A Harmonic Compensation Strategy for Grid-connected Inverter with LCL Filter
نویسندگان
چکیده
LCL filter has the characteristic of prompt attenuation over the high-frequency range, but the thirdorder control system exits the resonance problem. Nonetheless, the inherent non-linear characteristic and dead-time effects of switching tubes, along with the DC-side voltage secondary pulsation and grid harmonic pollution, arouse a wealth of low-order harmonics injected which is tough to be filtered. In this paper, a combined control scheme of repetitive control and state feedback is brought forward, in which both DC voltage feedforward and grid voltage feedforward are added. The proposed control strategy can eliminate resonance peak of LCL filter, suppress and compensate the low-frequency harmonics, so that quick response and tracking without static error of the system can be realized. Finally, the rationality of the harmonic analysis and the validity of control strategy are verified through MATLAB simulation and experiment results of the grid-connected inverter.
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