中文摘要：

采用电网电压前馈的并网逆变器，其滤波电感的感值、电流控制器的参数会影响逆变器并网功率因数。在电网电压前馈电流型并网控制策略的基础上，提出基于下垂特性的新型锁相环（phase-locked loop，PLL）控制方法，采用电网电压和并网电流相位差为反馈量调节锁相环的输出，可以实现并网逆变器单位功率因数运行，并且可以实现逆变器的反孤岛运行。给出该方法的控制框图，分析工作原理和锁相环下垂系数的选取方法，仿真和实验结果验证了该方法在改善逆变器并网功率因数和反孤岛能力方面的正确性和有效性。

英文摘要：

Power factor of grid-connected inverter with grid voltage feed-forward control is affected by the current-loop parameters and filter inductor. A novel control strategy based on dropped phase-locked loop （PLL） was proposed. The phase separation between the grid current and grid voltage was detected and the phase was used to calculate the PLL output frequency which determines the grid current phase. Unit power factor can be achieved and anti-islanding was also fulfilled. The control block diagram was given. The principle of the proposed method and the selection of droop coefficient were analyzed. The simulation and experiment results verify that the proposed method is effective in improving the power factor and the anti-islanding ability of grid-connected inverters.