含同步发电机和逆变器接口的微网小信号稳定性与灵敏度分析

small-signal stability of an islanded microgrid with a synchronous generator and an inverter-interfaced micro source using droop control is analyzed. The small-signal microgrid model is developed including the synchronous generator and its controller, the inverter-interfaced micro source and its controller, and the power network. The eigenvalues are calculated when the mechanical inertia time constant of synchronous generator rotor, the filter time constant of low-pass filter on the inverter side, the droop gains hange. The root locus of the principal eigenvalues are obtained when the main parameters change. The stability of the microgrid is discussed and the stable range of the main parameters aredrawn by comparing the eigenvalues, root locus and PSCAD time domain simulations. The participation factor of different state variables to the eigenvalues and the sensitivity of eigenvalues to the system parameters are investigated. The results show that the frequency stability is improved greatly by the synchronous generator when all micro sources use droop control,and the small-signal stability of the microgrid can be enhanced by increasing the mechanical inertia time constant andselecting an appropriate filter time constant of low-pass filter on the inverter side.