Robust predictive dual-loop control strategy with reactive power compensation for single-phase grid-connected distributed generation system

A robust predictive dual-loop control strategy with reactive power compensation is proposed for single-phase gridconnected distributed generation (DG) system located at the end of the feeder. The proposed control strategy mainly includes improved reactive current detection and robust predictive dual-loop control. To reduce the long time delay in the conventional reactive current detection, the improved reactive current detection method based on the derivative and i_p - i_q algorithm is presented. In the inner current loop, a robust predictive deadbeat control (RPDC) is proposed to reduce the control delay in digital signal processor, and also enhances system robustness due to the filter inductance mismatch. In the outer loop, proportional-integral controller is applied to stabilise the dc-link voltage, and power feedforward is used to speed up the system response. In z-domain, the stability of RPDC is discussed, and the proper parameters are selected. Simulation and experimental results verified the validity of the proposed strategy.