Modelling and Stability Analysis of a Three-Port DC-DC Converter with Virtual Impedance Control for Hybrid Energy Storage System

In order to improve the operation performance of DC power system in both steady and transient states, in this paper, a hybrid energy storage system (HESS) interfaced by proposed two-stage and switches shared three-port converter (TPC) with virtual impedance based power sharing control are studied. The modelling of the TPC and the control system are conducted, and the generalized state-space averaging method is used to establish the model of the three-port converter. Furthermore, the analysis on the influence of the dynamic characteristics and stability of system control loop due to the change of virtual impedance parameters is presented. Meanwhile, simulation and experimental verifications are implemented. The results show that the proposed virtual impedance based power sharing control in the TPC can be achieved and the stability of the system can be guaranteed.