Small Signal Model of Voltage Source Converter using Dead Beat Current Controller

Abstract

Background/Objectives: This study developed a new complete small signal model of VSC (Voltage Source Converter) using Dead Beat (DB) current controller with purpose of facilitating the small signal stability analysis of power system. Methods/Statistical Analysis: The small signal model development is presented step by step including the derivation of the entire system equations, they established in MATLAB m-file and verified by PSCAD simulations. Findings: As the most powerful tool for small signal stability analysis, the eigen value or transfer function technique is widely employed in modern power system analysis. However, it is only valid for a Linear Time Invariant (LTI) system. Recently the Dead Beat (DB) current control, which is characterized by relatively high bandwidth and excellent performance under unbalanced operating condition, is found as the best-tailored current control method for grid connected VSC application, specifically some severe operating conditions. Application/Improvements: In the simulation studies both of the large signal and small signal models are verified for every individual system components, as well as the entire integrated VSC system. It is demonstrated that the study can provide the foundation for outer loop controller design and small signal stability analysis. Keywords: Dead Beat (DB) Control, Linear Time Invariant, Proportional Integrator (PI) Control, Proportional Resonant (PR) Control, Voltage Source Converter