DC network stability and dynamic analysis using virtual impedance method

A stability and dynamic assessment method is proposed for converter interfaced DC networks. With the current loop modeled as a 1st order delay, an actively controlled DC terminal converter and its control can be modeled as a virtual impedance in S-domain. Terminal transfer functions can therefore be obtained using Thevenin's equivalent. Based on the modeling method, a case study concerning voltage variation suppression in a multi-terminal DC network is performed using root locus and open-loop margin analysis. The accuracy of the developed DC network model and its effectiveness for assessing system stability and dynamic performance is validated using circuit simulation in time domain