Causal Analysis and Resolution of the Voltage Instability between AC Drive Electric Locomotive and Power Supply Network

There occurs voltage instability between the locomotive and power supply network now and then when the AC drive electric locomotive is running.This problem is tried to be analyzed and resolved.The closed-loop transfer function of the DC voltage link control system is derived by analytical analysis and with the linear method.Conditions sufficient for robust stability of the DC voltage link close-loop system is derived in accordance with the small-gain theory.Reliability of the theoretical analysis is proved by simulation with Software Matlab.Finally,it is pointed out,when the inherent parameters of the system can not satisfy the Hurwitz stability criterion and small-gain theory simultaneously,further study,should be made and the problem can not be solved by adjusting parameter K.