A novel non-isolated high step-up high-power DC-DC converter based on coupled inductor (CI) and voltage multiplier cell (VMC) for renewable energy DC microgrids is presented in this study. A hybrid combination of three-phase interleaved boost converter with three CIs is chosen to reduce the current ripple at the input and meet the high-power requirement. Three VMCs connected at the secondary side of the CIs serve as gain extension cells. The voltage stress experienced by the switches is only a fraction of the output voltage as the gain extension is mainly achieved at the secondary side of CIs. Practical results obtained from the proposed converter which operated from a 60 V input and provided an output voltage of 1.1 kV while delivering 3 kW of output power prove the correctness of the design details and validate the proposed concept. © 2018, The Institution of Engineering and Technology.