Stability Analysis of Dual Active Bridge Converter With Input Filter and Constant Power Load

Abstract

Fast-scale stability of dual active bridge (DAB) converter with input filter under constant power load is analyzed in this article. Since the commonly used reduced-order average model is not effective to accurately describe the dynamic behavior of DAB converter, a discrete-time model is established. The bifurcation points of the system are predicted by using bifurcation diagrams. In addition, Poincaré map theory and the Jacobian matrix of the system are used for bifurcation analysis. The eigenvalue locis of Jacobian matrix are carried. Serval Hopf bifurcations and a saddle-node bifurcation, which are predicted by the eigenvalue locis, have been found in the converter. The influence of system parameters on the stability of the system is explained in detail. It is found that high output voltage bandwidth, input filter, and light load are the main causes of instability in this system. To stabilize the converter, a proper feedback control is presented. In addition, stable boundaries are given to help to avoid instability. All the findings have been verified by simulation and experimental results.