Terminal admittance based stability criterion for multi-module DC distributed system

The stability issues of multi-module DC distributed power system are studied. Physical understanding of terminal characteristics of each module is studied. All the modules are divided into two groups (Z type and Y type) based on the different terminal property type and different equivalent circuit is selected for each group. Equivalent circuits of total system are established to analyze the stability issue. Then, mathematical equations of total system are derived. Since the DC bus voltage of the total system is unique, the DC bus voltage is treated as response variable when the interaction among different modules is focused on. A generalized criterion based on the terminal admittance of each sub-module for multi-module distributed system is proposed. It is clear that the proposed criterion is independent of the power flow direction and the terminal characteristics of each sub-module are the key factor.