Abstract:The energy feedback device can feed regenerative braking energy of motor from dc bus of inverter to the power grid. Due to the parallel structure between the diode rectifier of inverter and energy feedback device, circulating current is easy to happen in the system when the energy feedback device is running. As a result, the inverter power loss will increase and efficiency of energy feedback system will reduce. Based on the analysis of the equivalent circuit within the condition of circulating current, it is found that the magnitude of circulating current is mainly related to the zero-switching vector. And then a dual-carried wave SVPWM modulation strategy is proposed. With this strategy, the switching state of energy feedback device is changed to suppress the circulating current and it will not increase additional hardware cost. The simulation results show the effectiveness of the proposed method.