Transient Voltage Model of PMSG Based on Phase-Locked Loop Linearization

With the rapid development of the new power system and the large-scale integration of new energy units, the grid strength in the areas with high concentration of new energy is gradually weakening, making the transient characteristics of the power system more complex. In order to control operational risks, it is necessary to conduct research on transient voltage analysis models for the integration of new energy units into weak grid systems. This paper establishes an analytical model of the transient machine-side voltage of a PMSG after a grid voltage mutation, and conducts separate tests for short-circuit faults and short-circuit fault clearing to verify the accuracy of the PMSG transient machine-side voltage analysis model. It is also observed that in weak grids, PMSG is prone to transient overvoltage issues after clearing a short-circuit fault. Additionally, in response to the nonlinearity of the trigonometric function of the phase-locked loop during the transient process, a modelling-method for linearizing the phase-locked loop is proposed and it is validated that the established linearized model is suitable for transient voltage analysis, laying a model foundation for studying the mechanism of transient overvoltage generation and formulating relevant strategies for transient overvoltage suppression in the future.