Under the short-circuit fault of weak grids

the interaction in the multiple paralleled renewable energy converter system is complex

and transient synchronization instability may occur due to the loss of equilibrium point. Existing studies assume the output current is constant and ignore the influence of transient reactive power support control

resulting in unclear instability mechanisms and inaccurate stability assessments. Regarding this

this paper establishes a transient analysis model for the multiple paralleled renewable energy converter system considering reactive power support control. The impact of factors such as the reactive current coefficient

current limit amplitude

line impedance

and grid fault depth on transient synchronization stability is analyzed. Then

the transient synchronization stability evaluation method and stability margin index for the system are proposed

and the impact of the above factors on the existence of the equilibrium point is quantitatively analyzed. In addition

the feasible region for multi-converter control instruction under transient stability constraints is constructed

and a transient synchronous stability control method based on control parameter optimization is proposed accordingly. Finally

the theoretical analysis and the control method is verified by the hardware-in-the-loop experiment.