Grid-Forming Converters control based on DC voltage feedback

TL;DR

This paper proposes a novel control strategy for grid-forming converters that incorporates DC voltage feedback to enhance power grid stability and prevent DC side voltage collapse during large load disturbances.

Contribution

It introduces a new control method for GFCs considering DC voltage feedback, addressing the issue of DC voltage collapse and improving grid stability.

Findings

The proposed control method prevents DC voltage collapse during large disturbances.

Verification on IEEE-9 bus system confirms effectiveness.

Enhances synchronization and stability of power grid with renewable energy.

Abstract

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.