State-Space Model of qZSI based PMSG-WPGSs for Transient Dynamic Studies

The use of permanent magnet synchronous generators (PMSGs) with full-scale back-to-back converters is rising as a common option in wind power generation systems (WPGSs). An efficient grid integration of PMSG-WPGSs is obtained through quasi-Z-source inverter (qZSI). Simultaneously, power electronic system integration concerns related to dynamics have arisen. Power electronics reduce damping of grid-connected converters, leading to dynamic issues. Several studies focus on qZSI dynamics, but the analysis of qZSI based PMSG-WPGS dynamics to evaluate transient interactions is not yet well addressed. This paper studies a qZSI based PMSG-WPGSs small-signal state-space model for Matlab/Simulink implementation in order to study these concerns. The model is applied to investigate qZSI based PMSG-WPGS dynamic response and it allows the influence of components and parameters on system dynamics to be assessed. Eigenvalues are obtained from the state-space model in order to study qZSI based PMSG-WPGS stability and the participation factors are also analyzed to find out the most influential circuit component or control on the different eigenvalues. PSCAD/EMTDC simulations are made to test the model.