一种基于ghγ坐标系的三电平四桥臂逆变器简化空间矢量脉宽调制方法  

A Simplified Space Vector Pulse Width Modulation Method Based on ghg Coordinates System for the Three-Level Four-Leg Inverter

作　　者：张志 陈浩辉 陈思哲[2] 张兆云 李义云 Zhang Zhi;Chen Haohui;Chen Sizhe;Zhang Zhaoyun;Li Yiyun(School of Electrical Engineering and Intelligence Dongguan University of Technology,Dongguan 523808 China;School of Automation Guangdong University of Technology,Guangzhou 510006 China)

机构地区：[1]东莞理工学院电子工程与智能化学院,东莞523808 [2]广东工业大学自动化学院,广州510006

出　　处：《电工技术学报》2023年第16期4324-4338,共15页Transactions of China Electrotechnical Society

基　　金：广东省基础与应用基础研究基金项目(2022A1515140009);东莞市科技特派员项目(20221800500072)资助。

摘　　要：针对中点钳位型三电平四桥臂逆变器拓扑,该文提出一种基于ghγ坐标系的简化三维空间矢量脉宽调制方法。该方法以各冗余小矢量为中心点,将原矢量空间降阶分解为若干个两电平四桥臂矢量空间,仅需要简单的坐标变换和计算就能得到开关器件的占空比,还能自动获取冗余矢量和相邻电压矢量并优化组成开关序列,克服了传统三电平空间矢量调制方法存在过多的四面体选择、占空比计算过程存在较多的三角函数运算和需人工查找冗余矢量并存储大量开关序列的缺点。同时,针对中点电位平衡的问题,提出一种通过调节冗余矢量占空比以精确补偿电容电荷量的计算方法。所提简化调制方法能拓展应用于多电平四桥臂逆变器中。最后,通过仿真和实验结果验证了该文所提方法的正确性和有效性。The topology of the three-level,four-leg neutral-point-clamped(3L4L-NPC)inverter is more complex than the traditional two-level and three-leg ones,which complicates the vector space(VS)and space vector pulse width modulation(SVPMW)algorithm.Traditional methods designate a subspace under theabgand abc coordinates system to simplify the VS.However,the disadvantages of excess tetrahedrons in the subspace,manually finding for redundant vectors,lots of storage space for switching sequences and poor scalability remain unsolved.This paper proposes a simplified SVPWM method based on the ghgcoordinates system.By decomposing the three-level VS into several two-level ones and designating the first small sectors as subspaces,combining the exact charge adjusting method for capacitance voltage on DC-side,duty cycles and switching sequences of the 3L4L-NPC inverter can be automatically calculated.Firstly,the decomposability of the three-level VS is discussed.Since it has the same characteristics in both horizontal and vertical dimensions as the two-level one,the three-level VS can be replaced by the two-level ones with redundant vectors as center points.Secondly,the two-level SVPWM method is simplified.Duty cycles and switching sequences can be calculated automatically through integer computation and space vector construction in the first small sector,which can be extended to the decomposed two-level VSs.Thirdly,rules for dividing the three-level VS are established.The selected two-level VS and its redundant vectors are calculated using the hexagonal layer where the reference voltage vector locates on gh plane andgaxis.Combining the improved two-level SVPWM method,tetrahedrons containing modulation information can be found without global searching.Finally,the charge that causes fluctuations in the capacitance voltage on the DC side is classified into three types:the charge difference left over from the previous modulation cycle,the initial supplementary charge in this cycle,and the adjustment charge provided by small vectors in

关 键 词：三维空间矢量脉宽调制 冗余矢量 空间矢量降阶分解 中点电位平衡 

分 类 号：TM464[电气工程—电器]