Impedance-based analysis of DC link control in voltage source rectifiers

This paper analyzes the dynamics influences of the outer dc link control in the voltage source rectifiers based on the impedance model. The ac-dc interactions are firstly presented by means of full order small signal model in dq frame, which shows the input voltage and load condition are the two main factors. Impedance model is then derived and the effects caused by the dc link voltage control are discussed. Oscillations in low frequency range may appear due to the dc link voltage control. Three case studies are presented, and subsequently validated in experimental tests. The experimental results demonstrate the effectiveness of the impedance model and staility analysis.