Study On Small Disturbance Characteristics Of Ac Side Of Grid-connected VSC

Abstract

This paper analyzes the small disturbance characteristics of voltage source converter (VSC) in the frequency domain, expounds the process in which the small harmonic disturbance of the grid voltage participates in the operation of the VSC, clarifies the generation mechanism of the disturbance frequency current and the disturbance coupling frequency current. The small disturbance impedance model of VSC considering the dynamic characteristics of phase-locked loop (PLL) is established by using the harmonic linearization method. The simulation model in PSCAD/EMTDC verifies the correctness of the small disturbance impedance model. Theoretical analysis and simulation show that the converter control parameters and PLL parameters will affect the impedance characteristics of small disturbance impedance.