【作者】 童小龙；

【导师】 许建平；

【作者基本信息】 西南交通大学 ， 电力电子与电力传动， 2013， 硕士

【摘要】 双向DC-DC变换器(Bi-directional DC-DC Converter,BDC)能够根据系统工作需要调节能量的传输方向,实现能量的双向传输,它在功能上相当于两个单向DC-DC变换器,是典型的“一机两用”设备。双向DC-DC变换器在航空电源系统、直流不停电电源系统、多端口混合供电系统以及电动汽车等场合都有相当广泛的应用,它可以使系统的体积和重量大幅减轻,具有十分重要的研究价值。单管正激双向DC-DC变换器的开关管电压应力较高,变压器磁通复位电路设计复杂；工作于升压模式时,单管正激双向DC-DC变换器需要采用脉冲重叠方式完成电感电流的换流,以实现能量的反向传输,从而导致驱动电路设计复杂,成本增加,系统可靠性降低。针对单管正激双向DC-DC变换器存在的这些问题,本文研究了一种双管正激双向DC-DC变换器,有效降低了开关管的电压应力和变压器设计难度；利用电感电流对元件寄生电容的充放电过程,采用无脉冲重叠换流,实现了能量的反向传输,在提高系统可靠性的同时,简化了驱动电路的设计。该变换器在电源电压较高、电压传输比较大的场合有很好的应用前景。文章详细分析了该变换器的结构及其在电感电流连续情况下的两种工作模式,分析了降压工作模式中低压侧开关管实现零电压导通的原理以及由元件寄生参数引起的开关管电流尖峰问题和抑制措施,从理论上论证了采用无脉冲重叠方式实现能量反向传输的可行性,并进行了仿真验证。最后通过制作双管正激双向DC-DC变换器的实验样机,验证了理论分析和仿真结果的正确性。更多还原

【Abstract】 Bi-directional DC-DC converter (hereinafter, BDC) can make the power flow in either direction according to external requirements, and can perform two or more functions. With the development of modern science and production, the needs of BDCs grow rapidly. The BDCs are widely used in aerospace power systems, DC uninterruptible power supplies, multi-port hybrid power supply systems and electric vehicle power systems. As the BDCs are used extensively, it is useful to reduce the size and weight of the power systems with great value of research.The one-switch forward BDC has problems of high switch voltage stress and complicated designing of the magnetic reset circuit of the transformer. Further more, in boost mode it has to use pulse overlapping method to make the inductor current commutate smoothly and to make the power flow in opposite way. However, the pulse overlapping method makes the designing of the driving circuit more complicated, the cost rise and the reliability of the system down. According to these problems existing in one-switch forward BDC, a kind of two-switch forward BDC is researched, which makes the swich voltage stress much lower and reduces the difficulties of the transformer designing. By using no pulse overlapping method can make the power-flow reverse as well through the parasitic capacitance charging-discharging by inductor current. This method improves the reliability of the system and makes the desining of the driving circuit much easier. This converter has good application prospect in occasions such as high voltage of power supply and large voltage transfer ratio. The constructure and the two operation modes in CCM (continual conduction mode of the inductor current) of the converter are analysed in details. Then the principle that the switches at the low voltage side achieved zero voltage conduction is explained, the problems of switchs current spikes caused by parasitic parameters and the suppression measures are explained as well. The feasibility of the converter that can make the power flow in opposite direction by using no pulse overlapping method is verified in theory and simulation confirmation followed. Finally, a prototype of the two-switch forward bi-directional DC-DC conveter is designed to verify the theoretical analysis and simulation results.更多还原