新能源发电占比的提高使得系统惯量下降，虚拟同步机可为系统提供惯量支撑。目前，虚拟惯量的配置主要是从小干扰稳定和频率稳定两者之一的角度进行分析的，鲜有研究同时考虑这2个因素。并且，虚拟惯量配置的研究主要针对电压源型虚拟同步机，很少针对电流源型虚拟同步机。为此，该文通过建立电压源型和电流源型虚拟同步机的同步主导回路模型，分析了虚拟惯量参数对2种稳定性的影响。研究表明，虚拟惯量的减小会提高系统的小干扰稳定性；然而，在功率扰动下，电流源型虚拟同步机的输出频率会叠加受虚拟惯量主导的Vq暂态分量从而产生超调，虚拟惯量过小会导致频率超调过大，不满足并网运行标准。因此，为了使系统具有良好的小干扰稳定性和频率稳定性，虚拟惯量的配置需要同时考虑这2种稳定性的约束。最后，在单机无穷大系统和孤岛两机系统的虚拟惯量配置仿真中验证了该结论。
With the increase in the proportion of new energy generation, the inertia of power system decreases. A virtual synchronous machine can provide inertia for the power system. At present, most of the parameter configuration of the virtual inertia is analyzed from the perspective of small-signal or frequency stability. These two factors have been simultaneously considered by a few studies to conduct virtual inertia configuration. Moreover, research on the configuration of virtual inertia mainly focuses on the voltage-source virtual synchronous machine, while a current-source virtual synchronous machine is rarely studied. To solve this problem, the influence of virtual inertia parameters on the small-signal stability and frequency stability is analyzed by establishing synchronous dominant loop models for voltage-source and current-source virtual synchronous machines. Results show that the small-signal stability of the system can be improved by decreasing the virtual inertia. However, under power perturbation, the output frequency of the current-source virtual synchronous machine will superimpose the transient component of Vq dominated by the virtual inertia, resulting in overshoot. If the virtual inertia parameter is too small, the frequency will not meet the grid-connected operation standard. Based on this, for the system to simultaneously exhibit good small-signal stability and frequency stability, the configuration of virtual inertia needs to be restricted by the two kinds of stability. Finally, the conclusion of this study is verified through the simulation of the inertia configuration of a single infinite machine system and an island two-machine system.
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