中文摘要：

针对光伏系统在电网电压跌落时可能产生过流、过压的情况，在传统双闭环控制策略的基础上，采用无功控制与Crowbar电路相结合的方法对光伏系统进行控制，使系统具有低电压穿越的能力。采用有功、无功电流协调分配的无功控制，不但能够解决电网电压发生跌落时的过流问题，而且能够根据电网电压跌落幅值，利用光伏电站自身的无功补偿特性向电网提供一定的无功功率；Crowbar保护电路则能够保证直流侧电压在安全范围内。最后通过仿真验证了该方法的正确性和有效性。

英文摘要：

The photovoltaic （PV） system may produce overcurrent, overvoltage when grid voltage drop occurs. To deal with the problem, based on the traditional double-loop control strategy, the method of combining reactive power control with Crowbar circuit, which can improve the capability of low voltage ride through （LVRT） is proposed. Through coordinating the active current and the reactive current, the method can solve the overcurrent problem. At the same time, by using the reactive compensation of photo- voltaic power plant, the method provides reactive power to grid based on the amplitude of grid voltage drops. Finally, the simulation results show the correctness and effectiveness of the control strategy.