Multi-Sampled Grid-Side Current Control for LCL-Filtered VSCs with Enhanced Dissipativity

For the grid-side current control of LCL-filtered grid-connected converters, capacitor current active damping is a common method to enhance dissipativity. However, the dissipation near the critical frequency can be jeopardized by the filter parameter deviation, which may result in high-frequency resonances. Besides, the grid voltage feedforward is often abandoned due to the stability consideration, which is however preferred in the practical application to enhance the transient performance. To tackle these challenges, a multi-sampled current control scheme is proposed in this paper. By combining the capacitor current active damping and the capacitor voltage feedforward, not only the dissipative range can be optimized up to the switching frequency, but also the robustness against the filter parameter deviation is enhanced. The validity of the proposed method is verified through the experiments.