零序和负序电压注入的级联型并网逆变器直流侧电压平衡控制  

DC Voltage Balancing Control for Cascaded Grid-connected Inverters by Injecting Zero-sequence and Negative-sequence Voltages

作　　者：季振东[1] 赵剑锋[1] 孙毅超[1] 姚晓君[1] 朱泽安[1] 

机构地区：[1]东南大学电气工程学院,江苏省南京市210096

出　　处：《中国电机工程学报》2013年第21期9-17,188,共9页Proceedings of the CSEE

基　　金：江苏省产学研前瞻性联合研究项目(BY2011156)~~

摘　　要：级联型并网逆变器可以无变压器并入高压电网,并且具有容量大、效率高等特点,对配合可再生能源大规模并网和增强电力系统稳定性具有重要的意义。但级联结构中存在直流侧平衡问题,这严重影响到装置的输出性能和可靠性。针对三相星型结构中的相间直流侧不平衡,在并网逆变器注入零序和负序电压的情况下,推导出其各相有功功率的数学模型并对比功率调节能力,提出一种结合零序和负序电压注入的相间直流侧平衡控制方法及其适用条件,较好地解决了直流侧平衡问题,兼顾了装置性能和功率调节能力。通过仿真和实验验证了该方法的有效性和可行性,实验结果表明,该方法即使在电网电压不平衡的条件下,也可以保证相间直流侧平衡。Cascaded grid-connected inverters can be transformerlessly connected to the high voltage grid and have the advantages of large-capacity and high-efficiency.It is of great significance to provide grid connection for large-scale renewable energy and to enhance the stability of power systems.However,the output performance and reliability of cascaded grid-connected inverters are seriously influenced by the DC voltage balancing problem which exists in cascaded configuration.Aiming at DC voltage balancing among phases of three-phase wye configuration,active power models of three phases are analyzed and compared by injecting zero-sequence and negative-sequence voltages.Considering the output performance and the power adjustment ability of inverters,the paper presents an interphase DC voltage balancing method and its applicable condition,which is combined using zero-sequence and negative-sequence voltages.This method can balance the DC voltages among phases even under the unbalanced system.Simulation and experimental results verify the feasibility and validity of the interphase DC voltage balancing method.

关 键 词：级联型并网逆变器 三相星形结构 相间直流侧平衡 零序电压 负序电压 

分 类 号：TM46[电气工程—电器]