Application of Thermal Balance Phase-Shift Control Strategy to Dual-Active-Bridge DC-DC Converter

热平衡移相控制策略在双有源桥DC-DC变换器的应用研究

Received: 20 December 2017

Abstract

With the development of the more/All electrical aircraft technology, the dual active bridge converter has been applied to the energy storage device to realize the bidirectional power flow in aircraft electrical system. The power loss of power device in DAB converter affects the operational life of the device and the reliability of the converter. So it is an important performance index to keep the temperature balance for power device in DAB converter. In this paper, the operational mode of dual active bridge bidirectional DC-DC converter in extended-phase-shift (EPS) control is analyzed and verified by experiment, find the reasons for difficult to achieve soft-switching under light load conditions, then proposes a novel thermal balance phase-shift control strategy on the basis of EPS. Experimental methods in this paper are alternation control mode and temperature feedback control mode. The thermal image and temperature was analyzed. The efficiency curve was plotted. The switching waveform was observed. the thermal balance was achieved to verify the effectiveness. and finally achieves the goal for improving the converter efficiency, reduces the devices heat stress, improves the reliability of the DAB converters and increases device lifetime.

摘要

随着飞机电气系统向多电化和全电化发展，机载储能装置的使用对双有源桥（dual-active-bridge，DAB）DC-DC变换器性能要求不断提高。DAB变换器中功率开关器件的热损耗影响着器件的使用寿命，因此也影响了变换器可靠性，所以对功率开关器件进行热平衡控制是一项很重要的指标。先通过对扩展移相控制策略下的航空DAB DC-DC变换器的工作模态和开关热不平衡现象进行分析和实验验证，找到轻载条件下难以实现软开关的原因，以及一次侧超前桥臂与滞后桥臂软开关条件的差异，从而提出一种在原有控制基础上的新型热平衡移相控制策略。通过时基交替控制模式和温度反馈控制模式2种方式进行控制效果实验，最终通过观测变换器热成像温度分布图、整机效率计算以及开关波形分析，验证了提出的算法实现功率器件热平衡控制方法的有效性，该方法可以提高变换器效率，减小器件应力，从而提高了DAB变换器的可靠性，提升器件寿命。