摘要

This paper presents a Phillips-Heffron model for the generation unit with current-controlled (CC) voltage source converter (VSC) as the interface. A concept of current angle is put forward for the CC-VSC, and the relationship between the current angle and the power angle is also quantified. Based on the current angle, a Phillips-Heffron model is established for the generation unit with CC-VSC, considering the dynamic of phase-locked-loop (PLL) in the weak grid. The model demonstrates that small-signal dynamics of the generation unit is similar to that of the traditional synchronous generator (SG) which is characterized by the electromechanical swing equations. Then the dynamics can be depicted by the famous inertia, synchronizing and damping coefficients. Small-signal stability of a CC-VSC-based single machine infinite bus system is analyzed by means of the traditional theory of power system. Based on the relationship between the current angle and the power angle, the Phillips-Heffron model of the CC-VSC is also used in stability analysis of multi-machine power system, and parameter optimizations of the CC-VSC are also studied for stability improvement.