摘要
Abstract
Cascade multilevel, high voltage and large capacity inverters have been widely used in electric power systems. Carrier phase shifted sinusoidal pulse width modulation (CPS-SPWM) technique is very suitable for the high power inverter. In the paper, bipolar CPS-SPWM and single pole double frequency CPS-SPWM modulation method are presented respectively, and a simulation model based on PSCAD/EMTDC software is built. Comparative analysis for these two methods is made by adopting frequency spectrum analysis method. Simulation results have proved that the lowest harmonics of the output voltage are centralized near the N times of the carrier frequency, and the equivalent switch frequency is improved by N (N is the number of the cascade SVG for each phase) times by adopting bipolar CPS-SPWM. The lowest harmonics of the output voltage are centralized near the 2N times of the carrier frequency, and the equivalent switch frequency is improved by 2N times by adopting single pole double frequency CPS-SPWM. Therefore, the single pole double frequency CPS-SPWM modulation method is better to eliminate the harmonics, and its output voltage fits sine wave better.关键词
大功率变流器/双极性CPS-SPWM/单极倍频CPS-SPWM/开关频率/仿真模型Key words
high-power converters/bipolar CPS-SPWM/single pole double frequency CPS-SPWM/switch frequen-cy/simulation model分类
信息技术与安全科学
