Impedance-Based Stability Analysis of Constant-Power-Source-Involved and Cascaded-Type DC Distributed Power Systems

This paper proposes impedance specifications for guaranteeing the stability of a cascaded-type DC distributed power system (DPS), which is formed by several cascaded voltage source modules, several load modules, and several constant power source modules. To analyze the stability of a cascaded-type DC DPS, there are conventional approaches like eigenvalue method, root-locus method, bode-diagram method and so on. However, the aforementioned stability analysis approaches will suffer from the incomplete system parameters if the modules of the DPS are designed modularly and independently. This paper defines time-invariant and decentralized impedance specifications for the modules of the cascaded-type DC DPS, where the impedance specifications are independent to each other. Thus, the modules of the cascaded-type DC DPS can be independently and modularly designed, as well the stability of the cascaded-type DC DPS can be guaranteed.