中国电力 ›› 2022, Vol. 55 ›› Issue (9): 88-97.DOI: 10.11930/j.issn.1004-9649.202103009

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适用于PET的负载电流前馈控制策略

李帅虎1,2, 王婷婷1, 刘制1, 彭寒梅1, 唐坤3   

  1. 1. 湘潭大学 自动化与电子信息学院,湖南 湘潭 411104;
    2. 长沙理工大学 电气与信息工程学院,湖南 长沙 410082;
    3. 资阳石油钢管有限公司,四川 资阳 641300
  • 收稿日期:2021-03-01 修回日期:2022-01-11 发布日期:2022-09-20
  • 作者简介:李帅虎(1981—),男,通信作者,博士,副教授,从事电力系统稳定分析与控制研究,E-mail:lishuaihu2010@126.com;王婷婷(1995—),女,硕士研究生,从事电力电子变压器研究,E-mail:wangtting2021@126.com
  • 基金资助:
    国家自然科学基金资助项目(多电力变换装置并网对电压稳定的影响及其预防性控制方法研究,51777179)。

Load Current Feedforward Control Strategy for Power Electronic Transformer

LI Shuaihu1,2, WANG Tingting1, LIU Zhi1, PENG Hanmei1, TANG Kun3   

  1. 1. School of Automation and Electronic Information, Xiangtan University, Xiangtan 411104, China;
    2. College of Electrical and Information Engineering, Changsha University of Science and Technology, Changsha 410082, China;
    3. Ziyang Petroleum Steel Pipe Co., Ltd., Ziyang 641300, China
  • Received:2021-03-01 Revised:2022-01-11 Published:2022-09-20
  • Supported by:
    This work is supported by National Natural Science Foundation of China (Study of Multiple Power Conversion Device Connection on Voltage Stability and Its Preventive Control Method, No.51777179).

摘要: 电力电子变压器(power electronic transformer, PET)由级联H桥(cascaded H-bridge,CHB)和双有源桥(dual active bridge,DAB)变换器级联组成,当发生负载突变时,PET的高、低压直流母线电压存在较大波动,无法迅速达到平衡。为了解决此问题,提出一种适用于级联系统的负载电流前馈控制策略。该策略由DAB级和CHB级的负载电流前馈2部分组成。前者是通过低压侧负载电流计算得到DAB级的补偿移相角,后者则考虑级联系统的输入输出功率守恒,将负载电流直接前馈到CHB级。同时,考虑到CHB级电流内环的延迟,CHB整流级采用一阶微分与功率均衡相结合的电流前馈控制策略。所提控制策略只需要采样低压直流母线负载电流,极大程度地节约了系统成本,且操作简单,易于实现。仿真和Starsim实验验证了所提控制方法的正确性和有效性。

关键词: 电力电子变压器, 级联H桥, 双有源桥变换器, 电压波动, 前馈控制

Abstract: Power Electronic Transformer (PET) consists of cascaded H-bridge (CHB) converters and dual active bridge (DAB) converters. However, the fluctuation of load causes large voltage fluctuation of high voltage DC (HVDC) and low voltage DC (LVDC) buses of PET. To address this problem, a load current feedforward control strategy for cascaded systems is proposed, which consists of two parts: the load current feedforward of DAB stage and CHB stage. The former obtains the compensated phase shift ratio of the DAB stage through calculation of the load current at the low voltage side, while the latter feeds forward the load current to the CHB stage with consideration of the power conservation of the cascade system. Moreover, considering the delay of the inner current loop of the CHB stage, the first order differential is introduced to the feedforward strategy in CHB stage, which further suppresses the voltage fluctuation on HVDC buses. The proposed control strategy only needs to sample the load current of LVDC bus, which saves the system cost greatly. In addition, the proposed strategy is easy to operate and implement. Simulation and Starsim experimental results verify the correctness and effectiveness of the proposed control method.

Key words: power electronic transformer, cascaded H-bridge, dual active bridge converter, voltage fluctuation, feedforward control