中文摘要：

动态电压恢复器（DVR）是补偿电压跌落，避免敏感负荷欠压脱扣的一种现代电力电子设备。针对相位敏感性负载直流电容储能利用率偏低的问题．提出一种基于离散相位过渡法的补偿策略，采用完全补偿法、同相补偿法、最小能量法之间的离散相位平滑过渡，缓解了负载电压相位跳变，有功功率交换降至最小。实验结果表明，该方法可有效延长DVR电压跌落补偿时间，从而降低直流链路电容容量，提高经济性。

英文摘要：

Dynamic voltage restorer（DVR） is a power electronic device that can compensate the voltage sag and avoid under-voltage tripping of sensitive loads.To solve the low utilization of DC-link capacitor for sensitive loads, a compensation strategy based on discrete phase transition method is presented.The method is a discrete and smooth phase transition between pre-sag,in-phase and minimal-energy compensation mode.The proposed strategy is able to mitigate the voltage phase jump and regulate the active power exchange to the least possible value.Experimental results show that the proposed method can effectively extend the DVR sag compensation time.The DC-link capacity can be decreased and the economical value can be improved.