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| For the grid side current fed LCL inverter based photovoltaic farms, the mechanism of high-frequency resonance is revealed in this paper: the photovoltaic power station is equal to the circuit in which the resistance is connected in series with the capacitor in a certain frequency region, and it will be possible to construct an equivalent RLC resonant circuit with inductive grid impedance to produce an unstable or weak damping circuit resonance, represented as a high frequency resonant component emerging in the grid side current of LCL inverter. In addition, this paper theoretically verifies the RLC equivalent circuit and analyzes its excitation conditions. Furtherly, the influence of the control function of the LCL inverter on the damping characteristics of the equivalent resonant circuit is analyzed. Finally, the correctness of the analysis is verified by simulation experiments. |
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| Keywords:High frequency resonance;impedance modeling;impedance stability criteria;negative resistance;photovoltaic generator;equivalent RLC resonant circuit. |
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