摘要
级联H桥AC/DC型电力电子变压器中的高频直流环节通常采用双有源桥电路DAB(dual-active bridge),并通过移相控制方式进行能量传递。单移相控制会在DAB中引入回流功率,增加系统损耗。在由理想直流电压源供电的DAB中,通过改进的移相控制可以显著抑制回流功率。然而在电力电子变压器PET(power electronic transformer)中,交流电网侧的PWM整流环节会引入二次脉动功率,导致其高频直流环节的输入/输出电压变比存在低频脉动,使得现有的回流功率抑制方法难以获得期望效果。针对这一问题,分析了在PET模块电容电压存在低频脉动的情况下,采用单移相和扩展移相两种控制方式下的回流功率分布特征;同时,结合功率通道型三相AC/DC电力电子变压器,提出了功率解耦和扩展移相协同控制的回流功率抑制方法;通过功率解耦控制,抑制模块电容电压中的低频脉动,维持高频直流环节输入/输出电压变比恒定,并结合扩展移相控制,抑制PET中的回流功率。仿真和实验结果验证了所提方案可以有效抑制三相AC/DC型PET中高频直流环节内的低频脉动功率及回流功率。
The dual-active bridge(DAB)circuit is commonly utilized as a high-frequency DC link in a cascaded H-bridge AC/DC power electronic transformer(CHB-AC/DC PET),and the energy is transferred by phase-shift control.However,the backflow power introduced by single phase-shift(SPS)control will increase the system's power loss.In the DAB powered by an ideal DC voltage source,the backflow power can be significantly suppressed by improved phase-shift control.Due to the second-order ripple power introduced by the PWM rectifier on the AC grid side,the input/output voltage ratio of the high-frequency DC-link has low-frequency ripple components,which makes it difficult for the existing backflow power suppression methods to obtain the desired effect.To address this issue,in the presence of low-frequency ripple components in the PET module capacitor voltage,the distribution characteristics of backflow power under SPS and extended phase-shift(EPS)control are analyzed.Meanwhile,a backflow power suppression method with the collaboration between power decoupling and EPS control is proposed combined with the power channel based three-phase AC/DC PET(PC-PET).Through the power decoupling control,the low-frequency ripple of the module capacitor voltage is suppressed,and the input/output ratio of the high-frequency DC link is maintained constant.Then,the backflow power of PET is suppressed in combination with the EPS control.Simulation and experimental results verified that the proposed scheme can effectively suppress the low-frequency ripple power and backflow power in the high-frequency DC link of the three-phase AC/DC PET.
作者
成林千
何立群
朱灿焰
黄培林
王乾丞
汪诚
CHENG Linqian;HE Liqun;ZHU Canyan;HUANG Peilin;WANG Qiancheng;WANG Cheng(School of Rail Transportation,Soochow University,Suzhou 215000,China;China Railway SIYUAN Survey and Design Group Co.,Ltd,Wuhan 430000,China;School of Automation,Nanjing University of Science and Technology,Nanjing 210094,China)
出处
《电源学报》
CSCD
北大核心
2021年第4期118-128,共11页
Journal of Power Supply
基金
国家自然科学基金资助项目(51707127)
江苏省自然科学基金资助项目(BK20190461)
江苏省智能配电网协同创新中心开放研究基金资助项目(XTCX201904)。
关键词
电力电子变压器
高频直流环节
回流功率
功率解耦
扩展移相控制
power electronic transformer(PET)
high-frequency DC link
backflow power
power decoupling
extended phase-shift(EPS)control
作者简介
成林千(1997-),男,硕士研究生。研究方向:电力电子技术。E-mail:20194246024@stu.suda.edu.com。;通信作者:何立群(1989-),女,博士,副教授。研究方向:电力电子与电力传动。E-mail:lqhe@suda.edu.cn;朱灿焰(1962-),男,博士,教授。研究方向:信号处理与控制。E-mail:qiwuzhu@suda.edu.cn;黄培林(1963-),男,博士,高级工程师。研究方向:轨道交通通信工程设计。E-mail:huangpl@126.com;王乾丞(1998-),男,本科。研究方向:电力电子技术。E-mail:qcwang@stu.suda.edu.com。;汪诚(1988-),男,博士,副教授。研究方向:电力电子化电力系统、新能源发电、微型电网。E-mail:chw714@njust.edu.cn。
