scholarly journals Frequency Domain Stability Assessment of Photovoltaic Power Generation Systems with Quasi-Z-Source Inverters

2021 ◽  
Vol 19 ◽  
pp. 160-165
Author(s):  
Luis Sainz ◽  
◽  
Ll Monjo ◽  

Photovoltaic power generation systems are one of the main renewable power sources, and quasi-Z-source inverters are becoming powerful devices to integrate these systems in AC grids. However, stability issues due to the damping behaviour of converters must be considered. There are several studies in this direction but instability concerns are not completely solved yet. This paper contributes with a procedure for the stability assessment of photovoltaic power generation systems with quasiZ-source inverters in the frequency domain. The study is based on the small-signal averaged model of the system expressed in the s-domain and the stability criterion derived from the frequency characteristics of the state-space matrix. The influence of the photovoltaic power generation system operating point on stability is studied by the proposed procedure. Eigenvalue analysis and PSCAD/EMTDC simulations are also performed to validate the obtained results.

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4150
Author(s):  
Lluís Monjo ◽  
Luis Sainz ◽  
Juan José Mesas ◽  
Joaquín Pedra

Photovoltaic (PV) power systems are increasingly being used as renewable power generation sources. Quasi-Z-source inverters (qZSI) are a recent, high-potential technology that can be used to integrate PV power systems into AC networks. Simultaneously, concerns regarding the stability of PV power systems are increasing. Converters reduce the damping of grid-connected converter systems, leading to instability. Several studies have analyzed the stability and dynamics of qZSI, although the characterization of qZSI-PV system dynamics in order to study transient interactions and stability has not yet been properly completed. This paper contributes a small-signal, state-space-averaged model of qZSI-PV systems in order to study these issues. The model is also applied to investigate the stability of PV power systems by analyzing the influence of system parameters. Moreover, solutions to mitigate the instabilities are proposed and the stability is verified using PSCAD time domain simulations.


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