Low Ripple Interline Power Flow Controller

Simple device adaptable to any requirement in terms of current and voltage reversibility


New concepts of Power Electronics (PE) converters known as Power Flow Controllers (PFC) or current flow controllers are proposed to tackle the management of power patterns’ distribution in a meshed MTDC system by inserting a controlled voltage in the loop. This voltage is in the range of the voltage drops of links (some kV). This PFC device is designed with passive components (capacitor and inductance) and Power Electronics Switches and do not require any connection to the ground. Any external source is mandatory since the energy of the links accumulated in the capacitors is balanced and shared thanks to the inductance. Thus, the PFC device is designed as a MV device. The energy needed for the converter operation (control boards, gate drivers…) can also be harvested from the capacitors since a voltage appears across these capacitors as soon as they are inserted into the grid. In addition, the presence of the inductance allows very smooth voltages and currents besides the limitation of the rate of rise of the current in DC fault operation. This low ripple PFC device has a proven ability to fit diverse power flow patterns for any network operation
requirements. The proposed design of the PFC is also scalable and modular in respect to the network operation. The component count is
low if the power flow patterns to be addressed are not numerous (for example inserted voltage and substations currents have not to change
their signs) making this solution especially attractive for these application cases.



Concepts validated in EMT simulation.


  • Enlarge the MTDC network operation
  • Medium Voltage PFC device
  • Low voltage and current ripples
  • Scalable and modular designs


  • Meshed Multi-Terminal HVDC grids
  • Parallel HVDC cables


  • Patent application WO2019016449 (A1)
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