Linear analysis of waveform distortion for HVDC and FACTS devices

A review of linearised small signal analysis techniques is given for power electronic plant modelling. The nonlinear time-variant nature of switching devices and ways to account for this behaviour using linear analysis are discussed. The HVDC converter is used as an example to illustrate the important considerations when linearising devices. Particular attention is given to dynamic variation of the switching instants, as this is shown to generate significant linear as well as nonlinear terms.