基于矢量分解的多电平逆变器简化SVPWM算法

为进一步提升多电平逆变器空间矢量脉宽调制(Space Vector Pulse Width Modulation,SVPWM)算法的计算效率,并增强其拓展性,提出了一种基于矢量分解的简化算法.介绍了一种基于虚拟作用时间的两电平SVPWM算法,不需经过区域判断即可实现基本电压矢量作用时间的统一计算,从而减少算法计算量;通过将参考矢量分解为多电平基本矢量和两电平参考矢量,将多电平空间中电压矢量的合成转化到两电平空间下进行,从而简化多电平SVPWM算法的实现.采用该算法生成多电平基本矢量作用序列及计算其作用时间的复杂度与电平数无关,扩展性较强,便于将其应用于多电平逆变器中.通过三相五电平NPC/H桥逆变器的PSCAD仿真及三电平逆变器的样机实验证明了所提方法的有效性.

A simplified SVPWM Algorithm for Multilevel Inverters Based on Vector Decomposition

This paper proposes a space vector pulse width modulation (SVPWM) algorithm with high expansibility and low computational complexity for multilevel inverters. Firstly, this paper presents a new two-level SVPWM algorithm based on virtual time, with a unified calculation method to determine the action time of the basic voltage vector. This algorithm can avoid regional judgment, reducing the amount of computation. Then, the implementation of the proposed multilevel SVPWM algorithm is introduced in detail. By decomposing the reference vector into multilevel basic vector and two level reference vector, the synthesis of voltage vector in multilevel space is transformed to two level space. The complexity of generating the sequence of multilevel basic vector and calculating its time of action has nothing to do with the specific level of the inverter. The effectiveness of the proposed method is proved by the PSCAD simulation of a three-phase five level NPC/H bridge inverter and the experiment of the three-level NPC inverter.