DC Transformer Impact on Voltage Dynamics in Hybrid AC-DC Power Distribution Networks

AC/DC power distribution networks use various types of power converters to interconnect their buses, active front ends between AC and DC buses, and DC transformers between DC buses. Different active front end control methods, like voltage or power regulation, can be implemented to set the power flow throughout the DC network. They offer equivalent steady state but behave differently during transients. In this paper, power distribution networks with multiple active front end converters operating in various combinations of voltage and power-regulating modes are analyzed. This study shows that using only voltage-regulating active front ends results in slower transients when DC transformers are integrated in the power distribution network while power-regulating active front ends have faster transients but can cause much larger voltage overshoots. A parametric model that accurately estimates the network transient is developed and experimentally verified.