Control Strategy of Disturbance Utilization Rate for Impedance Measurement of Railway Vehicle Inverter Based on Virtual Impedance

Aiming at the demand of impedance measurement of auxiliary inverters for rail trains, this paper proposes a topological structure suitable for impedance measurement of auxiliary inverters for rail trains. On the basis of this structure, aiming at the problem of insufficient utilization of a single type of disturbance source (taking current source disturbance as an example) under the traditional online active impedance measurement method of inverters, a measurement method based on virtual impedance is proposed to improve the utilization rate of disturbance. By adding a control strategy of virtual impedance, the impedance of the accompanying measurement equipment increases. It can be seen from the shunt characteristics of the parallel that the disturbance current divided by the measured equipment increases and the disturbance utilization rate increases. The feasibility of the method is verified by simulation.