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以无工频牵引变压器电力牵引传动系统为应用背景,对其中的全桥隔离DC/DC变换器开展研究。首先,全面地分析和归纳全桥隔离DC/DC变换器系统中存在回流功率的现象,定义电源侧回流功率和负载侧回流功率,为同时限制变换器两端回流功率提出一种三重相移控制方法。然后,在此基础上,给出最小回流功率控制算法。同时,为了减小变换器启动时的冲击电流,给出一种全桥隔离DC/DC变换器软启动控制方法。最后,研制了1.5 kW小功率实验平台并进行实验验证,实验结果表明,该软启动方法可有效地减小变换器启动时的电流冲击,所提出的三重相移控制方法相对于传统相移控制方法和双重相移控制方法显著提高了系统效率。“,”This paper focused on the full-bridge isolated DC/DC converter, which is a part of transformerless AC traction drive system in railway application. Firstly, the phenomenon of reactive power existing in the adopted DC-DC was comprehensively analyzed and concluded, and reactive powers of supply side and load side are defined. In order to limit two side’s reactive power of the DC-DC converter, a triple-phase-shift control method is proposed. On the basis of the-triple-phase-shift control, a minimum reflux power control algorithm is given. Meanwhile, in order to reduce the inrush current at the starting point, a soft-starting strategy is adopted to the full-bridge isolated DC/DC converter. Finally, these control methods are verified in a 1.5kW power experiment platform. The experiment results show that the soft starting strategy can reduce the inrush current at the starting point, effectively. And the triple-phase-shift control can improve the system efficiency obviously, which is better than single and dual phase shift controls.