Modeling and Frequency Analysis of a Dual H-bridge Current Flow Controller in Meshed HVDC systems

This paper investigates the modeling and operation of dual H-bridge current flow controllers (CFCs) in meshed high-voltage direct-current (HVDC) systems. Two operating modes of the CFC device, namely the `buck mode' and the `boost mode', are defined and analyzed. Small-signal models of the dual H-bridge CFC are derived in the s-domain for each operating mode. A frequency sweep procedure is carried out using PSIM to obtain frequency domain representations of the CFC to verify the validity and accuracy of the small-signal models. The dynamic performance of the dual H-bridge CFC is verified through time-domain simulations conducted in PSCAD/EMTDC.