  The renewable energy is connected to the power grid through power electronic
converters, which are lack of make the inertia of synchronous generator/machine
(SM) be lost. The increasing penetration of renewable energy in power system
weakens the frequency and voltage stability. The Grid-Forming Converters (GFCs)
simulate the function of synchronous motor through control method in order to
improve the stability of power grid by providing inertia and stability
regulation mechanism. This kind of converter control methods include virtual
synchronous machine, schedulable virtual oscillator control and so on. These
control method mainly use AC side state feedback and do not monitor the DC side
state. This paper analyzes the control strategy of GFC considering power grid
stability, including Frequency Droop Control, Virtual Synchronous Machine
Control and dispatchable Virtual Oscillator Control. The DC side voltage
collapse problem is found when a large load disturbance occurs. The control
methods of GFC considering DC side voltage feedback are proposed, which can
ensure the synchronization characteristics of grid connection and solve the
problem of DC side voltage collapse. The proposed method is verified by IEEE-9
bus system, which shows the effectiveness of the proposed method.
