Study of an active network DC/DC Boost converter based switched-inductor

Traditional Boost converter cannot provide a high voltage-conversion ratio. It is improper to use traditional Boost converter as the first-stage of the micro-inverter, when we need a high voltage gain such as the two-stage photovoltaic grid-connected micro-inverter in some occasions. Since the insolated DC/DC converters contain high frequency transformers, they have some disadvantages both in volume and conversion efficiency, the transformerless high step-up voltage gain converters have became the research hotspot. However, traditional transformerless high step-up voltage gain converters also bring some drawbacks: the converters are large, the voltage stress of the power devices is very high, the voltage gain is still limited and the control strategies are complicated. This paper proposes an active network DC/DC Boost converter based on switched-inductor, which has following advantages: higher voltage-conversion ratio, lower voltage stress, simpler control strategy. A prototype rated at 200W has been established in the lab, and the experimental results verified the correctness of the analysis.