Facing the requirements of low voltage ride through (LVRT), the disadvantages of traditional Crowbar technology appeared. In a failure, the rotor side converter (RSC) is short circuited, and the stator side of wide turbine loses its ability of providing reactive power for grid. This paper presents a new improved model of doubly-fed induction generator (DFIG) using DC-Chopper and series dynamic braking resistor (SDBR) instead of Crowbar. It can limit DC voltage and reduce the over-current of RSC, so it can protect DC capacitor and RSC. Because RSC is not out of service, in the control strategy, the RSC is controlled to make the stator side of wide turbine provide part of reactive power in a failure. At the same time the grid-side converter (GSC) operates in a state of variable power factor control. It can provide the most of reactive power to realize the LVRT.