The DC microgrid is through connecting the grid converter and the AC power grid

thus the bidirectionalflow of power and the stability of the DC bus voltage are achieved. The paper focuses on the nonlinear and the widerange mutation of working point of the bidirectional DC/AC converter. A nonlinear control strategy of two stage bidi-rectional converter based on sliding-mode variable structure is proposed. First

the nonlinear mathematical mode ofthe high frequency two stage bidirectional converter is established

with control target constant DC voltage and unitpower factor of AC grid and the state variables the voltage of DC side and the reactive current of AC grid. Second

thepaper design the sliding-mode plane function and the variable structure control of the DC/AC and DC/DC. Finally

the paper set the simulation model of control system of the DC microgrid and analysis the system performance of thedynamic and steady state under the different working conditions to demonstrate the effectiveness of the proposed con-trol strategy. The results show that sliding-mode variable structure control strategy has good performance of the dy-namic and static and robustness for parameter change and state mutation of the system.