Non-isolated Step-up DC-DC Converter Based on Switched Capacitor Cells
Farid Mohammadi, Gevork B. Gharehpetian, Hasan Rastegar, Mohammad Farhadi‐Kangarlu
Abstract
A non-isolated high gain step-up DC-DC converter for low power applications is suggested in this study.In the designed transformerless converter, the main switch current and voltage stress is reduced while maintaining high voltage gain.For instance, with a duty cycle of 0.5 a voltage gain equal to 5 is achieved while the normalized switch voltage stress is 0.4.Also, it decreases power losses of active and passive elements.In the proposed converter design, the switched-capacitor (SC) technique is used to obtain maximum voltage transfer gain using only one switch.The three modes of operation, i.e., continuous conduction mode (CCM), boundary conduction mode (BCM), and discontinuous conduction mode (DCM), are studied in detail.The small signal analysis (SSA) of the designed converter is investigated, and its steady-state model is examined under CCM.Performance of the proposed converter proposed in this study is assessed and tested using a prototype.Efficiency of the converter is recorded above 94% in a wide range of output powers.Overall, compared to the other converters, the results suggest satisfactory performance of the designed converter.An issue of the proposed converter is that its input current is not smooth due to using the switched-capacitor cell in its structure.This issue is alleviated by using input filters.