| Abstrakt: |
With the spreading of Photovoltaic (PV) grid-connected system, grid-connected reactive-load compensation and harmonic control is becoming a research focus. Unipolar and bipolar modulations are widely used in active power filter of PV grid-connected inverter. Unipolar modulation is good at harmonic, ripples and efficiency control, while bipolar modulation is good at grid-connected current control. A comprehensive comparison between the aforementioned modulation strategies in aspects of basic switching action, effects on operation mode, current harmonics，efficiency, is done in this paper. Base on it, a hybrid modulation strategy with the fusion of the unipolar and bipolar modulation is proposed in this paper. Numerical and experimental results show the lowest total harmonic distortion, and enhanced zero passage control are achieved by the proposed method, providing a reliable and efficient control strategy for PV grid connecting. [ABSTRACT FROM AUTHOR] |
