Voltage Feedforward Control with Time-Delay Compensation for Grid-Connected Converters
نویسندگان
چکیده
In grid-connected converter control, grid voltage feedforward is usually introduced to suppress the influence of the grid voltage distortion on the converter’s grid-side AC current. However, Owing to the time-delay in the control system, the suppression effect of grid voltage distortion is seriously affected. In this paper, the positive effects of the grid voltage feedforward control are analyzed in detail, and the time-delay caused by the low-pass filter (LPF) in voltage filtering circuits and digital control are summarized. In order to reduce the time-delay effect on the performance of feedforward control, a voltage feedforward control strategy with time-delay compensation is proposed, in which, a leading correction of the feedforward voltage is used. The optimal leading step used for this strategy is derived from analyzing the phase-frequency characteristics of LPF and the implementation of digital control. By using the optimal leading step, the delay in the feedforward path can be further counteracted so that the performance of feedforward control on suppressing the influence of grid voltage distortion on the converter output current can be improved. The validity of the proposed method is verified by simulation and experiment results.
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