In order to improve the shunt active power filter（ SAPF） to suppress the harmonic and weaken the chattering in grid operation

an improved index reaching law variable structure control strategy is put forward

combined with sliding mode variable structure control

introducing the state capacity and saturated function.Establish SAPF simulation model and experimental device. Simulation results show that the current total distortion after compensation decreased to 3. 25 %

A phase current is close to sine wave

through comparing the control strategy before and after improvement

and verify that the proposed strategy can effectively reduce the peak phenomenon

improve the robustness of active power filter on the basis of experiments.