王顺, 马兰, 朱磊磊, 杨帆, 谢锡锋, 舒泽亮. 单相PET级联整流SVPWM均压边界及拓展方法[J]. 高电压技术, 2024, 50(3): 1235-1243. DOI: 10.13336/j.1003-6520.hve.20221024
引用本文: 王顺, 马兰, 朱磊磊, 杨帆, 谢锡锋, 舒泽亮. 单相PET级联整流SVPWM均压边界及拓展方法[J]. 高电压技术, 2024, 50(3): 1235-1243. DOI: 10.13336/j.1003-6520.hve.20221024
WANG Shun, MA Lan, ZHU Leilei, YANG Fan, XIE Xifeng, SHU Zeliang. Voltage Balancing Boundary and Extension Method of SVPWM for Single-phase Cascaded Rectifier Based on PET[J]. High Voltage Engineering, 2024, 50(3): 1235-1243. DOI: 10.13336/j.1003-6520.hve.20221024
Citation: WANG Shun, MA Lan, ZHU Leilei, YANG Fan, XIE Xifeng, SHU Zeliang. Voltage Balancing Boundary and Extension Method of SVPWM for Single-phase Cascaded Rectifier Based on PET[J]. High Voltage Engineering, 2024, 50(3): 1235-1243. DOI: 10.13336/j.1003-6520.hve.20221024

单相PET级联整流SVPWM均压边界及拓展方法

Voltage Balancing Boundary and Extension Method of SVPWM for Single-phase Cascaded Rectifier Based on PET

  • 摘要: 电力电子变压器(power electronic transformer,PET)是交直流配电系统互联的重要接口设备,然而后级等效负载不平衡将造成前级整流器各模块的电压偏移。针对单相级联H桥整流器空间矢量调制均压失效问题,推导出基于最优矢量选择均压策略的边界计算方法。根据计算所得的负载不平衡度限制边界与级联模块数、调制度以及功率因数的关系,提出了变调制度和功率因数的控制策略以增加均压能力。该策略通过改变直流电压或降低功率因数来重建更宽的均压工作范围,确保原不平衡度均压极限的系统稳定运行。最后,通过三模块级联整流器的仿真与实验验证了该均压边界的正确性,以及所提均压拓展方法保障极端不平衡负载条件下均压的有效性。

     

    Abstract: Power electronic transformer is an important interface device for connecting AC/DC power distribution systems in the renewable energy generation grid. However, the DC voltage of the front-stage single-phase cascaded H-bridge rectifier will deviate because of the back-stage unbalanced load. In this paper, the voltage balancing boundary based on the optimal vector selection strategy is derived to solve the problem that space vector pulse width modulation (SVPWM) fails to balance the voltage. According to the relationships between the load unbalance index boundary and the number of cascade cells, modulation index, and power factors, a control strategy is proposed. The voltage balancing capability can be improved by changing the modulation index or power factors. Therefore, to ensure stable operation under severe unbalanced load conditions, a wider voltage balancing range is established by changing the DC voltage reference or reducing power factors. The balancing boundary and the effectiveness of the proposed expansion method, which guarantees equalization under extremely unbalanced conditions, are verified by simulation and experimental results with a three-cell cascaded rectifier.

     

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