Model Analysis and Sliding Mode Current Controller for Multilevel Railway Power Conditioner Under the V/v Traction System

To manage the power quality of a high-speed V/v traction system, a multilevel railway power conditioner (MRPC) is researched. According to the structure and equivalent models of the MRPC, basically the MRPC is a symmetrical system, and its four clusters can be divided into two cluster groups. According to the ac equivalent mathematical models of cluster groups, it can be considered as the relationships in the αβ frame, but not completely symmetrical, so the positive- and negative-sequence dq models for cluster groups can be derived. As the fluctuation and randomness of the locomotive loads, a sliding mode control system based on the exponential reaching law in the dq frame is explored to control the cluster ac currents, which can improve the dynamic performance and keep a good tolerance against parameter mismatches. Finally, an experimental prototype is developed, and the results show the feasibility and the robustness of the system.