ZVS三电平双管正激变换器的研究

【作者】 楼俊山；

【导师】 徐德鸿；

【作者基本信息】 浙江大学 ， 电力电子及电力传动， 2003， 硕士

【摘要】 随着人们对电网质量的要求日益提高，三相功率因数校正电路(PFC)将被广泛应用，在三相分布式电源中，需要一种能够承受高输入电压、高效率、高功率密度的后级直流变换器与之配套使用。将两个双管正激变换器串联起来组成的双正激三电平直流变换器，具有内在抗桥臂直通的能力和输入分压电容自动均压的优点，并且变压器的磁芯工作在磁化曲线的第一、三象限，磁芯利用率高。 本文首先分析了并联型双正激电路的工作过程，研究了环流形成的原因和抑制方法。然后探讨一种零电压开关(ZVS)双正激三电平直流变换器，通过在高频变压器副边和整流电路输入之间加入谐振电感，配合有限双极性的PWM控制，可以实现开关器件的零电压开通。本文分析了它的工作过程和主要参数设计，并在试验中制作了一个全桥整流的220V/3kW样机进行验证。另外制作一个全波整流48V/2.5kW样机，其中使用了碳化硅肖特基二极管和硅PiN二极管，比较了它们关断时的特性和对变换器效率的影响。更多还原

【Abstract】 Recently there is a high demand for better power quality. Regulations such as IEC 555-2 and IEC61000-3-2 have been carried out to encourage companies to use or develop "clean" power appliances. It is estimated three phase power fact corrector (PFC) will be widely used in the next generation of distributed power system. Most three phase PFCs are based on Boost converter, so the output voltage should be high in order to minimize the harmonics in the input current. Therefore a DC-DC converter which can handle high input voltage is needed. Put the two double forward converters in series and a three level DC-DC converter is formed. It inherits the merit of no shoot-through from the double forward converter, besides the voltage on the input capacitors can be self-balanced.In the thesis, first a converter of two double forward converters paralleling at the input is discussed. The principle of circulating current between the primary windings of high frequency transformer is analyzed and the way to restrain it is introduced. Secondly, a three level Zero-Voltage-Switching (ZVS) DC-DC converter based on double forward converter is put forward. The principle and parameter selection is discussed and verified on a 3.2kW/220V prototype. Another 2.5kW/48V prototype is also built on which the comparison between SiC schottky diode and Si PiN diode and the effect on the overall efficiency are made.更多还原