This paper applies the virtual synchronous generator to the back-to-back converter system, and proposes a control strategy to ensure the voltage of DC bus balanced, which both simulates the characteristics of the synchronous generator and realizes the power bidirectional flow. Compared with the traditional control strategy in dq rotating coordinate system, power switching of the virtual synchronous generator is smoother and the harmonic content is lower. Based on the modeling of the back-to-back system, this paper analyzes the advantages and disadvantages of the two control strategies according to three different performance indicators. The back-to-back system is used as an energy balance system to balance the power load distribution between two grids. Without the phase-locked loop and the dq decoupling module, the control design is simplified while the energy balance is achieved.