电流型双有源桥式双向DC-DC变换器的建模与解耦控制

Modeling and Decoupling Control of Current-fed Dual Active Bridge Bidirectional DC-DC Converter

对于电流型双有源桥式双向DC-DC变换器,分析了其工作原理与稳态特性。通过列出变换器半周期内的状态方程,对变换器进行小信号建模并推导出系统传递函数。由于系统在进行闭环控制时移相角与占空比之间的相互耦合会降低系统动态性能,因此需要采用解耦控制来解除二者之间的相互耦合,进而提出了一种稳态解耦控制策略。一方面通过建立相对增益矩阵来分析控制量与被控制量间的匹配关系来设计控制器,另一方面基于系统稳态过程增益矩阵得到系统稳态解耦矩阵,2个回路的相互影响通过加入系统稳态解耦矩阵而大大降低。最后通过仿真与实验对所提控制策略的有效性和合理性进行了验证。

For a current-fed dual active bridge bidirectional DC-DC converter,its operating principle and steady-state characteristics are analyzed.By listing its equations of state in a half-cycle,its small-signal model is established and the system’s transfer function is derived.Due to the intercoupling between the phase shift angle and duty cycle when the system is under closed-loop control,the system’s dynamic performance will deteriorate.To eliminate the intercoupling by means of decoupling control,a steady-state decoupling control strategy is proposed.On the one hand,a controller is designed by analyzing the pairing relation between the control and controlled volumes,which is based on a relative gain matrix.On the other hand,the system’s steady-state decoupling matrix is obtained based on its steady-state process gain matrix.The interactions between the two control loops are significantly reduced by introducing the system’s steady-state decoupling matrix.Finally,the effectiveness and feasibility of the proposed control strategy were verified by simulation and experimental results.