Study of analytical current ripple of three-phase PWM converter

The effects of the current ripple of three-phase PWM converters are very important for the design and control of this kind of converter, which is the most popular topology for the energy conversion system. Based on the previous study of single-phase converter's current ripple, analytical current ripple of three-phase converter is studied in this paper with the Thevenin equivalent circuit of 8 different voltage vectors. With the analytical expression, current ripple peak value and RMS value could be predicted and fit the simulation results and experimental results well. This analysis provides the basis for variable switching frequency PWM method discussed in the paper of “Variable Switching Frequency PWM for Three-phase Converter for Loss and EMI Improvement” in APEC 2012.