A High-gain Floating-Interleaved Three-level Boost Converter

To meet the high gain and high power of DC/DC converters, a high-gain floating-interleaved three-level boost converter (TL-FIBC) is proposed in this paper. The converter is composed of two three-level boost converters connected in a floating interleaved manner, which make the high gain as well as low input current ripple realized. Thus, The TL-FIBC can be used as the front stage boost part of the photovoltaic power generation system. In addition, because of the three-level structure is adopted in the internal subunits of the TL-FIBC, the voltage stress of switch is only one quarter of the sum of input voltage and output voltage. The operation principle is introduced firstly, then the gain characteristics of the proposed converter are investigated in depth. Afterwards, the control of flying capacitor voltage is adopted to make the voltages of the flying capacitor of upper and lower subunits equal respectively. Finally, a 2.5kW prototype with 68 120V input and 700V output is built, and the feasibility of the TL-FIBC and the correctness of theoretical analysis are verified.