Transient Stability Analysis of Hybrid Synchronization Control with Current Limitation

Grid-forming hybrid synchronization control (HSC) has garnered increasing attention due to its superior transient stability performance compared to VSG under current saturation conditions. However, current research on HSC primarily focuses on the impact of grid voltage fault severity and control parameters on transient stability. Clearly, saturation current is also closely related to the stable operation of HSC-VSC. This paper provides an in-depth analysis of the effect of saturation current on the transient stability of HSC-VSC. First, the second-order dynamic equation of HSC under current saturation is established. Next, the existence conditions of equilibrium points are analyzed to constrain the magnitude of saturation current. Then, a Lyapunov energy function is formulated, and stability criteria are applied to investigate the stability attraction domain for different saturation current magnitudes and angles. The results indicate that increasing the saturation current magnitude is detrimental to transient stability, whereas reducing the saturation current phase can enhance transient stability.