In view of the inter-phase capacitive voltage unbalance of static synchronous compensator which is based on cascaded H-bridge topology under traditional control framework

a kind of new new hybrid modulation algorithm is adopted and a novel nonlinear current control algorithm is proposed in this paper. Firstly

the modulation principle of new hybrid modulator is described on the basis of six-module thirteen-level cascaded H-bridge topology and the same capacitive voltage balance strategy which is suitable for novel hybrid modulation is illustrated. Then

the control model of static synchronous compensator under two-phase synchronous rotating coordinate is derived and the inter-phase capacitive voltage unbalance problem of conventional dq decoupling control is indicated. Aiming at the inter-phase capacitive voltage unbalance

a separated phase current control strategy under three-phase static coordinate is proposed. A nonlinear current controller is derived and designed in accordance with the second method of Lyapunov stability criterion

which obtains error-free tracking effect to the alternative current reference. Finally

a simulation model is set up under Matlab/Simulink environment. The simulation results show that the proposed control strategy can not only keep the inter-phase capacitive voltage consistent and stable

but can also have perfect dynamic response characteristics at different conditions.