ABSTRACT A novel nonisolated high gain DC–DC converter for renewable energy generation systems is proposed in this article. The converter integrates three‐winding coupled inductor, voltage multiplier cell and quadratic boost circuit, significantly enhancing the voltage‐boosting capability. The unique boost structure, formed by the three‐winding coupled inductor and the voltage multiplier cell, enables the converter to achieve a high voltage gain with a low total turns ratio of the coupled inductor and an appropriate duty cycle. Additionally, the three‐winding coupled inductor enhances the flexibility of voltage gain adjustment. The input side of the proposed converter is connected to an independent inductor, which simplifies the realization of continuous input current and the reduction of current ripple. The low voltage stress on the switching devices and the clamping diode facilitates the selection of switching devices with low conduction losses and fast recovery diodes contributing to improved converter efficiency. This paper provides a detailed discussion of the steady‐state analysis, parameter design, and loss analysis of the proposed converter, along with a comparison with existing high‐gain converters. Finally, an experimental prototype was built based on the design principles, and the experimental results validate the effectiveness of the proposed converter.