This paper for the first time comprehensively presents a multilevel space vector pulse width modulation (SVPWM) method based on the imaginary coordinate system. This method is probably one of the most efficient methods in fast multilevel SVPWMs. It avoids trigonometric operation, look-up tables and only requires simple logic judgement and arithmetic calculation. A distinct advantage of this method over other coordinate-transformation-based methods is that it does not need to transform from the imaginary coordinate system back to the a-b-c (or α-β) coordinate in order to select the redundant vectors using look-up tables. The redundant vectors or zero-sequence components are directly worked out in the proposed method, e.g., for balancing dc-link capacitor voltages, which avoids identifying the starting vector, vector rotation direction (clockwise or anti-clockwise), vector sequence, etc. as used in conventional methods. This paper entails each step to implement this SVPWM method, which can be replicated for multilevel converters with any number of voltage levels. The presented method has been used and validated by various converters, including a three-level and a five-level neutral-point-clamped converter. The archive value of this paper is that it demonstrates a milestone of fast multilevel SVPWM based on coordinate transformation.

中文翻译：

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基于虚坐标的冗余向量或零序列分量直接控制的快速多级SVPWM方法

本文首次全面提出了一种基于虚坐标系的多级空间矢量脉宽调制（SVPWM）方法。该方法可能是快速多级SVPWM中最有效的方法之一。它避免了三角运算，查找表，只需要简单的逻辑判断和算术计算。与其他基于坐标变换的方法相比，此方法的显着优势在于，它无需从虚坐标系转换回abc（或α-β）坐标即可使用查找表选择冗余矢量。冗余矢量或零序分量可以直接在建议的方法中计算出来，例如，用于平衡直流母线电容器电压，从而避免了识别起始矢量，常规方法中使用的矢量旋转方向（顺时针或逆时针），矢量序列等。本文涉及实现该SVPWM方法的每个步骤，该方法可复制到具有任意数量电压电平的多电平转换器。所提出的方法已被各种转换器使用和验证，包括三级和五级中性点钳位转换器。本文的存档价值在于它展示了基于坐标变换的快速多级SVPWM的里程碑。包括一个三级和一个五级中性点钳位转换器。本文的存档价值在于它展示了基于坐标变换的快速多级SVPWM的里程碑。包括一个三级和一个五级中性点钳位转换器。本文的存档价值在于它展示了基于坐标变换的快速多级SVPWM的里程碑。