In view of such problem as unbalance of capacitive voltage at DC side and instability of system operation of static reactive power generator（SVG） in the reactive power compensation

a kind of SVG dual closed loop control strategybased on the combination of sliding mode variable structure and internal model is proposed with the mathematical model in the dqO coordinate system as the basis.Adoption of sliding mode variable structure by the voltage loop improves the fast and precise control of the DC side capacitive in case of sudden change of load.While the adoption of the internal mode control by the current loop achieves accurate tracking of the signal.The cascaded 21-level SVG simulation model is built in Matlab/Simulink.It is shown by the simulation result that the SVG DC-side capacitive voltage by the proposed control strategy is controlled very well and operation of the system is stable and the reactive power compensation effect on the distribution network is better.The feasibility and effectiveness of the control strategy proposed in this paper is also verified.