This article presents a modulation scheme to suppress the transient dc bias current in dual active bridge (DAB) converters. The current in the transformer at the commutating time is associated with the initial current in a switching period, so there must be a dc bias current during the transient response. To investigate the modulation scheme for suppressing the transient dc bias current, the article reviews the optimal TPS control strategy, which is derived from the zero voltage switching with the minimum current stress in the transformer. By analyzing the dc bias current, the transient dc bias current can be evaluated by the current in the transformer at the symmetry line of the primary full-bridge voltage waveform instead of the current at the commutating time. It can be concluded that the expressions of the transient dc bias current for different working modes are unified. Therefore, the modulation schemes without transient dc bias current for different working modes can be also unified. On this basis, a universal strategy can meet all the transient cases. There is no need to identify or select the working modes and power conditions in the transient dc bias current control, which simplifies the implementation of the modulation scheme in the digital signal processor. Finally, an experimental prototype has been built to verify the effectiveness of the proposed modulation scheme.

中文翻译：

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用于抑制双有源桥式转换器中瞬态直流偏置电流的通用调制方案


本文提出了一种抑制双有源桥 (DAB) 转换器中瞬态直流偏置电流的调制方案。换相时变压器中的电流与开关周期的初始电流相关，因此瞬态响应期间必然存在直流偏置电流。为了研究抑制瞬态直流偏置电流的调制方案，本文回顾了最佳 TPS 控制策略，该策略源自变压器中电流应力最小的零电压开关。通过分析直流偏置电流，可以用初级全桥电压波形对称线处变压器中的电流来代替换相时的电流来评估瞬态直流偏置电流。由此可见，不同工作模式下瞬态直流偏置电流的表达式是统一的。因此，不同工作模式的无瞬态直流偏置电流的调制方案也可以统一。在此基础上，通用策略可以满足所有瞬态情况。瞬态直流偏置电流控制中无需识别或选择工作模式和功率条件，这简化了数字信号处理器中调制方案的实现。最后，建立了实验原型来验证所提出的调制方案的有效性。