General Modelling Method for Impedance of Voltage Source Converter

Voltage source converters (VSC) have been widely used in renewable energy generation, flexible ac/dc transmission and energy transfer devices, which result in a lot of system transient stability problems, but essential cause and the physical significance are not yet systematically analysed. Firstly the paper researches the working principle and stable mode of typical voltage source converters, when considering control strategy, circuit parameters and other influencing factors, and then, the general mathematical model of AC side and DC side impedance of voltage source converters is established with internal dynamic process based on the stationary reference frame. On this basis, all of states are studied on the influence of output impedance amplitude of VSC for the operation characteristics, the influence domain characteristics of impedance for the operation stability of converter, and the key components or parameters that affect the output impedance amplitude. In the meanwhile, the frequency-domain analysis is developed to verify the correctness of above results.