一种光伏用高升压比高效率直流变换器

以光伏为代表的新能源发电日益受到重视。为提高光伏发电系统的可靠性与发电效率,两级式光伏并网发电系统的前级DC/DC变换器对升压比和效率提出了要求。首先对FIBC拓扑的工作原理、高升压性能、低电力电子器件应力等进行详细分析,与传统Boost电路的对比结果验证了FIBC的优越性;然后建立了Boost和FIBC电路的损耗模型,给出了额定工况下的损耗分布和效率,结果表明同电路参数下FIBC具有更高的效率;接着利用交错控制技术,对FIBC电感参数进行了优化,进一步提高变换器效率;最后给出Boost与FIBC和优化FIBC在不同工作电流下的效率曲线,结果表明优化后FIBC效率提高明显,比Boost更适合用于低压大功率光伏发电系统中。基于Matlab/Simulink平台的仿真结果表明,使用交错技术可以优化电感参数,直流母线输出电压能够稳定在400 V。

A High Voltage Gain High Efficiency DC/DC Converter for PV System

The new energy power generation system, like the PV system, is getting more and more attention. In order to improve the reliability and efficiency of the two-level PV generation system, the high voltage gain and high efficiency of the front end is expected. The comparison result between the Floating-output Interleaved-input Boost-derived Converter(FIBC)and the Boost in voltage gain and power electronics device stress validates the superiority of the former. Then the loss models of both circuits have been presented, as well as the power distribution under the rated working condition, which shows that the FIBC is more efficient. Based on the interleaved technology, the parameter of the inductance is optimized and hence reduces the DC resistance and improves the efficiency. Finally, the efficiency versus current curve of the Boost, FIBC and the optimized FIBC is given, which shows that the FIBC is more suitable for low voltage high power PV generation system for its higher efficiency under large current. The simulation results validate the feasibility of optimizing the inductance using the interleaved technology, and the DC bus can be regulated well for grid connection.