基于环流注入的电力电子牵引变压器电压平衡控制方法

Voltage balance control method of power electronic traction transformer based on circulating current injection

以环流注入为基础,进行电压平衡控制时,需要计算输出电流幅值和相位,再生成环流参考值,使得平衡控制过渡时间较长。因此,提出基于环流注入的电力电子牵引变压器电压平衡控制方法。根据变压器的主电路结构,建立级联H桥数学模型。结合级联H桥和双有源桥结构,设计变压器电压平衡调制方案。利用电流瞬时值和调制信号,直接计算出二次谐波环流注入参考幅值,作为电压平衡控制的基础。最后,组建包含3个输入分量的闭环控制器,实现电力电子牵引变压器电压平衡控制。实验结果表明:所提方法与基于载波移相、基于纹波电压前馈、基于动态调整控制方法相比,电压平衡控制过渡时间减少了57.14%、73.91%和82.35%,提升了平衡控制效率。

Based on the circulation injection,when the voltage balance control is carried out,it is necessary to calculate the amplitude and phase of the output current,and then the circulation reference value is generated to make the transition time of the balance control longer.Therefore,a voltage balance control method of power electronic traction transformer based on circulating current injection is proposed.According to the circuit structure of power electronic traction transformer,the mathe-matical model of cascaded H-bridge is established.Combined with cascaded H-bridge and double active bridge structure,the voltage balance modulation scheme of transformer is designed.Using the instantaneous value of current and modulation signal,the reference amplitude of second harmonic circulation injection is directly calculated as the basis of voltage balance control.Finally,a closed-loop controller with three input components is established to realize the voltage balance control of power electronic traction transformer.The experimental results show that the proposed method reduces the transition time of voltage balance control by 57.14%,73.91%and 82.35%compared with the carrier phase-shifting,ripple voltage feedfor-ward and dynamic adjustment control methods,and improves the balance control efficiency.