Cost‐Effective Ultra‐High Step‐Up SEPIC‐Based DC‐DC Converter Integrated With Coupled‐Inductor for Solar‐Powered DC Microgrids

In DC microgrids powered by solar systems, the use of ultra‐high step‐up DC‐DC converters is considered an optimal choice, owing to the insufficient voltage provided by the panels and varying environmental conditions. This paper proposes a non‐isolated ultra‐high step‐up DC‐DC converter, combining a modified SEPIC structure with a voltage doubler rectifier cell and a two‐winding coupled inductor. The proposed converter features high voltage gain, continuous input current with low ripple, low voltage stress on components, and high efficiency. The synchronisation of the turn‐on and turn‐off times of the MOSFETs in the proposed converter eliminates the need for complex controllers. Additionally, characteristics such as common ground between input and output, which reduces electromagnetic interference (EMI), along with low cost and high power density, enable its suitability for solar systems. An analysis of the proposed converter under steady‐state conditions is carried out, and its advantages are assessed through a comparison with other similar structures. Furthermore, its controllability, stability, and dynamic response time are improved by implementing the pole‐placement control strategy. Finally, the analysis results are verified with tests on a laboratory prototype of the proposed converter in the power range of 200 W and a switching frequency of 40 kHz.