Wind power generation has been developed rapidly in recent years

and the low voltage ride-through(LVRT)ability has been a critical indicator measuring the transient operation ability of wind power. Much research has been done about how to improve the LVRT ability of doubly-fed induction generator(DFIG)

but some quantitative evaluation criteria of control strategies for LVRT are absent. Taking external voltage variation as a disturbance

some quantitative evaluation criteria of LVRT control strategies for DFIG adopting local input-to-state stability theory is proposed. First

the local input-to-output stability(LIOS)properties of different control strategies are analyzed combined with practical operation requirements of DFIG and responses of different control strategies under continuous external voltage disturbance based on the integral-integral estimate expression of LIOS. Then

as the input-to-output gain with a linear function form is more conservative

a piecewise linear function is adopted to estimate the input-to-output gain function with a corresponding algorithm designed. Finally

the merits of different control strategies are analyzed with the quantitative LIOS properties and quantitative evaluation index. A specific improvement strategy is raised with a case validating that it can make full use of advantages of different control strategies in the absence of additional hardware.