直流微电网高频振荡稳定问题的降阶建模及分析

为从等效电路角度揭示直流微电网高频振荡稳定机理,建立了直流微电网降阶电路模型.将直流电压控制单元降阶成等效电阻、电感串联电路模型,其中将下垂控制、直流电压控制及电流内环控制环节对系统高频稳定性的影响转化为可量化的等效电阻、等效电感.进一步结合采用等效电阻、电容并联电路的恒功率负荷模型,得到直流微电网全系统降阶电路模型,...

Reduced-order modeling and analysis of high-frequency oscillation stability in DC microgrid

In order to reveal the stability mechanism of high-frequency oscillation in DC microgrid from the perspective of equivalent circuit, a reduced-order circuit model of DC microgrid is proposed. The DC voltage control unit is reduced to an equivalent RL series circuit model, by which the influences of droop control, DC voltage control and inner-loop current control on system high-frequency stability can be analyzed quantitatively with equivalent resistance and inductance. Furthermore, the reduced-order circuit model of the whole system is obtained by considering the equivalent RC parallel circuit of constant power load model, on this basis, a high-frequency oscillation stability criterion of DC microgrid is proposed. Moreover, with the proposed reduced-order model, the control parameter impacts of DC voltage control unit on equivalent resistance, equivalent inductance and stability criterion are analyzed comprehensively, by which the reason of high-frequency oscillation in DC microgrid can be revealed from the perspective of equivalent circuit. Eventually, the proposed reduced-order model is verified by simulation in PSCAD/EMTDC software.