Quasi-proportional Resonance Control of the Single Phase LCL Grid-connected Inverter
A quasi-proportional resonance(QPR)control strategy was proposed for the problem that PI con-trol cannot achieve static-free control of inverted AC signals,in order to improve the gain at the fundamental fre-quency of the grid,and then achieve better tracking control of sinusoidal AC signals.Meanwhile,for the problem of resonance spikes in LCL filters,this paper proposes an active damping strategy based on capacitor current propor-tional feedback,and constructs a dual current loop control structure with capacitor current inner loop and grid-connected current outer loop to achieve resonance spike suppression.In order to verify the effectiveness of the pro-posed control strategy and control structure,a single-phase LCL grid-connected inverter simulation model was con-structed using the QPR control and capacitor current proportional feedback active damping strategy for simulation verification,and the simulation results showed that the proposed control strategy made the grid-connected current amplitude error about 0.03%and the total harmonic distortion of grid-connected current 1.47%,which effectively reduced the tracking and control error of the inverted AC signal.It effectively reduced the tracking control error of the inverter AC signal,improved the quality of the grid-connected current,and had good dynamic performance,which verified the adaptability of the proposed QPR control.
grid-connected inverterLCL filterQPR controlactive dampingdual current loop control
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