Transient Stability Analysis of Microgrid Considering Impact of Grid-Following Converter's Current Controller

The dynamics of current controller is usually neglected for simplification when assessing microgrid transient stability. Utilizing the Takagi–Sugeno method, this letter thoroughly examines the effects of current controller on transient stability estimations and reveals that completely ignoring the dynamics of current controller can cause overestimation on transient stability. The findings highlight a significant overestimation on lower boundary of angle about 29.2% even if current controller performs fast dynamics with bandwidth more than 28 times the fundamental frequency. Recognizing the impracticality of including current controller dynamics in microgrids with multiple converters, this letter proposes a stability-enhanced method through phase compensation in the current controller, which can improve the accuracy of transient stability assessments while still omitting current controller dynamics. In addition, a guideline for parameter design of phase compensation is provided. Theoretical findings are verified by hardware-in-loop experimental results based on OPAL-RT platform.