Based on traditional control strategy, it is very limited to low voltage ride-through (LVRT) of doubly fed wind power generators. It can not meet technical rule for connecting wind farm to power system of China. It has to add the hardware circuit if the control strategy is not improved. The popular method is to add crowbar circuit to the rotor side. A model of doubly fed wind power generators based on traditional control strategy is built in this paper. The theory of LVRT was analyzed. Simulation of doubly fed wind power generators with crowbar circuit was undertaken and an experiment was undertaken in order to verify its virtue. The results show doubly fed wind power generators with crowbar circuit is more practical, which provides a powerful reference for improving the ability of LVRT of wind farm wind.