基于固态变压器的电动汽车集群柔性并网控制方法

Flexible grid-connected control of electric vehicle cluster based on cascaded power electronic transformer

级联型固态变压器(SST)为实现电动汽车充放电集群高效稳定并网提供了一种可行的解决方案,但其体积较大、效率低、结构中存在的多直流侧电压不平衡等问题制约了工程应用。为此,本文提出了一种级联型固态变压器柔性并网优化控制方法,在建立数学模型的基础上分析了其直流侧电压的纹波特性,通过引入两级协调控制和比例积分谐振(PIR)控制器,在实现多直流电压平衡的同时,大大减少了直流侧电压的纹波。实验结果表明,与传统方法相比,该方法可以将直流侧电容值减少至原来的1/4左右,有效地减小了装置的体积和质量,提升了系统的效率。

Cascaded solid state transformer(SST)provides a feasible solution to realize the high-efficiency and stable grid-connection of electric vehicle charging and discharging cluster,but its larger size,lower efficiency and multiple direct current(DC)side voltage imbalance in the structure restrict its engineering application.Therefore,this paper proposes a flexible grid-connection optimization control method for SST.Based on the establishment of mathematical model,the ripple characteristics of DC side voltage are analyzed.By introducing two-stage coordinated control and proportional integral resonant(PIR)controller,the ripple of DC side voltage is greatly reduced while realizing multiple DC voltage balance.The experimental results show that,compared with the traditional method,the DC side capacitance can be reduced to one quarter,which effectively reduces the volume and weight of the device,and improves efficiency of the system.