Modeling and stability analysis of high voltage ratio bidirectional DC/DC converter applied to electric vehicle

Bi-directional DC/DC converter is widely applied in battery formation system, automatic cars, uninterruptible power supplies (UPS), micro-grid, etc. A novel coupled inductor bi-directional DC/DC converter is analyzed in this paper, which can overcome the shortage of non-isolated bi-directional DC/DC converters that its conversion ratio is restricted in a small range and high voltage/current stress. This paper analyzes the principle and closed-loop control of the proposed bi-directional DC/DC converter using the state space averaging method. The parasitic parameters and leakage inductance effect on stability have been considered and the unified compensation network has been designed under the constant Battery current control target. At the same time, the corresponding stability analysis is involved. Especially, the paper analyzes the influence on the stability of the whole system when the number of the charging and discharging battery is changing. Finally, the experimental results verify the correctness of the conclusion.