Selecting frequency and parameters of DC-fault tolerant non-isolated high power MMC DC/DC converter

• Non-isolated MMC DC/DC converter (NIMDC) parameters design is proposed. The goals are set to power loss of 1.5%, and voltage ripple around ±5%. NIMDC affect each other in a highly non-linear way. A DC fault analysis provides minimal inductors size as initial values. generalization the work using pu approach also This paper studies MMC-based non-isolated for transmission grids. key including operating frequency passive components evaluated with aim ensuring tolerance minimizing losses size. An analytical model used perform parametric while detailed verification. case study on 600MW, 320 kV/250 kV system reveals narrow range optimal cell capacitance arm inductance lower-side arms require substantially larger capacitors. With targeted ±5%, it recommended use 150 Hz frequency. For offshore applications, higher enables significantly smaller some increase losses. line inductor low-voltage side should be much than plays role dc responses.