Transformerless High Step-Up DC-DC Converters with Switched-Capacitor Network

High-voltage gain conversion is necessary for several applications, especially for low voltage renewable source applications. In order to achieve a high-voltage gain, the presented paper proposes a class of transformerless DC-DC converters based on three switched-capacitor networks. The proposed converters have the following characteristics: reduced voltage stress on the capacitors and power devices; obtained high voltage gain with small duty cycle; and reduced conduction losses in the power switches. To verify the operation principle of the proposed converters, the detailed analysis in different conditions of the proposed converters and a comparison considering existing topologies are also discussed in the paper. Moreover, the parameter selection and controller design for the converters are determined. Finally, to reconfirm the theoretical analysis, both the simulation and experimental results taken from a 400 W prototype operating at 60 kHz are given.