Transient Angle Stability Analysis of Grid-Connected Converters with the First-order Active Power Loop

As the increasing application of power electronic converters in electric power grids, the stability of grid-connected converters has become a major concern for reliable operations of the power grid. This paper analyzes the transient stability of grid-connected converters with the first-order active power loop. It points out that the conventional equal-area criterion, which has been widely used in the transient stability analysis of synchronous generators, may not apply to grid-connected converters, due to the different dynamic characteristics between converters and synchronous generators. To tackle this challenge, this paper employs the phase portrait to analyze the transient stability of power converters, and it is found that the better transient stability performance can be achieved if the grid connected converters are controlled as the first-order nonlinear system. Simulations and experimental results are given to verify the effectiveness of the theoretical analysis.