration simplifies on-site construction and facilitates equipment operation and maintenance. This paper studies the control strategy of the topology and determines the corresponding parameters, which can reduce the number of energy dissipation units that need to be retrofitted while suppressing voltage fluctuations. The feasibility of the scheme is verified through simulations and experiments. Finally, a technical and economic analysis is conducted in terms of the investment cost and control performance of the single-phase MMC with integrated energy dissipation equipment (IEDE-MMC). Compared with the three-phase IEDE-MMC, the investment cost is reduced by 33%, the DC voltage fluctuation range is reduced by 66.7%, and the lower limit of the SM capacitor voltage is raised by 10.8%.
Lu et al. (Mon,) studied this question.