Unified SISO Loop Gain Modeling, Measurement, and Stability Analysis of Three-Phase Voltage Source Converters

Frequency-domain modeling is an effective technique in the dynamic analysis of power electronic converters-based systems. In this paper, a unified single-input single-output (SISO) loop gain for three-phase grid-tied voltage source converters (VSCs) under both symmetric and asymmetric AC grids presented, which facilitates physical measurement stability analysis. Based on linear-time-periodic (LTP) technique, harmonic admittance model VSC developed stationary ( ?? )-frame, accurately captures coupling dynamics. This can be transformed into other existing models through coordinate transformations. According to idea mathematical induction, two-by-two recursive matrix (RAM) derived, easy include frequency components arbitrary order. It illustrated that coupled with grid due effect (FCE). Furthermore, RAM converted its equivalent SISO following concept gain. The system thus assessed by criteria (e.g., Nyquist criterion). addition, allows traditional perturbation scheme used detecting margin information. Finally, simulation results verify feasibility correctness theoretical presented above.