Stability Analysis of Energy Routing System Considering Droop Control

The energy routing system can use DC bus to connect multiple input and output converters. The structure of the system is complex, and the flow of energy is changeable. Therefore, a detailed and effective design is necessary. This paper takes impedance analysis method to analyze the smallsignal stability of the energy routing system which uses a DC bus structure with constant power load considering the droop control strategy of multiple converters. Firstly, a small-signal model is established for the converter module by combining control strategy. Secondly, based on the control of the bus side port voltage converter (BVCC) and the control of the bus side port current converter (BCCC) classification, derivation and summary of the application steps of unified impedance criterion in the energy routing system are obtained. Finally, the energy routing system under constant power load is simulated and analyzed. The result shows that the oscillation frequency at the time of system instability is consistent with the frequency of the intercept point of the impedance curve. Meanwhile, the increasing of the inductance value of the constant power load converter can improve the system stability. The result is identical to the theoretical analysis as well as verifying the applicability and accuracy of the unified impedance criterion applied in the energy router.