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.

中文翻译：

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基于直流电压反馈的并网变流器控制

可再生能源通过电力电子转换器连接到电网，缺少同步发电机/电机（SM）的惯性。可再生能源在电力系统中的渗透率不断提高，削弱了频率和电压的稳定性。并网变流器（GFC）通过控制方式模拟同步电机的功能，通过提供惯性和稳定性调节机制来提高电网的稳定性。这类转换器控制方法包括虚拟同步机、可调度虚拟振荡器控制等。这些控制方式主要采用交流侧状态反馈，不监测直流侧状态。本文分析了考虑电网稳定性的 GFC 控制策略，包括频率下垂控制、虚拟同步机器控制和可调度虚拟振荡器控制。出现大负载扰动时，会发现直流侧电压崩溃问题。提出了考虑直流侧电压反馈的GFC控制方法，可以保证并网同步特性，解决直流侧电压崩溃问题。所提方法通过IEEE-9总线系统的验证，表明了所提方法的有效性。