一种新型并网逆变器电流控制策略的研究

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

针对并网逆变器采用传统滞环空间矢量控制时存在的交流侧电流谐波总畸变率(Total Harmonic Distortion,THD)相对较大的缺点,提出分段控制的改进思想,即通过对交流侧误差电流矢量模值大小判断后,交替使用滞环控制与滞环空间矢量控制。给出电压合成矢量和交流误差电流矢量的空间划分方法,以及分段控制下开关状态的选择原则。利用Matlab/Simulink对改进前后的控制方案进行对比,结果表明改进后的控制策略不仅可以实现单位功率因数并网,还可以达到在减少开关损耗的同时,有效地降低交流侧电流谐波总畸变率(THD)。

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.