Research on the new current control strategy based on the grid-connected inverter

The improved segment control strategy is introduced aiming at the disadvantage of the larger AC current total harmonic distortion(referred to as THD) caused by the traditional space vector hysteresis control in the grid-connected inverter.The improved segment control strategy alternates hysteresis control and space vector hysteresis control strategies through the judgment of the AC error current vector modulus.The space region division of the voltage synthetic vector synthetic and the AC error current vector are given,and the selection principle of the switch state under segment control strategy is provided.Finally,the simulation model is established under Matlab/Simulink by comparing the traditional and the improved control strategies,the simulation results further demonstrate the improved control scheme not only can achieve the unity power factor,but also can reduce the AC current total harmonic distortion(THD)and the switching losses effectively.