随着光伏发电装机的持续增加，光伏故障输出特性的准确分析与计算成为电力系统安全运行的关键。逆变器的控制直接影响光伏发电系统的故障行为。当电网发生不对称短路故障时，现有光伏短路电流计算方法未考虑锁相环暂态过程，忽略了锁相偏差对短路电流的影响，可能产生较大误差。为此，分析了电网故障下光伏正负双序控制暂态响应，推导了正负序交直轴电流的表达式，分析了电流的跟踪特性，进一步提出了电网不对称故障下锁相偏差的计算方法，分析了正负双序控制过程中锁相偏差对光伏短路电流的影响，推导了正负序旋转坐标系下的光伏正负序电流表达式，从而得出了光伏短路电流的计算方法，并通过仿真分析验证了所提出的光伏短路电流计算方法的正确性。

With the continuous increase of photovoltaic power generation installed capacity, accurate analysis and calculation of photovoltaic fault output characteristics have become the key to the safe operation of power systems. The control of inverters directly affects the fault behavior of photovoltaic power generation systems. When an asymmetric short-circuit fault occurs in the power grid, the existing photovoltaic short-circuit current calculation methods do not consider the transient process of the phase-locked loop and ignore the impact of phase-locked deviation on the short-circuit current, which may result in significant errors. To this end, the transient response of photovoltaic positive and negative sequence control under power grid faults is analyzed, the expression of positive and negative sequence AC and DC axis currents is derived, the tracking characteristics of currents are analyzed, and a calculation method for phase locking deviation under asymmetric power grid faults is further proposed. The influence of phase locking deviation on photovoltaic short-circuit current in the positive and negative sequence control process is analyzed, and the expression of photovoltaic positive and negative sequence current in the positive and negative sequence rotating coordinate system is derived. The calculation method of photovoltaic short-circuit current is obtained, and the correctness of the proposed photovoltaic short-circuit current calculation method is verified through simulation analysis.