Comparison analysis of local stability criteria for the DC distribution power system based on impedance and admittance

DC distribution power system (DPS) develops rapidly making the stability issue more and more complicated and prominent. This paper revisits the major impedance-based criteria for DC DPS that have been developed so far. Recently, the harmonic stability problem in the multi-paralleled grid-connected inverters system is analysed based on global admittance (GM). Then, the modified Nyquist criterion is introduced to GM and the stability requirement of the system is obtained. As well know, admittance is the reciprocal of impedance so that the aforementioned impedance-based criteria could also be expressed in the form of admittance. Consequently, an admittance-based criterion for the stability assessment of DC DPS is proposed. Besides, comparison analysis is executed to identify their advantages and disadvantages. Finally, some meaningful simulation cases are presented to illustrate the main characteristics of the reviewed impedance-based and the proposed admittance-based criterion.