The invention relates to the stability analysis technology in the DC micro-grid technologies, and aims to provide a stability determination method for a DC micro-grid in the master-slave
control mode. The method comprises the following steps: using the unit connection method to carry on the Thevenin / Norton equivalent to the power modules of each power supply and each
constant power load so as to obtain the corresponding impedance /
admittance, and obtaining the impedance matrix of the main power supply, the
admittance matrixes of the slave power source and the
constant power load; according to the known
resistive load size of each node, obtaining the
resistive load admittance matrix, and obtaining the
system node admittance matrix according to the inter-node cable parameter; placing each matrix into the
stability criterion and calculating its pole; if all the poles are on the
left half plane, determining that the
system is stable; and if there is a pole on the
right half plane, determining the
system is unstable. The method is compatible with the inter-node impedance of the system, and has no specific requirement for the
system structure, and has a wide application range. The calculation is simplified in the system-level stability analysis and the stability of the complex DC micro-grid can be effectively analyzed.