| High step-up DC/DC converter is widely applied in fields such as switching power supply and renewable generation. The output voltage of low and medium power fuel cell,PV pane,battery and some other power sources is usually low, so high step-up DC/DC converter is needed to realize step-up. Then the power can be transferred to the power grid or load through an inverter. This paper studies on high efficiency high step-up DC/DC converters.The first chapter of this paper reviews the study on non-isolated high step-up DC/DC converters. Different types of high step-up DC/DC converters are briefly introduced.In chapter two, several kinds of DC/DC converters are analyzed firstly. Then two-phase interleaved Boost & Buck-Boost converter is chose to be the high step-up DC/DC converter in the lOkW fuel cell UPS system by means of loss analysis and efficiency comparison.In the third chapter, the design method of the two-phase interleaved Boost & Buck-Boost converter is introduced. Then on the basis of small signal modeling, current inner loop and outer voltage loop are designed. At last, experiment model is built to do experimental research.In chapter four, the efficiency optimization scheme of the two-phase interleaved Boost & Buck-Boost converter is discussed. The effect on efficiency promotion by using power MOSFET as power switches and inductor optimization is analyzed. Aiming at the scheme using power MOSFET as power switches, the cause of switch voltage stress overshoot is analysis and some measures are given for voltage stress inhibition. Finally, primary experiment results are given. |
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