一种基于3次谐波注入的并联三相四桥臂逆变器均流控制策略

2016-04-07陈轶涵龚春英南京航空航天大学江苏省新能源发电与电能变换重点实验室南京210016

电工技术学报 2016年4期

陈轶涵任磊邓翔龚春英（南京航空航天大学江苏省新能源发电与电能变换重点实验室南京 210016）

陈轶涵任磊邓翔龚春英
（南京航空航天大学江苏省新能源发电与电能变换重点实验室南京 210016）

摘要三相四桥臂逆变器（3p4l）在三相三桥臂逆变器的基础上引入第四桥臂，使得三相能够解耦控制并具备带不对称负载能力，在此基础上采用3次谐波注入可以提高逆变器的直流电压利用率。若将多个三相四桥臂逆变器单元共直流母线并联，能够实现扩容。但是并联单元的电感电流若不采取控制，会导致环流问题，严重时会损坏逆变器。在基于平均电流均流控制策略的基础上，采用一种适用于模拟电路实现的3次谐波注入方式。由于主电路元器件参数的不对称性，并联单元各自生成的3次谐波不对称，增大了并联单元之间的零序环流。针对该问题，提出一种基于各并联单元3次谐波信号平均值法的三相四桥臂逆变器并联均流控制策略。在保留3次谐波注入的同时使得并联模块四个桥臂电感电流得到控制，消除环流，实现了并联桥臂均流。最后通过仿真和实验验证了控制策略的正确性。

关键词：并联三相四桥臂逆变器平均电流控制零序环流 3次谐波注入

国家自然科学基金资助项目（51377079）。

Current Sharing Control Method for Parallel Three Phase Four Leg Inverter Based on Third Harmonic Injection

Chen Yihan Ren Lei Deng Xiang Gong Chunying
（Jiangsu Key Laboratory of New Energy Generation and Power Conversion Nanjing University of Aeronautics and Astronautics Nanjing 210016 China）

Abstract Compared with 3p3l inverter, three phase legs of three-phase four-leg (3p4l) inverter could be decoupled by appropriate control, 3p4l inverter could also work with unbalanced load. 3p4l inverter can improve DC voltage utilization by injecting 3rd harmonic into fourth legs. In recent years, paralleled inverter technology is widely used in power electronic converter system to improve power level, and this technology can also be used in 3p4l inverter. But if current is out of control, circulating current will exist in four legs of paralleled 3p4l inverter, which could damages the inverter seriously exists in four legs. In 3p4l inverter controlled by method with 3rd harmonic injection, zero-sequence circulating current caused by unbalance parameters arises in four legs between parallel inverter modules. Based on novel 3rd harmonic average value injection method, this paper, therefore proposes control strategy for eliminating the circulating current in 3p4l inverter. Finally, simulation and experimental results verify the proposed method.

Keywords：Parallel three phase four leg inverter, average current control, zero-sequence circulating current, third harmonic injection