两电平空间矢量脉宽调制的简化算法和电压谐波分析方法

A Simplified Algorithm and A Method of Voltage Harmonic Analysis for Two-Level Space Vector Pulse Width Modulation

传统的两电平空间矢量脉宽调制(space vector pulse width modulation,SVPWM)算法流程复杂,计算量较大。从传统算法的伏秒平衡方程出发,推导并求解了三相上开关器件脉宽时间所满足的线性方程组,提出了一种无需坐标变换和扇区判断的两电平SVPWM简化算法。该算法流程简单,计算量少,且在参考电压含不对称分量时仍与传统算法等价。在此基础上,针对采用同步SVPWM的两电平变流器,提出了一种电压谐波分析方法,给出了在不同零矢量分配方式下通用的电压谐波频谱计算公式,并定性分析了电压谐波的频谱分布特性。基于PSCAD/EMTDC的仿真结果验证了所提的两电平SVPWM简化算法和电压谐波分析方法的准确性。

The traditional algorithm for 2-level space vector pulse width modulation （SVPWM） is complicated with large computation. In this paper, based on the volt-second balance equation of traditional algorithm, the linear equations of the pulse time of switching devices in 3-phase upper arms are set up and solved, thus a simplified algorithm for 2-level SVPWM without coordinate transformation and sector judgment is proposed, which reduces a lot of computation and is much easier to implement. Based on the simplified algorithm, a method of voltage harmonic analysis for synchronous SVPWM is proposed, which presents the generic expressions of the voltage harmonic spectrum when the distribution of zero vectors is varied, and explains the distribution characteristics of voltage harmonics qualitatively. The accuracy of the simplified algorithm and the novel method of voltage harmonic analysis for 2-level SVPWM are verified by the simulation results based on PSCAD/EMTDC.