Three-phase AC–DC converter based on integrated transformer is a novel converter which is capable of handling high power levels and can realise power factor correction function. Owing to different parameter tolerances of the primary windings, grid current could be unbalanced, which usually could not be solved through traditional control methods. To handle this problem, a current balancing method is adopted in this study to improve former current control loop. Meanwhile, based on the principle of instantaneous power balance, a dual loop control strategy with an outer voltage loop and an inner current loop is designed. Besides, load current feedforward control is introduced to enhance the dynamic response. Moreover, phase-shift control is employed as the modulation method, in which duty ratios change along with sinusoidal signals. Simulation and experimental results show that the control strategy could make the three-phase current of the converter sinusoidal and balanced.

中文翻译：

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基于集成变压器的具有功率因数校正功能的三相交直流变换器不平衡电流分析

基于集成变压器的三相AC-DC转换器是一种新颖的转换器，能够处理高功率电平并可以实现功率因数校正功能。由于初级绕组的参数公差不同，电网电流可能会不平衡，这通常无法通过传统控制方法解决。为了解决这个问题，本研究采用了一种电流平衡方法来改善以前的电流控制回路。同时，基于瞬时功率平衡原理，设计了具有外部电压环路和内部电流环路的双回路控制策略。此外，引入了负载电流前馈控制以增强动态响应。此外，采用相移控制作为调制方法，其中占空比与正弦信号一起变化。