| Fuel cell has various advantages such as high efficiency of power generation, high power density, friendly interface, great stability and so on.Distributed power system is one of the most important applications of fuel cell. Compared to other kinds of power supply, power system based on FC has its superiority. Fuel cell will be widely used in the future as a new energy source, as the request for environment protection and energy conservation becomes more and more urgent and the influence of the rising cost of electricity transmission and the stress of power shortage becomes much more severe.Generating unstable direct current, fuel cell must be equipped with a Power Control Unit (PCU) to produce standard DC or AC power through regulation, control and management of the output. With the development of fuel cell products and technology, the researches on the power electronics supply base on fuel cell has showed the significance nowadays.The output voltage of a fuel cell single unit is usually less than 1V. As a result, the output of the whole fuel cell pack is not high enough for a distributed grid-connected power generation system,. Therefore, there must be an up-step converter between the fuel cell and grid-connected inverter.To increase the voltage between fuel cell output and inverter input, a 100V DC input and 380V double DC output DC/DC converter applied in a fuel cell grid-connected power generation system is discussed in this thesis.In the first chapter, the structure of FC power generation system and a front-end DC/DC converter which is suitable to FC grid-connected power generation system is briefly introduced. Then the topology of circuit is chosen and the object is confirmed.In the second chapter, the procedure of start-up, phase-shift is analyzed and the protection circuit is discussed. Then the parameters of the main circuits are calculated and the converter based on the 10 kW, 90v~130v output voltage PEMFC produced by Shenli company in Shanghai is designed.In the third chapter, the specific control circuits including phase-shift control, start-up control, protection circuit and IGBT driver circuit are proposed.In the fourth chapter, the experiment results and waveforms of specific points are given. |
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