Abstract: For structure of traditional centralized converters cannot meet emergency power supply requirements of mine local ventilators, a two-stage energy storage converter of mine local ventilator integrating charge and discharge was designed. The energy storage converter not only can use as an emergency power source when the power grid is out of power, but also can achieve reactive power compensation function during normal operation of power grid. A control strategy for two-stage energy storage converter was proposed. When dual-circuit power supply line of local ventilator works normally, the energy storage converter is in online operation mode, and the PWM inverter adopts P/Q control strategy, which mainly charges battery and compensates reactive power to the grid. When dual-circuit power supply line of local ventilator fails, the energy storage converter is in emergency supply mode, and the PWM inverter adopts V/f control strategy. A smooth switching control strategy based on state feedback and common current inner loop was put forward. The state of the V/f controller and the output of the P/Q controller are feedback to the input to solve the problem of current impact occurred during the switching of the two operating modes of the emergency power supply and online operation of the energy storage converter, so as to achieve smooth switching of the energy storage converter. The simulation results show that the control strategy enables the converter to operate stably and switch smoothly under two operating modes, which has good steady and dynamic state characteristics.