Stability analysis of distributed generation grid-connected inverter

Abstract

With the distributed new energy power generation increased, the power grid system becomes more and more complex, leading to its stability more likely to be affected. Among them, the resonance caused by impedance mismatch is particularly critical. The small-signal model of phase-locked loop and current control in the inverter control system have been established by using harmonic linearisation method. Combining the average model of inverter main circuit, the inverter output impedance model has been obtained. Using grid impedance and the inverter output impedance model, the stability analysis method based on impedance is used to analyse the influence of grid impedance on the stability of grid-connected inverters. Finally, the simulation proves the correctness of the analysis method.

Keywords

• invertors
• electric current control
• power grids
• distributed power generation
• phase locked loops
• power system stability
• linearisation techniques
• power system harmonics
• power grid system
• impedance mismatch
• small-signal model
• phase-locked loop
• current control
• inverter control system
• harmonic linearisation method
• inverter output impedance model
• grid impedance
• stability analysis method
• distributed generation grid-connected inverter
• distributed new energy power generation
• inverter main circuit average model