双馈虚拟同步机快速励磁控制和功角补偿策略

RAPID EXCITATION CONTROLAND POWER ANGLE COMPENSATION STRATEGY FOR DOUBLE-FED VIRTUAL SYNCHRONOUS GENERATOR

针对以激磁电势为目标控制电压的双馈虚拟同步发电机策略下运行功角大而带来的功率耦合问题,提出采用快速励磁控制消除功角扰动对无功控制的影响,采用功角补偿消除激磁电势扰动对功角有功控制的影响的功率解耦方案。在分析双馈电机数学模型及双馈虚拟同步机整体控制策略的基础上,构建计及无功控制环节的双馈虚拟同步机小信号模型。通过分析无功环节PI控制器参数对功角稳定性的影响,设计快速励磁控制策略。通过分析无功扰动与功角变化的关系,确定功角补偿传递函数。设定风速扰动、电网频率扰动和电网电压扰动3种不同工况进行验证。结果表明:所提控制策略可有效避免双馈虚拟同步机大功角运行时有功功率控制和无功功率控制间的相互影响,实现功率解耦。

Under the strategy of the doubly-fed virtual synchronous generator with the excitation voltage as the target control voltage,the power angle of the system is large,which will cause the power coupling problem.The rapid reactive power control strategy and power angle compensation synergy are proposed to eliminate power coupling.The rapid excitation control strategy can eliminate the influence of the power angle disturbance on the reactive power,and the power angle compensation strategy can eliminate the influence of the exciting voltage disturbance on the active power.On the basis of analyzing the mathematical model of the doubly-fed machine and designing the overall control strategy of the doubly fed virtual synchronous generator,a small signal model including reactive power control link is constructed.The rapid excitation control is designed by analyzing the influence of the reactive power PI controller parameters on the power angle stability.The angle compensation strategy is designed based on the analysis of the relationship between reactive power disturbance and power angle variation.The simulation is conducted under three different working conditions:wind speed disturbance,grid frequency disturbance and grid voltage disturbance.The results reveal that the proposed control strategy can effectively avoid the interaction influence between active power control and reactive power control when the doubly-fed virtual synchronous generator is running under high power angle condition.