Study on Steady-State Output Characteristics of Three-Level Boost Converter

The application of the three-level boost converter (TLBC) is able to reduce the voltage stress of power switches and diodes in the back-end circuit, also can reduce the volume and weight of energy storage components, and improve the overall power density of the DC–DC converter system. In this paper, the output characteristics of TLBC used as a voltage stabilizer in high-voltage applications are studied. The topology of TLBC is introduced, and the voltage–current relationship of the converter in five basic switching modes is analyzed with the equivalent circuits. The mathematical models are established for all modes. And then the continuous conduction mode (CCM) of TLBC has been analyzed and derived the voltage gain with different duty ratios in this mode. The working characteristics under CCM mode were analyzed from three aspects including ripple current, ripple voltage and controller design. The output characteristics of TLBC are obtained, which provides a theoretical basis for the design and application of TLBC. Finally, simulation experiments verified the conclusion obtained by analyzing the TLBC steady-state output characteristics.