中文摘要：

首先定量分析了对称规则采样和不对称规则采样正弦脉宽调制（SPWM）方法引入的延时,然后介绍了3种改进的SPWM方法：改进的不对称规则采样法、多次采样固定更新法和多次采样立即更新法,并对每种方法引入的延时进行了分析。最后,采用DSP和现场可编程门阵列（FPGA）,以同一个正弦信号为参考,同时生成了5种方法的SPWM波形,得到了各个波形基波分量与参考信号的相位差。从相位差可得到各种方法相对于参考信号的延时,与理论分析相一致,证明了所提的3种改进的SPWM方法可以有效地减小延时。

英文摘要：

The time delay caused by SPWM（Sinusoidal Pulse Width Modulation） with symmetrical or asymmetrical sampling is analyzed and three improved SPWM methods are introduced：improved asymmetrical sampling,multiple sampling fixed updating and multiple sampling immediate updating.The time delay caused by each improved SPWM method is also analyzed.DSP and FPGA are used to simultaneously generate the SPWM waveforms by five SPWM methods with a common sinusoidal reference signal.The phase difference of each SPWM method between its fundamental and reference is obtained and the time delay caused by each SPWM method is derived,which confirms the effectiveness of theoretical analysis and shows that three improved SPWM methods can reduce the time delay effectively.