Research on LCL-type three-phase photovoltaic grid-connected inverter based on passive damping

The traditional LCL filter has resonance phenomenon in the working process of three-phase photovoltaic grid-connected inverter system. Based on the analysis of the frequency characteristics of LCL filter equivalent circuit before and after the introduction of passive damping resistor, it is concluded that the resonance of the system can be suppressed after the introduction of passive damping resistor. In the meantime, the current double closed-loop control strategy used in the system is introduced in detail. Finally, the simulation model is built by Matlab/Simulink simulation platform to verify the feasibility of the research method of LCL-type three-phase photovoltaic grid-connected inverter based on passive damping.

A Photo-Voltaic Invert-er Cluster Resonance Suppression Method Based on Capacitor Voltage Feed-Forward

Photo-voltaic inverts usually use LCL filter for filtering, and LCL filter will bring resonance problems to the system. This paper focuses on invert-er side current feedback control (invert-er side current feedback, ICF). This paper proposes a method for suppressing resonance of photo-voltaic invert-er clusters based on capacitor voltage feed-forward. First, establish the ICF mathematical model based on HPF and CVF under the weak grid, qualitatively analyze the resonance mechanism of the cluster invert-er, then analyze the system control structure and stability according to the proposed method, and finally verify the effectiveness of the proposed method through simulation and experiment sexuality and correctness.