基于虚拟频率的隔离型双向AC/DC变换器最小电流应力控制策略

Minimum Current Stress Control Strategy of Isolated Bidirectional AC/DC Converter Based on Virtual Frequency

针对隔离型双向AC/DC变换器提出一种基于虚拟频率的最小电流应力控制策略。首先,分析了三重移相(triple phase shift,TPS)控制方法的开关特性,并设计了基于TPS的移相全桥最小电流应力控制算法。然后,针对输出功率与移相比呈非线性的特点,提出虚拟频率控制方法,该算法不仅可以将非线性控制简化为线性化,还可实现交直流变换器单级转换,有效减小中间母线电容,降低系统电流应力。最后,基于TMS320F28335的实验平台对所提出的控制策略进行了实验验证。实验结果表明,当功率双向传输时,所提控制策略能有效地减小变换器的电流应力。

We propose a minimum current stress control strategy based on virtual frequency for isolated bidirectional AC/DC converters.First,the switching characteristics of the triple phase shift(TPS)control method are analyzed,and the TPS-based phase-shift full-bridge minimum-current stress control algorithm is designed.Then,according to the non-linear characteristics of the output power compared with the shift,a virtual frequency control method is proposed.This algorithm can simplify the nonlinear control to linearization,and can also realize the single-stage conversion of the AC-DC converter,effectively reducing the intermediate bus capacitance and reducing system current stress.Finally,the experimental platform based on TMS320 F28335 verifies the proposed control strategy.The experimental results show that the control strategy in this paper can effectively reduce the current stress of the converter when the power is transmitted in both directions.