Dynamic modelling and simulation of a multiport DC hub with closed-loop control

Abstract

This thesis firstly studies a dc hub and proposes a control method for its multiport operation. The proposed control method is tested on a three-port dc hub in PSCAD/EMTDC and its stability and response to a transient are demonstrated. In addition, this thesis introduces a dynamic average-value model for a multiport dc interconnection hub based upon the concept of generalized averaging (i.e., dynamic phasors). The developed model is able to predict the transient and steady state response of a dc hub and its closed loop control system with comparable accuracy to and markedly higher computational efficiency than a conventional EMT model. Simulation results are presented for a three-port dc hub and are compared with detailed EMT simulation results from PSCAD/EMTDC. Simulation efficiency is significantly improved by applying the proposed average-value model.