基于Sigma-Delta调制的双两电平逆变器调制策略  

A Modulation Strategy of Dual Inverter Using Sigma-Delta Converter

作　　者：耿乙文[1] 王亮[1] 许家斌[1] 魏晨曦[1] Geng Yiwen;Wang Liang;Xu Jiabin;Wei Chenxi(School of Information and Electrical Engineering China University of Mining and Technology Xuzhou 221008 China)

机构地区：[1]中国矿业大学信息与电气工程学院,徐州221008

出　　处：《电工技术学报》2017年第18期239-247,共9页Transactions of China Electrotechnical Society

摘　　要：在多电平逆变器的调制中,Sigma-Delta调制器可以改善逆变器输出电压频谱,减少系统噪声。而将其运用到共直流母线的开绕组异步电机双两电平逆变器系统中时,由于开关状态和开关频率的不固定,无法采用传统的改变冗余小矢量作用时间的方法来消除系统中的零序电压。为此,针对共直流母线双逆变器系统,提出一种调制方法,该方法利用Sigma-Delta调制器过采样及噪声压缩技术,优化逆变器输出电压频谱;同时,利用两电平空间矢量图中两个互差120°的基本矢量所对应的系统零序电压为零的原理,将参考电压矢量分解为两个大小相等、方向互差120°的等效参考电压矢量,并由两台逆变器分别单独产生,以此实现对共直流母线的开绕组异步电机双两电平逆变器系统零序电压的完全消除。仿真和实验结果验证了该方法的正确性和有效性。Sigma-Delta converter can optimize the spectrum of the inverter and decrease the noise of the system in the modulation strategy of multi-level inverter.However,when using in the open-end winding induction motor fed by dual two-level inverters with common DC link,the traditional modulation strategy by changing short vector operation time to eliminate zero-sequence voltage is not applicable,because of the unfixed switch state and switch frequency.In this paper,a novel modulation strategy for dual two-level inverters with common DC link is proposed.The proposedmethod uses oversampling and noise shaping technology of Sigma-Delta modulator to optimize the voltage spectrum of the inverter.Meanwhile,according to the principle that the corresponding zero-sequence voltage value of two equivalent basic vectors is zero when the two vectors have a phase difference of120°in two-level space vector diagram,the reference vector can be decomposed into two equivalent vectors generated by two inverters respectively with equal magnitude and an angle different of120°.The proposed method can eliminate the value of zero-sequence voltage in dual two-level inverter with common DC link absolutely.Simulation and experimental results have verified the proposed method.

关 键 词：SIGMA-DELTA调制器 零序电压 共直流母线双逆变器 电压频谱 

分 类 号：TM464[电气工程—电器]