基于带通阻尼功率反馈的虚拟同步发电机控制策略

Virtual Synchronous Generator Control Strategy Based on Bandpass Damping Power Feedback

虚拟同步发电机(VSG)通过在虚拟惯量控制环节中引入阻尼功率反馈来抑制有功功率振荡。传统基于锁相环的阻尼功率反馈方案需要依赖电网电压信息,这违背了VSG要将并网逆变器控制成输出电压幅值和频率完全独立可控的自同步电压源的目标。而传统无锁相环阻尼反馈方案本质上将下垂控制和阻尼反馈简化成了一个下垂环节,因此不能同时满足功率振荡抑制以及电网一次调频的需求。为此,提出一种基于带通阻尼功率反馈的VSG控制策略,并对改进VSG控制策略的有功闭环特性进行分析,给出带通阻尼功率反馈环节的参数设计方法。该方案既可以有效抑制功率振荡,又可以消除阻尼功率反馈与下垂控制间的相互影响,进而保证VSG的一次调频以及有功功率分配性能可以满足电力系统的要求。最后,仿真和实验结果均证明了提出方法的有效性。

Damping power feedback is used in virtual synchronous generator（VSG） to restrain power oscillation caused by the virtual inertia of the active power control loop. The traditional damping power feedback strategy with PLL included depends on the measurement of the grid voltage phase, which acts against the control object that VSG makes grid-tied inverter to be a self-synchronizing independent voltage source. The traditional damping power feedback method without PLL included essentially merges the droop control and damping feedback into only one droop control, thus the VSG would not meet the requirements of power oscillation damping and primary frequency regulation of power system at the same time. To address this issue, this paper develops an improved VSG control strategy based on bandpass damping power feedback. The closed loop dynamic characteristics and parameters design process of the improved VSG strategy are also presented. The proposed strategy can remove the effect of damping power feedback channel on the droop control, as a result the primary frequency control and active power allocation performance of VSG can be ensured. Finally, both the simulation and experimental results prove the effectiveness of the proposed method.