VSC输出电流反馈型虚拟同步控制技术

VSC output current feedback-based virtual synchronous control technology

基于输出功率反馈的虚拟同步机(VSG)技术在网侧故障时,难以保持电压源暂态特性并实现精准暂态冲击电流限制,同时极易出现暂态同步失稳问题。为解决上述问题,提出一种基于电压源型变流器(VSC)输出电流反馈型VSG技术。外环控制直接采用VSC输出电流作为反馈控制量,不仅能实现构网和电压/频率主动支撑功能,还能保证在故障状态下外环控制具备稳定平衡点,降低暂态同步失稳风险,同时还能实现稳态下的电流限幅控制。电压内环采用基于相量分析的虚拟阻抗自适应选取方法,依赖就地量测信息进行虚拟阻抗快速自适应调整,以抑制故障瞬间暂态冲击电流。在PSCAD/EMTDC中搭建详细电磁暂态仿真模型,并构建相应的物理验证平台,仿真和实验结果表明,所提方法可以较好地抑制故障瞬间暂态冲击电流。

The VSG(virtual synchronous generator)technology based on output power feedback faces chal⁃lenges in maintaining the transient characteristics of the voltage source and achieving precise transient im⁃pact current limitation during grid-side faults,often leading to the risk of transient synchronization instability.To address these issues,a VSC output current feedback-based virtual synchronous control technology is pro⁃posed.The outer control loop directly utilizes the output current as the feedback control variable,which can not only enable network configuration and active support for voltage/frequency but also ensure that the outer control loop has a stable equilibrium point during fault conditions,reduce the risk of transient synchroni⁃zation instability,and also realize the current limiting control in the steady state.The vol-tage inner loop adopts an adaptive virtual impedance selecting method based on phasor analysis,and relies on locally measured information for rapid adaptive adjustment of virtual impedance to suppress transient impact cur⁃rents during fault events.The detailed electromagnetic transient simulation model is constructed in PSCAD/EMTDC,and a corresponding physical verification platform is established.The simulative and experimental results indicate that the proposed method effectively achieves transient current limitation during faults.